[pradeep]

I know that pinch turning is achievable with the roughing tool leading the finisher in Z by a a small distance.

But if we want to use it purely in roughing cycles, it is possible to have a zero lead in Z? i.e Is it possible that both tools are fully synchronised to work on exactly the same profile and at the same X and Z and have double feed?

Thanks in advance for any inputs.

[TheBigJW]

What if you just started one farther off the end of the part by half the feed per rev.

John

[littlerob]

I know that pinch turning is achievable with the roughing tool leading the finisher in Z by a a small distance.

But if we want to use it purely in roughing cycles, it is possible to have a zero lead in Z? i.e Is it possible that both tools are fully synchronised to work on exactly the same profile and at the same X and Z and have double feed?

If I understand the question right.... the answer is NO. If the material is not there, it is not there to remove, double the feed or not, but if the "second" rougher were a little bit behind the first, it could be "roughing" the next pass--same profile. We are talking about an NZ right (two turrets)? One roughing on top one roughing underneath?

Robert

[zooloader]

Pinch turning is when you have a Y axis and drop one tool below centre height, anywhere upto 0.5mm!

If you want to have one tool "leading" in Z it is normally at a larger diameter than the "trailing" tool, eg. 3mm DOC on 100mm bar stock = lead tool @ 94mm and trail tool @ 88mm with NORMAL feed rates.
This is good for straight turning.

I'm currently turning copper bars using both tools at same diameter and same Z postion, and DOUBLE the normal feed rate, and normal DOC. (Using upper and lower turrets, obviously).
This is good for profiling.

[pradeep]

Pinch turning is when you have a Y axis and drop one tool below centre height, anywhere upto 0.5mm!

If you want to have one tool "leading" in Z it is normally at a larger diameter than the "trailing" tool, eg. 3mm DOC on 100mm bar stock = lead tool @ 94mm and trail tool @ 88mm with NORMAL feed rates.
This is good for straight turning.

I'm currently turning copper bars using both tools at same diameter and same Z postion, and DOUBLE the normal feed rate, and normal DOC. (Using upper and lower turrets, obviously).
This is good for profiling.

Yes. This is what I was mentioning.
Does it not work well for roughing?

[zooloader]

It works great for roughing.

Some guys get it going so well, they don't need a finish tool.

Just make sure your tool offsets are spot on, and the tools pockets and seats are in good condition for repeatability.

Have fun!

[the thrill]

if you're on a mori dual turret machine (zt, zl, nz, nzl) you can use the G68 balance cutting cycle (rtb to get the format)

i've never heard of shifting Y in a pinch application... just double your feed rate because the tools only see 180 degrees of the material