Parting Off In The Mill

allloutmx · Dec 13, 2016

Ive never been a fan of using anything that looks like a keyseat or slotting cutter. Having evolved into a grown woman now and moving past the fear in slotting cutters, I plan on machining many parts from a single plate and at the end my intentions are to use a keyseat cutter or something of the like, to run around the profile of the part .700" deep but leave a small portion intact so I may break them off the sheet and continue with the manufacturing process. The shape of the part is not concentric to itself. The part layout allows for a 1/2" shank in between the parts. With a 1"dia cutter on a .5" shank, I will be engaging two parts at once in some areas and a .215 radial depth of cut. The part material is aluminum. Can anyone forsee any issues with such a large radial DOC? Im a little worried about chips stuffing up in there but there I go being an adolescent female again. Right now Im looking at a slotting cutter from internal tools but I am definitely open to suggestions. I was also thinking to have AB make me something special and try and get down to a 3/8 shank.

Thanks in advance
:cheers:

scojen · Dec 13, 2016

Alllout

Pictures or a sketch please !

Larry Dickman · Dec 13, 2016

I don't think you'll have a problem. Make sure you indicate the cutter in. Wobble is not your friend. Be sure to keep it wet, lots of coolant. And make sure you're clear of material before you feed up or down. :wall:

allloutmx · Dec 13, 2016

The grey circle is the cutter

The red line is for my reference-not a tool path

allloutmx · Dec 13, 2016

Larry Dickman said:
And make sure you're clear of material before you feed up or down.

Lol-one of my greatest fears. Kuhchunk

Vancbiker · Dec 13, 2016

I have several jobs that I cut off the stock held in a dovetail fixture. I use Internal Tools 78 series saws for that. Never done the two sided cut at once though. Your concern about chips is valid. There is a noticeable improvement in the sound of the cut when I'm really careful about aiming the coolant flow. I use a 1" diameter .078 wide tool and routinely go .325 radial depth in a single pass. 5k rpm and 50. IPM.

MaxPrairie · Dec 13, 2016

Is there a reason you cant use 10 or 20 thou tabs and pop out that way? Then you could decrease your spacing.

Bobw · Dec 13, 2016

Come on man, put your big girl panties on..

Single pass and DONE.

allloutmx · Dec 13, 2016

MaxPrairie said:
Is there a reason you cant use 10 or 20 thou tabs and pop out that way? Then you could decrease your spacing.

Perforating would be my last ditch effort but the spacing would probably stay the same for the sake of using a larger tool to cut the profile vs a smaller

allloutmx · Dec 13, 2016

Bobw said:
Come on man, put your big girl panties on..

Single pass and DONE.

That the one thats impregnated with MOly Dee? Looks pricey

Bobw · Dec 13, 2016

allloutmx said:
That the one thats impregnated with MOly Dee? Looks pricey

About $20 or so at the hardware store, works surprisingly well on Aluminum and Plastics...
I haven't had the balls to try it on any kind of steel.

I think the lightning bolt cut outs are what actually make the difference. Without those it probably couldn't
cut butter.

garyhlucas · Dec 13, 2016

I'd be a bit concerned about the part breaking loose at the end and getting tossed by the cutter.

dstryr · Dec 13, 2016

You will be money and time ahead to build these out of strips on your new robodrill rather than fucking around with this plate idea lol.

Build a mitebite fixture that runs 10 strips of 3 parts on your left side of the table and use a vise to second op them.

If you are dead set on the plate idea I'd drill and tap under the holes for all the parts. Screw in some bolts with a electric or air drive, profile down leave .010 connecting the plate then go around the oustside leaving .001 stock on the walls to break through. Then run a 3/8 x 45* dovetail tool to deburr the back sides.

Zahnrad Kopf · Dec 13, 2016

Really have to agree with Dino, here. ( don't let him see that ) Now that you're Fanucing Roboshite, you would do well to look at new methods that lend themselves to actually optimizing your set-ups and taking advantage of what that thing does well. Seriously. You're a smart guy and have made huge strides in a short time. Now it's time to start using your head and give your back a break.

SND · Dec 13, 2016

Ive done it on much smaller parts in stainless, usually part them off with a good carbide slitting saw, or sometimes with a woodruff cutter.

I'd try to use strips instead of sheet as well to buzz them all off in a straight line and easy chip clearing/coolant access all around.

allloutmx · Dec 13, 2016

The reason I am going with the plate is so that the machine may run "unattended". I have a decent amount of prototype work coming in, and since I also work a day job my hours of machine runtime at home are limited. So the idea is to run prototype work when I get home, leave the tools set up but I will have to swap them out at the end of the night with the trigger guard tooling, and run the plate on the back jaws. The plate will be bolted to a sub plate. That would have a 2-2.5 hr run time, so it would run while I slept, I could load it again in the morning, and if I had enough subplates ready to go, the wife could also load it during the day. This would allow me to leave the prototype work setup in the middle jaws and all I have to do is swap the tooling and the offsets.

If I were to cycle this job in and out any other way, Im not sure the setup iin/out would be worth the time. Initially, I had planned on doing this in strips using fixture plates, but I dont see the machine running long enough to warrant the nightly change overs.

Rstewart · Dec 13, 2016

Way to think outside of the box, but I'm not sure the plate would be the best.
Like Dennis said make a fixture to hold several pieces of bar stock. You'll still get the unattended run time you need I think.
What the hell do I know, the plate may work fine as long as it's supported well underneath.

allloutmx · Dec 13, 2016

Rstewart said:
Way to think outside of the box, but I'm not sure the plate would be the best.
Like Dennis said make a fixture to hold several pieces of bar stock. You'll still get the unattended run time you need I think.
What the hell do I know, the plate may work fine as long as it's supported well underneath.

Well it is a little bit of a gamble. Ive never done parts like this myself. But a change over is going to take 15min easy. I will have to do two change overs per night so thats 30min every night just doing change overs. 1st op is about 2.5min per pc so your looking at an hour 15 unattended vs 2hrs45min off the plate. The strips would be far easier but not nearly as efficient.

wheelieking71 · Dec 13, 2016

I vote strips as well. Lots of them.
I understand what you are doing and why. But, don't create cycle time, just to have a long cycle time.
Far less cutting if using strips! If you need more cycle-time (I get it!) figure out how to get more strips in the machine.

I am also betting the material will be significantly cheaper. And, depending on how you are holding that plate? you might have chatter issues.

I personally would nest them in strips, and use a 3/8" EM. What is your max RPM on that little beastie?

Back to your original question though. I have a custom brazed carbide jobbie from AB that I run in a much sketchier situation than you are proposing.
You will be fine. Staggered teeth FTW if you go HSS. As mentioned, you need coolant! (HSS works fine as well bye the way)
It might take you a few tries to dial in the smallest nubbie you can get away with, before they do dumb shit.

Spyderedge · Dec 13, 2016

Bobw said:
Come on man, put your big girl panties on..

Single pass and DONE.

I have done that actually, not carbide tipped but it cut through aluminum just fine on the ratty Bridgeport. Dangerous as #### though.

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