[Mike4703]

Today I was cutting rings in a piece of material that was made from a layer of brass bonded to a layer of fiberboard. The board was secured to the top of my rotary table with axis lined up with the Z axis. The board was large and extends past the edge of the rotary table. I had to take light cuts slowly as I got out near the edge. So I had the idea that I could make a helical cut that would take off .010" per revolution. It needed to go down to .070" so seven revolutions. I tried to do it in one line of code figuring that each axis motion would be proportioned to end up at the end point at the same time. So I multiplied 360 degrees by 7 to get 2520 degrees. So the code line read:

G01 A2520 Z-0.070 F50.

But when I ran it, it went down .070 each 360 degrees which was too much and I had to abort the movement. So I ended up breaking up the movement into seven lines that moved down .010" each. This worked Ok.

Is there any way to program this movement in one line of code?

Attached is a photo of the finished piece.

[SirDenisNayland]

with a macro you could pull:

#100=360
WHILE #100LT2520 DO1
G1 A[#100] Z-.01 F50.
#100=#100+360
END1
#100=360

6 lines..

Shrug. But, here's likely a better way:

The reason it went down .07 in one pass is because 2520 is equivalent to 360, so the control probably reads that as the same position, because really it is.

I'm going to assume you were in G90. Try with G91 and see what happens.. in this way you're not telling it to move to a specific position, but to move a specified amount from the current position.. and I think that may work.

[Mike4703]

You are right I was in G90. I'll try something in G91 tomorrow.