3D print hotend

Fortunately, all popular slicers can analyze 3D models and place supports automatically. A detailed list and descriptions of the most popular slicers are available in the article at this link.

Preparing the FDM 3D Printer

Loading Filament . Consumables for FDM 3D printers are round bars of plastic called filaments. The filaments are wound on spools or supplied in coils. Coils are cheaper, but they need to be rewound onto spools by hand or the plastic can get tangled up during 3D printing.

The filament must be fed into the extruder before printing can begin. To do this, the hotend must be heated to a temperature depending on the selected plastic. This information can be found on the packaging.

The filament is then inserted into the feeder, which feeds the filament into the hot end. If the automatic loading function is not provided, the filament can be threaded manually: to do this, you need to depress the drive gears of the feeder and gradually push the bar into the hot end until molten plastic flows from the nozzle.

Platform adjustment . Calibration of the 3D printer is very important, as the successful laying of the first layer depends on it. Before starting 3D printing, you need to make sure that the platform sits level. Many modern 3D printers are able to perform calibration automatically using built-in sensors, such as BL Touch. Otherwise, the platform must be manually leveled: for this, special adjustment screws must be provided under the platform.

The correct zero on the Z axis is the key to a successful start of printing

At the same time, do not forget to correctly set the zero on the Z axis, that is, the distance between the nozzle and the platform at the very beginning of 3D printing. If the distance is too low, then there will be problems with the supply of the melt, and if it is too high, then the plastic will not set to the surface of the stage.

Consumables

As we have already mentioned, FDM 3D printers are loaded with spools of filaments. The most common bar diameter is 1.75 mm, but there are also printers that work with filaments with a diameter of 2.85 mm. This point must be taken into account when buying plastic for 3D printing. The mass of the coils can be different - from 500 g to 3 kg and even higher. Pay attention to the recommendations of the manufacturer of your 3D printer and the design of the system itself: in some 3D printers, the spool mounts are located inside the working chambers or special compartments, so a spool that is too large may not fit.

Compatibility of 3D printers with different materials depends on the maximum extrusion temperature, nozzle material, the need for a heated stage and the use of a heat chamber. For example, to work with polysulfone, you will need an extruder with a hot end temperature of 350-380 ° C, and if you are going to work with abrasive materials, such as composites of the X-Line, Clotho and Technika lines, the brass nozzle should be replaced with a more wear-resistant one, such as steel. Key parameters are always indicated on the packaging and in product descriptions.

Some examples of 3D printing plastics:

Polylactide (PLA, PLA), acrylonitrile butadiene styrene (ABS, ABS) and polyethylene terephthalate glycol (PETG, Relax) are the most common and inexpensive polymers with different properties, well suited for most applications .

Thermoplastic polyurethane (TPU, Easy Flex), styreneethylenebutylene styrene (SEBS, Rubber), and thermoplastic polyester elastomer (TPEE, Flex) are flexible, elastic polymers that replace rubber and silicone. They require special working conditions, a detailed guide is available at this link.

FormaX, GF Max, UltraX, Clotho and rPETG GF are carbon and glass reinforced composites with increased strength and wear resistance.

Polyetheretherketone (PEEK) and polysulfone (PSU) are refractory engineering thermoplastics that can replace metals in some applications.

A complete list of consumables is available in our catalog.

Post-processing

Post-processing is the last production step. Depending on the geometry of the product, the material used and the task at hand, this may include:

Remove supports . Support structures are often essential and need to be removed once the 3D printing is complete. This should be done carefully so as not to damage the product itself. If you have a 3D printer with at least two extruders on hand, the supports can be printed with soluble materials, such as water-soluble polyvinyl alcohol (PVA). This is somewhat more expensive, but greatly simplifies the procedure and improves the final quality.

Sanding . The visibility of the layers depends on the diameter of the nozzle, but ribbing in general cannot be avoided - this is the specificity of the layer-by-layer 3D printing technology. When working with hard plastics, the surfaces can be sanded to the desired smoothness.

Painting . Items can be printed in different colors using multiple extruders or manually changing the filament, but this approach is limited. Fortunately, most polymers lend themselves well to being primed and then painted.

Polishing and smoothing . Perfectly smooth, glossy surfaces can be achieved in two ways: either by polishing after sanding, or by chemical treatment. In the latter case, a suitable solvent will be required for surface treatment. Which one depends on the polymer. For example, acetone is good for ABS, but not effective for PLA.

Bonding and welding . Connections are necessary in cases where the products simply do not fit into the working area of ​​the 3D printer. Many polymers can be bonded, but in some cases welding may be required, such as with a hot air gun.

Read more about post-processing in the article at this link.

Common problems

Web (left) and twist (right)

Curl . This usually occurs when the material to be laid cools, contracts and simultaneously pulls previously laid layers towards itself, causing them to break away from the table at the corners and edges.

Web . Thin threads of plastic between different parts of the model, appearing when the head is idle, may be the result of incorrect temperature, speed and retract settings. Some materials, such as PETG, are particularly prone to web formation due to their high fluidity.

Clogged nozzle . One of the most annoying faults that has ruined many models in the history of FDM 3D printing. Signs of a clogged nozzle are feed mechanism clicks and no melt flow from the nozzle. The reasons may be different: defective filament, incorrect temperature settings, inefficient cooling of the thermal barrier, and others.

Layer offset . Ripples or the so-called "ringing" on the walls of products most often indicates play or curvature of the shafts along the Z axis.

Under extrusion . Efficient material feeding problems can cause gaps in layers.

Overextrusion . The opposite is true here: Applying the melt too quickly leads to sagging.

A guide to troubleshooting the most common problems is available at this link, at the same time we suggest that you familiarize yourself with separate articles on cleaning nozzles and combating deformations.

Maintenance of the 3D printer

To keep the 3D printer in good condition, the following operations should be carried out regularly:

Cleaning the stage Before starting 3D printing, it never hurts to clean the stage with a cloth soaked in isopropyl alcohol and apply a fresh coat of glue, varnish or other adhesive if necessary. Read more about adhesion here.

Nozzle cleaning . Corks and carbon deposits are easier to prevent than to remove, so be sure to wipe the nozzle clean immediately after or at least before starting 3D printing.

Waste collection . During hot end warming up, 3D printers often "snot" - they squeeze out a small amount of melt before starting to build a model. Such "snot" should be promptly removed so that they do not interfere on the table and inadvertently do not fall into the moving mechanisms.

Consumable storage

Proper storage of filaments is a separate and very important aspect. First, many plastics age when exposed to ultraviolet light, so it is advisable to store the filaments in a dark place or opaque containers. Secondly, dust deposited on the bar can contribute to the formation of plugs in the nozzles. Thirdly, some plastics are very hygroscopic, that is, they easily absorb moisture, and this can lead to the formation of all kinds of defects.

The best option is to always store unused filaments away from sunlight in airtight bags or containers with silica gel sachets inside. The storage and drying of filaments are described in more detail in separate articles - here and here.

3D Printer Extruder - Complete Manual Heatle

Learn the basics of direct drive and Bowden extruders, hot and cold ends, nozzle sizes and materials, and find the best 3D printer cartridge for your needs.

The 3D printing process can be briefly described as follows: a filament of plastic material is fed into a heated metal block with a nozzle, where it is melted and extruded in a given form. This path is repeated, gradually building up until a solid three-dimensional object is formed.

The entire business task of handling the material, melting it and exiting for printing takes place in a block called extruder 3d printer .

In this article, we will look at the main sections of the 3D printer extruder, the options and advantages of different styles of extruders, popular models on the market, as well as cartridge heaters for 3D printers and other items.

What is an extruder

The 3D Printer Extruder is a set of parts that together process and move a plastic filament.

Some consider the extruder to be just the motor and associated parts that push and pull the filament, others the entire assembly including the heated part that melts and deposits the filament.

For simplicity, this article treats the entire assembly as an extruder. To begin with, while explaining the key components of a 3D printer extruder, we will divide it into two elements: a cold zone and a hot zone.

Cold zone

As the name implies, the cold zone is exactly that - cold. It's The top part of the 3D printer's extruder system, into which the filament is fed and then passed into the hot zone to be melted and extruded onto the print bed.

The appearance and location of the cold zone on your 3D printer depends on whether it is a direct drive or Bowden drive extruder (both of which are detailed below).

There is no filament heating here. The cold zone consists of the extruder motor and gear train, which are usually mounted either on the printer frame or on the print head itself, depending on the type of extruder, and a PTFE tube to smoothly guide the filament into the hot end.

What happens in the cold zone?

With the heatsink removed, on this e3D Titan Aero we can see the inner workings of the 3D printer's extruder.

Essentially, the cold zone consists of a stepper motor, some form of gear, a toothed bolt or gear, a spring-loaded idler (usually a bearing of some kind) to hold the filament, and then a PTFE tube to guide the filament.

A humble stepper motor with a metal gear required for a 3D printer's extruder drives the filament extrusion in most if not all modern desktop 3D printers.

However, one stepper motor is not enough to feed the filament to the hot end. The parts attached to and operating the stepper motor drive shaft must physically grab the filament and push it on its way to the hot end.

In this cutaway view of a 3D printer extruder, we see a metal gear and a plastic gear with a toothed shaft.

This usually uses a combination of toothed gears and toothed bolts or shafts (in the image above we see a metal gear and a plastic gear with a toothed shaft) serving as a pressure wheel along with a bearing or other rigid frictionless material.

Here we see a plastic lever with an integrated bearing, an extension spring and a plastic gear with a toothed shaft. Together they apply pressure to the filament and force it through the extruder.

Alternatively, there are versions of the cold end of the 3D printer extruder that use a slightly different arrangement of parts to feed the filament. Such deviations are often claimed to provide increased traction and yarn delivery.

Here we see both sides of the Prusa i3 Mk3 cold end, including the Bondtech extruder gear.

As mentioned, there are varieties of 3D printer extruders that use these parts in slightly different layouts. Each has its pros and cons. Next, we will look at what is the difference between a direct drive 3D printer extruder and a Bowden 3D printer.

Direct drive extruders

The Direct Drive 3D Printer Extruder is different in that it places the extruder motor directly above the heating unit. This arrangement minimizes the travel distance of the filament to the hot end and can enable more reliable 3D printing of flexible filaments.

The advantage of using direct drive is more precise retraction control. Due to the location directly above the hot end, there is less distance between the clamp and the thread passing through the thermal barrier into the heating block. Consequently, the filament has less room to bend and deform under pressure.

Bowden extruders

Bowden Style 3D Printer Extruder The does not mount directly on the top of the hotend like a direct drive 3D printer extruder, but the motor and gear assembly mounts on the frame of the printer. This gives this type of extruder an advantage over its head-mounted direct drive brother: speed.

By placing the mass of the 3D printer's extruder on the frame instead, the printhead is freed up to print at higher speeds without sacrificing print quality.

A side effect of placing the 3D printer's extruder this way is that the filament now has to travel a long way in a tube that's a fraction wider than it is. There should be enough room along the entire length of the tube for a slight bend in the thread. When pulling in the thread between strokes, this slack in the thread shortens the pull-in distance. Without correction (i.e., an increase in retraction), this results in a delay in relieving the pressure exerted on the hot end. In short, you can get confused if you don't change your retract settings.

Heating block (Hotend)

Inside the knot, known as the hot end, the filament passes into a heated chamber where it changes from solid to liquid. Sounds simple, and mostly it is. Although there is a lot more to make the filament silky extrude onto the build plate.

What happens in the heating zone?

The E3D Titan Aero combines a heating block and an extruder in one compact unit. The hot end usually only has the central parts of this image: the heatsink (and fan), the heating element (micro cartridge heater), the heater block, the thermistor, and the nozzle.

A typical 3D printer hot end consists of a specific sequence of parts. There is a slight difference depending on whether you are using PTFE/PEEK or a full metal hot end. Here we explain the all-metal hot block.

First, it is a filament supply tube. In both a Bowden 3D printer extruder and a direct drive extruder, it will just be a PTFE tube coming from your cold filament feeder.

You can sometimes find direct drive 3D printer extruders where the filament runs straight into the print head.

On a Bowden 3D printer's extruder, this feed tube inserts the filament directly into the thermal barrier via a heatsink. The thermal barrier that is screwed into the heatsink is often a threaded stainless steel (or other non-conductive metal such as titanium) tube.

Split in two (note the two separate threads in the image below - longer for the heatsink, shorter for the heater block) and machined on the inside, the thermal break allows the filament to pass freely into the extrusion nozzle.

Clockwise from bottom left: steel thermal barrier, aluminum heating block and brass nozzle.

But since we're dealing with precision and a material that liquefies for rapid recooling, the 's temperature management is critical. The thermal barrier, in combination with the heat sink, maintains a certain limit at which the filament is exposed to high temperatures.