Inaccurate circles/squares ...thoughts ?

Hello,

I use my sherline for customer work. I used to use a manual sieg x2, and I was able to produce squares/rectangles that were almost perfect by just counting units on my hand wheel, now with the sherline, I figured I would be able to get perfect shapes, but it looks like the mill is going to far, or not far enough etc. This isn't too much to expect right?

I used a interapid switzerland dial gauge (accurate to .0005") to measure backlash. And I entered everything in to the .ini while also adding 1.5 - 2x the acceleration or whichever unit I needed to change. I had to go back into the .ini a couple times, but now when I got +.01 mm 10 times on any axis, and then go -.01mm 10 times back I end up in the exact spot I started. Completely eliminating backlash, at least within the system. My largest backlash adjustment was .2 mm the smallest being around .03mm. Seems like a lot, could that be the problem, making up that much backlash?



It looks like my circles look a lot better. When I say a circle, I mean I'm taking a approx. 1mm endmill and having the machine cutout a (the most common is 7/16th") circle. My rectangles/squares just look like garbage still. It's just ridiculous in my mind. How much better I could get on the Siegx2 manual mill just using the hand dials.

Do you know what else there is to adjust to do a better job?

Just an added note, please see my attached latency test. This is the most latency I can get, which is pretty darn low latency, right?

Here's a couple links to some other engraving work my mill has done. I'm not sure how it produces such accurate looking engravings, yet the squares, circles look so off.

imgur.com/MTw22YF

imgur.com/UdQRnu5

imgur.com/TmO3ycK

imgur.com/JmRRifO

Here is my Config file.

Hi

The controller software is only as good as the machine.

What you saw as backlash was probably flex and general slackness

As far as I am concerned Sherline are an expensive desktop toy, only suitable for cutting soft materials slowly.
Some of their designs defy logic as far as rigidity is concerned.

For instance this at $1300 plus for the CNC version, for which you could buy a used industrial machine
There are so many flimsy flex points, I would be surprised if it cut anything harder than plastic well.



Your Seig was heavy cast iron with proper cast iron beds, column etc.

Sherline have a following in the US, next to none here and none at all with me I'm afraid

regards

Well geeze, wasn't expecting an answer like that. Anyone else have any thoughts ? Any other sherline owners want to shed some light?

Would you mind elaborating on mapping compensation ? I clicked the link you put in, but I don't see anything about it. I think I'm going to try and mount the mill to my table better, and see if that makes a difference.

Ok, I see it now. I'll have to look into that more, because I don't know what it means to map the screw out. I do notice that it says if you specify a comp_file, backlash is ignored.

Thank you for pointing that out to me.