How does Z stock to leave work in g71 type 2

Hi all,

I am about to run a g71 type 2 program on my lathe. I have never run a g71 type 2 before.

My g71 line looks like this:

G71 U.05
G71 P101 Q102 U.005 W.005 F.003
N101 G00 X.6 Z.1
.....

Question:

If I tell the machine that the stock to leave is +.005 on the Z (w) like on the line above, I understand it will leave .005 on the front of the faces, just like on a standard g71 type 1. My question is, will the g71 type 2 REMOVE .005 of material if the tool is feeding down a face while turning in the negative z direction?

For example, if you have an angled land on a diameter, I understand the tool will leave +.005 on the front of the land in the z. However, will it remove .005 on the back of the land during a g71 type 2?


Angelw you probably know this

Thanks,

Chris

cgrim3 said:

Hi all,

I am about to run a g71 type 2 program on my lathe. I have never run a g71 type 2 before.

My g71 line looks like this:

G71 U.05
G71 P101 Q102 U.005 W.005 F.003
N101 G00 X.6 Z.1
.....

Question:

If I tell the machine that the stock to leave is +.005 on the Z (w) like on the line above, I understand it will leave .005 on the front of the faces, just like on a standard g71 type 1. My question is, will the g71 type 2 REMOVE .005 of material if the tool is feeding down a face while turning in the negative z direction?

For example, if you have an angled land on a diameter, I understand the tool will leave +.005 on the front of the land in the z. However, will it remove .005 on the back of the land during a g71 type 2?


Angelw you probably know this

Thanks,

Chris

Click to expand...

Hello Chris,
Your understanding is correct. Whatever you leave as a finishing allowance for the leading edge of the tool by specifying a W+ value, will cut more by the same amount with the trailing edge of the insert.

If the faces to be cut with the Leading and Trailing Edge respectively are both not perpendicular to the Z axis, then its common to specify W as Zero and increase the finish allowance for X by specifying a larger U value. This will provide a small finishing allowance for both the Leading and Trailing Edge faces.

If the face being cut with the Leading Edge is perpendicular to the Z axis and the face cut with the Trailing Edge not, then a finishing allowance can be set with W for the Leading Edge face and a larger X finishing allowance specified so that a finishing allowance will result for the Trailing Edge face.

Regards,

Bill

Thank you Bill that was very helpful. I appreciate it.