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Author Topic: Consistent inconsistancy  (Read 2072 times)

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Consistent inconsistancy
« on: April 04, 2014, 03:13:53 PM »
Hi,
I wonder if someone might be able to help as I'm not entirely sure what to search for.
I got my router running for the first time a few days ago, I've made some good parts but am encountering this weird inconsistency seen in the image attached (excuse the tool going off the work in the 2nd attempt ), I'm making a blank synth panel, the holes should be placed equidistant in each corner and are on the path viewer. It's like the scale is changing during the job but it doesn't look like regular missing steps? The exterior dimensions are perfect.
« Last Edit: April 04, 2014, 03:18:08 PM by Render »

Offline RICH

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Re: Consistent inconsistancy
« Reply #1 on: April 04, 2014, 03:22:15 PM »
Is the gcode correct for the hole placement? Post the file.

RICH
Re: Consistent inconsistancy
« Reply #2 on: April 04, 2014, 03:55:02 PM »
Hi, I've attached the gcode, I'll try some other similar shapes and see if I get the same issue.
Cheers
Re: Consistent inconsistancy
« Reply #3 on: April 04, 2014, 06:35:31 PM »
So I redrew a similar part and generated new gcode, still the same weird issue. if I stop the job close to the end and jog the machine from the zero the path view shows the end about 15mm off what should be the end, if I rewind and regen the toolpath and do the same the path view is correct (that's probably a rubbish explanation, sorry ;)).
« Last Edit: April 04, 2014, 06:50:10 PM by Render »

Offline RICH

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Re: Consistent inconsistancy
« Reply #4 on: April 05, 2014, 08:50:12 AM »
The code is ok and believe it's your machine.
The problem seems like it is happening in the lead in move to cut the outline.

There are a number of reasons this can happen.
Test your machine to make sure that the steps per unit are correct, check for backlash, find out max velocity and set
max velocity and accleration properly. Make sure your router is not causing any interference / EMI.

That said you should be able to return to a zero point within a 0.1mm or better not 15mm after the code is run.
Simlply said you need to confirm that the machine is capable before you can start cutting.

Once that is confirmed one  can better make a few simple test comments to get things right.

RICH

Re: Consistent inconsistancy
« Reply #5 on: April 05, 2014, 11:51:57 AM »
Thanks for the response. I should have mentioned that the previous day I had already cut a few parts and all where around 0.1mm accurate, I've attached a pic of a couple of them, a fairly similar type of job to what I was doing yesterday. The steps per unit seemed perfect, no noticeable backlash and pretty conservative max velocity/acceleration. It's not that the zero was offset by 15mm, the spindle would return to a point very close to where the zero should be, but display the end of the part as being 15mm closer than it should be. Running the move in the air with the spindle running and off, and at a variety of speeds all ended up with the holes placed in a similar wonky position.
Re: Consistent inconsistancy
« Reply #6 on: April 05, 2014, 01:15:14 PM »
I'm not entirely sure why but all seems to be running fine today.