Material selection
Opened this issue · 6 comments
Printing hotend parts out of RYNO is not a good idea. RYNO gets soft at 70C the hotend gets close to the build plate for extended periods especially on the first couple of layers and for extended time periods if the part is large. Bed can be 100 C (or slightly more) so heat from bed will deform RYNO part (hotend front part and fan shroud.
The glass transition temperature for PETG's is close to 88C. I'm pretty sure heat dissipates exponentially over distance through air, so your 3D printer's hotend parts will remain quite safe from bed temps even at 100C. Pulses and other printers with printed parts can be placed inside enclosures, and the parts do not deform even at very warm temps for long periods of time. Proof of this can be found on the Pulse heated bed wire cover, which is mounted very close to the heated portion of the bed, but never suffers from deformation.
However there is a danger of mounting a hotend directly to a printed part. The danger being is if your hotend fan shuts down, and the printer's hotend is left hot the mount can deform as the very conductive aluminum heat sink transfers heat up, and into the printed mount. That is the only danger of using a printed part for hotend components.
I could dig up some pictures of deformed fan shrouds - but its mute I printed it from HIPS and that solved that problem currently rebuilding it and fixing a lot of problems with the pulse. That was one printer that did not live up to expectations.
The Pulse fan shrouds are printed in NylonX, which has a better chance of resisting deformation. I've never seen an issue with my fan shroud deforming. HIPS also has a glass transition temp of 88C, so it has the same chance of deforming as RYNO which is a blend of PETG.
Look the glass transition temp. means very little as to structural integrity. Nylon and with that Nylonx has a glass transition temperature of 70 C BUT nylon will still maintain almost all of its structural integrity up to 170C no take PLA which will deform in a hot car but if you anneal it it can withstand 150C and I have tested that. Now just take a toaster oven and print a stick of RYNO and some HIPS and some Nylon and heat it and see which deforms first. We have boiled HIPS parts and they were stiff while being boiled. Yes the glass transition point describes a temperature when polymers start to behave differently but it does not mean that that one for a particular task behaves differently. According to your logic then Nylon(x) would be a worse choice than PETG for a heat shroud and we both know that this is not so. Now Ryno was the material of choice for the 3DP parts of the Pulse when I bought it and it gets softer and looses mechanical integrity before most other PETGs. You are entitled to your opinion, I saw it happen. Matterhackers sent me another fan shroud it happened again - quickly (within less than 1 kg - then I printed it in HIPS and it stopped happening for probably printing something like 20 more kg of HIPS and ABS with the bed at 100C. So for your own benefit I suggest you do the oven test. I did - printed sticks, supported them on both ends and put a 5/16 nut on it in the center and then turned the temp up and noted the temp at which it failed side by side
Interesting findings! I'll have to try out some thermal tests. I can say though that I personally haven't had issues with deformed RYNO. Although I don't think its the heated bed causing the deformation of the fan shroud you experienced, I'd bet its the hotend doing that to you.
Could be but then it was fixed and yes i did run the pulse with a .8 and lots of Nylons, HIPS and ABS and the Hotend between 255 and 275 and I never made it to 2 weeks before something needed fixing and yes I was using the pulse 24/7 at times I ran 1kg/day through it. Now I got a Chiron and I just got a predator monday - to early to say on the preditor but the Chiron has failed 2x in the past 5 monts - both a broken wire and I ran over 80kg of filament through it so far and now this one and the robotics clubs one and the predator are runing 24/7 to print PPE stuff for the epidemic the chirons with a .8 nozzle pumping through close to a kg of hips a day. And the pulse... well its being rebuilt probably will post some pics in the MH community when its done Gets a proper powersupply and some wiring fixes and an enclosure etc maybe finally make it do all the things I was told it would