Flexible Filaments

Print flexible filament It's more complicated than working with rigid filaments. By their very nature, they present various problems when using them, especially if you don't have a 3D printer. prepared to work with them. However, with a good configuration of our 3D printer It is very easy to get great results with good printing speed.

In this section you will find everything you need to work with flexible filament in your 3D printer . If you notice anything missing, please don't hesitate to contact us.

First Steps

Extruder for flexible filament

The most important thing to print with flexible filament is to have a good extruder. Most commercial 3D printers already incorporate one extruder Compatible printers: For more information on compatible printers, visit the corresponding section in the section of this article for the material you want to print. If you have a RepRap printer and don't have a compatible extruder, there are several alternatives on the market, as well as many free-design extruders that you can use to improve your printer.

The key points to keep in mind when choosing an extruder are the following:

• Filament guidance

• Friction

• Filament traction

• Nozzle size

Filament guidance

Any minimal space between the flexible filament pusher system and the filament inlet to the hot-end can cause the filament start rolling into this gap.

To solve this, we need in our extruder this gap does not exist. The objective is that the filament go fully guided to the hot-end.

Commercial extruders prepared for printing with flexible materials won't present this problem. If you have a RepRap extruder, you have two options: either build a new one that's ready or print a wedge-shaped part that solves this problem. Although the best option is to upgrade our extruder .

Friction

Excessive friction of the filament with the elements of the extruder may cause problems in feeding material.

There are several things we can do to solve this problem. The first is to use direct extrusion systems. A Bowden system generates excessive friction between the filament and the guide tube.

We must also ensure that the distance between the pulleys and the hot-end is as small as possible.

Another very important aspect is working with hot-end barrels that incorporate a PTFE tube. The PTFE tube reduces friction and acts as a thermal insulator, preventing the filament from expanding before reaching the hot-end's heating zone.

Filament traction

Unlike with rigid filaments, achieving good traction with flexible material it's more complicated.

We must look for a extruder that allow us to adapt the pull exerted on the filament. The most commonly used system for this has always been a lever-like arm, pressing the filament with the force of a spring.

We now have more complex systems that offer better results . We also work with two toothed pulleys instead of one pulley and one bearing. If the filament slips on the bearing, we won't achieve optimal traction.

Nozzle size

The nozzle size is related to the quality of the printed parts. The smaller the size, the lower the layer height we can achieve and, therefore, the greater the definition of the part.

However, when dealing with flexible filament A nozzle size that is too small can cause excessive pressure inside the hot-end, which will result in an uneven output flow of material.

The printing speed that we can achieve with flexible material It is also directly related to the nozzle size. The best quality/speed ratio can be achieved using nozzles measuring 0.4 to 0.6 mm.

Once we have chosen the perfect extruder to work with flexible filament , let's see the first steps to start printing.

The first thing is, of course, loading the filament into our printer. To do this, the ideal is to work with an exclusive hot-end for flexible filament .

If this isn't the case, we'll first remove the old filament. It's advisable to extrude a little before removing the filament. This will remove impurities from the nozzle outlet and ensure the material flows properly.

Once removed, we will set our hot-end to the recommended temperature for working with each material (see corresponding section). Once the filament is inserted and we see that it comes out of the nozzle, it is advisable to extrude a little filament, especially if we are changing from a hard one like PLA or ABS.

And we're almost ready to print! Now, depending on which filament you're working with, you should visit its corresponding section for specific considerations.

Tips

To achieve perfect results, it is necessary to modify our printing profile depending on what we want to achieve.

Hanging parts

It is possible to print hanging parts with eFil, but for this, you'll need an extruder with a layer fan. Most extruders today have one.

By activating the layer fan when our 3D design has exposed parts, we will ensure that these solidify sooner and serve as support for the following layers.

Medium

Using support with eFil can be difficult to remove, as it will adhere too tightly to the part. Therefore, it is recommended that you add supports with minimal contact with the part when designing the part.

Troubleshooting

Threads

The appearance of threads on a piece may not be critical to the result of our printing but it can cause a poor finish.

The parameters directly related to these problems are retraction and printing temperature. Decreasing the printing temperature and increasing retraction should eliminate threading. We must be careful not to stray too far from the recommended parameters.

A very interesting option that almost all slicers include is the "Avoid crossing perimeters" option. This will force the machine not to cross the perimeters of the part while the head is moving. This will largely prevent the appearance of threads, although it can have a negative impact on printing time.

Adhesion to the printing surface

Typically, parts coming loose during printing isn't a problem with flexible filaments. In fact, we may encounter excessive adhesion that prevents us from detaching the parts once printed.

To help with the removal of the pieces we can use acetone or alcohol.

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