So it took me a bit to realize the issue I was having and where it was coming from. I’ve been making jigs on my 5 pro 4x2 with VFD for my laser. They’re fairly good sized, usually about 12x18 inches give or take. But every time I would put it in the laser and line it up, my engraving wouldn’t line up exact. After multiple failures and redesigns of the files, thinking it was me messing up the alignments between the different software, I put the jig in the laser with a large square and it rocked back and forth in the corner, meaning the cutout of the jig from the CNC wasn’t square and that is what threw everything off. I had moved my machine so I went back to square one (pun not intended) and broke the bed down and squared the machine back up. It was off by about 3/16ths. Got it back in square, tightened everything back down, remeasured to verify square after tightening up everything, and ran a test cut. A simple 4 inch square cutout. Checked it with my Woodpecker square and it was still a hair off even over only 4 inches. Two corners diagonal from each show a little light, while the other two corners show square.
I’m sure it’s something that I did/did not do, just need to know what else I should check. Going to run another test with circles and larger squares here shortly to try and see if I can get more data on what exactly is happening.
Yes, checked and fixed the square of the machine and double checked after tightening and running it a couple times to make sure.
Pictures of cut settings attached. Even stepped it down and went with C3D 201 bit and settings to make sure it wasn’t the bit I was using being off by a fraction.
Also is a picture of the cut results with measurements. Can’t figure out a way to show the piece with the square held up on it, but marked the corners that were square and ones that weren’t. Measurements also bear that out as well. Cuts straight along Y axis but not along X. Not a huge difference, but the fact that over this 5in piece I can see daylight through a square tells me its enough to cause issues for sure.
You’re cutting almost to the full depth of the cutting flute — try adding offset geometry and cutting as a pocket down to tab height and leaving a roughing clearance to take a finishing pass?
Where possible avoid slotting and add geometry and cut as a pocket
and/or
and consider leaving a roughing clearance and taking a finishing pass.
This is a simple square cut out off a piece of 1/2 plywood. And using the most conservative cut settings. I normally run bits way higher then this is being run at. There shouldn’t be any reason to have to do offsets or pockets to reduce issues with slotting in this material. I do offsets on my hardwood projects regularly, which also aren’t coming out square now that I’ve gone back and checked them. I’m running a hardwood design that I’ve done multiple times before right now with offsets to see if it happens on this as well.
Seems like maybe the X-gantry isn’t sitting square across the Y-rails - slightly scewed from one side to the other. So squares are slighly parallelogram in shape.
Perhaps the Y-limit sensors need adjustment to set the gantry properly square on initialization?
This got me thinking more, and I really appreciate it. X axis was hitting dead straight across every time, Y axis went at a tiny little angle. Made a little test grid of lines in X and Y to see where it was happening. Finally powered it down, ran the Y axis all the way to the rear stops, then all the way to the front stops, powered it on and let it initialize and run back to the rear. Then I ran the grid test again and its dead on the Y axis now. Not sure exactly what it was in the end, but that fixed it so I’m calling it a win. Thanks again!
