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Author Topic: Rotary and Linear Accel Trouble  (Read 2401 times)

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Rotary and Linear Accel Trouble
« on: November 25, 2006, 01:20:55 PM »
I'm having a problem which has been discussed here before but I don't think it was every resolved or completely explained. I just added a 4th axis rotary indexer to my router.  When I cut X,Y,Z alone or A alone everything is fine, but when I cut X, Y or Z at the same time as A the acceleration drops to a SUPER low rate. It ends up taking 6 seconds to accelerate to full speed on the A axis.  I am setting my diameter correctly on the settings page and I have verified that everything does eventually reach the correct feed rates, it's just the acceleration that get screwy.  Here are my settings...

Motor Tuning:
X + Y:
Steps: 1833.864039
Velocity: 600
Acceleration: 15

Steps: 4710.03
Velocity: 60
Acceleration: 15

A (rotary):
Steps: 40
Velocity: 16200
Acceleration: 3000

A Axis is set to Angular
A Diameter is set to 1.5" (testing with a 1.5" dowel)

From what I read on the couple of posts that came up searching for angular acceleration, it looks like Mach uses the accel setting that is the lowest for all axes involved which makes sense. However, it is accelerating at a small fraction of the lowest acceleration axis so something seems very wrong.  If I can't fix it, jobs that used to take 10 minutes on my old proprietary controller will now take hours to cut with Mach which can't be right since every other type of operation is way faster than my old box. I'm assuming I'm missing something here.

Any ideas on how to resolve this?

Offline Chip

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Re: Rotary and Linear Accel Trouble
« Reply #1 on: November 25, 2006, 02:18:44 PM »
Hi, Patricktoomey

There are some issues that need to be addressed in the software I think, Try below setting's

Set your F speed to F16200, I now it doesn't make sense, F100 should be 100 %.

The A axis is probably holding you up, This will allow your other axises to limit cut speed,

Adjust A axis F speed down to get the actual cut speed where you want it.

How many step's dose it take for 1 full turn of your A axis, what is the reduction ratio.

Hope this Helps, Chip