Z-Axis Headaches!

Hey guys, ordered a TinyG a week or so ago, and finally had time to play.  I’m using it to control a Shapeoko, and have the X & Y axis working a treat.  I converted Alan’s config, and am using that.

When I try and tune the Z-Axis, I get very inconsistent results with the below settings.  The motor vibrates, sorta like it’s over-driven, and drops steps if it turns at all,  but not quite the same – hard to describe.  The Z-Axis mechanics are fine, and I can drive the same motor / axis with a Pololu board without a problem.  I can swap X/Y with Z and the problem follows the Z axis.

In a fit of troubleshooting, I tried changing the steps per mm for Z from 1.25 to 10.  If I do this, my stepper starts acting normally!?  I also tried varying the feedrate, but was really not able to produce consistent results with $3tr set to 1.25 at all.  Same results varying the microstepping – seems like the only thing that made a consistent difference was the steps/mm.

I’m using Kysan 1124090 steppers on all the axis, a 32amp 12vdc power supply.  Swapping back to a RAMPS board with the same motors and power supply works fine as well.

I’m sure there’s something fundamental I’m overlooking – just can’t figure it out!  Here’s the setup I converted from the .h file on the shapeoko wiki.

G21
$1ma=x
$1sa=1.8
$1tr=34.5
$1mi=8
$1po=0
$1pm=1

$2ma=y
$2sa=1.8
$2tr=34.5
$2mi=8
$2po=0
$2pm=1

$3ma=z
$3sa=1.8
$3tr=1.25
$2mi=8
$2po=1
$2pm=1

$xvm=16000
$xfr=16000
$xtm=170
$xjm=5000000000
$xjd=0.05
$xsm=1
$xsv=-1000
$xlv=100
xlb=2
$xzb=1

$yvm=16000
$yfr=16000
$ytm=170
$yjm=5000000000
$yjd=0.05
$ysm=1
$ysv=-1000
$ylv=100
$ylb=2
$yzb=1

$zvm=1200
$zfr=1200
$ztm=50
$zjm=5000000000
$zjd=0.05
$zsm=1
$zsv=-400
$zlv=100
$zlb=2
$zzb=1

• This topic was modified 12 years ago by SystemsGuy.