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Reversed machining
« on: March 03, 2013, 05:45:04 PM »
Not sure if this has ben posted before, as I wasn't sure what the 'Topic' would have been listed as..but here goes...

Has anyone come across a situation where Mach3 has machined something in reverse, WILST it views correctly in the toolpath display.

It's actually not reversed but machined as if it's been done from the back. 

I am new to this and thought I'd do some experimenting with the machine I have just built, buy machining my name.  I used 3mm plastic and pocketed the 20mm high letters at 2mm.  Whilst it appeared to machine OK, it wasn't 'till it had finished that I realised that something wasn't right.

The letters were as if it had been machined from the underside!!

The view in Toolpath Display was fine.

Has anyone come across this before?
Re: Reversed machining
« Reply #1 on: March 03, 2013, 05:54:15 PM »
BTW - These aren't letters, but geometry done in ParaCad, then saved to a .dxf file and imported into SheetCam to toolpath.

Offline Chaoticone

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Re: Reversed machining
« Reply #2 on: March 03, 2013, 06:21:27 PM »
You may well have the axis going in the wrong direction.  This can be fixed by reversing the axis in homeing and limits, or changeing the active state of your driection pins in motor outputs or moveing the wires on the motor or drive.  Have a look at the members doc board or google Right hand rule for CNC.  For now, stick with the first option listed above if you need to swap directions.

Brett
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!
Re: Reversed machining
« Reply #3 on: March 03, 2013, 06:55:16 PM »
I have checked the wiring and that's fine.  But I still cannot get this to work.  It seems like it's just the X axis.

I have tried both, reversing the axis in and Home/Limits and setting Active Low on the P&P's.  I can get it to match
the toolpath display but then References in the wrong direction, even if I reverse the Neg Home setting.

Frustrated!!

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Re: Reversed machining
« Reply #4 on: March 03, 2013, 07:28:51 PM »
Well, reversing the axis in home and limits should change the direction the machine thinks is +.  Changeing the home neg. check box should change the direction it travels to home.  Once you change your settings, click ok and then exit and restart Mach and see if the settings are right and try homeing and see if everything is following the right hand rule.  What version of Mach are you running?

Brett
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!
Re: Reversed machining
« Reply #5 on: March 03, 2013, 07:43:21 PM »
Hi.  Version 3.043.037.  still no different.  The machine works fine until I load a file!  But the display is 'backwards'.  I think it's just X that's out, but I can't figure out why.  I have tried changing everything in both H/L's and P&P's but all that does is stuff up the homing procedure.
The Right Hand Rule is correct to the machine when jogging, but NOT when a file is loaded. 

When Jogging, X+ is right to left, Y+ away from me (front to back).  In the Toolpath Display, when a file is loaded, X+ is LEFT to Right.  Y is still front to back (correct).
Re: Reversed machining
« Reply #6 on: March 03, 2013, 07:51:40 PM »
Directions are all relative to the tool, not the table.  Moving X+ should move the tool to the right, or the table to the left.  Y+ should move the tool towards the back of the machine, or the table towards the front of the machine.  Z+ should move the tool up, or the table down.

Regards,
Ray L.
Regards,
Ray L.
Re: Reversed machining
« Reply #7 on: March 03, 2013, 08:03:31 PM »
My gantry is on the right hand side so X+ moves right to left.  Y+ moves away from me (front to back).
Re: Reversed machining
« Reply #8 on: March 03, 2013, 08:08:55 PM »
I am trying to attach an image of my machine and problem but it won't allow....says "Sorry! There is already an attachment with the same filename as the one you tried to upload. Please rename the file and try again"
Re: Reversed machining
« Reply #9 on: March 03, 2013, 08:11:15 PM »
My gantry is on the right hand side so X+ moves right to left.  Y+ moves away from me (front to back).


Then that's your problem.  If you insist on operating your machine like that, then everything will come out reversed.  G-code directions are very clearly, and rigidly defined.  You don't get the re-define axis directions.

Regards,
Ray L.
Regards,
Ray L.