Accuracy tuning

Hey guys,

I need your help in accuracy tuning.
The servos are tuned well, now. So the F-Error is about 0.0001mm at F10.000mm/min in all axes.

But when it comes to cutting material, let's say a rectangle part of 20*30mm it cuts 20.045*30.045mm
Where is the mistake?
All the bearings ect. are like new- with the original Siemens 810M control it cuts on 0.001mm like programmed.

I hope you guys can help me with that.

Thanks, Joel

Encoder scale maybe ?
1000 ppr imstead of 1024 ppr ? Or similar, like metric to imperial ballscrews....

Hey Andy,


The machine has 1250 Imp. Encoders - x4 = 5000 Imp/turn
The motors have 22 teeth, the leadscrews have 44 so the Ratio is 1:2
The leadscrew has a 5 mm thread pitch.

So what I did is calculate 5000 / 5 =1000- that's what stands in my ini file.

Is that wrong?

Greetings

is there a tool involved in the cutting
so you got the 0,045 offset

Andy? You mean Tom, right ?
If you are certain the encoders are 1250, that is good, so now you should do that calculation for 5.08mm leadscrew.
But do first check if the tool is compensated as PL7i92 mentioned, he might be on to something as you got the same distance error on both axis despite traveling diferent distances.

Oh shit, sorry ! I meant tommy / Tom
I think I just saw andy

Sure is there a tool involved, that is also compensated- Same dia like before with the siemens control, now with linux it is driving me crazy

So I need to compensate the error with the new encoder calculation with a pitch of the error +5mm ?

Thank you guys!

backlash?

Oh lord,
I've made a mistake in writing down my actual setup.

The machine has 10mm pitch ball screws- so 1250*4=5000 | 1:2 Ratio = 5000*2 =10.000 | 10mm per turn =10.000/10 =1000 Imp/turn

So the Ini is definitly correct.

What I also have tested so far is set a dial gauge at lets say G54 X0 then moved G0 X250 G0 X0- It shows nearly 0, about 0.004-0.005 overschoot.

So the last part could be a mechanical problem?
What I dont want to understand is, that with the siemens controll, the mill just machined the programmed contour, and why should it now be more worse than before....

Thanks guys!!!