Heat is still causing me some grief! Since my last post about some of the parts of my MPCNC deforming due to heat, the rest of the parts have gone to hell too. Everything is loose/sloppy and many parts have cracked.
It has to be either heat, poor quality PLA (this is a definite possibility, more on this later), or my printer was not dialed in correctly (poor layer adhesion or something). Bottom line is I need to reprint everything.
Not all doom and gloom though. I looked at this set back as an excellent opportunity to experiment with printing different materials, and perhaps improve the stiffness of my machine. Win, win I think?
Now I mentioned before about poor quality PLA. The three spools of black PLA I bought specifically for printing the parts for the MPCNC were cheap, like really cheap. I didn’t know any better at the time, but I now understand that there is a HUGE difference between cheap/nasty china PLA and quality PLA, seriously…. chalk and cheese!
I initially didn’t know what to reprint in. Nylon? ABS (I HATE printing ABS), PETG looked good on paper, some PLA blends? Poly-carbonate? There is a lot of cool stuff out there if you go looking.
After a lot time on google I had it narrowed down to Taulman Alloy 910 (Nylon), Taulman Tech-G (PETG) or Polymaker Polymax (Some sort of PLA blend). I ordered a roll of each and got my print on.
I wont go into too much detail of each material (there is a wealth of info on all three products online) but I will say that all three printed beautifully! The Tech-G (PETG) in particular is an absolute joy to print! My new favorite filament!
PETG is immensely strong (no more cracking parts), has a much higher glass transition temp than PLA (no more deforming parts), has very low elongation under tension (this should help with rigidity) and its translucent, purely cosmetic I know, but being able to see the inner structure of your prints is hella cool!
I still have a lot of printing to go, but rest assured that I will update as the RE-build continues.
One quick note before I go. I was intrigued as to just how strong the PETG was compared to regular PLA. The first part I printed was a replacement mount for my makita router. Here is the part that failed in service, with the bolt only “nipped” up (just snug)
With the new PETG part in place I deliberately tried to over tighten the bolt to “stress test” the new part. This was the result of that experiment!
Yes the part deformed/streched, but it didn’t crack or break and while looking a little worse for wear, it is still perfectly serviceable. I’ve actually being using it to mill with for the last week!
Sorry for the long post. I’m not sure if anyone else has had issues with PLA parts deforming/stretching? Maybe it was just the el cheapo PLA. Who knows.