Not getting the desired sizing results

Hey all!

I’ll start off by stating that I’ve the forum before I posted this :slight_smile: All my attempts fixing this problem came from solutions from this forum.

Alright the problem. When I cut a 50mm square I get 49 mm in the y and say 49.something in the x.

The machine:

  • 1000mm x-carve
  • X-controller
  • Makita router. 10,000 RPM at slowest setting

Solution attempts

  • Took the machine apart and squared it
  • Calibrated $100, $101 & $102 with a 500mm ruler. So without load it runs (as good as) perfect.
  • Measured the cutting bit and used this in Easel.
  • Run the machine slower. About 1/4 or 1/5 of the recommended cutting settings

This last solution gave me the best results so far. But I get the feeling this slow movement is too slow for the router. The bit now gets hotter.

What is this newbie doing wrong?

Thoughts, should I upgrade the nema 23 motors?

Using Easel as shape editor or other software?

You have several factors working against you, that one need to take into account:
1 - a 3mm bit may not be 100% 3mm, it may be slightly undersized (most common)
2 - Tool deflection (a thin bit may flex from the side way forces applied during cutting
3 - System deflection, there is in every system a certain amount of “give”

Modern / industrial machines have compensation modes to account for these effects, an Xcarve or similar hobbyist machine do not and we need to “learn” our machine in order to make it produce the desired size.

Yes, sir.

I use Illustrator to draw the shapes. And export/import them as .SVG… While typing this, I come to think of the following. When I import the svg it NEVER imports on the right size. I always have the scale it all. I always type in the size and I just checked. Easel ignores the decimals I type in. Never noticed this before. this CERTAINLY should give me some error.

How could we xcarvers solve this? Measure the difference and use path offset?

The results a few hours later. A lot better, but stll 0,19 mm off.

First of all we would need to make our system as rigid as possible, with >zero backlash or anything that may provide “give”. At one point we reach the world of diminishing returns :slight_smile:

One way to counteract this is to make a roughing pass and leave some material left (0,2-0,5mm for instance) and run the path once more with a different federate/depth to act as a finishing pass.

How precise is our requirement? How accurate is my calliper? What is close enough?

You mention you start with SVG, what is your measured size if you make the object in Easel, send code via Easel so there is no conversion taking place?