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Author Topic: Mach3 always hesitates in arcs and circles  (Read 4941 times)

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Offline ger21

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Re: Mach3 always hesitates in arcs and circles
« Reply #10 on: September 15, 2017, 07:01:12 AM »
2nd thing. When I activate CV feedrate and set to 100 it makes it jerk more.

Which is why I told you to turn it off.
Gerry

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Re: Mach3 always hesitates in arcs and circles
« Reply #11 on: September 15, 2017, 07:34:38 AM »
I tested it and yes I have put if off. But still not a smooth curve

Offline Tweakie.CNC

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Re: Mach3 always hesitates in arcs and circles
« Reply #12 on: September 15, 2017, 08:08:16 AM »
 Hi stephanisk,

Could you .zip and post a copy of your problem Gcode ?

Tweakie.
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Offline rcaffin

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Re: Mach3 always hesitates in arcs and circles
« Reply #13 on: September 18, 2017, 03:32:39 AM »
Quote
Manuals work best when they're read, usually several times!
Better make that 'Many many times' for Mach3!

If you are using subroutines there may be a slight hesitation between subroutine calls - but it is quite slight.
Sounds like a CV problem to me, OR possibly flex in the framework.

Cheers
Roger
Re: Mach3 always hesitates in arcs and circles
« Reply #14 on: September 18, 2017, 07:52:19 AM »
Hi Tweaky

Here you will find the G-code (in txt-file, this forum doesn't allow me to post it in .zip)

Greetings
Stephanisk

Offline Tweakie.CNC

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Re: Mach3 always hesitates in arcs and circles
« Reply #15 on: September 18, 2017, 11:13:32 AM »
Hi Stephanisk,

I have just run your Gcode here (I had to reduce it to 0.25 scale to fit on my engraving machine) and my machine motion appears to be smooth between Gcode line transitions etc. so I think that rules out the Gcode as being the problem.

Could you attach your <profile> .xml file (copy and rename it to a unique name such as stephan.xml before attaching) then we can check your Mach3 settings.

Tweakie.
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Re: Mach3 always hesitates in arcs and circles
« Reply #16 on: September 21, 2017, 11:24:05 AM »
hi,

here is my mach3mill xml file. I hope this is the one with all the settings. I do believe it is :)

Thanks for all your help so far. Hope we find the problem.

regards,

Stephane
« Last Edit: September 21, 2017, 11:25:41 AM by stephanisk »

Offline Tweakie.CNC

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Re: Mach3 always hesitates in arcs and circles
« Reply #17 on: September 22, 2017, 02:08:07 AM »
Hi Stephane,

Unfortunately I am unable to test your .xml settings - I don't have an XHC controller and your settings will not run under Mach3 parallel port control.

Could you try reducing your X and Y axis Velocity settings by 50% (in motor tuning) and setting the Acceleration number to at least 10% of the Velocity number (save the changes) - does this make any noticeable difference ?

Tweakie.
« Last Edit: September 22, 2017, 04:23:52 AM by Tweakie.CNC »
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Offline rcaffin

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Re: Mach3 always hesitates in arcs and circles
« Reply #18 on: September 22, 2017, 02:39:47 AM »
Anchor a dial indicator to the spindle and mount a smooth block on the table. Now measure how much flex you get when you put a load on the spindle of 1 - 2 kg, on each of X & Y axes. Having measured in one direction, try the other direction - you wiol get both flex and backlash of course.
Then repeat while stressing the table instead.

Cheers
Roger
Re: Mach3 always hesitates in arcs and circles
« Reply #19 on: September 22, 2017, 05:33:56 AM »
Hi Roger,


Thanks for your input. What is it that you want to measure? The rigidity of the machine?

The whole machine weighs about 3000 kg. The bridge itself is about 1200kg. This is about as heavy duty as a flatbed router can be to be honest. U could mill some steel with this if u wanted too. So there is no actual flex when I put pressure on spindle or table. The dial says 0. ;)

Regards

Stephane