2" Banggood Face Mill Issues

[tonydi]

I would try dialing up that RPM. I assume that you are running that face mill in mild steel? If so, then try 1200 RPM so you can get your SF/M to up 600ish. Then, feed the mill according to what gives the best results. I would do a DOC of something like .005".

That seemed like such a fast speed, considering the size and number of cutters, even more than I use for a regular end mill of much smaller size. But I'll give it a shot tomorrow and see what happens.

Whoops sorry I missed that @tonydi

No problem, David. I get wordy and so I'm used to some of my info getting lost.

 

[matthewsx]

It seems counter-intuitive but often going at it hard and fast is exactly what's needed. Carbide wants to work hard, that's what it's made for.

John

 

[Lo-Fi]

Yep, you need to work it hard for the best results. Dial up that rpm and don't be scared to give it a decent DOC and feed. In steel, if the chips are curling off like little bullets and turning blue, that's when I get the best surface finish with my 3" face mill. ~1500rpm, 0.5mm DOC and ~100mm per minute for that tool. Bizarrely, it leaves the parts quite cool with the chips carrying all the heat away! Babying it in speed or feed gives less than great results, but light DOC is OK.
That being said, I've got an import 25mm insert end mill with cheap APMT inserts and have yet to achieve the same great finish as the 3" with square SPMN Valenite brand inserts. I'd definitely recommend steering away from import inserts and trying to find some NOS branded ones. I get some bargains on Sandvik and suchlike on ebay, which knocks spots off the cheap import stuff.

One final thought: put an indicator under it in the spindle and check that all the inserts are running the same height. I wouldn't be surprised if the pockets in the holder aren't true and they've not running the same height, which also has an impact on finish.

Interested to see how you get on.

 

[38super]

Make sure the shell mill is snug to the arbor, found out mine was loose. Fixed with a couple washers

 

[tonydi]

Make sure the shell mill is snug to the arbor, found out mine was loose. Fixed with a couple washers

It is tight although I did add a hardened washer under the SHCS when I first got it just because.

Ok, I cranked the speed up to 1200 RPM today and while the finish is slightly better it still is pushing the metal and not cutting it. The red section is a .010" DOC with a feed around 2"/min. The yellow section was from yesterday's slower speed test.

I checked the insert heights and they were all within +/- .0015" of each other. I don't know if that's good or bad, though.

I then put a block of 6160 and ran it at 900 RPM and while it's also better than yesterday's slower speed run, it's still not much to write home about and it also seems more like it's pushing metal instead of cutting it. Both pieces had ugly burrs along the edges which was another indication that it's not cutting.

I didn't want to push it any faster because things start falling off of shelves at 1200 RPM. ;-)

 

[macardoso]

So you might be also running into an issue where the rigidity and accuracy of the tool and your machine are coming into question.

First off, your mill is not the most rigid thing in the world (not an insult - mine isn't either) and running a 2" facemill might be flexing the column, head, spindle, etc.).

Second issue is the tool itself. How much runout (TIR) does it have. It is likely you are only cutting on one insert. Same goes for the axial positioning of the inserts. Are they all pretty close to flat or does one stick out further?

Finally I question how accurately the insert pockets are machined. Are the inserts being held at the correct angle for cutting. This one is very hard if not impossible to measure at home. High end indexable tooling is very expensive and there is a good reason for that.

 

[bill70j]

Any ideas if I can make this thing work or did I just put too much faith in the YouTube reviews and the face mill is just not suited for the little machine?

FWIW, I have that exact same face mill and use those Blue Nano inserts for steel and these inserts for aluminum.

I get a very nice finish when limiting DOC to 0.010" and using 200SFM for steel and 400SFM for aluminum.

My mill is an old Enco BP clone - so maybe that's the difference. Also, I wonder if your material is mild steel. Looks like it might be something harder than 1018?

 

[higgite]

tonydi,

When you take a .010" DoC, is the work piece actually .010" thinner than before the cut? In steel? In aluminum?
Do you lock the Z-axis when you make a pass with the face mill?

Tom

Edited for clarification... hopefully.

 

[bill70j]

Tom:

Yes, using this face mill purchased from Bangood, I expect to come within +/- 0.0005 - or better - of target DoC on mild steel and on aluminum. That would be for a final, finishing cut.

Bill

 

[higgite]

Tom:

Yes, using this face mill purchased from Bangood, I expect to come within +/- 0.0005 - or better - of target DoC on mild steel and on aluminum. That would be for a final, finishing cut.

Bill

Bill, I should have been more clear. I was asking the OP in hopes of finding out if his face mill was actually making the intended DoC or just skimming over the top. You're supposed to magically know what I meant. I also wonder if he locks down the Z-axis when he makes a pass. I've edited my original post to make things clearer. Thanks.

Tom