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Alchement TPU Filament

Posted by Dennis

20160221_184343I delved into my first TPU filament.  There weren't a lot of options on Amazon, indeed there was a dearth of filament choices as all were unavailable.   But I found a vendor that had some in stock through Amazon and the handful of reviews were good. The only moderate review was from someone trying to feed it through a bowden tube and honestly why would you downrate a product for that?   It's like giving a gasoline car a bad rating because you tried to run diesel through it.

Anyway I got my filament, a nice red although the reds always seem to be slightly orange hued to me and this was no different.  It was packaged in a plain box, no fancy (i.e. costly) color printed box or labels.   It was well sealed in plastic with a silica gel packaged inside.20160222_100256

I was a little apprehensive about trying it since I'd read bad things about flexible filaments, they drip, they ooze, don't retract, retract more, and the postings had people printing this particular brand all over the place from 200 to 240C.

But I created a new profile for TPU based on my PLA profile. I increased my extruder to 225C as that seemed to be right in the middle of the manufacturer's recommendation.   I left my bed at 60C.  I turned the print speed down to 25mm/s.  Retraction I left alone at 1.35mm which has worked for me in both PLA and PETG.20160221_184321

I printed a calibration cube first just to see what would happen.   it came out great although a little undersized.  19.57mm x 19.78 mm.   With PLA my MendleMax 3 will print somewhere between .05 and .1 mm off 20mm.20160222_093223

It worked so well I then looked to see how it would do on overhangs and with oozing between pin towers.   It worked extremely well as you can see.  Interestingly the most whiskering I got was after it was done with the overhang piece and still printing the pins.   Up to that point the pins were very good and then immediately after the overhang piece was finished they started to get a little blobby and with whiskers.

20160222_093105It might be worth having a sacrifice piece if you're going to be printing some thin verticals to help wipe off the excess.

Still I was so happy with the quality of the print that I did a 3DBenchy test.  These images are it next to my first 3DBenchy in PLA which I believe I printed the same day I tightened the last bolt on the printer.

As you can see it's very good quality.  Note that both were printed at a .25 layer height.    In the pictures that show both boats the one on the left is the TPU one.

I'm going to print myself a watchband next.  I also have a kilo of Hatchbox TPU coming in that will be able to do a direct comparison between the two.






Posted by Dennis

So I just started my first roll of eSun's PETG and I must say I like it.  The only change in my settings that work great for PLA was to increase the temperature to 245C.    There may be other temps that work that was just the first one I tried and it worked fine.

My first 20mm calibration cube printed at 19.95mm x 20.75mm.   I could adjust it a little more by changing belt tightness but honestly my OCD isn't 'that' bad.   I really really like my MendelMax 3.   The output quality has been great out of the gate and I've had no issues with it whatsoever. I've gone through 4 and a half or so rolls of PLA and now working on the PETG.

Stanford-Easter-Bunny-Voronoi2_preview_featuredI then printed some overhang tests and those printed perfectly as well up to 60 degrees.  I haven't tried a bridge per se but I did print this bunny by Virtox and it printed great without any stringing between the openings.

In the interests of 'science' I crushed the little bunny and it took a surprising amount of force to crush such a flimsy looking print.  I didn't take a picture before I crushed it so I'm using an image from the thingiverse post.

The diameter of my spool of filament was right at 1.74mm with minimal change over a couple of meters.

I did have a minor clog in the extruder nozzle from switching over from PLA, probably a tiny whisker of PLA left and when I heated it up to 245 it turned into glass.  It wasn't a full clog, just enough to cause filament skipping on fast runs.  I pulled the PETG out and then used a trick I've come up with using a single thread from a piece of steel cable.   I don't have a drill that small obviously but that tiny thread of steel cable fits with only minimal space to spare and it worked pretty well to clean up the nozzle.

One thing I've noticed with PETG is that when doing an unclog procedure there's no stretch like you get with PLA and I'm sure it's leaving PETG in the nozzle.  It doesn't look at all like the end of a PLA unclog pull.   I was using 160C to do the unclog as a rough guess and there's almost no information online so I guess I guessed wrong.

But I got it cleaned up without have to disassemble my E3V6 head, which while it's an easy head to clean up, is still a bit of pain.

I've printed a couple of flashlight mounts, a skull to compare against the same skull I printed in PLA and it's all good.

I like it enough that I've ordered another couple of rolls in other colors from eSun and unless those just end up bad, I don't think I'll be going back to PLA any time soon.  Maybe for a super detailed print since PLA supposedly prints finer than PETG but I haven't tested that directly.

And in theory if you get the clear/natural 'color' you can print food grade (again in theory) objects.  I have no need to print something to eat or drink off/out of but there you go, it's possible if you need it.

One thing to note is that PETG prints fairly shiny and this exaggerates the layers of the print.  It's no different than painting any material with a glossy material. Not sure there's a 'fix' for that other than possibly spray painting it with a flat color.