Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: jonny quest on February 11, 2013, 08:38:49 PM

Title: losing steps on Z. Yes another thread about this. how to troubleshoot
Post by: jonny quest on February 11, 2013, 08:38:49 PM

My Z randomly misses steps. seems to only do it on rapid Z retract, so then I lose my zero... amd BAM. Into part or table I go. Yes I do have my velocity and accel set pretty low.

Problem is it's not repeatable. it only happens when I'm 55minutes into a 1 hour job and it slams my $175 indexable cutter into the vise. Yeah me.

I've searched this board... and most of the time it's a mechanical issue. this isn't.... been down that road.

Would posting my XML help? Could switching to Sherline mode help? Does Kernel speed have any effect?

Title: Re: losing steps on Z. Yes another thread about this. how to troubleshoot
Post by: jonny quest on February 11, 2013, 09:14:58 PM

http://www.geckodrive.com/using-heds-encoders

I was thinking of trying this. This link shows what to do with the 320x, I'm using the older 320.

I found a 1uf 35v capacitor at Radio Shack... think this would be beneficial to me?

Title: Re: losing steps on Z. Yes another thread about this. how to troubleshoot
Post by: Tweakie.CNC on February 12, 2013, 02:02:09 AM

Hi Jonny,

Just my opinion…

Anything that reduces electrical noise and produces cleaner signals has to be good.

As you only seem to be having problems on the Z retract I would suggest that you reduce the Velocity and Acceleration on this axis until you find a 100% reliable setting.
(Just as an example my 100% reliable X and Y rapids are 4500mm/min @ 450mm/sec/sec whereas my Z rapids are only 1000mm/min @ 100mm/sec/sec – quite a large difference 1 : 4.5).

I don’t think you should ever assume that the issue is not of a mechanical nature, always consider all possibilities.  ;)

Tweakie.