What's new
What's new

practical limits of parting off

Cole2534

Diamond
Joined
Sep 10, 2010
Location
Oklahoma City, OK
I have some 1" steel rod that needs OD profiled and cut to length, about 7-1/4" long and .900" OD. This gives a weight of 24oz, 1.5lbs. I'm not worried about them hitting the conveyor or the material being dented, this is a first op and it'll all get cleaned up. I do not have a parts catcher.

What I want to know is what tactics I can use to keep the slugs from bouncing around like crazy in the lathe. Limiting the spindle RPM is probably the first move to make, what else is there?
 
What I want to know is what tactics I can use to keep the slugs from bouncing around like crazy in the lathe.

I have never had a problem with parted-off pieces "bouncing around like crazy." They seem to just fall off klunk.

Big question here is, how many ? If you are barfeeding a thousand this won't work but for a smaller number, if you're worried, you can part off to maybe .050" away then finish the program, whack the thing with a deadblow hammer, and toss your part in the basket.

If you are barfeeding go ahead and try a few, I bet you find they don't flail around very much at all.

You can also build a little box for them to fall into if you are doing very many. Without knowing your turret and tailstock setup it's hard to give any better suggestions.
 
Mazak QT15n, bar pulling 100 of them this go.

I've never parted anything this large (that's what she said), but I'm constantly surprised with how some 1.3" x 1.2" slugs land in various places.
 
I am guessing you don't have any way to rig up a support? Just slow down the RPMS the last .100 or so and kick up the feed.. You should be able to figure out the sweet spot where they snap and drop from their own weight and keep the cycle time close to keeping the same RPM all the way down
 
Some of our barfed parts leave a 1.75" diameter x 5" length remnant. We part em in half. The first half drops to the conveyor while spinning and the second half gets kicked out by the barfeeder. Each piece weighs more than your parts. No issues.

When running 100 parts, you just need to plan on how you're going to remove them. At 7.25" length, they might jam the conveyor, so probably plan on fishing them out manually.
 
Mazak QT15n, bar pulling 100 of them this go.

I've never parted anything this large (that's what she said), but I'm constantly surprised with how some 1.3" x 1.2" slugs land in various places.

I don't think you'll have a problem, but if you do and you have a spare turret station, I'd turn up a cone and stick it in the empty spot. Then part to .050"-ish, drop to 50 rpm or so, run the cone in and force the longy part off from the bar, either with a straight z move or go in a ways in z then do an x.

But I suspect you won't have to.

I don't like slowing down the rpm at that small diameter very much, kinda hard on the tool, but some people do that ...
 
Some of our barfed parts leave a 1.75" diameter x 5" length remnant. We part em in half. The first half drops to the conveyor while spinning and the second half gets kicked out by the barfeeder. Each piece weighs more than your parts. No issues.

When running 100 parts, you just need to plan on how you're going to remove them. At 7.25" length, they might jam the conveyor, so probably plan on fishing them out manually.
Good point. I may put some expanded metal over the conveyor to catch the parts but let chips pass.
 
If allowed, spot drill the face. Later you can take up a center to the part. Needn’t even touch the part but only prevent it from whirling around
 
I'm with EG. Part-off to about .100" or so, using the tailstock to help stabilize during the cut.
Rather than reaching in by hand and breaking the part off, we would use the turret for the job, all programmed.
With no parts catcher, you can use Rubbermade totes or similar inside the machine, catching parts and chips. Just swap out baskets every so often...
ToolCat
 
At 7.25" length, they might jam the conveyor, so probably plan on fishing them out manually.
Can confirm. Haha.

Ran some over the weekend and they didn't like going out via the chip conveyor. At 6pts per bar I'm at the machine pretty frequently so I left the conveyor off while running the cycles, fished them out by hand, and then turn the conveyor on while I changed bars.

Not ideal, sure as hell beats running them on the manual lathe!
 








 
Back
Top