aluminium troubles

6082/HE30 alloy should be easy to get a finish on but it can age harden over the years and then you can get problems with mottled looking finishes and tearing , as said I would try material from a different supplier and hope it's not been lying around the warehouse for too long. also generating the width of the grooves with a narrower tool rather than plunging in with a full width tool will usually give a better finish under most circumstances.

hi,

the diameter is 45mm 1 3/4" its supposed to be T6 grade

just machined a previous sample (machined outside) finish is completely different and quality is excellent,

so i'm now drawn to the material as being the issue

thanks for all your help.

thought I was going mad

If the grooves are 5mm wide then the part is on the order of 70mm diameter. Speeds and feeds seem ok. What is the nose radius on the CCGT inserts? The CCGT inserts are much less sensitive to small DOC and fine feeds than CCMT inserts.

I'm with Hollowpoint, my bet is on the material, or rather less likely contaminated coolant.

Andrew

Much too slow yet again; that's what comes of checking facts and figures before posting.

Edited By Andrew Johnston on 25/11/2019 11:21:53

I get a mirror finish on 6082 with no coolant and hand ground HSS tools.

Regards Ian.

You seem to be ticking all the right boxes with coolant and tooling, I think the material may be wrong. These threads always seem to benefit in more than one way. I had no idea that MGMN inserts were available in H01 grades, now I have a box of Korloy MGMN 300-M H01 on order and a box of cheap Chinese MGMN 200-G H01, thanks to Jason B's post.