[supermud]

Our company recently switched all Aluminum over from 2011-T3 to 6061-T6511. We are having many issues now with chip control. During turning and boring operations, the chips do not break and it is forcing the operators to have to continuously stop the machine and rip them off. We use a variety of CNC turning centers and currently use WNMG trigon turning tools and a variety of boring bars.

Does anyone have any tips to get these chips to break via different tooling or programming practices? Thanks in advance for any help!

[fizzissist]

Tried a positive rake insert? I love the WNMG's for SS, but like a positive rake for aluminum, and with a heavier feed the chips usually break up pretty well as they fold back up on themselves.
The 6061 is stringy by nature.

[supermud]

Thanks for the reply fizz. Haven't tried the positive rakes yet, but do have one on order. Hopefully that will do it.

[supermud]

Is this aluminum a problem for everyone, or is it just us?

[newc]

CNMP431 Kennametal grade KC730.

Roughing -

OD's:
600-800 surface feet
.060 depth of cut
.015 feed per rev

ID's:
same speed
.030 depth of cut
.008 feed per rev

Finish cuts can be .006 depth or so, .003-.004 feed
Slow down speed if chatter is a problem (sometimes as low as 100 SFM)

regards.,
newc

[fizzissist]

I haven't used the Iscars, but this looks like it might be the ticket.

ISCAR Cutting Tools - Metal Working Tools - Iscar Catalog : WNMG-PP

Not sure offhand which inserts there are which will give you the positive rake AND those cute little dimple/bump chipbreakers right behind the cutting edge...but with sufficiently heavy feeds they should work great.

I'm inclined to think that the stringy chips would be more a problem with shallower DOC, and lighter chip loads. But since I often ran very short runs back to back switching from 304L SS to 6061 and back, I used the same inserts, and just programmed to do multiple retracts to make sure chips were getting cleared. It was always a PITA, but it worked.

I'd like to hear what inserts you end up using and how it worked out.