giggler
Mon 12 September 2011, 14:59
Hi,
I'm testing my machine and am cutting a collet holder from 18mm MDF. I have some problems with the finish.
It's going slightly diagonal in the Y axis, perhaps also in the X, I'm not sure. I can physically move the Y axis when motor is enabled, I've put locktite on the pinon and when I move it by hand, both ways move the motor spindle with no backlash.
There are a number of circular pockets in the drawing, the cut on them seem fine which got me thinking it's not backlash or other unwanted moving parts.
The motors are belt drive. The drives are made by pacific scientific, they have a reduced current mode where after a period of time, current is reduced. I have enabled this feature and after 1S of no steps, there is a noticable by eat, sound. I'd describe it as a step, so perhaps this is where my unwanted movement is comming from? It's just a stab in the dark really.
Other things, the CAM s/w produced some very small arc's and I know turbocnc has known bugs with small arcs. Could this be the accumlated error I'm seeing?
It's only in the Y i'm tempted to think it's possibly mechanical but can't prove it as the motor seems firm and repeated cuts of same gcode file produce very similar results.
See attached the nc file I used, here are image links to work:
http://i.imgur.com/Pk3x5.jpg
http://i.imgur.com/AVL8Y.jpg
Thanks in advance,
dc
I'm testing my machine and am cutting a collet holder from 18mm MDF. I have some problems with the finish.
It's going slightly diagonal in the Y axis, perhaps also in the X, I'm not sure. I can physically move the Y axis when motor is enabled, I've put locktite on the pinon and when I move it by hand, both ways move the motor spindle with no backlash.
There are a number of circular pockets in the drawing, the cut on them seem fine which got me thinking it's not backlash or other unwanted moving parts.
The motors are belt drive. The drives are made by pacific scientific, they have a reduced current mode where after a period of time, current is reduced. I have enabled this feature and after 1S of no steps, there is a noticable by eat, sound. I'd describe it as a step, so perhaps this is where my unwanted movement is comming from? It's just a stab in the dark really.
Other things, the CAM s/w produced some very small arc's and I know turbocnc has known bugs with small arcs. Could this be the accumlated error I'm seeing?
It's only in the Y i'm tempted to think it's possibly mechanical but can't prove it as the motor seems firm and repeated cuts of same gcode file produce very similar results.
See attached the nc file I used, here are image links to work:
http://i.imgur.com/Pk3x5.jpg
http://i.imgur.com/AVL8Y.jpg
Thanks in advance,
dc