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The easier way to find the edge in the settings is to profile say a 50mm circle with each pass say 0.2mm deeper, so soon its starts to get clear what's happening
50mm circle inside a square is the method i use to test for eventual axis or electronic problems
I ran Gcode to move X to 10mm then back to 0, 1000 times and same with Y and checked position everything seemed good.Quote:
Originally Posted by pippin88
http://www.mycncuk.com/threads/13525...399#post115399
I would have seen backlash with that check right?
Not really no. Even if it has backlash it will still follow the same pattern back and forth so you wouldn't notice.Quote:
Originally Posted by Desertboy
Have a look at some vids that show how to properly check it.
If your sizes are out by more than say 0.2mm I'd say it wasn't a backlash issue. I've never really seen backlash values of more than 0.08mm which would make a circle smaller by only 0.16mm.
If you had 1mm of backlash you'd feel it by shaking each axis, it would feel like it's falling off.!
Tell me about it!!Quote:
Originally Posted by JAZZCNC
1 thing I'd say as well is I often use cheap nasty Chinese cutters for roughing through then swap a decent cutter for a finish.
Those Chinese ones can vary in size a chunk.
I can rough a new 6mm 3flute bit using it to finish as well and I won't fit a bearing in the hole.
Then next I'll leave 0.5mm on with the same cutter, swap it for a 4flute Cobalt bit for finishing and be able to just get the bearing in.
That's with my drawings modified where a circle is set 0.1mm lager than I actually want it.
My Benchtop only has 3000rpm at the spindle so I find Cobalt work better for me as I can hog it a tiny bit.
Those Carbide bits are designed for higher rpm and I've shattered a few so there used for finishing only too.
No, that will not show backlash.Quote:
Originally Posted by Desertboy
Look up what it is and how to check it.
You need a proper measuring instrument, e.g a dial indicator. You move the axis in one direction into the dial indicator, zero the dial indicator then move the axis in the opposite direction a defined amount. You then check the dial indicator reading and compare to what it should be.
I had a blonde moment today, I dug out my old pc which has linuxcnc on it and brought it home to try with the machine I was just going to wire the X,Y,& Z see if the sizes are still out and if so are they out the same amount.
When I got home to set it up I forgot a VGA monitor lol, no HDMI out on this machine.
I need to go work again tomorrow so will have to wait another day.
At the moment I've set the motors to ~3amps on the stepper drivers by jumpers they should be ~ 4amps and they don't get warm even after hours of machining but I will connect them to the PC so I can autotune everything.