Cooling extremes. Not enough and the layer below flexes, accuracy in small detailed prints goes out the window. Too much and you might as well be picking powder off the print bed with the lack of adhesion.
Masses of cold air helped with the tiny Ultimaker robot test print, each layer taking seconds to print. It ruined the worm drive and gear printed with Simplify3D, each layer taking much longer to print. The worm looks ok, as soon as I tried to apply light pressure to remove support material it crumpled.
Knowing how cool the previous layer has got looks key to printing fast while maintaining the best possible quality and adhesion. Some may have constant airflow and want to add dynamic cooling delay, others may be able to increase airflow.
Maybe an IR camera is still the solution to the problem. If the print head is shielded from view one of the Panasonic GridEye AMG8832 8x8 pixels IR FPA (<$40!) might be our answer.
So does the gear print OK when you don’t overcool it? That should be one of the settings in your slicer. (I’ve also, especially with PLA, had to re-orient pieces with respect to the fan to get more uniform cooling.
Is this for a traversing mechanism for your re-spooling rig? If so:
This guy made a rolling ring drive that uses 623 bearings. It’s a home brewed version of something Uhing makes. Uhing’ line of rolling ring drives includes a version that reverses when a limit stop toggles a little lever on the unit. If you decide to try the “over engineered” route again, that might be interesting!
Thanks Frank, I don’t think it’s under extrusion. I was using Cura to try and slice/print the gear set having failed with Slic3r. Cura’s little robot was printing a number of times thanks to the issue of needing to close the Print dialogue box. The tiny details helped me realise there was a cooling issue, watching it up close I could see the PLA curling up rather than staying flat. There are no gaps from under extrusion in either print. But even with Cura the slicer doesn’t put enough support material down for the worm drive and the start of the object rocks back and forth under the print head so was aborted early (left of photo). With Simplify3D the solid top of the the gear is perfect. It’s sliced such that the gear teeth are almost an afterthought, tacked on, not an integral part. Possibly because I’ve asked for too many shells.
I had a problem on my mendelmax when printing PLA (large pieces), the PLA was curling like … , my heatbed was 60° C but when measuring I found the middle of the heatbed 60° but the outside of the bed was only 50 or less … So I isolated the heatbed and set the temperature to 70° … now It stays very flat … almost no curling. I print directly to the glassplate, no glue or blue tape … best results ever
