G41 G42 question

[cnc prog]

hello, i have some problems on a 3ax mill, when i G00 to were i would like to start my profile i dont use any D offsets until i start to cut. should i be starting half the diam. of my endmill away from were i realy want to be?
should i call the D offset before i rapid to my start point?

[ger21]

Some controls require a lead-in move where the comp is appplied.

[cnc prog]

can i leed in more then one axis? i have tried leed-in moves from 3/4 inch away from my start with x and y and had bad luck. could it be that im trying to machine machine an arc? , im using a G17 (xyI,J,and R). the machine is a daewoo dmv fanuc control

[HuFlungDung]

G18? Are you sure? for XYIJ? Doesn't sound right.

Try a short straight line movement on your lead in, before you call for a radius. Depending on the geometry, the machine may throw other errors. What does bad luck mean?

[rickyt]

also do you have the dia. or radius of the cutter in the tool call out. Do you have a cam system or just hand coding?

[ajl6549]

How about a prog. example?

[cdlenterprises]

Keep in mind that the lead in moves have to be a G1 move. I don't know of any machine that will let you rapid with cutter comp. on. It could look something like this:

Assumptions: X0Y0 = lower left hand corner
Z0 = top of the part
sample code to "lead in" to mill outside of a part

G0 X-.5 Y0. Z.1
G1 Z-.25 F50.
G1 G41 X0 D1
.......
.......
G1 X0
G1G40X-.5
G0Z.1
...

Hope this helps.....

[ger21]

Originally Posted by cdlenterprises Keep in mind that the lead in moves have to be a G1 move.

Not always. Mach3 will let you lead in with an G2 or G3. As will the Masterwood router we have at work.

[cnc prog]

no worries dudes, i worked it out, it was a raidus isue

[uav]

Here is demonstrative example to toolpaths and G-code with G42.