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General Mach Discussion / Re: Rotate Mill head
« on: October 24, 2014, 01:45:52 AM »
Hi QA:
You don't say if you can rotate the mill head, to enable the spindle to be parallel to the X axis, however there is a lot to read before you will get something to work. In the terminology of G-code, the three planes are as follows:
G17; X,Y plane, with the Z axis perpendicular to the plane.
G18; X,Z plane, with the Y axis perpendicular to the plane.
G19; Y,Z plane, with the X axis perpendicular to the plane. This is the active plane you are describing.
If you will look in the G-code definitions, starting with the descriptions of G02, G03, they discuss the relative offsets to be used for each of the above planes. For the G19, the offsets are J and K.
You can play with some lines of code, and watch the tool path screen. The G-codes in the Mach3 program have very few examples to go by. I do not have the book, but the best source for G-code description are the books by Peter Smid. His CNC Programming Handbook in up to the 3rd. edition.
Look on Amazon, they have an entire page for the books on CNC by Peter Smid.
Changing the plane of activity from the normal X,Y is pretty obscure for this forum. I had to do a machine job using G18, to enlarge a mold cavity, and it took a lot of playing around to get it working. I ended up doing the job, but there was a bug in the Mach3 display, and instead of showing a half-circle cavity, it showed a full circle. At first I thought I had written the code wrong, but doing a dry run, with no tool, the motion tool path on the screen was actually correct, and did not move into the upper half of the circle shown on the screen. In my case, the path was the center of a ball mill, and milled a perfect half-circle cavity.
Smids books are not cheap, but from all I have read, they are the best.
John
You don't say if you can rotate the mill head, to enable the spindle to be parallel to the X axis, however there is a lot to read before you will get something to work. In the terminology of G-code, the three planes are as follows:
G17; X,Y plane, with the Z axis perpendicular to the plane.
G18; X,Z plane, with the Y axis perpendicular to the plane.
G19; Y,Z plane, with the X axis perpendicular to the plane. This is the active plane you are describing.
If you will look in the G-code definitions, starting with the descriptions of G02, G03, they discuss the relative offsets to be used for each of the above planes. For the G19, the offsets are J and K.
You can play with some lines of code, and watch the tool path screen. The G-codes in the Mach3 program have very few examples to go by. I do not have the book, but the best source for G-code description are the books by Peter Smid. His CNC Programming Handbook in up to the 3rd. edition.
Look on Amazon, they have an entire page for the books on CNC by Peter Smid.
Changing the plane of activity from the normal X,Y is pretty obscure for this forum. I had to do a machine job using G18, to enlarge a mold cavity, and it took a lot of playing around to get it working. I ended up doing the job, but there was a bug in the Mach3 display, and instead of showing a half-circle cavity, it showed a full circle. At first I thought I had written the code wrong, but doing a dry run, with no tool, the motion tool path on the screen was actually correct, and did not move into the upper half of the circle shown on the screen. In my case, the path was the center of a ball mill, and milled a perfect half-circle cavity.
Smids books are not cheap, but from all I have read, they are the best.
John