Inventables Community Forum

Cuts aren't identical

I’m cutting multiple pieces of the same art on a single board. The goal is to glue the pieces together to get a double or even triple thickness. The problem is that when I glue them up some of the layers aren’t the same. The differences are ever so slightly different, but more than what I can live with!

Anyone have a similar experience or have suggestions on what I’m doing wrong?

TIA

Somethings moving. Work piece (probably), bit not tight , somethings not as it should be.

You’d be surprised…I know…

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Thanks. We’ll tighten everything up and see what happens.

Have you calibrated your machine? This is always a good idea …

{:0)

Brandon Parker

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Are all pieces oriented the same with the grain?
If not the difference could be from bit deflection from wood density variations.

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If you need real precision and repeatability with a belt driven machine, you’d be better off cutting the parts in the same location on the machine. Even on a perfectly calibrated machine, there will be variations in the steps/mm at different locations within the work area.
If you’re cutting metal, cut the parts in the same location.
If you’re cutting wood or plastic, you should be able to get to an acceptable tolerance by just tuning up the assembly of the machine.

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Thanks for the help.

Calibrated the machine. Double checked for square. Tightened up the bit. Locked down the material. All seems to be in order.

Initially I had the same artwork 3-up on a sheet of .5" MDF. Cut them all out with the same settings and then cleaned up the tabs and tried to glue together. It’s almost as if each piece is slightly skewed because I can get one edge aligned and the other isn’t and vice versa. So then I added 4 dowel holes, one at half depth, one at full depth, and flipped the 3rd piece with the dowel holes at half depth. Same alignment issue. It wouldn’t be a big deal if I could just sand down all the edges that are off, but it’s fairly detailed and and there’s just no way to be efficient at all with all the sanding that would need to be done.

Then I started cutting one at a time in the same spot and still had some issues. I think I’m going crazy. It doesn’t compute. I’m uploading the art so you can see. It’s about 10" across. The pieces are only about 1/32" off but to get into all the nooks and crannies to clean up is a lot of work. I was hoping to mass produce a little bit. It’s most likely a user error, but I guess I’m just trying to see if I have unrealistic expectations.

Don't Panic Eighth In Xcarve

What kind of bit do you use, RPM, feed rate and depth per pass?

Sounds like your spindle is not square to the waste board. That results in a cut that is sloped/stepped on the side. The deeper the cut the more noticeable.
Pocketing an area with a 1/2" bit will also reveal this condition.

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@HaldorLonningdal The bit is the 2 flute straight end mill, the DeWalt 611 is set to the lowest speed, feed rate and depth are default values supplied by Easel for MDF and bit. I’m not sure what those are, but I can find out.

@MarkA.Bachman I’ve checked for square on everything using levels and engineering squares. It all seems to be square. Admittedly I checked the spindle squareness at the mounting hardware and not the bit itself so maybe I need to check that. I also didn’t check its squareness along the Y axis so … I guess I’ve got some more work to do on that.