Soft Filaments

The amount of printable materials increases steadily. Especially soft filaments are very interesting, because one can print flexible parts with them. The generic term for this is TPE, thermoplastic elastomer.

To test the applicability of soft filaments on our machines, we started some test prints. The object we used was the cute octopus from makerbot respectively its sibling with a hat.

1. TPE94

TPE94 (we don't know any trade name) comes from one of our filament suppliers. One application of this material is the production of flippers. For test purposes a 3mm filament was produced for us. The name comes from its shore hardness.

The test print of TPE94 was revealing. Since we know from Soft-PLA that soft filaments tends to compress directly after the extruder so that its force cannot be transferred into the tip of the nozzle anymore, we reduced the print speed. At about 15mm/s, that is 25% of the usual print speed (of PLA or ABS), we didn't observe any clogging.

Furthermore it showed that this material has a comparatively high thermal capacity. Fresh printed layers stay warm and soft for a very long time. The result is that additional layers don't have a solid ground to base on which causes a wobbly object. Also an additional fan didn't help in the desired way. The solution was to add less material, that means thinner layers.

A clean print could be achieved with a 0.25mm J-Head hotend, 0.15mm layer thickness, 205°C and a print speed of 10mm/s:

TPE94-cute-octo1

TPE94-cute-octo2

2. TPE70

TPE70 (we don't know any trade name, too) comes from the same filament supplier. The material properties are excellent. With a shore hardness of 70 we are in the area of rubber. Applications are for example interdental sticks. 

Because of the flexibility of this material we also couldn't print it with high speed. Problems with heat dissipation have not been observed. That's why we could use our Beta-Head hotend. But the even softer consistency of this filament at the beginning often lead to the above described compression and resulted in a clogged nozzle. Good results could be achieved with 260°C. The surface of the printed objects was notably smooth. The elasticity is similar to the one of a rubber carnival mask.

TPE70-cute-octo1

 TPE70-cute-octo2

3. Layfomm 40

Layfomm 40 is an experimental filament of Kai Parthy. It is a two-compound thermoplast which consists of a soft foam and PVA (polyvinyl alcohol). PVA is used as addition agent which can be removed with water after the print. The residue is the soft foam, which couldn't be processed with conventional 3D printers.

Layfomm 40 is relatively hard in comparison to the above mentioned TPE, so it's not necessary to print it with reduced speed. The recommended print temperature is 225-240°C.

Test prints with Layfomm 40 showed amazing results. A fresh printed object is hard but slightly bendable. Unfortunately it tends to delaminate, that means that the single layers don't stick to each other very well. An increased print temperature of 255°C with reduced print speed to the half didn't show any improvement of the layer adhesion.

After rinsing with water over two days, where water was changed 2-3x per day, a soft foam remained. But after drying the object became harder - and shrinked! Probably the PVA was not completely removed.

layfomm40

The dried object was brittle. After compression and deformation tests it broke:

layfomm40-2

Summary:

Soft plastic materials provide completely new possibilities in 3D printing. With multi compound printers one can produce, in combination with other plastic materials, for example flexible connectors. Unfortunately not everybody will be able to print soft filament with his 3D printer. Especially for machines with bowden-system extruders compression and other deformations might cause clogging. This is why Kai Parthy developed the Porolay-series, which allows the processing of this materials in spite of their high elasticity.

Layfomm 40 is already available. TPE70 will be available very soon in our webshop. TPE94 was not really printable with our Beta-Head hotend. This is why we are still considering if we should add it to our assortment.

Greetings from the sunny lake constance

The 2PrintBeta - team

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Tour-de-BetaProtoMobile

The aim was to create a 3D printer which is designed to be mobile, not just an Ultimaker with batteries.
On the MakeMunich 2013 we showed that it is working and looking quite nice.



But walking a few steps on a faire is not a real mobile test.

I used the first sunny days this year to test my mobile 3D printer "BetaProtoMobile" in the streets of constance.
So I loaded the battery, copied a suitable gcode onto the SD-card and went shopping.



First I thought, the print will be very bad, because sometimes the printer was shaked pretty hard.
But the result was very good.



The next test was printing during a bus tour.
The streets are not the best, so it was shaked again for almost half an hour.
Again the result was perfect.



The end of the tour was the university of constance, where I visited some friends.
It was a real fun walking around with a mobile 3D printer.
Many people stopped and asked questions.

I made a short video about this tour which can be watched on youtube.

Greetings from the Lake Constance
BonsaiBrain


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