Making a 3D bar with your own hands. Home bar production or the economy should be economical. The accuracy on the extruder is quite high

A small report on the purchase and installation of an extruder kit for a 3D printer. For those looking to add color printing to their printer.

The upgrade of the 3D printer was long overdue, I especially wanted to try color printing - to get a double extruder on a Tevo Tarantula printer. At one time, the Large and Dual versions were not available, I just took Large, but with an aim that someday ...

But it has come someday. Upgrade kits were purchased in advance: (extruder coolend) with a high-torque motor, as well as a "hot" part - with two channels for two plastic colors. The set included the necessary wires, heaters, temperature sensors.
For revision you will need:
- high-torque engine. That is, a stepper that will not spin quickly, but for sure. A moment is needed to "push" the plastic through the nozzle. And if the nozzle is 0.8 mm, then a high torque is not needed, then for small nozzles with a hole of 0.3 ... 0.2 mm it is necessary, the torque increases several times. Alternatively, the use of a motor with a gearbox.
- set for the extruder mechanism. These are clamps, roller, gear wheel, spring, flanges.
- engine mounting bracket.
- motor connection wire. Usually, the truth is immediately included with the engine.
- if the board does not have an output for the second (third) extruder motor, then you will need to buy a 2-in-1 splitter adapter to install a new motor driver.
- plastic feed tube (Teflon tube OD = 4 / ID = 2, that is, external diameter 4 mm, internal 2 mm. tubes with an internal diameter of 4 mm usually go not for 1.75 bar, but for 3 mm bar) - Bowden tube ".

for the "hot part":
- two radiators E3D or one double.
- two heating blocks
- heating cartridges and thermistors.
- thermal barrier blower fan.

To build and configure:
- Straight arms
- modified firmware
- setup and calibration. Consider the distance between the nozzles. Keep in mind that along the X and Y axes the second hot end has slightly "ate" the distance. The nozzles must be at the same level (in height). Even 0.1mm makes a difference in the final print quality. For a delta printer, the two nozzles are very difficult to calibrate.

A few words about popular mixing / double hotends.
These are the so-called Chimera and Cyclops.
is a deep modification of the E3D hot end with a flat radiator, two inlets (flanges) and two heating blocks.


Cyclops (Ciclop) - an analogue of the Chimera, the same radiator and two channels, but a common heating block and one nozzle.

Inside the block, two channels are combined into one

The change of plastic occurs by retracting one bar and feeding the other. Minus - plastics should have a similar melting point, since there is one heater, a common and a common thermal sensor. That is, it will not work to "make friends" PLA and, for example, ABS. But ABS and HIPS are quite. Accordingly, it is not suitable for printing PVA supports with plastic, since PVA has a low melting point and at 200-210 ° C it already overheats and a plug is obtained in the channel.
There is also a Diamond hotend, I will not focus on it, because apart from a non-standard nozzle of 0.4 mm for big money, they can not offer anything.

So, it was decided to take everything as a kit, reinsuring against various incompatibilities and additional waiting. A feeder + motor kit and a separate twin extruder kit were ordered.

MK7 / MK8 All Metal Remote Extruder Kit Specifications
Bar diameter - 1.75 mm
Movement material - anodized aluminum ("7075 aviation" alloy)
Placement: Left, Right, Center.
- 2 fittings for PTFE tubing with a diameter of 4 mm
- motor connection cable
- engine 17hd40005-22b
- U-roller 624ZZ
- fastening bracket
- MK7 grooved gear
- hexagon
- spring
- set of screws.

Now a little more detail about the purchased kit. Everything came in a simple package and in a bubble wrap. The package is heavy enough.


A huge plus is full metal, that is, the absence of plastic parts in the extruder mechanism. Why is it a plus - because there are already backlashes (working out) in mine, plus the plastic mount is damaged. Reprinted, but not the cake. Better to let everything be metallic.
So nothing was harmed on delivery. Unpack it boldly!


High torque stepper motor marking.


Cogwheel with groove.

Additional information for those who want to buy the kit separately

Specifications


Compare with the characteristics of "regular"

Further . There are three types: for installation on the left, right, center. They are distinguished by milling on the "handle" - a lever that is pressed when refueling plastic. You can estimate if you already know the location of the extruder.


This kit comes with a straight toothed gear, if you take it, then this is another plus.

You can take here


Hotend



And to him


Plus thermistor, heating cartridge, plastic flanges, tube.
You can install not a cyclops block on the radiator, but ordinary volcano-type blocks, two pieces. Only necked tubes are needed without threads.


Everything is basic. IMHO, it's cheaper to buy everything in a set, with heaters, thermistors and a fan.

We begin to assemble the kit. This is not a tricky thing.
Install the gear. It will be required with a 1.5 hexagon.


Further in this order: bracket-base-lever-spring.
Naturally, the bracket is first attached to the right place on the printer, otherwise you will not be able to fix it, since the grooves will be under the motor housing. For clarity, I will build it first without installing it on the printer.


Pay attention to the different lengths and diameters of the screws. Each is designed for its own hole.


Next, install the lever and springs
It turned out something like this.


Then we fasten the flanges for the bar


Here is a photo of the kit before "fitting"


Trying on a printer. The printer is now equipped with a simple extruder with a modified E3D (which has a tube up to the nozzle itself). To install the Cyclops hot end, you will need to replace the X-axis carriage.


For the final installation, I still have to print the extruder mount, or find a convenient position for the bracket to mount on the 2020 profile.

So, a few words about the Tevo Tarantula firmware modification.
We go to the online firmware designer
And immediately load your Configuration.h. We get the opportunity to modify the known working firmware of our printer.


On the fourth tab "Tools" click "add extruder". By default, we only have one, Extruder0.


Add Extruder1.


And we configure it. Specify pin as needed.


Please note that if you have a mixing hot end with one heater and one thermistor, this must also be specified in the firmware.
Heater0 and Temp0 for the main extruder. If the second one has a separate heater block, then we indicate Heater2 and Temp2 for the second extruder. Then we save, fill it into the printer and try.

In the control program or from the display, we give the task to feed N mm of the bar. For example, 100 mm. And then we measure the result: more or less could have come out. We take into account the difference, enter the correction factor into the firmware and recheck again. The operation is best done with the bowden tube removed.
Here, in the Configuration.h file, in the "default settings" section, we write the number of DEFAULT_AXIS_STEPS_PER_UNIT steps for the extruder (the fourth value, the first three are the X, Y, Z axes).
#define DEFAULT_AXIS_STEPS_PER_UNIT (80,80,1600,100) // custom steps per unit for TEVO Tarantula


We calculate the correction factor and enter it. For example, it squeezed out more than necessary, not 100, but 103 mm. We divide 100/103, and enter the result into the firmware.
#define DEFAULT_AXIS_STEPS_PER_UNIT (80,80,1600,97.0874) // custom steps per unit for TEVO Tarantula


We save, compile, upload, check.

Additional Information - Calculating the Number of Extruder Steps

If anything - the calculation of the number of steps of the extruder DEFAULT_AXIS_STEPS_PER_UNIT is calculated by the formula:
steps per mm = micro steps per rev * gear ratio / (pinch wheel diameter * pi)
where micro steps per rev is the number of motor microsteps for 1 revolution = 3200, that is, 16 microsteps per step, 200 steps per revolution
- the number of microsteps of the motor for 1 revolution
gear ratio - the ratio of the number of teeth in the extruder gearbox. There is no reducer in my Tevo, therefore = 1
pinch wheel diameter - diameter of the pusher screw cavity
After calculation, it is all the same to check according to the above method.

The FB group has some posts on

Currently, the most affordable price for filament for 3D printers is more than $ 20 per 1 kg, the cost of filament from reliable manufacturers or with any special characteristics (color, additives) reaches $ 50.

Thus, when printing 3D models, reducing material consumption and its cost are becoming key factors in increasing the economy and, accordingly, the profitability of 3D printing.

Extruder Liman

The first public step towards this was an open source invention announced in March 2013 - an extruder for self-creating filament for 3D printers. Inventor Hugh Lyman submitted his car to the competition and won the grand prize from the Kaufman Foundation and Maker Faire. One of the main conditions of the competition was the price of the device - no more than $ 250. The winning extruder allows extruding a filament with a diameter of 1.75 or 3 mm with an error of 0.01 mm, and this was already the second version of the presented device, the first did not pass at the price. Lyman's invention is open source, allowing anyone to use and build it.

With a homemade extruder, you can save up to 80%. A high-quality filament costs about $ 50 per 1 kg, while buying a kilogram of pellets will cost only $ 10. And if you buy a 25 kg package of granules, then each kilogram will cost only $ 5.

Fischer's extruder

Inspired by Lyman's extruder, Ben Fischler from San Diego, California decided to try creating an easy-to-use version for users. STRUdittle is an ultra-compact device and can make ABS filaments at an extrusion rate of 30-60 cm per minute.

The accuracy on the extruder is quite high:

• Accuracy 0.05 mm with free filament withdrawal;
• The error is 0.03 mm when using the spool automatically winding the finished thread.

Fischler's project launched on Kickstarter to make this product available to the masses. The necessary funds have already been collected, and the complete device is offered to participants with funding for $ 385. Moreover, in addition to the complete set, those who already have a similar extruder are also offered separately only a mechanism for automatic filament unwinding for $ 100. And the device itself is supplied with a nozzle size according to the customer's choice, including without it at all - for the manufacture of materials of non-standard sizes.

Let's continue on the topic of how the filament is fed into the melting zone (HotEnd "a).

In the photo, the classic reprap extruder is the ancestor of all 3d-printing mechanisms for self-made people.

It is worth noting that the reducer (with a ratio of at least 1: 5) necessarily needed to drive a filament with a diameter of 3.0 mm. The purpose of the gearbox is to increase the torque on the shaft by reducing the speed. In other words, it will twist harder, but slower, but we, just, do not need a high rotational speed - the plastic must have time to melt.
If we are dealing with a bar of 1.75 mm or even smaller diameter, then we do not need to make a gearbox. Although, if a very weak motor is used (for example, from an old Epson printer, which I used at first), then the gearbox still has to be done.

The photo shows just such an engine and an extruder made on its basis from parts from old printers.

In industrial 3D printers, the extruder looks very similar:

The photo shows the heart of the Stratasys printer - the same comrades who invented (and patented) the technology of printing with molten plastic.

There are, of course, more sophisticated options, but they are difficult to implement, so they are not suitable for independent (handicraft) production:

Since 3 mm plastic is much (!) Cheaper than thinner versions (moreover, more common), then we will make the drive, counting on a more toasty filament. And already plastic 1.75 (and similar ones) we will be able to "push" with this extruder without any problems at all. In this case, only a small modification of the hot end is required (more on that later).

So.

First, we need an engine. Moreover, stepping and very desirable bipolar, otherwise you will have to tinker with the control. You can distinguish it from unipolar (another type of shagoviks) by the number of conclusions. There should be 4. In this case, it will be possible to use a typical control driver (Pololu). A diagram of such an engine:

The color of the wires can be absolutely any, so we check where which windings are with a tester. As for the beginning / end of the winding - we will determine this experimentally when connecting the engine.

In principle, you can also connect a motor that has 6 terminals - the main thing is to correctly determine where which windings are, after which there will simply be 2 unnecessary wires that can be simply cut off.

In this case, the "yellow" and "white" wires will remain unconnected.

You can pick up a lot of useful things from old printers, but the engines there are very weak, especially in new inkjets, therefore they are suitable for use only with gearboxes with a very large gear ratio. Here is an example of such engines:

Of all this variety, only Epson EM-257 will go for use as a filament drive - it just has the required number of pins (4), as well as a more or less good torque on the shaft. Here are some more similar engines:

They are, of course, rather weak for our purpose, and, ideally, it is better to use the analogue of Nema17 (the one used in the original reprap), but they can be bought for a penny on any radio market or picked out from old iron. By the way - do not take Soviet DSHI-200 as a basis for the extruder, which are very popular among machine tool builders, because they are too heavy to be pulled as a print head.

Of those available in Russia, one can single out the site of the Elektroprivod store, which sells an analogue of Nema17 - FL42STH. I chose FL42STH47-1684A motors for the printer, which are great not only for the extruder, but also for driving all axes.

Now we need a reducer.

It is clear that the smaller its dimensions, the better for us - the total mass of the print head will be less, and accordingly the positioning speed (as well as the printing speed in general) will be higher.

Initially, it was planned to use a stepper motor with an industrial planetary gearbox, like this:

But finding it in Russia at a normal price is simply unrealistic, and in China they are not sold at all for affordable means, therefore, as always, everything is done on our own.

For myself, I determined (in the end) the ideal option - a planetary gearbox pulled out of an old screwdriver, converted for use with a stepper motor.

The donor looks something like the photo. And in disassembled form something like:

The photo is not mine, but in principle these planetary gearboxes do not differ much from each other. Therefore, we are looking for a dead screwdriver and forward - to disassemble.

As before, we will need an intelligent turner to help fit the drive gear from the original screwdriver engine onto our stepper. It will also be necessary to grind the housing cover for the output shaft bearing. I will post photos of my version later (I will have to disassemble the finished extruder). It is possible, in principle, to make a drawing of the lid, which was carved from aluminum, although the turner usually only needs a simple explanation "on the fingers" of what exactly we want to get from him.

It seems like it's time to take the camera in hand and start a detailed photo session of all the intricacies of the process, otherwise the Internet runs out of pictures that ideally fit my description.

Printing on a modern 3D printer is carried out using plastic filament obtained from various materials. High-quality 3D printer filament is created from consumables such as ABS, PLA, HIPS. The use of high-quality raw materials allows manufacturers to create materials that are unique in terms of operational and technical properties, on the basis of which a variety of things can be made.

Basic materials

The production of filament for a 3D printer is most often carried out on the basis of two materials - this is PLA (polylactide). Both materials meet the requirements of biodegradability, biocompatibility, thermoplasticity and are created on the basis of renewable resources, namely corn and sugarcane. The raw materials are ideal for the manufacture of a wide variety of products in the medical, food and other industries.

Filament for printing on a 3D printer must be of high quality in order for the final product to please with performance properties. Plastic filament for a 3D printer is a more convenient type of raw material for such equipment compared to granules, since it is easy to replace, it can be printed in several colors at once, and the material consumption is significantly lower.

Features of production

3D printing is very expensive due to the high cost of the consumables themselves. To reduce the cost of printing, craftsmen create portable devices for home use.

Thus, you can create a filament for a 3d printer with your own hands much cheaper. Technologically, this process is not too complicated, the main thing is to observe the temperature regime and certain proportions of the mixture. In the standard version, the production of yarn is carried out in several stages:

1. First, the initial mixture is prepared. To obtain a substance with the desired parameters, it is important to mix the main components in the right amount. The thread acquires a certain shade due to the addition of chemical. Precision of the proportions is a guarantee that the color of the thread and in the future the polymer itself will be resistant.
2. Loading into the bunker. After preparation, the mixture enters the dispensing tank, and then is fed into the extruder.
3. A homogeneous mass is being prepared. All components placed in the extruder are mixed to create a plastic mass.
4. A plastic filament for a 3d printer is being produced. A homogeneous mass is forced through a special nozzle using a screw. It has a certain diameter, which is equal to the thickness of the future thread.
5. The thread is cooled and dried. The viscous plastic, already in the form of threads, enters the bath with water, where they are cooled. They also gain flexibility. From the cooler, the finished filament is fed by means of special rollers into the dryer, where it dries up under the influence of hot air.

After drying, the filament for the 3D printer is wound on a spool. Due to its flexibility, strength, plasticity, it is ideal for use on all types of printers. The diameter of the thread is different - 1.75 mm or 3 mm, which varies depending on the nozzles used on the equipment. The use of different pigments allows you to achieve a variety of color solutions for the filament.

Filabot original

You can make filaments from plastic for a 3D printer, but for this you need to create your own extruder. We will tell you how to do this a little later. In addition, the easiest way is to purchase ready-made portable and mobile devices, for example, Filabot Original. This 3D printer filament making machine can make filament from plastic with a diameter of 1.75mm or 3mm. The equipment works with a wide variety of plastics - ABS, PLA and HIPS.

The device works with plastic granules, allowing you to keep the temperature under control. There is a filter to prevent the ingress of contaminants. The universal power is sufficient for home use. To obtain different colors of the thread, dyes are used. The choice of this equipment is supported by its high productivity: it takes about 5 hours to obtain one kilogram of yarn.

Filabot wee

The modern line for the production of filament for 3d printers is represented by the Filabot brand. Equipment with a wooden case is much cheaper, and you can buy it both ready-made and as a kit for assembling yourself. Like the device described above, this one works on the basis of popular types of plastics. A wide color palette is achieved using granular dyes. You can also add granular carbon fiber to the mix to increase the strength of the finished bar. The model is equipped with two replaceable nozzles, so you can produce filament for a 3D printer with a diameter of 1.075 or 3 mm.

Filastruder

In the 3D industry, the Filastruder extruder is known for its versatile assembly, so anyone can set up filament production at home. Thanks to its clever design and ease of use, the model is ideal for extrusion.

Having such a device at home, you can set up the creation of threads for 3d printers with your own hands. The only caveat is to correctly select the proportions of the components used, dyes. In just 12 hours of operation, the equipment is capable of producing 1 kg of filament, while the final productivity depends on such parameters as the diameter of the nozzle, the extrusion temperature, and the materials used.

Lyman Extruder

This device is unique in that it was one of the first to be used for the production of plastic rods. It is noteworthy that the design of the equipment won the main prize at the Desktop Factory Competition, which was held in 2013. Due to the extreme simplicity of the design, the equipment itself turned out to be the cheapest in comparison with other analogs. Another interesting fact is that all instructions are publicly available. You can download blueprints and create an extruder to make filament for your 3D printer at home.

About making homemade appliances

Very often, those who want to work with 3D printers begin to create devices for producing filament themselves in order to reduce their costs. In fact, such devices, with their economy and usefulness, are still not so good:

• the thread may turn out to be of low quality, insufficient or incorrect thickness, which will affect the deformation of the final product or even the impossibility of printing it;
• when heated, plastic can emit harmful substances that will have to breathe both during printing and during processing of raw materials;
• reprocessing of colored plastic will not be possible, since you will not be aware of the composition of the plastic and the dye.

It is difficult to create really high quality plastic on DIY extruders. Therefore, it is better to purchase portable equipment of proven brands.

How to get cheap filament

To produce 3D printer filament requires the use of off-the-shelf ABS plastic granules. But this is too expensive and costly, so at home you can create a material based on an ordinary plastic bottle. The essence of the event is simple:

• the PET bottle is crushed into flakes;
• the resulting mass is heated until it reaches the melting point;
• the thread of the required diameter is squeezed out through the hole of the extruder mechanism (the tip is responsible for it);
• the resulting filament is cooled under a stream of air and then wound on a drum.

In general, setting up production is not as difficult as it seems. It is more difficult to find quality materials to make filament strong, reliable, safe and suitable for 3D printing applications.

By the way, about In some countries there are outreach campaigns aimed at recycling plastic caps. Spanish scientists propose to create filaments from them for printing, since bottle caps are based on high-density thermoplastic polyethylene. PET-based 3D printing is a popular phenomenon that offers an inexpensive alternative to PLA or ABS. The only difficulty is that this process, with its economy, is too long, and you will have to work hard to create a thread in the right amount.

Any of the 3D printers has its own design features. The main thing in such devices is, it is also called a print head. The role of the head in the operation of the printer is extremely simple. Its role is in the extrusion of plastic through the nozzle, as a result of which a drawing is formed in three-dimensional format. A logical question arises: is it possible to do it yourself?

What are the features in these devices

During the operation of a printer using 3D technologies, as a rule, filamentary is used. There are different types, but for such printers they usually take PLA or ABS. But, a large selection of raw materials has little effect on the design of the print head, as a rule, they are made by different manufacturers in a similar type. Here is the extruder design for a modern 3d printer goes on sale:

1. Cool-end is a filament feeding unit. In its design, several gears and an electric motor are necessarily present. The filament is removed from the respective spool from the process of rotation of the gears, then it passes through a heating element, where the plastic is exposed to high temperature and becomes soft. This allows further this viscous plastic to be extruded by using a nozzle and to give it the desired shape.
2. Another hot-end block is a nozzle with its own heating element. In its manufacture, aluminum or brass alloys are used. This block has a very high thermal conductivity. The heating component has a built-in spiral wire, two resistors, and a thermocouple to adjust the heating temperature of the device. During operation, the hot-end heats up and thereby the plastic melts. A very important point in the operation of both units is the cooling of the working platforms. This is provided by a special heat-insulating insert between the blocks.

Is it possible to make a homemade extruder for a 3d printer

If you nevertheless decide to make your own extruder for a 3d printer, you need to choose an engine. But, here it is possible to use old motors from a printer or scanner (working, of course). If you are not sure which motor will work best with a homemade extruder for a 3d printer, a forum with experts in this field will help you figure it out. To fix the motor, you need a housing made of a suitable material, a hot-end, as well as a roller - its function of pressing. To make the body itself, different materials can be used, as well as its shape, you can make it at your discretion. It is imperative to use a spring to adjust the pressure roller, as the thickness of the rod does not necessarily match the requirements perfectly. The material must adhere to the feeding component. But it also cannot be made tight, since in this case plastic particles can break off during the printing process.

You can purchase a hot-end, although this is not the cheapest purchase, in this case, a home-made extruder for a 3D printer will be a good investment of money. Although you can find and study its drawings and do it yourself. So, radiators are created from an aluminum alloy, it is necessary to remove warm air from the barrel of the device. Then it will be easy to avoid excessive overheating of the device during printing. It is very practical to use an LED radiator, and use a fan for cooling. A hollow metal tube is used to create the barrel of the hot-end. It connects the radiator to the heating element.

For self-design of the heating element in the 3d-extruder, a plate of aluminum alloys is selected. Drill a hole in this plate to secure the hot end. After that, holes are drilled for the mounting bolts, resistor and thermistor. The resistor heats the plate, and the thermistor regulates this heating temperature. To create a nozzle, as a rule, a nut with a rounded end is used. The easiest way to process a nut is from a brass or copper alloy. The bolt is secured with a vice, then screw a nut onto it and drill a hole in the center. This is the way to create an extruder not too troublesome at home or in the field.

For some models of such printers, the equipment includes two extruders, which makes it possible to print an image in two colors or create structures from a soluble polymer. But, if you managed to make one extruder for a 3d printer with your own hands, then it will also be possible to make a double one.