Trying to understand Compensation for Turning

[thebestjessins]

So I've been running into a problem frequently that to me seems like it should be simple but I can't figure out a clean way to do it. I turn a lot of decorative pieces and recently got into CNC stuff with an old 2- axis using a Fanuc controller. I understand pretty well how to use the cutter compensation for just moving the cutter to the right, or just to the left but when the I want to do a radius in or out, like a large ring groove or a raised 1/8" half round I am not sure how to do it neatly. When the cutter gets halfway through the radius it switches from being on one side of the material to the other and it cuts wrong. It does not like trying to switch sides in the middle of the cut. If it's an outside radius I can use a right and a left tool and blend it in the center I feel like for shallow bumps I should be able to use a neutral and have it comp for both sides in one pass. On groove cuts it seems harder to blend perfectly because it's in the center and when it moves the cutter to the left or right to begin the comp it puts a line on either side of the blending. I've tried to use a large radius shaper but the geometry gets really hard when it's not just an even groove. Sorry if this isn't making sense and I can clarify if it helps. Is there a easier way to do these kind of cuts?

Similar Threads:

• Newbie- I clearly don't understand something
• Newbie- Trying to understand what I need?
• Help me understand

[thebestjessins]

So today I was having trouble with a decorative facing radius that blended into another radius. From the center there is a large arc that sweeps to the collet until it's vertical, then into a smaller radius that curves back toward the carriage that ends in a sharp ring like radius. Sort of looks like a top with a ridge around the edge. I can use g41 with a 7 style cutter to cut the radius that moves back outward and then half of the ring radius but I can't use it to cut the larger taper because of the tool shape. I feel like I should be able to use a neutral tool to cut both of the larger sweeping radius cuts but it doesn't seem to cut correctly like that. It stays on the right but it cuts one of the curves wrong. Can you switch between g41 and g42 while cutting? Is there rules as to when like during vertical or horizontal cuts? I would prefer to do this in a few continuous cuts as possible and it seems like something I should be able to do without a huge amount of effort but it's not working for some reason. I don't have any issues with cuts that are all one direction but when they come back on themselves I can't get a system figured out that works reliably. And just fudging numbers around doesn't seem very practical or repeatable.

[timlkallam]

So today I was having trouble with a decorative facing radius that blended into another radius. From the center there is a large arc that sweeps to the collet until it's vertical, then into a smaller radius that curves back toward the carriage that ends in a sharp ring like radius. Sort of looks like a top with a ridge around the edge. I can use g41 with a 7 style cutter to cut the radius that moves back outward and then half of the ring radius but I can't use it to cut the larger taper because of the tool shape. I feel like I should be able to use a neutral tool to cut both of the larger sweeping radius cuts but it doesn't seem to cut correctly like that. It stays on the right but it cuts one of the curves wrong. Can you switch between g41 and g42 while cutting? Is there rules as to when like during vertical or horizontal cuts? I would prefer to do this in a few continuous cuts as possible and it seems like something I should be able to do without a huge amount of effort but it's not working for some reason. I don't have any issues with cuts that are all one direction but when they come back on themselves I can't get a system figured out that works reliably. And just fudging numbers around doesn't seem very practical or repeatable.

My lathe with a Fanuc ,cutter comp only works ascending or descending not both at the same time.
If you can program without cutter comp off you won't have this problem.
I haven't used cutter comp on a lathe in 20 years. I feel there just no need for it if the cam software
compensates for it. But for the mill I use cutter comp daily.

Get some cam software you can get Autodesk fusion for free.

https://forums.autodesk.com/t5/desig...t/td-p/6280628

[dcoupar]

A drawing of what you are trying to program, and a sample of your program would be nice...

[mbservice]

Need a drawing if you send by private message I'll give you the program