Hey everyone! I’ve run into an odd problem and I’m hoping that someone can clear it up for me.
I have a simple project in carbide create, a cribbage board. On the back, I have one pocket for the cards, one for the pieces. Both pockets are centered in create, but both are off-center when I cut them out. I’ve verified that the dimensions of the work piece are entered correctly and that the bit is properly zeroed, but both pockets are off to the left about half an inch. I’ve noticed this with the top of the board as well. I don’t have this issue with any other projects. I’d prefer to know why this is happening and fix the issue rather than just setting the pockets off-center in the create file. I did that with the top. Both files are attached.
The bottom pocket being centered in CC, if the cut is shifted it could be
that the stock dimensions in CC do not match the actual stock: but you said you checked, so that’s not it.
that you did not zeroed correctly on the bottom left corner of the stock: but since you don’t seem to have the issue with other projects, unlikely. Still, can you detail how you zeroed for that project?
that the X axis slipped during the cut: have you checked the set screws on the X axis motor pulley? Have you cut other projects since then ? It’s a common culprit
that for some reason the G-code does not match what’s in the CC file now, for example if you saved G-code, then adjusted stock dimensions, and forgot to re-save the G-code again. Can you upload the G-code file for a check ?
Side note: the top part is not centered in CC, is that on purpose ?
The stock piece is 5.5" x 15.5" (for top and bottom) and that’s what CC is set to.
To zero the cutter: Turned the machine on, clicked on initialize. Then, I used the jog feature to get the edges of the bit just at the lower-left side/bottom and barely off the surface. I then clicked on "set zero then “zero all”.
I have cut other projects before and after this one. This project was off-center since day 1. I should just remake it, but I’d love to know why I’m having the issue so that I don’t get it again.
Yes, the top part is off-center on purpose so that’s it’s actually centered when cut. I was on auto-pilot this morning and forgot to offset the bottom. That’s when I decided to post.
(that black dot is at X=2.875, and the other side of that inner square is at X=2.625, so the middle is at exactly X = 5.5" / 2
which leaves used with a zeroing problem or stock dimension (but you ruled that out).
When you say,
do you have the center of the cutter on the corner of the stock ? Aligning the edges of the bit doesn’t work, as the cutter’s center will be offset one cutter radius away from the corner then. But that alone would explain a 1/8" offset, not 0.5"…
Ah. When I was shown how to set this thing up, he used the edge of the bit and not the center. (Not my machine) That would explain a few things but, like you said, it wouldn’t account for the half inch.
No. The only important thing to that the center of the bit is zeroed where you declared the zero point to be on your stock in CC, and this happens to be the lower left corner in this case. It’s just how the G-code is generated, the toolpath you see in the preview represents the path of the center of the tool, and the generated G-code tells the machine to perform movements relative to where that zero point is.
Honestly, manually zeroing on a corner is not very convenient or precise. When you own a touch probe this is different, then you would just have to install your probe on the corner and CM will do the math for you based on endmill size to find where the corner of the stock is. But when I need to zero manually on a square stock like that, I prefer to set the zero point at the center in CC, then draw two diagonal lines on the stock from corner to corner, and zero manually where the two lines cross. It is much easier (for me) to visually align on a large cross, than eyeballing whether the center of your bit is exactly above the corner of the stock. Maybe try that, and see if you still have an offset? For centered pockets, it also makes things independent of stock dimensions, so less chances to have an offset if the stock dimensions are not exactly the ones you entered
Well, I properly zeroed the bit this time (still in the corner) and I’m still off-center.
I re-created the file in CC, used the exact same measurements, dimensions, zeroing, etc, (aside from thickness, I used some scrap) and this time it’s centered. For the hell of it I then reloaded the old file and ran it. It was off-center, so it’s something in the original file that’s causing the error even though there seems to be nothing wrong with it. Weird.
Oh well, there’s no point it digging into it further. I’ll just recreate the top part in CC today and get cutting!