Fail Of The Week: How Not To Build A Filament Extruder

Fail Of The Week: How Not To Construct A Filament Extruder

It would be great if you could make your own filament. At first glance it seems simple, but as a [Thomas Sanladerer] When he found out he was a student there were a lot of details that can interfere with your design. His extruder is working, but he wouldn’t suggest redoubling your efforts. In fact, he hopes that if you try to do it yourself, you can learn what not to do.

In all fairness [Thomas] was a low budget student trying to save. For example, he tried to drive the auger with a drill. Why not? It looks like a drill. But he found that was unsatisfactory and switched to a pair of wiper motors with a built-in gear train.

The wiper motors allowed him to get some ABS filament, but the machine had more problems. Further findings were to keep the water cooling tank closed so that water does not splash on the electronics and it is difficult to view the filament with a CCD sensor.

The controller is a simple Arduino. There are three heat zones before the plastic reaches the die. As you would expect, there is a PID controller to control the machine.

[Thomas] says the flow rate was too high so slowing production may have helped. A smaller snail is also on his list of things that he would do differently in retrospect. The melting area needed a thermal break, much like the hot end on a 3D printer, to keep hot plastic from creeping up and plugging towards the cooler part of the pipe.

With his current experience and a larger budget, we have no doubt that he could have a working extruder. As it is, we always like to learn from other people’s sub-optimal builds. It is a little humbling to show you failed projects on the internet, but it is a valuable service indeed.

We want an extruder that can recycle our garbage parts. We’ve seen some really cheap builds, but we don’t really know how well they work.

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Various examples of items printed with programmable filament technology

New filament tech lets common 3D printers construct multi-material gadgets

Usually when using a commercial 3D printer it is quite difficult to print a single object that contains multiple materials. However, an experimental new system could make it easier by using a “programmable filament”.

Most consumer 3D printers create objects using a process called fused deposition modeling. To do this, they are loaded with a spool of polymer filament, which they then heat to the melting point and then extrude from their pressure nozzle. In this way they build objects, one horizontal layer at a time.

Typically, when you want to 3D print an object that contains multiple types of polymers (such as those with different colors) you will have to switch the various polymer filament spools in and out of the printer as the different parts of the object will be printed.

This can potentially get very fiddly. For example, if you were to print a vase with different colored vertical stripes on the sides, you would have to switch between filaments on each printed layer. This is where the programmable filament system comes into play.

Various examples of items printed with programmable filament technology

Haruki Takahashi

First, the computer model of the object to be printed is analyzed and it is determined which parts of this object are printed from which polymers in which order. The existing 3D printer is then used to create a custom spool of filament, the various sections of which are made from the various polymers.

This coil is printed as a flat horizontal spiral. To begin with, all of the sections that need to be made from the first type of polymer are printed with gaps in between for the other polymers to enter. The one or more other polymers are then deposited in these gaps, the connections between the various filament sections being interconnected.

While the process still requires the user to manually change the various source coils, this only needs to be done once for each type of polymer used.

Once the resulting multipolymer composite coil is loaded into the printer, the object can be printed all at once. At those points in the building process where changes between the polymer types must occur, the extruded “programmed” filament changes accordingly.

The system is being developed in collaboration with scientists from Meiji University (Japan), Osaka University and Texas A&M University. It is demonstrated in the video below.

An article on the research was recently presented via the online ACM-UIST conference.

Source: Haruki Takahashi (YouTube) via IEEE Spectrum

Programmable filament – UIST2020 (long version)