Development of the manufacturing process of the part. Course work
A typical TP is developed on the basis of an analysis of the set of existing and possible TPs for typical representatives of product groups. It should be rational in specific production conditions and have the unity of the content and sequence of most TO for a group of products with common design features.
The design of technical processes depends on the type of production.
For simple parts, detailed route technical processes are developed with the contents of operations and transitions, as well as the maintained sizes. Typical manufacturing processes are usually equipped with universal machine tools and standard equipment. Universal and group devices are used.
In large-scale production, billets, castings, hammer stampings, welded structures and other types of billets, the use of which are economically feasible, are widely used as billets.
The technological process should ensure the manufacture of parts of a given quality and volume of production, satisfy the requirements of high processing productivity, the lowest cost of production, safety and ease of working conditions.
The properties of parts are formed in stages - from operation to operation, since for each processing method (turning, grinding, etc.) there are possibilities to correct the initial errors of the workpiece and obtain the required accuracy and quality of the machined surfaces. This is due primarily to the physical nature of the processing method.
When designing a technological operation, it is necessary to strive to reduce its complexity. Processing productivity depends on cutting conditions, the number of transitions and working strokes, the sequence of their execution.
The number and sequence of technological transitions depend on the type of workpieces and the accuracy requirements for the finished part. The combination of transitions is determined by the design of the part, the location of the cutting tools on the machine and the rigidity of the workpiece. Transitions in which strict requirements are met for accuracy and surface roughness, it is sometimes advisable to separate out in a separate operation, using single-seat single-tool sequential processing.
The shape of the “cover” part is regular geometric; it is a body of revolution. The value of surface roughness corresponds to the accuracy classes of their sizes and methods of processing these surfaces. To process a part, it is enough to use a turning, boring, lingering, grinding and gear hobbing operation.
DEVELOPMENT OF ROUTE TECHNOLOGY
When developing a technological process, one should be guided by the following principles:
when processing billets obtained by casting, untreated surfaces can be used as bases for the first operation;
when machining all surfaces with blanks as technological bases for the first operation, it is advisable to use surfaces with the smallest allowances;
first of all, those surfaces that are basic in further processing should be treated;
at the beginning of the technological process, those operations should be carried out in which there is a high probability of marriage due to a defect.
The technological process is recorded operationally, listing all the transitions.
A005 Turning operation
BThe lathe with ChPU 16K30F3
ABOUT
2. Cut the end to a size of 24 ± 0.3
3. Cut into the size of w90.6 +0.2
4. Waste to size w 66.8 +0.2
4. Chamfer 1x45
5. Remove the part.
T
A010 Turning operation
BThe lathe with ChPU 16K30F3
ABOUT1. Install the part in the cartridge.
2. Trim the butt to size 22
3. To grind in the size sh120
4. Waste to size 75.6 +0.2
6. Remove the part.
TThe cartridge is self-centering, a cutting tool T15K6, a persistent tool cutting through passage T15K6, a ruler, a caliper.
A 015 Radial Drilling
B Radial Drilling 2A534
ABOUT 1. Install item
2. Drill a hole Ш9 ± 0.2
3. To bore hole Ш14
4. Remove the part.
TDrill P6M5, Ts6ovka P6M5 vernier caliper.
A 020 Horizontal milling operation
B Horizontal milling 6R83G
ABOUT 1. Install part
2. Milling flats in size 109.
3. Remove the parts.
T Disk mill T15K6, caliper, roughness sample.
A 025 Operation grinding
B Circular grinding machine 3Б161
ABOUT 1. Install the part.
2. Grind the part to the size Ш90
3. Remove the part.
A 030 Intra grinding operation
B
ABOUT 1. will install the item
2. To grind a hole in the size sh66N7 +0.03 with a roughness of Ra0.8.
3. Remove the part.
T
A 035 Intra grinding operation
B. Internal grinding machine 3K2228A
ABOUT 1. will install the item
2. To grind a hole in the size sh75N7 with a roughness of Ra0,8.
3. Remove the part.
T Mandrel, grinding wheel, caliper, roughness sample.
Operation 040 Control final.
CALCULATION OF PROCESSING MODES
The main elements of cutting during turning are: cutting speed V, feed S and cutting depth t.
The cutting modes during processing of the part will be calculated by the calculation method.
a) When turning, the cutting speed is calculated by the formula:
where T is the average value of resistance, min;
(with one-tool processing T \u003d 60 min)
t is the depth of cut;
S - feed;
C v \u003d 56; m \u003d 0.125; y \u003d 0.66; x \u003d 0.25.
The value of the feed rate S is taken from t. 11-14.
The value of the coefficients C and exponents is chosen from t. 8
The coefficient K is determined by the formula
where K m - coefficient taking into account the influence of the material of the workpiece;
K p - coefficient taking into account the surface condition of the workpiece;
K u - coefficient taking into account the material of the tool;
The value of the coefficients K m, K u and K p choose from t. 1-6.
K m \u003d 0.8; K u \u003d 1; K p \u003d 0.8.
Determine the number of revolutions of the spindle of the machine.
where V is the cutting speed;
D is the diameter of the treated surface;
Determine the main technological time
where l r.h. - the length of the stroke of the cutter, mm;
i is the number of passes, pcs.
b) Cutting speed during milling:
v \u003d C v · K v · D q / (T m · t x · s y · B p · Z p);
where B p and Z p are reference coefficients.
For cutting, grooving:
K Mv \u003d 0.80; K Pv \u003d 0.85; K iv \u003d 1.68.
The results of calculations according to the above formulas are entered in the set of documentation for the technological process in the corresponding columns of the route-operational map.
RATING OF TECHNICAL OPERATIONS
Technical standards of time in the conditions of mass and mass production are established by the calculation and analytical method. In serial production, the norm of piece-calculation time is determined Tshk according to the following formula:
where T p-s - preparatory-final time, min;
n - the number of parts in the party;
Tsht - the norm of piece time, min.
The rate of piece time can be determined by the formula:
where T about - the main time, min .;
Tv - auxiliary time, min .;
Tob.ot - time for maintenance of the workplace, for rest and personal needs min.
Auxiliary time is determined by the formula:
where T us - the time to install and remove parts, min .;
Tso - time for fixing and detaching the part, min .;
Stupid - time for management tricks, min .;
Tees - time for measuring the part, min.
Time for servicing the workplace, for leisure and personal needs is determined by the formula:
Operating time T op is determined by the formula:
Next, we will calculate for all technological operations using the above formulas, we will enter the results in the set of documentation for the technological process in the corresponding columns of the route-operational map.
Since 1975, a unified system of technological preparation of production (ESTPP) has been implemented in our country, the main purpose of which is to establish a system of organization and management of technological preparation of production, regulated by state standards.
According to GOST14.004-83, technological preparation of production means a set of measures that ensure technological readiness of production (the company has complete sets of design and technological documentation and technological equipment) for the implementation of a given volume of output with established technical and economic indicators.
The basis of ESTPP is the development of technological processes.
The degree of detail of the description of technological processes is specified in GOST Z.1109-82,
1. Route description of the technological process is an abbreviated description of all technological operations in the route map in the sequence of their execution without indicating transitions and technological modes. Such a description of technological processes is carried out in a single, and for non-critical parts, and in small-scale production.
2. The operational description of the technological process is a complete description of all technological operations in the sequence of their execution, indicating transitions and technological modes. Operational technological processes are used in large-scale and mass production.
3. The route-operational description of the technological process is the route description of the entire technological process and the operational description of some operations, as a rule, forming the product quality. Such technological processes are used in small and medium series production.
In the organization of production, technological processes are divided into:
1) a typical technological process is a technological process of manufacturing a group of products with common design and technological features;
2) a group technological process is a technological process of manufacturing a troupe of products with different design, but common technological features;
3) a single technological process is a technological process of manufacturing or repairing a product of the same name, size and design.
The initial data for the design of technological processes for processing billets are:
1) a working drawing defining the material, structural forms and dimensions of the part;
2) technical conditions for the manufacture of the part, characterizing dimensional accuracy and surface quality, as well as special requirements (hardness, structure, heat treatment, balancing, weight adjustment, etc.);
3) annual release program.
When designing technological processes for existing industries, in addition, it is necessary to have information about the availability of equipment and its loading, measuring and cutting tools, technological equipment, free areas and other production conditions. In addition, the design uses: reference and regulatory materials; catalogs and passports of equipment; fixture albums; GOSTs and normals for cutting and measuring tools, tooling; standards for accuracy, roughness, allowance calculation, cutting conditions and technical regulation; tariff-qualification directories and other supporting materials.
The basis for the development of technological processes laid two basic principles: technical and economic. In accordance with the technical principle, the designed technological process must fully ensure the fulfillment of all the requirements of the working drawing and technical conditions for the manufacture of a given part.
In accordance with the economic principle, the manufacture of the product should be carried out with minimal labor and production costs. The technological process of manufacturing products should be performed with the most complete use of the technical capabilities of the means of production, with the least expenditure of time and cost of products.
To establish the possibility of ensuring the required accuracy, a dimensional analysis of the technological process is carried out.
Chain building begins with the task. The initial or closing link of the technological dimension chain can be: 1) a drawing dimension with a regulated tolerance that is not directly maintained during processing; 2) the operational allowance for processing, based on the minimum value of which it is necessary to establish the operational dimensions for all stages of data processing of interconnected surfaces. Consistently attach to it the constituent units involved in solving the task, until the circuit becomes closed.
In fig. 6.12 are examples of constructing dimensional chains based on various conditions. Processing of end surfaces 1 - 5 (Fig. 6.12, a) is performed in four operations. The linear dimensions sustained at the same time are shown on operational sketches. Dimensional chains are compiled for each operational sketch.
At the first milling-center operation, the ends are processed 1 and 5 (Fig. 6.12, b), maintaining the sizes B 1 and B 2. Since the technological size B 2 coincides with the design A 4, then there is no need to recount it. Butt 2 subsequently it is necessary to process, therefore, the technological size B 1 is not design, and therefore, its recalculation is necessary. For this, a dimensional chain is compiled for the first operation (Fig. 6.12, c). The closing link in this dimension chain is the machining allowance Z 1.
Fig. 6.12 Dimensional analysis of the process
At the second turning operation, the ends are processed 3 and 4 (Fig. 6.12, in) and dimensions are maintained IN ( and IN 2 . Surface 3 is a tuning base for getting size IN 2 . Since in the future it is supposed to finish the ends 3 and 4, then technological dimensions and IN 2 are not design, therefore, their recount is necessary. For this, two dimensional chains are compiled (Fig. 6.12, h). When sizing IN 1 and IN 2 closing links are allowances, respectively Z 2 and Z 3.
In the third turning operation, the end is processed 2 (Fig. 6.12, d) and the size of G. is maintained. This size is not design, therefore, to determine it, a dimensional chain is built (Fig. 6.12, and). The closing dimension in this chain is A 1.
At the fourth round grinding operation, the ends are finally processed 3 and 4 (Fig. 6.12, e). Surface 3 on this operation is the tuning base for obtaining the technological size D 2 which matches the design size A 3, therefore, there is no need to recount it. To determine the technological size D 1, we compose a dimensional chain (Fig. 6.12, k), in which the closing link is the size A 2.
Combining the constructed operational dimensional chains (Fig. 6.12, e) allows dimensional analysis of the entire process.
In accordance with ESTPP, the development of technological processes for manufacturing machine parts for new production is carried out in the following sequence.
1. Set the type of production with the calculation of tact or batch size.
2. Pre-select the possible methods for the preparation of blanks, make their technical and economic comparison and choose the best option.
3. To compile several possible options for route technologies, make their technical and economic comparison and choose the best option.
4. Develop an operational technology for the manufacture of the part:
a) surface treatment plan to achieve the required accuracy and roughness;
b) equipment selection;
c) the choice of basing schemes;
d) the calculation and purpose of allowances;
d) dimensional analysis of the process;
e) the choice of the tool, its material and technological equipment, if necessary, their design;
g) calculation and purpose of processing modes;
h) selection of measuring tools, if necessary, their design;
i) rationing and assigning the category of workers.
5. Calculation of technical and economic indicators of the designed technological process.
6. Design of sites, departments, workshops.
Work on the creation of technological processes for existing production has some features. It includes:
1. Analysis of the source data for the development of the technological process.
2. The selection of the current standard, group technological process or the search for an analogue of a single process.
3. The choice of the original workpiece and the method of its manufacture,
4. The choice of technological bases.
5. Drawing up a technological processing route for existing equipment.
6. Development of technological operations.
7. The choice of technological equipment for control and testing. If necessary, order them.
8. The choice of means of transportation.
9. Appointment and calculation of allowances.
10. Rationing.
11. The calculation of economic efficiency.
12. Registration of technological processes.
One of the most progressive directions in the development of technological processes for the manufacture of machine parts is their typification.
The typification of technological processes means such a direction in technology that consists in the classification and typification of machine parts and their elements and then in the integrated solution of problems arising from the implementation of technological processes of each classification group.
The rule for the development of typical technological processes is regulated by GOST 14.303-83.
The first step in typing is to classify parts.
A class is a set of parts characterized by a commonality of technological problems to be solved under the conditions of a specific configuration of these parts.
A sign for the classification of parts are:
1) part configuration;
2) dimensions of the part;
3) accuracy of processing and quality of the processed surfaces;
4) material details.
Given these signs, parts can be divided into 17 classes: shafts, bushings, discs, eccentric parts, crosses, levers, plates, covers, housings, dowels, racks, elbows, headstock, gears, shaped cams, spindles and worms, small fasteners.
Moreover, with the development of mechanical engineering, other classes of parts characteristic of individual industries are added to this classification (for example: turbine blades, ball bearings, etc.)
In turn, classes are divided into subclasses, groups, etc.: for example, shafts are smooth, stepped, hollow.
The design of typical technical processes is carried out in the following order:
1. According to the drawings of the plant’s products, parts are selected that are similar in design and technological features (Fig. 6.13, a - and).
2. A complex part is being created (Fig. 6.13, k). They are guided by the following:
a) for the complex part is taken the most complex part of the group, which includes all the surfaces found in other parts of the group (Fig. 6.13, g).If among the simpler parts of the group there are separate surfaces (for example, a cone, chamfer) that are absent in a complex part, then these surfaces are artificially added to the drawing of this part;
b) overall dimensions the complex part has the largest;
c) the highest dimensional accuracy;
d) roughness parameters are the smallest of the parts included in the group
The sequence and content of technological operations and the manufacture of complex parts are established.
MINISTRY OF EDUCATION OF THE RUSSIAN FEDERATION
RYAZAN STATE RADIO TECHNICAL
ACADEMY
Department of REA Technology
Explanatory note to the course project
at the course "Engineering Technology"
on the theme "Development of the manufacturing process of the part
screen RGRA 745 561.002 »
Project completed
student gr. 070 A.A. Boltukova
Project Manager
Assignment ………………………………………………………………………………………………………………… ..
Drawing details ………………………………………………………………………………………………………………… ..3
Introduction …………………………………………………………………………………………………………… 5
1. Designing a technological process using a standard ...................... ....... .. ....... ..6
1.1 analysis of the source data ……………………………………………………………………………… ... …… .6
1.2 Definition of the design and technological code of the part …………………………………… ..7
2. Evaluation of the indicator of manufacturability of the design of the part
3. The choice of the method of manufacturing the parts …………………………………………………………………………… ... 9
4. The selection of blanks and technological bases ……………………………………………………………………… ..10
5. The purpose of the processing modes ……………………………………………………………………………… .... 12
6. The choice of technological equipment …………………………………………………………………………… ..13
7. Technical regulation ……………………………………………………………………………………… .14
7.1 Cutting with guillotine shears ……………………………………………… 14
7.2 Cold stamping ………………………………………………………………………………………… .15
8. Determination of the type of production ...................................... 17
9. Technical and economic indicators of the developed technological process ……………… ... 18
10. Calculation of the batch size of parts, blanks
12. Occupational safety measures ……………………………………………………………………… 23
13. Conclusion ………………………………………………………………………………………………………………… ..24
14. Bibliographic list ……………………………………………………………………………………… .25
Appendix 1 …………………………………………………………………………………………………… ..… 26
Appendix 2 ………………………………………………………………………………………………………… ..… 27
Appendix 3 ………………………………………………………………………………………………………… ..… 28
Appendix 4 …………………………………………………………………………………………………… ..… 29
At present, in our country there is such a situation that the development of industry is the highest priority of all the tasks set. In order for Russia to take a strong place among the leading world powers, it must have a developed sphere of industrial production, which should be based not only on the restoration of factories founded in the Soviet period, but also on new, more modernly equipped enterprises.
One of the most important steps on the path to economic prosperity is the training of specialists who would not have strictly limited knowledge within their profession, but could comprehensively evaluate the work they perform and its results. Such specialists are economic engineers who understand not only all the intricacies of the economic aspects of the functioning of the enterprise, but also the essence of the production process, which determines this functioning.
The aim of this course project is to familiarize directly with the production process, as well as evaluate and compare its effectiveness not only from an economic, but also from a technological point of view.
The production of the product, its essence and methods have the most significant impact on the technological, operational, ergonomic, aesthetic and, of course, functional characteristics of this product, and, therefore, on its cost, on which the price of the product is directly dependent, the demand for it from users, sales volumes, profit from sales, and, therefore, all economic indicators that determine the financial stability of the enterprise, its profitability, market share, etc. Thus, the way products are manufactured has an impact on the entire product life cycle.
Today, when the competitive market forces manufacturers to switch to the highest quality and cheapest products, it is especially important to evaluate all aspects of the production, distribution and consumption of the product at the stage of its development in order to avoid inefficient use of enterprise resources. It also helps in improving technological processes, which are often developed not only on the basis of market needs for the manufacture of new products, but also taking into account the desire of manufacturers to cheaper and faster way to obtain existing products, which reduces the production cycle, reduces the size of production working capital, and, therefore, stimulates the growth of investment in new projects.
So, the design of the technological process is the most important stage of production, which affects the entire life cycle of the product and can become decisive in making decisions about the production of a product.
Technological process - the main part of the production process, including actions to change the size, shape, properties and quality of the surfaces of the part, their relative position in order to obtain the desired product.
Typical Process It is unified for the most typical parts with similar technical and design parameters. High-class engineers develop a technological process for standard parts, and then, with their help, make up working technological processes for a specific part. Using a typical process allows us to simplify the development of those. processes, improve the quality of these developments, save time and reduce the cost of technological preparation of production.
The development of the technological process includes the following steps:
Definition of a technological classification group of a part;
Selection by code of a typical technological process (selection of the method for obtaining the part);
The selection of blanks and technological bases;
Clarification of the composition and sequence of operations;
Refinement of selected technological equipment.
To determine the technological classification group of the part, it is necessary to study the source data, which contains information about the part and the equipment available for its manufacture.
The source data contains:
· Detail drawing
Stamp assembly drawing
· specification
As a result of studying these data, we obtain:
Detail - screen - is a flat part with a design code:
RGRA. 755561.002.
Material: Steel 10 GOST 914-56 - high-quality low-carbon steel with a carbon content of 0.2%. This alloy is well welded and machined, as well as cold pressure. These properties prove the usefulness of cold stamping for the manufacture of this part.
Assortment: 1 mm thick sheet. Hot-rolled sheets are usually made from this material.
Roughness: for the entire surface of the part, the height of the profile irregularities at ten points Rz \u003d 40 μm, the arithmetic mean deviation of the profile Ra \u003d 10 μm. Roughness class 4. The surface of the part is formed without removing the top layer.
Degree of accuracy: the greatest quality 8
Technological process: in this case, it is most advisable to apply cold stamping.
Cold stamping - This is the process of forming forgings or finished products in dies at room temperature.
Mass Details:
M \u003d S * H \u200b\u200b* r, where S is the area of \u200b\u200bthe part, mm2; H is the thickness, mm; r - density, g / mm3
Serial stamp
Stamp - a deforming tool, under the influence of which the material or workpiece acquires the shape and dimensions corresponding to the surface or contour of this tool. The main elements of the stamp are the punch and the matrix.
The design of this stamp includes a punch for punching a hole with a diameter of 18 mm, as well as a punch for cutting the outer contour of the part.
This stamp is a sequential multioperational stamp, which is designed for stamping parts from sheet material. The preparation of the workpiece takes place in 2 stages: first, a hole with a diameter of 18 mm is punched, then the outer contour of the part is obtained.
When finding the technological classification group of the part, it is necessary to add the technological code of the part to the existing design code of the part.
To determine the technological code of a part from the available data, we will determine a number of features, and then find their code according to the "Design and Technology Classifier of Parts":
Table 1.
| № | Sign | Value | The code |
| 1 | Manufacturing method | Cold stamping | 5 |
| 2 | Type of material | Carbon steel | At |
| 3 | Volumetric and dimensional characteristics | 1 mm thick | 6 |
| 4 | Type of additional processing | With a given roughness | 1 |
| 5 | Specification of the species will complement. processing | tumbling | 1 |
| 6 | Type of monitored parameters | Roughness, precision | M |
| 7 | Number of executive sizes | 3 | 1 |
| 8 | Number of Designs items received will add. Processing | 1 | 1 |
| 9 | Number of sizes | 4 | 2 |
| 10 | Assortment of material | hot rolled sheet | 5 |
| 11 | Material grade | Steel 10KP sheet 1,0-II-H GOST 914-56 | D |
| 12 | Weight | 6 g | 4 |
| 13 | Accuracy | quality-8, Rz \u003d 40, Ra \u003d 10 | P |
| 14 | Dimensioning System | rectangular coordinate system sequentially from one base | 3 |
Thus, the full design and technological code of the part has the form:
RGRA. 745561.002 5U611M.1125D4P3
Manufacturability - this is a property of the design of the product, providing the possibility of its release with the least expenditure of time, labor and material resources while maintaining the specified consumer qualities.
The value of the processability indicator is defined as complex through the values \u200b\u200bof particular indicators in accordance with OST 107.15.2011-91 by the formula:
ki - normalized value of a particular indicator of the manufacturability of the part
The design of a part is technological if the calculated value of the technological indicator is not less than its standard value. Otherwise, the design of the part must be modified by the designer.
Evaluation of the manufacturability of part 5U611M.1125D4P3
table 2
| Name and designation of a private indicator of manufacturability | Name of classification attribute | Character Graduation Code | The normalized value of the indicator of manufacturability |
| The indicator of the progressiveness of the formation of KF | Technological method of obtaining, determining the configuration (1st category of technological code) | 5 | 0,99 |
| The indicator of the multinomenclature types of processing Co. | Type of additional processing (4th category of technological code) | 1 | 0,98 |
| The indicator of multinomenclature types of control QC | Type of controlled parameters (6th digit of the technological code) | M | 0,99 |
| The indicator of the unification of structural elements Ku | The number of sizes of structural elements (9th category of the technological code) | 2 | 0,99 |
| Index of processing accuracy CT | Processing accuracy (13th digit of the technological code) | P | 0,96 |
| Rationality indicator of dimensional bases Kb | Dimensioning system (14th digit of the technological code) | 3 | 0,99 |
The normative value of the processability indicator is 0.88. Calculated. Therefore, the design of the part is technologically advanced.
The technological process is accompanied by a number of auxiliary processes: warehousing of finished products and finished products, equipment repair, manufacturing of tools and equipment.
The technological process conditionally consists of three stages:
1. Getting blanks.
2. Processing blanks and receiving finished parts.
3. Assembling the finished parts into the product, their adjustment and adjustment.
Depending on the requirements for dimensional accuracy, shape, relative position and surface roughness of the part, taking into account its size, weight, material properties, type of production, we select one or more possible processing methods and the type of equipment.
The part is a flat figure, so it can be made of sheet material using a stamp.
Product manufacturing route:
1) preparatory operation:
1.1) selection of blanks;
1.2) mapping of material cutting;
1.3) calculation of processing modes;
2) procurement operation - cut sheets into strips on the guillotine shears according to the cutting map; This operation is performed by a low skilled (1 ... 2 category) carver using guillotine shears.
3) stamping operation - giving the workpiece the shape, dimensions and surface quality specified by the drawing; this operation is performed by a more skilled (2 ... 3 category) worker - puncher, using a stamp equipped with a press.
4) tumbling operation - deburring; this operation is performed by a 2 ... 3 digit mechanic on a vibrating machine
5) control operation - control after each operation (visual), selective control for compliance with the drawing. Dimension control is carried out using a caliper - for the contour of the part, and with the help of plugs - for holes.
The blanks must be selected in such a way as to ensure the most rational use of the material, the minimum labor input of the blanks and the possibility of reducing the labor input of manufacturing the part itself.
Since the part is made of flat material, it is advisable to use sheets in the form of raw materials. Due to the fact that the part is manufactured by cold stamping in a serial stamp, the sheets for feeding into the stamp must be cut into strips. It is necessary to find the most rational way of cutting material, which is determined using the formula:
where A is the largest part size, mm
δ is the tolerance on the width of the strip cut on the guillotine shears, mm
Zн - guaranteed smallest clearance between the guide rails and the strip, mm
δ "- tolerance on the distance between the guide strips and the strip, mm
a - side jumper, mm
Using the tables, we determine for this part:
Round workpieces are suitable for this part.
The largest part size is A \u003d 36 mm.
Jumpers a \u003d 1.2 mm; in \u003d 0.8 mm
Tolerance to the width of the strip cut on guillotine shears δ \u003d 0.4 mm
Guaranteed smallest clearance between the guide rails and the strip Zn \u003d 0.50 mm
Tolerance for the distance between the guide strips and the strip δ "\u003d 0.25
Longitudinal cutting:
We get the utilization of the material:
Where SA is the area of \u200b\u200bthe part, mm2;
SL - sheet area, mm2;
n is the number of parts obtained from the sheet.
As a result, we get:
Let us analyze the transverse cutting:
Thus, longitudinal cutting is more economical, since in this case the cutting coefficient of material use is greater than with the transverse one.
Here are the cutting patterns for the longitudinal cutting of the material (Fig. 1, 2)
a \u003d 1.2 t \u003d D + b \u003d 36.8
Fig. 1. Cut strips
Fig. 2. Cut the sheet.
Based on the design of the stamp, the workpiece is based on the stop and the guide bars of the stamp, and the punches are based on the geometric center of the die punch (on the part’s office).
The greatest accuracy is ensured by the coincidence of design and technological bases. In this case, it will be difficult to ensure high accuracy, since a serial stamp involves the movement of the workpiece from the punch to the punch, which, of course, increases the manufacturing error of the part.
Processing Modes represent a set of parameters that determine the conditions under which products are manufactured.
The stamp of sequential action involves first - punching holes, and then - cutting along the contour. Felling and punching are operations of separating part of the sheet in a closed loop in a stamp, after which the finished part and waste are pushed into the matrix.
For the part obtained by stamping, the calculation of the modes consists in determining the stamping forces. The full stamping force consists of the efforts of punching, cutting, removing and pushing the part.
The punching condition is determined by the formula:
where L is the perimeter of the punched hole, mm;
h is the thickness of the part, mm;
σav is the shear resistance, MPa.
From the table we find: σav \u003d 270 MPa.
Thus,
The force of cutting a part along a contour is determined by the same formula:
The determination of the required forces of pushing the part (exit) through the matrix is \u200b\u200bmade according to the formula:
where KPR is the pushing coefficient. For steel Kpr \u003d 0.04
Similarly, the force is determined to remove the waste (part) from the punch:
where KSN - pushing coefficient. For steel KSN \u003d 0.035
The full stamping force will be found by the formula:
where 1.3 is the safety factor for strengthening the press.
For this part we get the full stamping force:
Tooling represents additional devices used to increase labor productivity, improve quality.
For the manufacture of the part of the separator, based on the available equipment, it is advisable to use a stamp of sequential action when cutting holes and the contour of the part is performed sequentially, which allows the use of a simple stamp design, and guillotine shears and a mechanical press are required as equipment for the technological process.
Guillotine shears are a machine for cutting paper bales, metal sheets, etc., in which one knife is fixedly mounted in the bed, and the other, set obliquely, receives a reciprocating motion.
The main parameters, which is the most indicative for the selected equipment and which ensures the execution of the modes provided for by the technological process, are the stamping and pressing forces for the press, and for the guillotine shears the largest thickness of the cut sheet and its width.
Table 3
Characteristics of scissors H475
The calculated stamping force Pn \u003d 63.978 kN is selected [according to Appendix 5, 3051] in such a way that its rated force exceeds the value of the required stamping force.
Table 4
Characteristics of the press KD2118A
Process Rationing consists in determining the value of the piece time Тш for each operation (in mass production) and the piece-calculating time Тшт (in mass production). In the latter case, the preparatory-final time TPZ is calculated.
Values \u200b\u200band TSh are determined by the formulas:
; Tshk \u003d Tsh + Tpz / n,
where That is the main technological time, min;
TV - auxiliary time, min
Tob - time for servicing the workplace, min;
TD - the time of rest breaks and personal needs, min;
TPZ - preparatory-final time, min;
n is the number of parts in the batch.
Main (technological) time spent directly on changing the shapes and sizes of the part.
Auxiliary time spent on installing and removing the part, controlling the machine (press) and resizing the part.
The sum of the main and auxiliary time is called operational time.
Workplace Maintenance Time It consists of the time of maintenance (change of tool, adjustment of the machine) and the time for organizational maintenance of the workplace (preparation of the workplace, lubrication of the machine, etc.)
Preparatory closing time normalized to a batch of parts (shift). It is spent on familiarizing yourself with work, setting up equipment, consulting with a technologist, etc.
We calculate the rationing of the technological process of cutting a sheet of material into strips.
Since strips of material are fed into the serial stamp, it is necessary to cut the sheets of steel 10 into strips whose width is equal to the width of the workpieces. For this we use guillotine shears
Operation - cutting strips of steel sheet 710 x 2,000;
pitch - 38.75 mm;
18 strips from a leaf;
18 x 54 \u003d 972 pcs. - blanks from a sheet;
manual method of feeding and installing the sheet;
manual way to remove waste;
equipment - Н475 guillotine shears;
40 knife strokes per minute;
way to turn on the foot pedal;
friction clutch;
the position of the worker is standing.
1. The calculation of the norm of piece time for cutting steel sheet
1.1. Take a sheet from the foot, put scissors on the table, set on the back stop. The time for these operations depends on the area of \u200b\u200bthe sheet and is usually indicated per 100 sheets.
With a sheet area of \u200b\u200b100 sheets, 5.7 minutes.
Following the instructions for the calculations:
1.1.1) when calculating the norms of piece time per workpiece, time by standards is divided by the number of workpieces obtained from the sheet;
1.1.2) when installing the sheet on the back gauge, we take the time according to the standards with a coefficient equal to 0.9;
1.1.3) the correction factor for a steel sheet thickness of 1 mm is 1.09.
1.2. Turn on the scissors 18 times. Since you need to get 18 strips: 17 inclusions of scissors in order to separate the strips from one another and another one to separate the last strip from the rest of the sheet. The time spent on this depends on how you turn on the guillotine shears.
When you press the pedal while sitting - 0.01 min per lane.
1.3. Cut blanks 18 times. The duration of this operation depends on the capabilities of the scissors.
At 40 strokes per minute and a friction clutch, 0.026 min per lane.
1.4. Push the sheet all the way 18 times (since the sheet is divided into strips with the remainder, so it is necessary to separate the last strip from the waste). The duration of this action depends on the sheet length and pitch.
When the length of the sheet along the cutting line of 2000 mm and the pitch of sheet advancement 38.75< 50 мм время - 1,4 мин на полосу.
1.5. Take the scissors off the table, put them in the foot.
With a blank area of \u200b\u200b0.83 minutes.
Table 5.
Calculation of piece rate for cutting steel sheet
* - see paragraph 1.1.2.
The unit time rate is calculated by the formula:
That is the main cutting time;
Tv is auxiliary time;
nd - the number of parts in the sheet.
for 100 parts;
Operation - cutting a part along a contour, holes in a part from a strip;
stamp with an open emphasis;
manual method of supply and installation of the workpiece;
manual method of waste disposal;
working position - sitting;
crank press with a force of 63 N;
150 slider strokes per minute;
clutch clutch;
way of inclusion - a pedal.
2. The calculation of the norm of piece time for stamping parts from the strip.
1.1. Take the strip, grease on one side. The necessary operations for preparing blanks for cold stamping are the removal of scale, dirt, defects, coatings and lubricants. The time spent on this depends on the area of \u200b\u200bthe workpiece.
With this area, the time per 100 lanes is 5.04 minutes.
2.2. Set the strip in the stamp as far as it will go. This operation is necessary to ensure the conditions of basing, its duration depends on the type of stamp, the length and width of the strip, as well as the thickness of the material.
With a band width of 38.75 mm, the initial time is 5.04 minutes per 100 bands.
With a strip length of 2 m, the coefficient is 1.08;
for a closed stamp - 1.1;
for steel with a thickness of 1 mm - 1.09.
2.3. Turn on the press. The duration of this action depends on the position of the worker and how to control the press.
To turn on the press with the pedal while sitting - 0.01 min per lane;
2.4. Stamped. The time taken by stamping depends on the equipment used.
For a press with the number of slider strokes equal to 150 and the friction clutch - 0.026 min per strip.
2.5. The time taken to advance the strip a step depends on the width and length of the strip and the type of stamp.
For a strip 38.75 mm wide, the main time is 0.7 min per 100 strips;
for a closed stamp - coefficient 1.1;
the coefficient for a strip 2 m long is 1.08.
2.6. The duration of the strip (grate) removal operation is determined based on the strip of material.
With a band of 38.75 x 2,000 - 3.28;
for a closed stamp - 1.1;
the coefficient for steel with a thickness of 1 mm is 1.09.
Table 6.
Calculation of the norm of piece time for stamping parts
Norm of piece time:
nd - the number of parts obtained from the strip;
CRC - coefficient taking into account the position of the worker (sitting - 0.8);
aobs - time for the organizational and technical maintenance of the workplace, for a crank press with a pressing force of up to 100 kN, equal to 5% of the operational time;
aotl - the time spent by workers on rest and personal needs, with a workpiece weight of up to 3 kg, is taken as 5% of the operational time.
According to GOST 3.1108 - 74 ESTD, the type of production is characterized by the coefficient of consolidation of operations. At the design stage of technological processes, the following calculation procedure is used coefficient of consolidation of operations (seriality) behind the workplace (machine):
where Tm is the output beat, min;
T sh Wed - average piece time for the operation, min.
Release Beat calculated by the formula:
F - the actual annual fund of the machine or workplace hours, h (we take F \u003d 2000 h).
N - annual product release program, pcs.
Average piece time defined as the arithmetic mean of the process operations. We assume that time is mainly spent on cutting and stamping.
n is the number of operations (with the indicated assumption k \u003d 2)
It is given that the annual screen release program is equal to 1000 thousand pieces.
Release tact min.
Piece time min.
Average piece time min.
The coefficient of consolidation of operations.
Depending on the value of KZo, we choose the type of production: at 1< Кзо <10 крупносерийный тип производства.
Large-scale production is characterized by the manufacture of products in periodic batches. In this production, special, specialized and universal equipment and devices are used.
For economic evaluation, mainly two characteristics are used: cost and labor.
Labor input - the amount of time (in hours) spent on the manufacture of one unit of the product. The complexity of the process is the sum of the complexity of all operations.
The complexity of operations consists of the preparatory-final time Tpz per unit of production, and the piece time Tsh spent on this operation. The complexity of the operation T is numerically equal to the piece-calculation time Tshk, which can be calculated by the formula:
where n is the number of parts in the party, is determined by the formula:
where 480 min - the duration of one working estimate in minutes;
The preparatory-final time for the shift consists mainly of the duration of the preparatory-final operations for cutting and stamping. We accept:
min per shift;
mines per shift.
We calculate the complexity of the cutting operation:
Piece cutting time: cutting;
The complexity of the cutting operation: min;
We calculate the complexity of the stamping operation:
Piece cutting time: cutting;
Number of parts in a batch: pcs;
The complexity of the stamping operation: min;
The reciprocal of the technological rate of time T is called production rate Q:
According to the obtained value of the complexity, production rates:
The performance of the technological process is determined by the number of parts manufactured per unit of time (hour, shift):
where f is the fund of working time, min;
The amount of complexity for all operations of the process (in this case, two: cutting and stamping).
Process performance: shift parts.
In the economic evaluation of the manufacturing option of a single part, it is enough to determine it technological cost. It differs from the full one in that it includes direct costs for basic materials and production wages, as well as costs associated with the maintenance and operation of equipment and tools.
where Cm is the cost of the main materials or blanks, rubles / pc .;
З - wages of production workers, rubles / pcs .;
1.87 - coefficient taking into account the cost of reimbursing a worn tool, tooling and expenses for the maintenance and operation of equipment, combined, make up 87% of the salary.
The cost of the main material is determined by the formula:
where M n. R. - the consumption rate of the material or the mass of the workpiece, kg / pc .;
With m.o. - the wholesale price of the material or workpiece, rubles / kg;
mо - mass of sold waste, kg / pc .;
Co - the cost of waste is taken in the amount of 10% of the cost of the main material, rubles / kg.
The mass of waste sold is determined by the formula:
where Mz is the mass of the workpiece, kg / pc .;
MD - the mass of the part, kg / pc.
The mass of the workpiece is calculated by the formula:
where V is the volume of the workpiece;
ρ is the density of the workpiece material, g / cm3;
Sl is the area of \u200b\u200bthe sheet;
tl - sheet thickness;
n is the number of parts from the sheet.
The mass of the workpiece: kg.
The mass of the part has already been calculated earlier: Мз \u003d 0.006 kg.
The mass of realized waste: kg.
Wholesale price of steel 10: m. \u003d 1100 rub. · T \u003d 1.1 rub. · Kg.
Then the price of waste: Co \u003d 0.1 · 1.1 \u003d 0.11 rub. · Kg.
The cost of the main material: rub. on the part.
Salary depending on the specific conditions of manufacture of the part can be expressed as follows:
where KZ is the coefficient taking into account additional payments to workers' wages (on holidays, for night shifts), as well as social security contributions;
ti - the norm of piece time for the execution of a technological operation, min./ pcs .;
Si is the qualification rate of the worker, rubles / h;
n is the number of technological operations.
In this case, we take into account 2 operations: cutting strips on guillotine shears and stamping parts. According to the already calculated values:
t1 \u003d 0.0015 min .;
t2 \u003d 0.034 min .;
The qualification category of the worker performing the cutting operation - II; and stamping operation - III.
The tariff rate of the first qualification category of the worker is accepted - 4.5 rubles per hour. The tariff rate for each subsequent qualification category of the worker increases by 1.2 times.
For workers in mechanical workshops, wage supplements are about 4.5%, and social security contributions - 7.8%, i.e. C3 \u003d 1.13.
As a result, we get the salary per unit of the product:
Finally we get the technological cost per unit of production:
10. Calculation of the batch size of parts
Production program: N \u003d 1000 thousand pieces
The actual annual time fund: F \u003d 2000 hours.
Then the rhythm of production should be: det / hour
If Tm stamping \u003d 0.034 min, then det / hour
From the time it takes to install and remove the stamp t \u003d 30 + 10 \u003d 40 min, and the worker’s salary is of the 3rd category Зр \u003d 4.5 rubles / hour * 1.44 \u003d 6.48 rubles / hour.
Then rub
- Let c2 ’\u003d 0.01 * 10-3 rubles. Then batch size details
- Let c2 ’’ \u003d 0.001 rubles. Then batch size details
Calculation of the size of the batch of blanks
From the adjustment of the stops of the guillotine shears 3.5 minutes, the clearance between the knives should be 16.5 minutes, then t.p. \u003d 3.5 + 16.5 \u003d 20min, and the costs of setting up a worker of the II category of rubbands / hour.
If Tm cutting \u003d 0.0015min, then lanes / hour.
Let c2 ’\u003d 0.01 * 10-3 rubles, then the band.
11. Recommendations for setting up scissors
Clearance between knives depending on the thickness and strength of the material being cut, they are controlled by moving the table, for which it is necessary to loosen the nuts of the table mounting bolts to the bed and use the 2 adjusting screws to set the necessary clearance, after which the nuts must be tightened. To install knives after regrinding, it is recommended to use gaskets made of foil or other thin sheet material.
The size of the gap is determined by the table. 11 century
Adjustment of stops. For trimming strips of various widths, the back, front and side stops, stops-angles and stops-brackets are used. Adjustment of a back emphasis produced by moving it using the handwheels on a ruler or templates. If the adjustment is made according to the template, then the latter is set edge-on against the lower knife, and the rear stop is pushed close to the second edge and fixed with screws. Adjustment of the front stop is made according to the template laid on the table. Stops-angles, stops-brackets and side stops fasten to a table in various provisions depending on need.
Back emphasis
Knives38.75 38.75
Bottom knife
Upper knife
Bottom knife
Fig. 3. Adjustment of scissors.
12. Work safety
The main objective of safety measures is to ensure safe and healthy working conditions without reducing its productivity. For this, a large complex of measures is being taken to create such conditions.
In order to prevent occupational injuries, the moving parts of the machines, the working areas of equipment, and technological equipment are equipped with protective devices (barriers, gratings, covers, shields, etc.). To ensure an air environment in the workplace that meets sanitary standards, machines, other technological equipment are equipped with individual or group suction devices.
Environmental protection is of great importance. To reduce pollution, it is necessary to use non-waste technologies, the creation of treatment facilities, allowing reuse of the same volumes of water, air in protective systems.
When developing technological processes for the manufacture of parts, it is necessary to provide specific measures to ensure safe working conditions, environmental protection in the manufacture of the part in question.
To ensure occupational safety on cutting operations with the help of guillotine shears, in addition to the safe design of the tool, the worker must use fabric gloves to feed the sheet of material inside the scissors so as not to injure his hands, and also a dressing gown to avoid damage to clothing when greasing the sheet.
Environmental protection during cutting is carried out by means of the disposal of waste remaining after cutting the sheet into strips, and when working with grease, it should be carefully applied to the sheet of material.
When stamping the worker needs to be extremely careful when turning on the stamp, since it is not equipped with barriers, and also use fabric gloves to feed a strip of material into the stamp.
Punching waste must be disposed of without harming the environment.
Thus, the use of a typical technological process facilitates the design, construction of parts, its manufacture and control.
Thanks to the savings not only of the time that would have been spent on developing in the absence of such a “prototype”, but also the reduction of the costs required to correct and recycle the waste using unworked technologies, equipment and accessories, it is possible to obtain good economic indicators of the manufacturing and assembly process even for small batches of products and equipment.
The greatest time when using a typical process has to be spent on the technological preparation of production, which is necessary to fit the "prototype" for a particular part. Considering that many operations from the CCI are standard and could well be performed using computer technology, the prevailing tendency is to pony or at least partially automate the process of technological preparation of production.
Applications References
1. Drits M. E., Moskalev M. A. "Technology of structural materials and materials science: Textbook. for universities. - M. Higher. school, 1990 .-- 447 pp., ill.
2. Zubtsov M. E. "Sheet stamping". L .: Engineering, 1980, 432 p.
3. Design and technological classifier of parts.
4. Lectures on the course "Technology of engineering production" Lobanova S. A., 2001
5. Mansurov I.Z., Podrabinnik I.M. Special forging and pressing machines and automated complexes of forging and stamping: a Handbook. M.: Mechanical Engineering, 1990.344 s.
6. Reference rationing / Under the general ed. A.V. Akhumova. L .: Mechanical engineering, 1987.458 s.
7. Technology of engineering production. Methodical instructions for course design / Ryazan. state radio engineering Acad; Comp .: A. S. Kirsov, S. F. Strepetov, V. V. Kovalenko; Ed. S. A. Lobanova. Ryazan, 2000.36 s.
8. Rules for processing technological documents: Guidelines for course and diploma design / Ryazan. state radio engineering Acad; Comp. A.S. Kirsov, L.M. Mokrov, V.I. Ryazanov, 1997.36 p.
Economic efficiency of metal forming. The process of obtaining forgings hot forging. Calculation of cutting conditions during drilling. Turning Technology. The benefits of stamping in closed stamps. Precision workpiece processing.
FEDERAL EDUCATION AGENCY
STATE EDUCATIONAL INSTITUTION OF HIGHER PROFESSIONAL EDUCATION
DON STATE TECHNICAL UNIVERSITY
Department "Technology of structural materials"
APPROVED V.V. Rubanov "______" ________ 2008 EXPLANATORY NOTEFor term paper Technology of automated mechanical engineering and instrumentation (the name of the discipline) on the topic: Development of a technological process for manufacturing a part Author of the work ___ Zatsepin Aleksey Viktorovich Specialty_Robots and robotic systems Designation of term paper ____________ Group _______________ Project manager ______________ Work __________ __________________________ __________________________ __________________________ (date) (estimate) Rostov-on-Don 2008 Table of contents 1. INTRODUCTION 2. The main part 2.1. The process of obtaining forgings of hot die forging 2.2 Calculation of the cutting mode during drilling 2.3. Turning Technology 3. Conclusion References INTRODUCTION:
Metal forming.
Metal forming, a group of technological processes, as a result of which the shape of a metal billet changes without violating its continuity due to the relative displacement of its individual parts, i.e., by plastic deformation. The main types of O. m.d .: rolling, pressing, drawing, forging and stamping. O. ppm is also used to improve surface quality.
The introduction of technological processes based on O. m. D., Compared with other types of metalworking (casting, cutting) is steadily expanding, due to the reduction of metal losses, the ability to provide a high level of mechanization and automation of technological processes.
O. p.m. can be obtained products with a constant or periodically changing cross-section (rolling, drawing, pressing) and piece products of various shapes (forging, stamping), corresponding in shape and size to finished parts or slightly differing from them. Piece products are usually machined. The volume of metal removed for all this depends on the degree of approximation of the shape and size of the forging or stamping to the shape and size of the finished part. In some cases, O. m. D. Receive products that do not require machining (bolts, screws, most sheet metal stamping products).
O. p.m. can be used not only to obtain blanks and parts, but also as a finishing operation after machining a part (burnishing, rolling by rollers and balls, etc.) in order to reduce surface roughness, harden the surface layers of the part and create the desired distribution of residual stresses, in which the service properties of the part (for example, resistance to fatigue failure) are improved.
O. m. D. carried out by the impact on the procurement of external forces. The source of the deforming force can be the muscular energy of a person (during manual forging, punching) or the energy created in special machines - rolling and drawing mills, presses, hammers, etc. The deforming forces can also be created by the action of a shock wave on the workpiece, for example during explosive stamping, or by powerful magnetic fields. for example with electromagnetic stamping. The deforming forces are transmitted to the workpiece by a tool, which is usually solid, experiencing small elastic deformations during plastic deformation of the workpiece; in some cases, elastic media are used (for example, during stamping - rubber, polyurethane) or liquids (for example, during hydrostatic pressing).
Distinguish between hot and cold O. m. D. Hot O. m. D. Characterized by the phenomena of return and recrystallization, the absence of hardening (hardening); mechanical and physico-chemical properties of the metal change relatively little. Plastic deformation does not create bandedness (unevenness) of the microstructure, but leads to the formation of bandedness of the macrostructure in cast billets (ingots) or to a change in the direction of the fibers of the macrostructure (strands of non-metallic inclusions) during O. p. The streakiness of the macrostructure creates an anisotropy of mechanical properties, in which the properties of the material along the fibers are usually better than its properties in the transverse direction. In cold O. ppm, the process of plastic deformation is accompanied by hardening, which changes the mechanical and physicochemical characteristics of the metal, creates the banding of the microstructure and also changes the direction of the fibers of the macrostructure. During cold O. m.d., a texture arises that creates anisotropy of not only the mechanical, but also the physicochemical properties of the metal. Using the influence of O. ppm on the properties of metal, it is possible to manufacture parts with the best properties with a minimum mass.
At O. p.m., a change in the stress state diagram in a deformable workpiece allows one to influence a change in its shape. Under conditions of uneven comprehensive compression, the ductility of the metal increases the more, the greater the compressive stress. The rational choice of O.M. operations on p. M. And the conditions of deformation (hydrostatic pressing, extrusion with back pressure, rolling on planetary mills, etc.) not only allows you to increase the permissible change in shape, but also use O. p.m. for the manufacture of parts from high-strength, hardly deformable alloys.
The scientific basis for the design and management of technological processes of O. m. D. Is the theory of O. m.d. The main tasks of the theory of O. m.d.:development of methods for determining the effort and work spent on deformation, calculation of the size and shape of the workpiece, the nature of the change in its shape, methods for determining the permissible (without destruction or the appearance of other defects) changes in the shape of the workpiece, assessment of changes mechanical and physico-chemical properties of the metal during its deformation and finding optimal conditions for deformation.
2. The main part
2.1 The process of obtaining forgings hot forging
Hot stamping is a type of metal forming, in which the forging is formed from a heated billet in a special tool - a stamp. The stamp is a metal detachable form made of high alloy die steel. At the final moment of stamping, when both halves of the stamp are closed, they form a single closed cavity - a stream, corresponding to the configuration of the stamped forging.
Depending on the type of stamp, forging is distinguished in open and closed stamps.
Stamping in open dies (Fig. 1a). Open dies are called dies, in which around the entire external contour of the stamping stream there is a special groove 2, which is connected by a thin slit 1 with a cavity 3 forming a forging. During stamping, the excess part of the metal located in the cavity and forming an overlay (burr) along the contour of the forging is displaced into the groove at the final moment of deformation. The formation of a barb leads to a slight increase in metal waste, but it does not require high demands on the accuracy of the workpieces by weight. By stamping in open dies, forgings of all types can be obtained.
Fig. 1 Stamping scheme in stamps:
a - open; b - closed
Stamping in closed dies (Fig. 1b). Closed are called dies in which the cavity of dies 4 remains closed during deformation. The formation of a barb is not provided for in them. When stamping in closed dies, it is necessary that the equality of workpiece and forgings is strictly observed. Therefore, the process of obtaining blanks is complicated, since during the cutting, high accuracy of the blank must be ensured by weight. Most often, in closed dies, forgings are produced, stamped along the axis of the workpiece (upset on the end) round and square in terms of the type of rings, bushings, gears, pistons, rods with a flange and others.
Development of a process flow chart
The development of the technology of hot volumetric stamping includes designing forgings, determining the mass, type and size of the initial billet, determining the temperature range of hot forming, calculating the current conditions for stamping. The process flow diagram is mainly determined by the configuration and size of the part to be obtained. According to the drawing, the details make up the forging drawing.
Forgings design.
Forging refers to a group of forgings stamped along the axis of the workpiece (stamping at the end), round in plan. To obtain forgings of this type, we use stamping in a closed stamp. The plane of the die connector is selected at the lower end of the part disk (diameter D2, height H).
1. Determination of the mass, type and size of the original workpiece.
1.1 determine the mass of the part, kg:
G d \u003d V d 10 -3 s 10 -3,
Where V d - volume of the part; mm 3, s density siali, 7.8 g / cm 3
The volume of a part is calculated as the sum of the volumes of its three parts:
V d \u003d V 1 + V 2 + V 3 \u003d p / 4 (D 1 H1 + D 2 H 2 + D 3 H 3).
Due to the insignificant size limit deviations of the dimensions, we carry out the calculation according to the nominal dimensions of the part, mm: V d \u003d 3.14 / 4 (75 2 * 15 + +125 2 * 20 + 70 2 * 40) \u003d 469035
G d \u003d 469035 * 10 -3 * 7.8 * 10 -3 \u003d 3.6
1.2 1.2 Tolerances and tolerances are selected from the table data:
D 1 75 ... 1.5; H 1 15 ... 1,4;
D 2 125 ... 2.1; H 2 40 ... 1,4;
D 3 70 ... 1,5; H 3 20 ... 2.2;
Part Dimension Tolerances:
D 1p \u003d 75 +1.6 - 0.8 N 1p \u003d 15 +1.5 -0.7
D 2p \u003d 125 +1.7 -0.9 H 2p \u003d 40 +1.5 -0.7
D 3p \u003d 70 +1.6 -0.8 N 3p \u003d 20 +1.5 -0.7
D 4n \u003d 15 +1.5 -0.7
1.3 determine the estimated mass of forgings:
G p \u003d 1.25 * G d \u003d 1.25 * 3.6 \u003d 4.5
1.4 allowances and tolerances are selected according to the tabular data:
D 1 75 ... 1.5; H 1 15 ... 1,4;
D 2 125 ... 2.1; H 2 40 ... 1,4;
D 3 70 ... 1,5; H 3 20 ... 2.2;
Sizes of forgings, mm:
D 1p 75 + 2 * 1.5 \u003d 78; H 1p 15 + 1.4 \u003d 16.4
D 2p 125 + 2 * 2.1 \u003d 129.2; H 2p 40 + 2 * 1.4 \u003d 42.8
D 3p 70 + 2 * 1.5 \u003d 73; H 3p 20 + 2.3 \u003d 22.3
Forgings on the dimensions of forgings:
D 1n \u003d 78 +1.6 - 0.8 N 1n \u003d 16.4 +1.5 -0.7
D 2p \u003d 129.2 +1.7 -0.9 H 2p \u003d 42.8 +1.5 -0.7
D 3p \u003d 73 +1.6 -0.8 N 3p \u003d 22.3 +1.5 -0.7
Punching slopes b take 7 ?.
The radii of curvature r of the outer corners r1 \u003d 2; r2 \u003d 2.5; r3 \u003d 2.
The inner radius is 10 mm.
1.5 determine the mass of forgings, kg:
G p \u003d V p 10 -3 s 10 -3
Where V p - the volume of forgings, mm 3
The volume of forgings is calculated as the sum of the volumes of its three parts, each of which has the shape of a truncated cone, mm 3:
V p \u003d V 1p + V 2p + V 3p.
The calculation is carried out according to the minimum horizontal and
h 1p 7? maximum vertical dimensions, mm.
The volume of the truncated cone is determined by the formula, mm 2
V 1n \u003d p / 3 H 1n (R 2 1n + r 2 1n + R 1n * r 1n) \u003d 3.14 / 3 * 17.9 (40.8 2 +38.6 2 + 40.8 * 38, 6)
R 1n \u003d r 1n * H 1n tg7? \u003d 38.6 + 17.9 * 0.12228 \u003d 40.8
V 2n \u003d p / 3 H 2n (R 2 2n + r 2 2n + R 2n * r 2n) \u003d 3.14 / 3 * 44.3 (69.6 2 +64.15 2 +69.6 2 +64 ,fifteen)
R 2n \u003d r 2n * H 2n tg7? \u003d 64.15 + 44.3 * 0.12228 \u003d 69.6
V 3p \u003d p / 3 H 3p (R 2 3p + r 2 3p + R 3p * r 3p) \u003d 3.14 / 3 * 23.8 (41.5 2 +38.6 2 + 41.5 * 38, 6)
R 3n \u003d r 3n * H 3n tg7? \u003d 38.6 + 23.8 * 0.12228 \u003d 41.5
V p \u003d 88044 + 617513 + 118905 \u003d 824462
G p \u003d 824462 * 10 -3 * 7.8 * 10 -3 \u003d 6.4
Calculation of the mass of forgings after completing its drawing shows that the mass of forgings after the appointment of all allowances, tolerances and slopes remains in the same table range, and does not require recounting.
1.6 Determine the mass and size of the original workpiece.
The volume of the workpiece, taking into account 2% waste, mm 3
Vz \u003d 1.02 * Vp \u003d 1.02 * 824462 \u003d 840951
Diameter of the workpiece, mm
Dz \u003d 1.08 \u003d 1.08 \u003d 80.9 (with m \u003d 2)
We take Dз \u003d 82 - the closest larger diameter from a number of standard steel diameters.
Workpiece length, mm:
Lз \u003d Vз / Sз \u003d 840951/5278 \u003d 159
Where Sz is the cross-sectional area of \u200b\u200bthe workpiece, mm 2:
Sz \u003d (pD 2 s) / 4 \u003d 3.14 * 82 2/4 \u003d 5278
2. Determination of the temperature range of stamping.
We determine the temperature range of hot pressure treatment in which the metal has the highest values \u200b\u200bof ductility, impact strength and the lowest value of strength. To do this, we find the point corresponding to the carbon content of 0.15 (for Steel 15) on the abscissa axis of the iron – carbon state diagram. We draw a perpendicular line from this point to the intersection with the solidus line, below which the alloy is in the solid state. The intersection point corresponds to a temperature of 1425? C. The maximum temperature of metal heating is taken at 100-150? C less, accept 1300? C. Similarly, we determine the temperature on the line of the curve points A 3, which is equal to 850? C. The temperature of the end of the stamping is taken at 25-50 ° C more, to prevent the formation of hardening and cracks in the product, we take 900 ° C.
3. The approximate mass of the falling parts of the stamping hammer, kg:
G \u003d (3.5 + 5) F p \u003d 4.2 * 134.5 \u003d 564.9,
Where F p the projection area of \u200b\u200bthe forgings on the plane of the stamp connector, cm 2
F p \u003d p D 2 2p / 4 \u003d 3.14 * 130.9 2 * 10 -2 / 4 \u003d 134.5;
D 2p is the smallest diameter of the forging.
2.2 Calculation of cutting conditions during drilling
Drilling is the formation of a hole in a continuous material by removing chips with a cutting tool - a drill. Drilling
carried out by combining the rotational movement of the tool around
axis - the main motion of cutting, its translational motion along the axis of the feed motion (Fig. 1). On a drilling machine, both movements are communicated to the tool.
For the speed of the main movement V take the peripheral speed of the point of the cutting edge, the most remote from the axis of the drill, m / s (m / min):
V \u003d p * d * n / (1000 * 60)
where d is the outer diameter of the drill, mm, n is the frequency of rotation of the drill, min-1.
The feed S (or feed speed) is equal to the axial movement of the drill per revolution, mm / rev.
Under the cutting mode during drilling refers to the combination of values \u200b\u200bof the cutting speed and feed.
The cutting process during drilling proceeds in more difficult conditions than during turning. During cutting, it is difficult to remove chips and supply coolant to the cutting edges of the tool. When removing chips, its friction occurs on the surface of the grooves of the drill and drill on the surface of the hole. As a result, chip deformation and heat generation increase.
An increase in chip deformation is affected by a change in the speed of the main cutting motion along the cutting edge from the maximum value on the periphery of the drill to the zero value at the center.
For the speed of the main cutting movement during drilling, take the peripheral speed of the point of the cutting edge farthest from the axis of the drill, m / s (m / min):
V \u003d p * D * n / (1000 * 60),
where D is the outer diameter of the drill, mm; n is the rotational speed of the drill, rpm The feed S (mm / rev) is equal to the axial movement of the drill per revolution. For the cutting depth when drilling holes in a solid material take half the diameter of the drill, mm:
t \u003d D / 2, and when drilling t \u003d (D-d) / 2, where d is the diameter of the hole to be machined, mm.
After turning, the part enters the drilling operation.
1. In this part, it is necessary to drill 1 hole with a diameter of d \u003d 15mm. The material of the part is steel with a tensile strength of uv \u003d 400 MPa. The material of the twist drill is high-speed steel grade P18. Cooling - emulsion. We will drill on a machine model 2H135. Calculation of the cutting mode:
2. Determine the feed S by the formula
S \u003d Stable * Ke,
where Stable \u003d 0.28 (mm / rev). Choose from the table, depending on uv \u003d 400 MPa, when drilling holes with a depth of 1? 3d, with an accuracy of no higher than the 12th level in the conditions of a rigid technological system (1? 3d? 36 \u003d 12); Ke - correction factor for feed, Ke \u003d 1, since a hole is drilled with a depth of 1< Зd, с точностью не выше 12-го квалитета и в условиях достаточно жесткой технологической системы(В связи с отсутствием дополнительных значений и параметров). S = (0,28-0,32) * 1 = (0,28-0,32) мм/об
The feed on the machine is set within the selected table range. We accept S \u003d 0.28 mm / rev.
3. The cutting speed V is determined by the formula:
V \u003d (Cv * dnv * Kx) / (Tm * Syv),
where Su is a coefficient taking into account physical and mechanical properties
workpiece material and processing conditions;
T - drill resistance, min;
By applications 2 and 3 we find:
K y \u003d K mx * K ux * K lx - correction factor for cutting speed;
K mx \u003d K g * (750 / uv) ny - correction factor that takes into account the influence of physical and mechanical properties of the processed material;
K g - coefficient taking into account the material of the tool (for drills made of high speed steel and the processed material - carbon steel Kg \u003d 1);
nv-exponent (for drills made of high-speed steel of the processed material - carbon steel at<400 МПа, nv=0,9);
K ux is a correction factor that takes into account the influence of tool material (for high-speed steel K ux \u003d 1);
К lх - correction factor taking into account the depth of the hole being machined (at a depth of 1? 3d, Кlх \u003d 1);
V \u003d * 1 (750/400) -0.9 * 1 * 1 \u003d 16.6 m / min \u003d 0.27 m / s.
4. Determine the frequency of rotation of the spindle of the machine n, obtained by calculation:
n \u003d 1000 * V / (p * d) \u003d 1000 * 16.6 / (3.14 * 15) \u003d 352 min-1
On the machine we accept the nearest lower speed n \u003d 250 min-1.
5. Determine the axial force when drilling P0 according to the formula:
P0 \u003d Cp * d xp * S ur * Kp \u003d 55.6 * 15 * 0.28 0.7 * (400/750) 0.75 \u003d 213 kgf;
From the application we find Cp \u003d 55.6, XP \u003d 1.0, UR \u003d 0.7.
where Kr \u003d (UV / 750) 0.75 \u003d (400/750) 0.75 - correction factor, depending on the material of the workpiece; n-- exponent (when processing carbon steel n \u003d 0.75).
According to the passport data of the machine, the greatest axial force allowed by the feed mechanism of the machine is 1500 kgf. Therefore, the assigned feed S \u003d 0.28 mm / rev is permissible.
6. Determine the torque MK from the forces of resistance to cutting during drilling by the empirical formula:
Mk \u003d Cmd xm S ym Km \u003d 23 * 15 2 * 0.28 0.8 * (400/750) 0.75 \u003d 1166 kgf * mm;
Cm \u003d 23; Xm \u003d 2.0; Um \u003d 0.8.
The torque is provided by the machine (the permissible torque is 4000 kgf * mm).
7. The effective power Ne spent on the cutting process:
Ne \u003d Mkdop * n / 974000 \u003d 4000 * 250/974000 \u003d 1.02 kW.
8. The estimated power of the electric motor of the machine Ne:
Ne \u003d N / s \u003d 1.02 / 0.7 \u003d 1.45 kW,
where z-efficiency of the mechanisms and gears of the machine z \u003d 0.7
9. Determine the main time T0. This is the time spent directly on drilling with a "manual" supply of the tool to the workpiece:
L \u003d l + lvr + lper \u003d 75 + 7.5 * ctg59 + 3 * 0.28 \u003d 80.34 - the total length of movement of the drill, mm;
where l \u003d 2 * d - hole depth, mm
1вр \u003d d / 2 * ctg-depth of insertion of the drill into the workpiece, mm,
1per? 3S-- tool overrun length, mm;
We take the angle at the top of the drill 2c \u003d 118 °, recommended for
steel processing. Thus:
That \u003d 80.34 / (0.28 * 250) \u003d 1.15 min
Hole size tolerance: D 4 \u003d 14.4 +1.5 -0.7
2.3 Turning Technology
Having considered the technological process of obtaining forgings of hot die forging, we turn to the consideration of the technology of turning.
When developing designs of machine parts, the surface treatment of which is expected on the machines of the turning group, it is advisable to take into account a number of special requirements ensuring their manufacturability.
Parts processed on the machines of the turning group must contain the largest number of surfaces having the form of bodies of revolution. The design of the part must be such that its mass is balanced with respect to the axis of rotation. Processing balanced workpieces eliminates the effect of mass imbalance on the accuracy of the manufacture of surfaces of parts. When designing parts, it is necessary to use a normal range of diameters and lengths, which allows the use of a standard cutting tool. Non-rigid shafts and bushings (long thin shafts and thin-walled bushings) should be avoided in designs. The rigid design of the bushings, glasses, cylinders allows them to be processed in cam chucks, without resorting to special devices. When processing non-rigid parts, the geometric shape error of the treated surface is always greater than when processing hard parts.
CHARACTERISTIC OF THE ROLLING METHOD
The technological method of shaping the surfaces of workpieces by turning is characterized by two movements: the rotational movement of the workpiece (cutting speed) and the translational movement of the cutting tool - the cutter (feed movement). The feed movement is parallel to the axis of rotation of the workpiece (longitudinal feed), perpendicular to the axis of rotation of the workpiece (transverse feed), at an angle to the axis of rotation of the workpiece (inclined feed).
Varieties of turning: turning - processing of external surfaces; boring - processing of internal surfaces; cutting - processing of flat (end) surfaces; cutting - separation of the workpiece into parts or a segment of the finished part from the workpiece - bar stock.
On vertical semiautomatic devices, automatic machines and turning and rotary machines, workpieces have a vertical axis of rotation, on lathes of other types - a horizontal one. On lathes perform rough, semi-finishing and finishing processing of the surfaces of the workpieces.
Cutting is the process of cutting a metal layer with a cutting tool from the surface of a workpiece to obtain the desired geometric shape, dimensional accuracy and surface roughness of the part. To achieve this, it is necessary that the workpiece and the cutting edge of the tool move relative to each other.
The main movements in metal-cutting machines are cutting movements, which ensure cutting of the metal layer from the workpiece, and including the main movement and feed. The main thing is the movement, which serves directly to separate the chips. Quantitatively, it is estimated by the cutting speed, denoted by the letter V, with a dimension of m / s (m / min). When turning - this is the rotation of the workpiece.
Feeding - movement, providing continuous cutting of the cutting tool into new layers of material of the workpiece. The feed is indicated by the letter 8 with an index indicating the direction: Spr-longitudinal, Sp - transverse feed. When turning, the feed is the translational movement of the caliper. Feed Dimension mm / rev
Processing a workpiece on a lathe is called a turning operation. The operation is the finished part of the process performed by the worker on one | workplace over a specific item. The simplest element of the technological operation is the transition - the processing of one surface with one tool under certain cutting conditions. If the layer to be cut is large, then it can be removed not in 1, but in 2 or more passes — multiple movements of the tool over the surface.
After receiving the part from the foundry, we will draw up a route for the turning operation of processing the part, select a tool and enter it in table 2.3.
table 2
Ust-novy | Transitions | Transition Schemes | Cutter Type | ||
Install the workpiece in the chuck and secure. Trim the end face as "clean." | Scoring | ||||
Sharpening73 +1.6 -0.8 to w70 +1.6 -0.8 for a length of 40 +1.5 -0.7 | Thrust | ||||
Sharpen w 129.2 +1.7 -0.9 to w 125 +1.7 -0.9 for a length of 20 +1.5 -0.7 mm Install the workpiece in the chuck and secure, trim the stick in size 75 +1.6 -0.8. | Thrust Scoring | ||||
Sharpening78 +1.6 -0.8 to w75 +1.6 -0.8 for a length of 20 +1.5 -0.7 | Thrust | ||||
Bore inner w14.4 +1.5 -0.7 to w15 +1.5 -0.7 for the entire length | Boring checkpoint |
2. The choice of tool.
According to the turning route, select a feed cutter. When turning the specified roughness 20, we use the grade of carbide cutting insert - T15K6 with the geometry: (c \u003d 90 °, c1 \u003d 45 °, g \u003d 10 ° b \u003d 12 °,
r \u003d 1.0 mm. Durability period T \u003d 80 min.
3 Calculation of the cutting mode for transition A2.
The cutting depth t is taken equal to the allowance t \u003d z \u003d 1 mm.
4 Select the feed S. S \u003d 0.5 mm / rev.
5 Determine the cutting speed.
V \u003d С V / (t Xv * S Yv * T m) \u003d 350 / (1 0.15 * 0.5 0.35 * 80 0.2) V \u003d 184.2 m / min
6 Calculate the speed:
n \u003d 1000V / (p * d) \u003d 1000 * 184.2 / (3.14 * 15) \u003d 3910 min-1
We specify nst according to the passport data of the machine (see table. 6) and take the nearest lower nst \u003d 3150 min-1.
7 Determine the actual cutting speed:
Vph \u003d (p * d * n cm) / 1000 \u003d (3.14 * 15 * 3150) / 1000 \u003d 148.4 m / min
8 Define the main component of the cutting force (table. 7):
Pz \u003d s p * t Xp * S Yp * V Pr \u003d 2943 * 1 * 0.5 0.75 * 148.4 -0.15 \u003d 783.4 N.
9. Define the cutting power:
NE \u003d Pz * Vph / (1040 * 60 * h) \u003d 783.4 * 148.4 / (1040 * 60 * 0.8) \u003d 2.32 kW,
h \u003d 0.7 - 0.9 - the efficiency of the mechanisms and gears of the machine.
Since Ne \u003d 2.32< 10 кВт =Nст, то обработка на данных режимах выполняется.
3. Conclusion
After completing this course work, I got acquainted with the development of the technological process for producing hot die forging, with the technology of turning and drilling.
Let's draw some conclusions:
1. Stamping in closed dies shall:
1) To provide forgings of a certain geometric shape and size;
2) When stamping in closed dies, it is necessary to strictly observe the equality of the volumes of the workpiece and forgings;
3) A significant advantage of stamping in closed dies is the reduction in metal consumption, since there is no burr;
4) Forgings obtained in closed dies have a more favorable microstructure;
5) When stamping in closed dies, the metal is deformed under conditions of comprehensive uneven compression at high clamping stresses than in open dies.
In the course of the course work, a technological process was developed for the production of the part by hot stamping. The following issues were also considered: 1. Calculation of the forging of the part. Defined machining allowances, tolerances for size deviations.
2. Defined the technical scheme for the production of forgings, made graphic material, which includes a drawing of forgings.
2. When machining parts, the following requirements must be observed:
1) the accuracy of processing blanks, the quality of the surface layers;
2) the correct choice of the cutting tool (the hardness of the material of the cutting part should significantly exceed the hardness of the material of the workpiece, the shape of the tool should correspond to the operation);
3) the technological map should reflect in detail all operations of the technological process;
4) when developing the design, the parts to be processed on the machines of the turning group must contain the largest number of surfaces having the form of bodies of revolution. The mass of the part must be balanced relative to the axis of rotation. It is advisable to avoid complex shaped surfaces, adhere to standard sizes and shapes of parts, which allows the use of a standard cutting tool.
3. When developing the design of the part to be machined on drilling machines, it is necessary to adhere to the following technological requirements:
1) holes, to which high demands are placed on accuracy, must be made through, not blind;
2) the surface into which the drill crashes should be perpendicular to the movement of the drill;
4) all elements of the part must be freely accessible during processing and measurement;
The basis for increasing the economic efficiency of metal forming, of course, is technological progress. Technological progress is the process of improving production, technological methods and forms of organizing labor and production, consisting in the continuous improvement of production on the basis of new technology, scientific achievements and best practices.
5. List of used literature:
1. Development of a process flow diagram for producing hot forgings. Method. Instructions for the implementation of practical work. DSTU, Rostov n / A, 2004.11 p.
2. Technology of turning. Method. instructions for doing practical work. DSTU, Rostov n / A, 2000.11 s.
3. Calculation of the cutting mode during drilling. Method. instructions for doing practical work. DSTU, Rostov n / A, 2000.11 s.
4. Forging and stamping: a guide in 4 volumes of T.2 Hot stamping. Ed. E.I.Semenova. M.: Mechanical Engineering, 1986. 592 p.
5. Technology of structural materials. Textbook for engineering specialties of universities / Under total. ed. A.M. Dalsky, 2004.512 s.
6. Course and diploma projects (works). Rules for registration. Enterprise standard. DSTU, Rostov n / A, 2001.34 s.
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Introduction
Mechanical engineering is one of the most important sectors in the industrial complex of our country. For the national economy, it is necessary to increase the output of engineering products and increase its quality. Technical progress in mechanical engineering is characterized not only by an improvement in the design of machines, but also by continuous improvement of the technology for their production. It is important to make any machine or part qualitatively, economically and on time with the minimum cost of living and materialized labor.
The development of new progressive technological processing processes contributes to the design of more modern machines and mechanisms, and reduce their cost. The urgent task of improving the quality of machines and, above all, their accuracy. In mechanical engineering, accuracy is especially important for improving the operational quality of machines. Ensuring the required accuracy at the lowest cost is the main task in the development of technological processes.
The main tasks in the field of engineering and the prospects for its development:
approximation of the shape of the workpiece to the shape of the finished product through the application of methods of plastic deformation, powder metallurgy, special profile rolling and other progressive types of workpieces;
automation of technological processes through the use of automatic loading devices, manipulators, industrial robots, automatic lines, CNC machines;
concentration of transitions and operations, the use of special and specialized machines;
the use of group technology and high-performance equipment;
the use of effective cutting fluids with their supply to the cutting zone;
development and implementation of high-performance constructions of cutting tools made of hard alloys, cermets, synthetic superhard materials, high-speed steels with increased and high productivity;
widespread use of electrophysical and electrochemical processing methods, the application of wear-resistant coatings.
In the course project in accordance with the assignment provides for the development of the technological process of manufacturing the "Shaft", which is one of the most important parts of the mechanism for transmitting rotation at a given gear ratio.
1. General technical part
1.1 Service purpose of the product. Analysis of design and specifications
The shaft belongs to the class of shafts. The shaft is designed to transmit rotation at a given gear ratio.
On surface 3 there is a keyway for the key for mounting the mating part. At the end 1 there is a threaded hole M8-7H for attaching the part preventing axial displacement of the part from surface 3. On surface 15 there are straight-line slots designed for fastening the mating part. Grooves 5, 9, 14 - are technological and serve to exit the cutting tool. Groove 17 is for mounting the snap ring.
Table 1.1 Technical Requirements
|
Name of surface, nominal value, mm |
Surface purpose |
Accuracy |
Roughness Ra, microns |
|
|
End L \u003d 290 mm |
||||
|
2, 6, 10, 12, 18 |
Chamfer 1CH45є |
Loose |
||
|
Outside cylindrical W 25 mm |
Auxiliary design base |
|||
|
Keyway 40x4x4 |
||||
|
End L \u003d 50 mm |
Auxiliary design base |
|||
|
Outside cylindrical W 24.5 mm |
Loose |
|||
|
End L \u003d 53 mm |
Subsidiary |
|||
|
Outside cylindrical Ш 29.5 mm |
Loose |
|||
|
Outside cylindrical W 40 mm |
Loose |
|||
|
End L \u003d 81 mm |
Auxiliary design base |
|||
|
Outside cylindrical W 30 mm |
The main design base |
|||
|
Slots straight-line |
Auxiliary design base |
|||
|
End L \u003d 87 mm |
Loose |
|||
|
Outside cylindrical Ш 28.5 mm |
Loose |
|||
|
Chamfer 1.6CH45є |
Loose |
|||
|
Inner cylindrical M8 at L \u003d 18 mm |
Auxiliary design base |
1.2 analysis of the manufacturability of the part
The shaft refers to parts of the "shaft" type.
The shaft is made of steel 45 (GOST 1050–88), which is relatively well processed by cutting.
From the point of view of rational selection of the workpiece, the shaft gear belongs to fairly technologically advanced details. As a blank, you can use rolled metal as the cheapest type of blank.
The geometric shape of the part consists of surfaces that are formed by the rotation of the generatrix relative to the axis and ends.
The surfaces are open for approaching and moving the cutting tool. The configuration of the part does not allow its complete processing in one installation. Therefore, the processing route will consist of a series of sequential operations and transitions.
The configuration of the part provides a normal input and output of the tool.
The shaft design allows the use of typical processing steps for most surfaces.
Indicators of accuracy and roughness are within the economic range: 6 accuracy and roughness Ra 0.63 microns.
It is possible to implement the principle of constancy of bases in basic operations. Selected bases provide simple, convenient and reliable fastening. This allows the use of relatively simple and cheap devices.
The part is machined in the centers and has sufficient rigidity, as l / d< 10 (294/42 < 10).
The design of the part provides shock-free processing.
In basic operations, the possibility of using standard cutting and measuring tools and accessories (feed-through cutter, contour cutter, groove cutter, worm cutter, key cutter, center drill, end mill, center, ruler, vernier caliper).
Structural elements do not cause deformation of the tool at the input and output.
As a result of the foregoing, the part is technologically advanced.
1.3 Material, its composition and its properties. Heat Treatment Modes
The shaft is made of steel 45 GOST 1050–88. Steel 45 belongs to the group of carbon quality structural steels. This is an improved steel with a normal manganese content. [ 1.17]
Table 1.2 The chemical composition of steel
Table 1.3 Physico-mechanical properties of steel
Table 1.4 Types and modes of heat treatment
|
steel grade |
|||||
|
Heating temperature | |||||
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