I am asked a lot about extruders, namely where to buy, how to do it yourself, and most importantly - which one is better. Therefore, I decided to convey to the readers the information on the topic of extruders that is relevant for 2015.

What is a 3D printer extruder

The extruder of a 3D printer is a device for dispensing, melting and extruding filament through a nozzle.

Today the most popular filament standard is 1.75 mm, and nozzles in home 3D printers are most often from 0.25 mm to 0.5 mm.
The extruder consists of 2 parts:
1. Mechanism for feeding (pushing) the filament
2. Print head (hot end)

We will not talk about the feed mechanism in this article - if there are those who wish, I will write a separate article. And our task now is to deal with the hotend.

As an example, I will consider the now popular hot-end from E3D (e3d-online.com)

Hot end device:

1. The barrel of the hotend. This part connects the radiator and the heating block, but the main thing is that plastic passes through and begins to melt inside the barrel. The most important point here is the narrow section in the middle of the trunk. This is a thermal barrier, it is necessary in order not to let the heat higher, that is, we make the plastic melt at a certain point and not earlier. If the plastic begins to melt earlier, then this will entail a large frictional force, because too much melt has to be moved. In addition, it is in this narrow zone that the so-called piston is formed - hard unmelted plastic tightly adheres to the walls of the barrel and pushes the melted down.
The barrel is made of stainless steel. it has low thermal conductivity.

2. Radiator. Serves to remove heat from the top of the barrel. Manufactured from aluminum.

3. Heating block. The main task is to distribute heat from the heater to the barrel and nozzle, in which the plastic melts. Manufactured from aluminum.

4. Heater. It is a heating element with a diameter of 6 mm, which is inserted into the heating block. A powerful 5 Ohm resistor was previously used as a heater, and now it is a ceramic heater in a metal sleeve. You can find one on Ebay for "12v Ceramic Cartridge Heater".

5. Nozzle. The diameters of nozzles can be from 0.2 to 1 mm, now the most common and practical nozzles are 0.4 mm, because they give a compromise between print speed and quality. Oplo is usually made of brass.

Which hotend to choose?

The choice is large enough and now more than 10 types of hot-end designs are available, so I will not describe all the variety and will limit myself to my recommendations.

J-head. Over the course of 3 years, I have tried many hot-ends like J-head - there were both original, several versions and many versions from Chinese manufacturers. Therefore, I can safely say that the J-head type design works well and, moreover, is compact. Refractory plastic is used as a thermal barrier, and there is a Teflon tube inside the hot-end, so it prints PLA with plastic without problems, unlike metal hot-ends, where PLA can get stuck if melted earlier than necessary.

E3Dv6. The proven hotends of this company are still gaining popularity. I see the reason for their success in the fact that they just laid out the drawings for open access and, in fact, made a good all-metal hot-end - it just works as it should.

Is it worth it to do it yourself

Having made a hot-end yourself, you can save quite a lot if you want to experiment with different nozzle diameters and if you need several hot-ends.

You can do just one lathe and a set of thin drills with which it is quite difficult to work (0.2-0.4mm). You just need to buy a heater and a thermistor. Therefore, let's think sensibly - if you are not a master of metal turning, then you have only one option - to buy a ready-made hot-end.

When choosing a hotend, you should not save money by buying an untested design, or at a strangely cheap price - after all, this is a working tool of the printer and the print quality depends on it.

Where to buy a hotend

A large selection can be found on ebay.com for "3d printer hot end", for example. And also in online stores selling spare parts for 3D printers. Make sure that the package includes a thermistor and heating element, otherwise you will have to look for them separately.

Each 3D printer has design features. The main role in any device is played by the 3d extruder, the second name of which is the print head. The essence of her work is simple: she squeezes out plastic through a special nozzle, due to which a three-dimensional pattern is formed.

Design features

The 3D printer works on the basis of several types of filamentous plastic, but most often ABS and PLA plastic are used. And despite the variety of consumables, all printheads are created according to the same principle and differ little from each other. 3d printer extruder device following:

• Cool-end block feeds filament. It includes gears and a drive from an electric motor, as well as a pressure mechanism. Under the influence of the rotation of the gear, the plastic thread is removed from the spool, passed into the heater, where, under the influence of high temperature, the plastic becomes viscous. This structure makes it possible to extrude the filament through the nozzle to give it the desired shape.
• Hot-end block is a nozzle with a heater. To create it, brass or aluminum are used, which are distinguished by high thermal conductivity. The heating element also includes a nichrome wire spiral, a pair of resistors, and thermocouples that regulate the temperature. During operation, the hot-end heats up, due to which the plastic melts. Timely cooling of the working platform plays an important role, which is provided by a special thermal insulating insert between the hot-end and cool-end.

A type of print head is a bowden extruder, which differs in that the hot-end and cool-end are spaced apart in terms of location: a heater with a nozzle is located on the industrial printing golprinter, while the feeder is located on the printer frame. The filament is fed through a long Teflon tube. Its main purpose is to protect the thread from possible bends so that it is fed into the hot-end with optimal speed and pressure. The good thing about the bowden extruder is that it makes the print head smaller and lighter, but on the other hand, the transfer of plastic to the nozzle is not as reliable.

How to choose an extruder?

An extruder for a 3d printer must be chosen correctly, taking into account several important points:

1. Material... modern printheads are equipped with cast elements or created on the basis of 3D printing. Of course, cast modifications are distinguished by their strength, which is especially important for areas that have a large load. On the other hand, 3D printed parts are much cheaper.
2. Filament feeding... The quality of this mechanism plays an important role as the filament must be fed to the heater continuously and accurately. This is the only way to ensure uninterrupted printing. Plastics can become entangled on their way to the nozzle, so choose printers with a high power electric motor to minimize entanglement.
3. Feed roller type... Very often, as a result of poor adhesion of the material to the feed roller, the thread begins to slip. Especially often such situations arise when using nylon filament on those devices where only ABS or PLA plastic can be used.
4. Nozzle size... The extruder can be equipped with nozzles of different diameters. An important role in the selection is played by the purpose of the products themselves. For example, if objects must be carefully and detailed traced, then the nozzle is chosen with a smaller diameter. The smaller the nozzle, the higher the likelihood of clogging, therefore better plastic extrusion is provided with a powerful electric motor.

How to do it yourself

To make an extruder for a 3D printer an extruder with your own hands, you will need to select a stepper motor. However, motors from old scanners or printers can also be used in this capacity. To mount the motor, you will need a housing, a pressure roller and a hot end. The body is made of different materials, and its design can be very different. The pinch roller must be spring-adjustable because the bar thickness is not always ideal. The material adheres to the feeder, but the adhesion should not be too strong, otherwise the pieces of plastic will break off.

You can buy a hot end (the purchase will cost about $ 100), or you can download blueprints and create it yourself. The radiator is made of aluminum and is needed in order to remove heat from the barrel of the hot-end. This will help prevent premature heating of the print media. A good solution is an LED heatsink, and cooling is done with a fan. The barrel of the hot end is created from a hollow metal tube that connects the radiator and heating element.

The thinnest part of the tube is a thermal barrier that prevents heat from entering the top of the extruder. The main thing in hot-end is to ensure that the filament does not melt ahead of time, which will lead to clogging of the nozzle.

The heating element in a 3d extruder is created by hand from an aluminum plate. A hole is drilled in it to attach the barrel of the hot-end, then more holes are drilled for the mounting bolt, resistors, and a thermistor. The plate is heated by a resistor, and the task of the thermistor is to regulate the operating temperature. The nozzle can be created from a blind nut with a rounded end. It is better if the nut is brass or copper - these metals are easy to process. A bolt is attached in a vice, then a nut is screwed onto it, and a hole is drilled in the center. Thus, it is easy to create an extruder at home.

Some printer models are equipped with dual extruders - this allows you to print two-color objects or create support structures from a soluble polymer. That is, two types of plastic can be used simultaneously on such a device. True, simultaneous printing is still impossible, so each extruder is activated when necessary.

Assembling a Mosaic printer from a set of parts from MakerGear is described in the article Assembling a 3D printer with your own hands. You probably noticed that there is a detailed discussion of the 3D printer device, but it is not a question of the print head. This is the topic of today's conversation.

We will look at the types of extruders and methods for manufacturing individual parts of this complex mechanism in order to understand how to make an extruder with our own hands (video about drilling a nozzle at the end of the article).

The print head of a 3-d printer pulls the plastic bar, heats it up, and pushes the hot mass out through the nozzles.

Wade extruder

The picture shows a simplified diagram of a Wade extruder. The device consists of two parts. At the top is the cold-end (cold end) - the mechanism that feeds the plastic, at the bottom - the hot-end (hot end), where the material is heated and squeezed out through the nozzle.

Bowden Extruder

There is another design of the device, where the cold and hot parts are divorced, and the plastic enters the hot-end through a Teflon tube. This model, where the cold end is rigidly fixed to the printer frame, is called the Bowden extruder.

Its undoubted advantages include the following:

• the material does not melt ahead of time and does not clog the mechanism;
• the print head is considerably lighter, which allows for faster printing.

However, there are also disadvantages. The filament of plastic at such a great distance can twist and even become entangled. The solution to this problem may be to increase the power of the koldand engine.

Cold end

E3D-v6 assembly

The filament rod is pushed downward by a gear driven by a gear motor. The feed wheel is rigidly attached to the motor shaft, while the pressure roller is not permanently fixed, but in a floating position and, thanks to a spring, can be moved. This design allows the plastic filament not to get stuck if the diameter of the bar deviates from the specified size in some areas.

Hot-end

The plastic enters the bottom of the extruder through a metal tube. It is here that the material heats up and flows out in liquid form through the nozzle. The heater is a nichrome wire spiral, or a plate and one or two resistors, the temperature is controlled by a sensor. The upper part of the mechanism should prevent early heating of the filament and not let heat go up. Heat-resistant plastic or a heat sink is used as insulation.

Feeder

First of all, you need to choose a stepper motor. It is best to buy an analogue of Nema17, but motors from old printers or scanners, which are sold very cheaply on radio markets, are also quite suitable. For our purpose, we need a bipolar motor with 4 leads. Actually, you can use a unipolar one, its circuit is shown in the figure. In this case, the yellow and white wires will simply remain unused, they can be cut off.

As a rule, the motors from the printers are weak, but the EM-257 (Epson), as in the picture below, with a torque on the shaft of 3.2 kg / cm, is quite suitable if you are going to use filament Ø 1.75 mm.

For a bar Ø 3 mm, or with a weaker motor, you will also need a gearbox. It can also be picked up from disassembled old tools, for example, a planetary gearbox from a screwdriver.

Alteration will be needed to fit the gear wheel of the screwdriver motor onto the shag, to align the axis of rotation of the motor with the gearbox. And the cover for the bearing of the output shaft also needs to be made. A gear is installed on the output axle, which will feed the plastic bar to the heating zone.

The extruder body is used to mount the motor, pinch roller and hot end. One of the options is shown in the figure, where a red filament rod is clearly visible through the transparent wall.

You can make a case from different materials, having come up with your own design, or, taking a ready-made kit as a sample, order printing on a 3-d printer.

The main thing is that the pressure roller is adjusted by a spring, since the thickness of the bar is not always ideal. The adhesion of the material to the feeder should not be too strong to avoid chipping off pieces of plastic, but sufficient to push the filament into the hot-end.

It should be noted that when printing with nylon, it is better to use a feed gear with sharp teeth, otherwise it simply will not be able to hook the bar and will slip.

All-metal hot end

E3D hotends are widespread and popular. You can buy it on ebay.com for $ 92 (without delivery) or download drawings that are freely available on the official website of the company (http://e3d-online.com/), which you can use to do it, saving a lot.

The radiator is made of aluminum and serves to remove heat from the hot end barrel and prevent premature heating of the print media. An LED radiator is quite suitable; to enhance the cooling effect, you can also direct a small fan at it.

The barrel of the hotend is a hollow metal tube connecting the radiator and heating element. Made of stainless steel due to its low thermal conductivity.

This is how the detail looks in section and its dimensions for a bar Ø 1.75 mm.

The thin part of the tube serves as a thermal barrier and prevents heat from spreading to the top of the extruder. It is important that the filament does not start to melt ahead of time, because in this case, the bar will have to push too much viscous mass. As a result, the frictional force increases and the tube and nozzle become clogged.

If you drilled the part yourself, you need to polish the barrel hole. For rough grinding, fine sandpaper "zero", fixed with tape on a drill of a smaller diameter, is suitable.

It is obligatory to finish polishing to a mirror shine (with thread and paste GOI No. 1), then it is useful to fry the hole with sunflower oil to reduce the friction force. To prevent the plastic from warming up too early, you can cover the bottom of the tube in the radiator with a thin layer of thermal paste.

Another possible problem is that molten plastic under the pressure of the incoming bar can seep up and cool in the cooling zone, causing the barrel to clog and stop printing. To combat this, you can use a Teflon insulating tube, which is inserted into the barrel of the hot end before the zone where the filament begins to warm up.

Heater

Heater plate

An aluminum plate is used as a heating element. If you have not been able to find a thick block that is suitable for the size, a 4 mm thick aluminum strip, which can be purchased at building materials stores, is quite suitable. In this case, the heating element will be in two parts. It is necessary to drill a central hole for the hotend barrel, and tighten the bolt to clamp the entire structure in a vice. Then drill the required number of holes for the constituent elements of the heater:

• mounting bolts,
• two resistors,
• thermistor.

A ceramic 12v heater or a 5 ohm resistor can be used to heat the plate. But for our unit, two 10 Ohm resistors are better suited, since they are much smaller in size, and connecting in parallel will just give the required resistance of 5-6 Ohms.

The temperature will be controlled by a 100 kΩ NTS thermistor, brand B57560G104F, with a maximum operating temperature of 300 ° C. Thermistors with a lower resistance cannot be used, they usually have a large error at high temperatures.

It is necessary to ensure a tight connection of the resistors with the plate, since the air gap inhibits heating. It is important to choose the right sealant here. It is best to use ceramic-polymer pastes (KPDT) with a working temperature of at least 250 ° C. For additional thermal insulation, it is good to wrap the entire hot-end with fiberglass.

Nozzle

A blind nut with a rounded end is ideal for making a nozzle. Better to take a part made of copper or brass, as these metals are relatively easy to process. It is necessary to fix a bolt in a vice, screw a nut onto it and drill a hole of the required diameter in the center of the rounding.

This can be done as follows: on a drill, clamped in a conventional drill, fix a collet chuck with a drill of the required diameter. An interesting construction turns out.

The most successful hole is considered to be 0.4 mm, since with a smaller diameter, the speed slows down, and with a larger one, the print quality suffers.

Here's another way to drill a nozzle (video in English).

As you can see, making an extruder for a 3-d printer with your own hands is quite difficult. But if you know that you will not be able to make some part on your own due to the lack of the necessary materials or tools, it is not necessary to purchase a complete set, you can buy any part of the extruder separately and continue working.

Enjoy printing.

Texas-based re: 3D is accepting pre-orders for next-generation large-format Gigabot FDM 3D printers and specialized extruders for printing granular plastics.

The small but successful Austin-based manufacturer goes on Kickstarter for the third time, having crowdfunded Gigabot 3D printer in 2013 and then Open Gigabot in 2015. As the name of the line suggests, the company specializes in large-format 3D printers.

The new device Gigabot X was no exception - in fact, a variant of the flagship Gigabot 3+, but with a new extruder. Currently, the company produces three versions of the third generation 3D printer, differing in the size of the construction area - 590x600x600 mm (Gigabot 3+), 590x760x600 mm (Gigabot 3+ XL) and 590x760x900 mm (Gigabot 3+ XLT).

Re: 3D engineers initially focused on creating systems for 3D printing with plastic waste, and not only for environmental reasons, but also for economy. The developers are gradually moving towards the goal, and the next stage is the transition to printing with granules, because the cost of filament in comparison with granular plastic of the same mass easily grows by an order of magnitude. In addition, granular plastic is available in a wider range than ready-made filaments.

The appearance of the first 3D printers contributed to the accelerated development of the IT segment. The uniqueness of the equipment, capable of reproducing structures in three-dimensional format, is the reason for its high cost.

Therefore, the emergence of home-made devices with similar functions did not come as a surprise. They are used in domestic conditions, and when working with them, consumables are required. More often it is referred to as filamentous plastic, for example, ABS or PLA. A person who wants to assemble a 3D printer or its separate part (extruder) with his own hands must have the necessary knowledge and experience. He must know about extruder calibration, Cool-end and Hot-end cooling.

What will be discussed:

Mechanical components

It is possible to purchase parts for assembly in a set, but those who are not looking for easy ways often decide to make their own. They will need:

• fasteners for forming the frame;
• working platform;
• device for heating and temperature control;
• metal guides;
• gears for electric drives;
• extruder.

The main difficulty in making a 3D printer is the correct configuration of the last three elements. Of great importance is the drive, which is installed to move the platform on one axis. The second becomes the key to moving the print head.

Self-assembly of the mechanical part is carried out using plywood sheets, screws of a suitable size and clamps that provide fixation. The photo shows a standard kit for making a 3D printer with two print heads.

Electrical components

The design feature is a filament extruder for a 3D printer. Thanks to him, the output of consumable material and the creation of the pattern directly occurs. More often they do not risk doing it on their own, but are purchased in specialized stores. The assembly begins with the preparation of the necessary parts.

Its functions include filament feeding (plastic filament). It consists of an electric motor, a bar and gears. The threads are wound on a spool provided for this.

Hot-end

It is a duo of nozzle and heating element. The filament passes through the latter and changes its state of aggregation, turning into a viscous mass, which is then squeezed out using a nozzle. The final stage is the layer-by-layer application of this composition.

The parts of this dual extruder 3d printer part are made from brass or aluminum alloys. Thanks to this, the heat is conducted quickly enough. The block consists of a wire coil, a thermocouple (it regulates the temperature) and two resistors. The elevator is cooled by a thermal insulating insert. It sits between Cool-end and Hot-end. This detail is shown in the photo.

Assembling the extruder

Do-it-yourself production of an extruder for a 3D printer is as follows.

The engine is selected

Most often, this part is replaced with a working motor from a printer or scanner; it can be purchased on the radio market.

If the motor for the extruder is too weak, an additional gearbox is required. A suitable replacement for the purchased part will be one that was previously part of the screwdriver. The extruder of the bar for a 3d printer will also need a reducer. The motor is connected due to the housing, the pressure roller and the hot-end, they must be positioned as in the photo.

Adjusting the pinch roller

A prerequisite is the thoughtful interaction of this element and the spring. The latter is installed due to possible shortcomings in the calculation of the parameters of the 3D printer bar.

Too strong adhesion of the filaments to the feed mechanism will cause particles of the consumable to separate.

Hot end creation

It is much easier to get it, most craftsmen do just that. For self-production, you will need drawings that can be downloaded from the Internet. An aluminum alloy is needed for the radiator.

This element removes warm air from the barrel of the device, which is a hollow tube. In its functions, the connection of the heating element and the radiator. This prevents the printer from overheating.

An LED radiator is considered a good option, while the device will be cooled using a fan. The barrel of a hot-end 3D printer is a metal hollow tube. When creating an extruder, you must take into account the melting time of the filaments. If they melt earlier than expected, the nozzle will clog.

Assembling the heating element

First of all, you need an aluminum plate. In it, moves are made to attach the thermistor, hot-end and resistor.

In a 3D printer, there may be more than one extruder, for example, as shown in the photo. This fact should be taken into account when creating a drawing of a device. The functionality of such equipment is an order of magnitude higher than that of standard equipment, for example, printing in two colors and manufacturing structures from soluble polymer materials.

The final stage of creating a 3D printer with your own hands includes calibrating the extruder, connecting the electronics, adjusting the printing process, and implementing the right software.

Bigrep One Printer Review

This model is characterized by the presence of two extruders, the presence of a heated working platform and impressive dimensions. Bigrep One (pictured) is designed for professionals who specialize in the production of quality 3D products.

Another plus of the Bigrep One 2 3D printer with two extruders is its cost. Against the background of prices for similar devices, it is more acceptable, therefore it is in great demand.

Celebrate the following benefits of the Bigrep One printer:

1. Working volume 1.3 m3.
2. Low cost of 3D models.
3. No need for tooling of finished products.
4. The ubiquity of use.
5. Economy and productivity.
6. 3D printing camera.
7. Comprehensive range of possible filaments (ABS and PLA filaments, nylon, flexible elastomers).

Bigrep One is a new generation of printers that are expanding the use of 3D technology.

Conclusion

The extruder is a significant part of a 3D printer. It affects the quality of finished items, the printing procedure itself. Malfunctions in it entail the loss of expensive plastic threads. Deficiencies in calculating the diameter of the rods, lack of calibration, incorrect positioning of the body axes lead to negative production results. An example in the photo.

Therefore, before you start assembling the printer, review the possible designs of this device, determine the exact parameters of the bar and the number of extruders (one, two or more).