Over the last week I have been playing around with a 10m sample of Sainsmart TPU.
If you don’t know what TPU is, its a flexible filament that is extremely strong when printed correctly. It is in the same area of filaments as NinjaFlex, SemiFlex ect. After hearing how easy it is you print. I had to get some to test.
The official description from Sainsmart is:
Thermoplastic polyurethane (TPU) is a high strength flexible filament. TPU is essentially polyurethane, it belongs to the TPE class of thermoplastics (similar to the stuff NinjaFlex is made of).
In addition to being stronger compared to other flexible materials on the market, we found TPU to be easier to print with, with great layer to layer bonding.
The shore hardness of our TPU is: 95A
TPU is resistant to oil, grease and abrasions and has many applications including; automotive, power tools, sporting goods, medical devices, drive belts, footwear, inflatable rafts, profile applications, etc. TPU is also a popular material found in outer cases of mobile electronic devices, such as mobile phones.
The TPU I recommend can be found: here
Its recommended printing temps are 200°C-220°C. So 99.9% of printers can happily print this all day and night. It is slightly more stiffer than NinjaFlex, so should work well for those of you with bowden setups.
Being a flexible filament, I started off using the standard rule of NinjaFlex which is very well documented – Print slow. I set up a new profile on Simplify3D with 30mm/s, hotend to 220°C and heated bed to 30°C.
This printed and the print was fine. But the finish wasn’t as expected. It was rough and matte. Which isn’t how proper TPU should be, it also popped alot while printing.
Over the next few hours I played around with the settings. Higher bed temps up to 60°C, hot end between 200°C and 230°C, print speeds – anything from 10mm/s to 60mm/s and fan on fan off. Nothing seems to make a change. I was getting close to thinking I had a dud sample. When I came across some info online.
The info was pretty much that the best hotend temperature they had found was 195°C. I dropped my hotend and it started to print perfect. Perfect black lines, perfect layers and the finish was shiney – as it should be! But that wasn’t the end of my problems – I forgot I had been testing printing at 60mm/s before. Which to my surprise this was printing perfect until I came to bridging a small section the extruder couldn’t keep up and started to have problems with the filament.
After starting again. I was left with the print below. Its almost prefect. I need to play with my retraction settings to get it 100% perfect.
In the end the settings I have settled on are:
Heated Bed: 60°C
Print Speed: 30mm/s
0.1mm addon retraction
Min layer time = 30secs