I just recently finished my build, and after running a LOT of sharpie drawings, I was confident enough to put the DW660 on the end instead and start cutting wood. I ran two cuts last night. One at the speeds provided in the ESTLCAM walkthrough provided on this site, and the other by dialing the speed back to 35% using the feed rate control in Repetier. On the first cut, the cut made it a few letters in and dove deep into the wood. It maintained the same depth once it plunged. I stopped it and looked over my z-axis thoroughly. No slipping. I then left the tool off, kept it well above the table, and watched the entire print. It didn’t once plunge like it did previously. The last print, at 35% feed rate, made it all the way to the very end, and I finally saw what was happening. The CNC was making some small circles and attempted to immediately retract when finished. It got stuck on the side wall of the wood (I assume from not being done cutting yet and trying to retract) which caused the Z motor to skip almost the entire 5mm retract. Thats where it plunged deep into the wood when it made the 5mm step back down. I think a few other people have had this issue too, but I haven’t really seen a fix.
My initial thought was I wish I could use the “dwell” feature in Gcode to tell the machine to wait X seconds before and after every z movement. This would allow the bit to finish a good clean cut rather than still having pressure on the side wall during the retract. Does that sound reasonable to anyone else? Or is there a better suggestion for a solution? I don’t think it’s possible to have ESTLCAM add these waits in, but I may just write a program to run the gcode through that will add the waits before and after each Z. I appreciate any feedback!
EDIT: realized I had a video of the first run through (regular speeds set in the ESTLCAM walkthrough). After watching this, I’m not sure if waiting before retract would’ve helped for this one. It looks like it just completely skips the retract, even though its in a wide open, precut area, and cuts through the material on its way to make the next letter. Then it gets there, and plunges another 5mm (right at the end of the video, when I frantically dash for the “Kill Job” button.) I used the same Gcode for both runs, and it didn’t plunge at this spot the next go round, so I’m 110% sure its not a gcode issue. Any thoughts?