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Very odd issue. Please help.
« on: March 07, 2015, 05:28:39 PM »
I have a very odd problem I just cannot get my head round. When I use a profile ramping procedure I get an issue whereby the x will stop and ramping will begin short of the correct position. For example if the toolpath is a simple square with multiple stepdowns and profile ramp transitions. The x will travel and to the correct position and begin the profile ramping procedure to the next corner of the square contour toolpath where it again follows the corect position, it will then make the next two corners Correctly, so we have 2.5 sides of the square correct, now the next side, this is where it messes up, it will begin correctly however fall 4mm short and turn the final corner, where it will cut to the first 4mm out of joining up. With multiple depths in the toolpath, this will then cut all the way to end of that line and turn the 3 corners correctly until the final one where it will again be 4mm short.

Now I know this sounds like I'm loosing steps, however the machine return to zero perfectly after the toolpath has ended.

It's got me completely baffled, I have checked the gcode to see if the issue was there but the x values for that cut match on each depth of cut. I have removed all g moves. And repeated the toolpath multiple times over same test piece with the same result every time.

What is making the x stop early on every pass on one side of a square yet it begins correctly and then goes back to 0,0,0 like it's not messed up.

All other milling procedures without ramps are exact.

Completely confused please help!!!

Cheers Jon.
Re: Very odd issue. Please help.
« Reply #1 on: March 07, 2015, 08:17:50 PM »
Please post that sample file.
Someone may be able to replicate your problem and find a solution.

Re: Very odd issue. Please help.
« Reply #2 on: March 07, 2015, 09:22:48 PM »
Sorry guys I said it begins in the wrong place, that was ment to be edited to say finished in the wrong place. Took me a while to work out where the error was occurring but it actually starts correctly. I will post the file here soon. Cheers.
Re: Very odd issue. Please help.
« Reply #3 on: March 09, 2015, 12:20:26 PM »
okay, this seems to happen with tool offset on, with it off it starts and finishes in a square however is exactly 4mm smaller in the x direction than it is supposed to be. i have attached the code of the square in question, and i have also attached another file of the square in question within an outer rebate, which when run, mills the outer rebate with all dimensions exact only it has the same issue on the center square, (what the hell is going on?) so surely this rules out the post processor settings? would be very appreciative if someone can look at it and tell me whats going on because none of this is making sense to me right now.

Thanks Jon.

« Last Edit: March 09, 2015, 12:23:27 PM by Jonny5 »
Re: Very odd issue. Please help.
« Reply #4 on: March 09, 2015, 12:31:26 PM »
Just to clarify: with tool offset set and on, start position is correct, falls short on 3rd side of square cut, with it off it mills the square without error except for coming out 4 mm small in x direction. I am using climb milling for both pockets (rebates).

Both Tool paths are created in inventor hsm, The version with outer rebate is created from one pocket operation with same settings for both outer rebate and inner rebate.

« Last Edit: March 09, 2015, 12:39:07 PM by Jonny5 »
Re: Very odd issue. Please help.
« Reply #5 on: March 09, 2015, 03:05:48 PM »
fixed. I had an active high on a direction pin for my a axis (slaved y), something i put in when i changed my drivers and was a quick fix to reverse the axis to test.. completely forgot to turn of and reverse motor polarity, And it seems to have fixed the issue which makes sense as to why it was 4mm out.. 1 mm lost for each corner. what doesn't make sense is why the outer rebate was exact. and why the issue was in the x direction when the a is in the y. But there we go.