VM-22 Milling: D2 61 Rc with ceramic (Updated with PN's & Tons-o-Pictures!)

[AMCjeepCJ]

Cuts like butta! This mill is putting the hurt on these parts. It's hilarious watching all the red hot flying off without coolant! I'm amazed how easy this is with the right feedrates, rpm's etc. It's a 2 inch cutter going 1500 rpm at 60 ipm with doc of .023" (4 flute with round inserts...)

These are my baselines and it'll be getting tweaked over the next few days...

I've been having trouble finding this kind of info, so here are the fruits of my labor so far... My part has HEAVY to SEVERE interrupted cuts but I developed a custom tool path that is minimizing shock to the inserts and they are holding up marvelous. These parts are 12.5" O.D. by 5.5" I.D. and I'm facing 1/2" off of the thickness. (0.250" off both sides.) It's roughly 50 inch^3 of material in around 45 minutes.

Like I said, these are my baselines and I'll probably be able to cut at least a third off the time when I get this figured out. My insert costs are running around $15 per part machined, so I'm going to keep working on this but wanted to post a little something for people having trouble finding this kind of info...

Laters!!

((PS: due to the nature of the part this is cutting nearly three times quicker than quoted to the customer so I'm not exactly in a big yank to improve the speeds and feeds to the point where I risk anything, I know these are conservative feedrates for ceramics...)

The picture on the left is an EXTREME close-up with a 10 megapixel camera. The actual surface feels VERY smooth to the touch. The other pic is through the protective windows, so it's not super clear... You get the idea though, super hot!!

[AMCjeepCJ]

Machine is CAT 40 with 24 horsepower running around 16-23% on the load meter while cutting .023" deep by 1.450" wide.

Anyone doing this type of work please add some comments, I obviously just started doing this and would like feed back.

BTW, I'm indexing the inserts every five Z moves down and my inserts aren't chipping bad, so I'm getting roughly 16 edges per $15 insert...

[AMCjeepCJ]

I reprogrammed the tool path three times and that seems to be the KEY, figure out a way to get rid of interrupted cuts. I knew ceramic didn't like them and the IR rep didn't think it (ceramics) would even work on the edges where the bad stuff is located but through a little trial and error it seems to have cured most of the problem. Definitely NOT going to be able to use canned cycles for these kinds of applications~

[AMCjeepCJ]

Oh damn, it caught the coolant lines on fire! I wondered if that could happen~

This is just a bad picture of the sparks with NOTHING on fire....for now~

[AMCjeepCJ]

If you're going to do this on a Milltronics keep in mind the way covers have rubber wipers that the chips melt into and make a real obnoxious noise when you rapid traverse. It sounds kinda like sand in a bearing if you know what I mean. It isn't hurting anything but it's something to keep in mind if you haven't done this before. Maybe running coolant in the back and front WITHOUT hitting the cutter might fix this problem.

Update: My cutters are getting way more than 16 cutting edges per insert and they ended up only being $13 a piece for a per part cost of around $8 not $15 like I said earlier.

I'm sure someone who knew what they were doing could improve upon this a bunch but I'm just posting to hopefully help anyone with this problem find somewhere to start. I've found that trying to track down this info gets kinda pricey if you don't have a good place to start~

[msomerville]

How did you mount your air blast? I have thought about getting away from flood coolant for some applications.

[AMCjeepCJ]

One of the guys in the shop had 2 chillers for welding helmets. I ended up buying one because he was low on cash and adapted it to hook up to my programmable air blast. It just mounts straight up to the pipe thread with no special holder. I'm using the adjustable pop together pop apart coolant lines with a small end that came on the mill. Basically the airflow sucks but I only aim it at the holder to try to keep that temp as low as possible. It'll blow snow under the right conditions so you need to be careful it doesn't freeze closed.

PS
Above I wrote it took around 45 minutes to remove the 50"^3 but that includes changing inserts four times, and flipping the part twice. The actual cycle time as far as cutting is more like 30-33 minutes...

[davereagan]

Hello,
I am curious how your mill sounds while running. Do you feel the linear ways are handling the load well? Also, whose inserts are you using? Greenleaf Whisker WG-300? I saw them running some kind of steel at 45 Rc on a bigger 40 taper Hurco at Westec a couple of years ago. I just looked at the specs on your machine. It looks like they beefed the Z guideways up, and it weighs in with a Daewoo Mynx 4020 at 16,000 lbs. Nice. Did you go with a 70mm spindle bearing or 60?

Dave

[AMCjeepCJ]

60 because I normally cut aluminum but it cuts really free in the D2 and other than the aforementioned interrupted cut, it sounds REALLY smooth and the finish is very VERY nice! I'm kinda shocked really, I never expected such a good finish, I'm not even grinding these anymore, just straight off the mill to the customer since the size and finish are spot on to spec.

I bought an Ingersol Rand

1 PC TFMRN-D2.00-12-CH.F 344.00 EA
20 PCS RNGX1207CH AS20 INSERTS 13.20 EA
1 PC CAT40 3/4" PILOT SHELL MILL HOLDER #531-192 73.92 EA
INVOICE TOTAL 681.92

Total I bought 50 inserts and a retention stud and it all ran just $1,100.00

I didn't shop around so you might do a lot better on price but since they gave me everything (multiple cutters and free inserts,) including a technician for free to use for an afternoon, I can't complain.

One side note though, the rep (who used to be a tool and die guy,) brought out another holder with a four tipped insert and it cut exactly like you would expect 61 Rockwell tool steel to cut, AWFUL!! It was a recommended cutter but it was just plain bad for my application although it might be the right one if the part were shaped differently. It also did not cut nearly as freely as the full round ceramic inserts.

The holder obviously has negative rake which looks weird to me every time I pull it out but even with out replaceable seats it is one of the best designed holders I've EVER seen. It is incredibly well built and IR shell mills have a free replacement warranty just like Mitsubishi but they don't advertise this fact, you need to ask your rep...

[AMCjeepCJ]

I finally busted an insert. Well, to be honest I've broken four but this was the worst one so far. This is also probably going to be the first one that made it impossible to flip to use the backside for bout 10 more cutting edges. In other words, it cost me about $6.50 in lost edges, lol. Not sure what happened but my guess is that I didn't index it far enough and it gave way. My theory is that I'm occasionally using a little bit of the previously used portion and it causes a massive crater to form almost instantly. Only once did I stop the machine and actually reindex the insert, every other time I just looked it over to make sure it wouldn't hit the cutter head and ruin it, then just continued with the cut until the next programmed index.

BTW: I again let the last one (pictured below left) cut broken, (chipped out about 1/3 of the face and by FAR the worst break so far,) and other than the extreme extra sparking it didn't even raise the load meter more than 1 or 2 % and actually might have been cutting a little free-er. (Is that a word??) Another thing worth mentioning is that the inserts are so thick and with the negative rake you could literally brake it nearly in half without harming the seats on the cutter body. Another nice feature is this thing has bolts not tiny screws holding in the ceramics. You don't want to reef on it too hard but it'll take the abuse no problem. I've been using a couple of Mitsubishi cutters up until now and the IR is a much more durable piece of tooling.

I'm telling you what, I have roughly 1200 pounds of chips to make and I'm about half way finished already and believe me I've been anything but consistent on being at work the past two weeks. This job is a breeze! I can honestly say that I've never been happier with a purchase than I am with this particular cutter, it is far and away the nicest cutting, most reliable setup I've had in a long long time! I was dreading this job and now it's actually turned out to be really relaxing and surprisingly quiet cutting. I was super stressed at first but once I figured out what was going to catch on fire and literally burn with a flame when I wasn't looking, it became much easier. It's been about as easy as cooking hot pockets in a microwave~

Estimated IQ level required to use this cutter: 74

Pictures show the broken cutter, a new cutter and one of multiple piles of chips which are extremely light and brittle, they kind of crush to nothing when you squeeze them~

[AMCjeepCJ]

This is kind of important but I failed to put it in earlier. If you're doing this on a 40 taper it is recommended that you don't exceed 2" in diameter of the cutter by very much. You end up getting undesirable results easier if you get too wide. Plus it's extra stress on the machine for minimal return on cycle times.

Also failed to mention the inserts are .500" O.D. so on a 2.000" cutter taking .023" DOC you are really cutting around 1.400" to 1.600"+- when you calculate your SFM. Don't accidentally calculate it off of a 2.000" diameter or you'll be running the RPM's too slow for ceramics. I was told 600sfm to start but I'm a little below that if I recall correctly~

Incidentally I quite by accident took a .200" DOC pass and it cut fine but pushed my part around the magnet, no ill effects on the cutter or inserts at all. (It honestly left the best finish I've gotten so far ) I'm keeping it at .023" because if the insert completely explodes there is about .040" clearance before it hits the cutter body, giving me a bunch of time to stop the machine before I ruin a $344.00 cutter. If I was a little richer, I'd push it harder~

Hope this helps someone out. I'll probably quit posting on this thread unless peeps have questions I can try to help on...

Later!!

[carbidecraters]

Prehard milling and cover wear can lead to some really worn ways. ( )

I would also use a pointier tool and ditch the round insert.