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1. ## mach3 wizard for to adjust gcode to work piece

hello all,

i am looking for a tool to change the gcode to the actual position of your workpiece on the machine table.

lets say you have an irregular shaped piece on your vacuum table with two points that would define the location. lets say you have a star and if you probe two ends of the star rays you would know the position.

now i am looking for a tool that would change the gcode, the x and y values, to fit the actual position of the work piece. so you probe two points and the gcode is changed.

i think i read somewhere a while ago about such a tool but i cannot find it.

does anybody know?

thanks,
michael

2. ## Re: mach3 wizard for to adjust gcode to work piece

According to Dan Fritz explain coordinate rotation & scaling?

Axis scaling (G51, G50) and axis rotation (G68, G69) are options that not very many people use, but they are helpful in some situations.

The scaling option expands or shrinks all the points around a "center point". You can scale one axis at a time, or you can scale multiple axes if you want. It's useful for compensating for a shrinkage factor, or for making non-circular arcs. For example, if you program your machine to mill a square pocket, you can set the scale center point to the center of the pocket, scale X to say, 90%, and you'll cut a rectangular pocket with the X dimensions shrunk by 10%. If the center point you specify isn't in the center of the pocket, the pocket will be scaled in X like before, but it will also "shift" in the X axis also.

Rotation is similar. All the points in your program will be rotated around a center point by the angle you specify. Rotation is nice if you have a fixture that's not quite lined up with an axis, and you want to avoid using an indicator it to make it straight. Some machines like Monarch use a probing routine to check the fixture and compensate with a wee bit of rotation automatically.

I've used rotation to mill the profile of a large 50-tooth gear by programming one tooth of the gear in a subroutine, then calling the sub 50 times with an angular rotation each time. I used some macro statements to calculate each angle for the G51 command.

... Just be sure to cancel these functions after you use them!

Some other tips
Do G68/69 coordinate rotation. Scaling before rotation.
You must scale XY then Z

3. ## Re: mach3 wizard for to adjust gcode to work piece

If you simply want to move a part around on the table Use one of these to offset the Point of origin X0,Y0

G52
G92
G54-259 fixture offsets

Just a thought, (;-) TP

4. ## Re: mach3 wizard for to adjust gcode to work piece

thanks kdoney,
i think the g68 is what i am looking for.

i thought of writing a macro but i dont have much experience with it. so here is what i thought:

first in your cad software you take one point on your model and define that as zero point.
then take a second point, measure the x and y difference, and the distance. the distance will later be the radius.

on your machine toggle to the first point and zero axis.

enter the x and y difference and move the machine to that point.

unlikely the machine will be exactly over the second point so you would now toggle on a circle arround the zero point where the radius is the distance between point 1 and 2.

if youre above the second point you can see how many degrees you had to toggle and use that for the g68.

would that work or does anybody have a better idea?

thanks,
michael