I’ve started printing out my feeders (AS2) and I’m having a little trouble assembling them.
The design is clever and I am able to get the feeder moving with the servo motor. They almost work.
My problem is the pieces do not fit together well. The interferences are too tight. That is holes are too small for pins that are too big. I end up spending a lot of time cutting away and drilling plastic to make things fit. The feeder frame also doesn’t engage deeply with the printer rail block because it is slightly too big.
Is this normal?
Am I missing something on my print settings?
I am using a Prusa MK3s and a Creality Ender S3 V3. Default PLA settings in Cura. 200 C temperature, 60 C bed. 0.4mm nozzle, 0.2mm layer.
I’ve performed an xyz calibration cube and the printer is accurate.
Ok, I have made some changes to my slicer (cura) settings and I’ve improved the fits.
I selected “print thin walls” and it has printed the small air gap between the top spring on the feeder. Before the slicer was fusing the spring leaf to the body of the feeder. My fault.
second I’ve recalibrated my Z offset. This has tightened up my x y precision slightly and may help the interferences. The Z offset was set by feel but now I set it using test strips and a micrometer. It influes the x y runout. Mostly my fit issue was 1) the pawl gear wasn’t spinning freely on the shaft and 2) the feeder block wasn’t fully engaging with the feeder nose. 3) the nub on the feeder that engages with the aluminum extrusion slot was too big and wasn’t engaging in the slot.
I’m running a new print job to see if I can get closer dimensions with these new slicer settings.
Not sure anyone is reading this but I’ll still write it down for anyone having trouble printing feeders.
my printers needed adjusting and slicer settings modified to get the best possible prints for the feeders. The tolerances are actually quite tight. I had to drill out the ratcheting gear a touch to get it to fit. I also had to print the feeder at 99.8% scaling on my setup.
I had to slow the outer walls down. Slow to 30mm/s. The default slicer settings were 90mm/s and it was causing bulging issues which hurt dimensional accuracy. And as I said the fits are tight. Intentionally likely due to stabilizing the feeder on the rail.
lastly the t-nut quick release clamp didn’t print well on my cheap printers. The filament fused together and the inner hub wouldn’t rotate on the flip release lever. I went back to the old design for the mount A.
so things are working well. I will assemble a dozen feeders now that I have the printing sorted. Embarrassed to say I’m printing much better prints now. I had to squeeze out more precision from my machines than just printing Benchy.
the nub locking into the rail is still tight even at 99.8% scale. I need to take fifty micron or so off the surface with a file to get them to fit in the aluminum channel.
Print consistency is indeed a rather complex issue, involving not only the performance of the 3D printer but also the type of material used, print temperature settings, cooling configurations, and even the ambient room temperature.
For reference, I have been using the Bambulab A1/P1S printer as my default for printing. With the default 0.4mm nozzle, 0.2mm layer height, and standard print speed, it consistently produces very stable print results.
The design itself already accounts for some assembly tolerances, typically around 0.2mm. If the printed result is unsatisfactory, some post-processing may be required.
Depending on the material and the ambient temperature, it may be necessary to fine-tune the printing temperature and enhance cooling capabilities (insufficient cooling can result in poor print detail).
So yes, this is primarily a matter of adjusting 3D printing parameters. Generally, most parts are easier to print using PLA, and with good cooling, they can achieve excellent detail.
Leo I have it working thanks. I needed the adjustments I mentioned. My printers are likely inferior to a Bambu Labs. But I’ve been able to adjust the printer speeds for inner and outer walls and it has made a dramatic improvement in dimensional accuracy.
I’m very impressed with your design. You’ve made some clever design decisions to avoid overhang. The cam quick release does not work on my print because the gap fuses too much. Again this could be my settings. I am using the older mount A and it securely holds the feeder.
I haven’t placed a board yet but up to now I am amazed how you’ve offered such a complete package at this price point.
I’ll be in touch as I get further along with manufacturing my PCBA.