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Offset dont add up
« on: July 13, 2020, 06:26:49 AM »
Im sorry to have to post this again but I got a super clever answer from one member and that seems to have frightened other off.

I just need to know can this be done with offsets

I need to accurately drill holes in PCB'. I fetted a USB microscope which gets the 0.2mm crosshairs etched on the PCB fill screen.

At this point I zero x and y in G54.

The difference between the crosshairs and actual workpiece zero and the camera crosshairs and the spindle adds up to an offset of -88mm in x and -63mm in y.

So if I simply move the spindle -88 and -63 then rezero in G54 the program performs fine and all the holes drill in place.

But it is a nuisance doing this every time.

I thought if I put the offsets into G55 manually I would be able to bring this offset in after setting x and y to zero in G54, but when I zero the machine coordinates the G54 offsets alter to numbers that make no sence. There seems to be a legacy value from the machines move before zeroing.

If I the switch to G55 the offset is way out and it misses the board completely.

How can moving the head work and changing to G55 not.

How can I either in zeroing the machine coordinates also make the G54 zero so that when I switch to the G55 the new zeros is at the -88 and -63 position.

It seems like whackamole as soon as I alter one offset it moves all the others and the -88 and -66 become corrupted.

Am I just missing the point .

All I want to do is zero in the crosshair. then tell it that really zeros is -88 and -63 from where the spindle is sitting.

Thanks in advance if any of you can help.

I feel like I am in limbo.

Nothing seems to add up.

Best regards

Forbin One

Offline Tweakie.CNC

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Re: Offset dont add up
« Reply #1 on: July 13, 2020, 07:00:29 AM »

Perhaps take a look at the method I use for Tool Position Setting;  http://www.tweakie.byethost10.com/17.htm

(Use the Screen Editor to add a VB button to your screen that contains the offset between your crosshair and cutter. Clicking the on-screen button moves the cutter by that amount).

Re: Offset dont add up
« Reply #2 on: July 13, 2020, 09:23:06 AM »
Very Much appreciate you help, been to the page and it is obvious to me that if I am going to become the master like yourself I need to learn to integrate VB scripts into my Mach3. Thanks again. Working my way through your pages after this.

Offline ZASto

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Re: Offset dont add up
« Reply #3 on: July 13, 2020, 04:34:34 PM »
Tweakie's laser can be substituted with small endoscopic camera, as I wrote you in other thread.
You will have to edit your screen set adding 2 DROs (for camera offset), two buttons for turning tha camera on and for setting XY zero with measured offsets, contained in extra DROs.

You can find Big-Tex blue toolsetter screenset and modify it, as I did.
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Re: Offset dont add up
« Reply #4 on: July 13, 2020, 05:26:11 PM »
I will add my own reply and thank Zastro and Tweakie but I have worked out an even simplet soluition.

I simply park the crosshairs of the usb microscope over the Crosshairs on the pcb etch and on the main screen, touch the x dro and overide the value with the offset and the same with Y. It just accepts its where i want it to be and cracks on.