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Author Topic: Is it possible to check part location in GCode.  (Read 5195 times)

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Offline bowber

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Is it possible to check part location in GCode.
« on: September 11, 2009, 06:58:41 AM »
Hi

I have a part that I cut out by hand (triangle) at the moment in plastic and I would like to use my router to clean up the outside shape.
Problem is the table isn't big enough to fit more than one at a time, this means I still have to rough them out of the sheet by hand to be able to still get 7 per sheet.

So I was thinking that I could mark 2 points from the card template and have the Gcode check these points with the cutter before continuing and cutting the outside. I would have the shape marked on the table so the part would be roughly located.

My question is how would I do this? Can I hand code these points in and have Mach wait until I press the enter key?

Regards
Steve

Offline bowber

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Re: Is it possible to check part location in GCode.
« Reply #1 on: September 12, 2009, 06:12:55 AM »
Hi

Will M00 do what I want? From what I've read if I insert an M00 after the position move then mach will wait until I've pressed the cycle start button.

Steve

Offline ger21

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Re: Is it possible to check part location in GCode.
« Reply #2 on: September 12, 2009, 07:14:48 AM »
I'd route the shape into a spoilboard, to mark the location, then place the parts over the route to align them. Not sure how you'd hold them down if cutting all the way around, though. Or make a dedicated fixture to hold and locate them.
Gerry

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Offline RICH

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Re: Is it possible to check part location in GCode.
« Reply #3 on: September 12, 2009, 07:34:02 AM »
Steve,
Your rough cut piece must allow for a finish cut of the profile, such that, if the piece when placed on the table is somewhat angled releative to X or Y axis, the profile can still cut within the roughed stock. I would know a dimension from one of the points to the program origin.  Then you just place the rough piece on the table,
move to one point, ref all axis, now move the distance to the origin, rereference the machine, and your ready to go.

For a quick set up you may want to use set up a laser which will give you a visual for aligning the piece. Only a couple of bucks to do and woud save time.

Need to consider  how your going to hold the piece down as Gerry mentioned.

RICH    

Offline Hood

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Re: Is it possible to check part location in GCode.
« Reply #4 on: September 12, 2009, 08:55:28 AM »
M1 will probably be better as its an optional version of M0 so can be turned on or off via a button. If you have it on the code will stop and wait for a Start, if you have it off then it will be ignored.
 I often have this just after a threading cycle on my lathe, I can check the thread is correct and if not alter the code slightly and re run the thread. Once the thread is good then I turn off optional stop for the rest of the parts and it just runs through to the end without stopping at the M1.
Hood

Offline bowber

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Re: Is it possible to check part location in GCode.
« Reply #5 on: September 12, 2009, 10:21:19 AM »
The only reliable way i have of holding it down will be the three corners as they are rounded off, think of a triangular road sign (which it sort of is).
I could most likely just route in the shape in the bed and place it over and as long as the inner line is covered the cutter will remove some material, these aren't accurate or fitting into anything I'm just trying to improve things, and be cleaner) as I currently finish them by hand on a belt sander. and why have the router if not to do these sort of things.

Problem with routing the shape in the spoil board is that I have to zero to the same place every time I use the code(I could drill right through so it didn't get routed out later though), If i just have 2 points then I can zero in a convenient place and go to the first point line up a mark and then go to the second point and kind of swivel the blank round the first point.

I think I'll have a go with both ways and see which works best, having the shape routed into the spoil boards means only one setup so may be faster on the rest.

Hood, what sort of switch is needed? would a toggle switch do this and do you just put it between 2 pins, one being an earth or do I also need a small resistor?

Thanks
Steve

Offline ger21

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Re: Is it possible to check part location in GCode.
« Reply #6 on: September 12, 2009, 10:29:13 AM »
If you have home switches, you should be able to easily locate the shape in the spoilboard. Or, just do a single straight edge, and rotate the part after each edge. Do the corners on the belt sander? If you have a lot of these, a dedicated vacuum fixture would save you a ton of time, as no further cleanup would be required.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html

Offline Hood

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Re: Is it possible to check part location in GCode.
« Reply #7 on: September 12, 2009, 10:34:12 AM »
Hood, what sort of switch is needed? would a toggle switch do this and do you just put it between 2 pins, one being an earth or do I also need a small resistor?

Thanks
Steve

You can either use the On Screen switch (M1 Optional Stop) or set up a momentary on your panel and either use a Brain or an OEM Trigger.
Hood

Offline bowber

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Re: Is it possible to check part location in GCode.
« Reply #8 on: September 12, 2009, 11:29:29 AM »
Thanks Hood, think I'll try teh on screen M1 for testing.

I haven't fitted home switches to this router, my mill has them, as I didn't want the complication and extra wiring. I'm not to worried about it hitting and end as the frame is much stronger than teh steppers driving it.
However I home by eye and have set up the table size slightly smaller than the travel so the soft limits operate before it ever gets neat ot hitting anything.

As I said I'll try both and see which works best, all I really needed was the M code for the pause, I'd forgotten about them and had been looking at all the G codes.

Thanks
Steve

Offline ger21

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Re: Is it possible to check part location in GCode.
« Reply #9 on: September 12, 2009, 11:33:10 AM »
I home mine against the frame. Squares it up perfectly and gives me a repeatable reference position.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html