Unpredictable results

[funhawke]

Bummer - no change. Did four "ones" separately. With each I changed speed settings, acceleration - No change on any. One odd thing though - although I ordered the cut order with the v pattern first then the outside cut pattern second, it cut the outside cut first?? In each at the upper left of the curve - there is a substantial shift.

[funhawke]

Current settings

Settings.jpg (625.85 KiB) Viewed 1683 times

[Techgraphix]

I made a small test for acceleration and startspeed setting of the gantry but when you rotate the lines 90 degrees it can be used for the X aswell, probably:
you see two columns of 15 x 45mm engraved at 20% 500mm/sec and a scangap of 1mm in a piece of paper..
I set the acceleration of all axis to the max the controller can handle (50000). then you see what happens: on the left column you see beltstretch etc. I had to reduce the acceleration till the lines became straight (right column) for the gantry that was at 10000.
But my steppers are 3NM running at ~50V 3Arms coilcurrent (yes the get quite hot)
Running this columns takes you only a few seconds and maybe you can get the right values a lot faster. at least close enough to test it again on your material..
Hope it helps a bit

Pattern.JPG (75.48 KiB) Viewed 1671 times

Oh and is your shift in one direction only? X?
can you also dump a picture of your user-settings-page?

BTW as you write that the cut-stitch goes highwire, I tested the stitch-pattern only (not the V's ) at absurd high values for acceleration 100000(onehundred-thousend) a startspeed of 50.000(fifty, which is the maximum you can enter) a max speed of 2000mm/sec and all values on the user settings page set to the max.. higher values are not accepted by the controller
I also set the speed to 1000 (it was 40)..
except for the beltstretch deformation (my belts are only 10mm wide, so not the best for high speed machines ) and a heavily shaking machine, the end of the line is perfectly aligned with the start.. even when I repeated it on the same position twice.... just perfect..
So I guess you still have to find the problem in loosing steps of your motor or a problem with your stepperdriver.. my system does it just fine, as expected..

Kees

[funhawke]

Still working on this problem. I keeps appearing in small items which have some detail - the cuts seem to move. I think I have tried every possiblility in speed, acceleration - changed x and y positioning of the object but still no success. Its concerning when I do an intricate design that it will skew somehow. Haven't been able to see a pattern in the fails. In this case I tried a test pattern. The "v's line up well as does the outer cut when I send them to the cutter separately but when sent together either the outside cut or the v cuts skews - approx .5mm