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Blind Broach Standalone Machine

70olds

Aluminum
Joined
Jun 21, 2016
Good Morning,
I am looking to do edit* a large quantity of* a blind broaching operation akin to a small keyway that's .25" wide x 1" deep inside a 1.25" bore but I want to take it out of the machine and set up a standalone operation. This is a recurring thing that's not going away. I'd rather not use a 5 axis machine to broach a part for time and expense reasons, which is unfortunately how we are doing them now. It can be completely mechanical, just has to have some semblance of safety since it will be operator run. As long as I can set a fixture in it to hold my part and then set stops to make fine adjustments that should be about all I need. Any idea who makes such a thing that I can look at?
EDM is not feasible for the time it takes to do.
 
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If it's really blind, I think the cheapest sinker edm would be the best bet, unless it's like ten parts. If you can have a relief groove then there's a lot more methods but no tool likes to run up against a hard stop. And those internal keyway cutters don't work very well, are fragile and expensive and that's kinda tight for them. Might be the best bet if there's only ten parts tho.

(Shaper tools do not like to run up against solid metal, guys. Jesus. Altho he could potentially use like a keyseat cutter to put a relief mostly under the keyway. Or sort of halfway mostly).
 
If it's really blind, I think the cheapest sinker edm would be the best bet, unless it's like ten parts. If you can have a relief groove then there's a lot more methods but no tool likes to run up against a hard stop. And those internal keyway cutters don't work very well, are fragile and expensive and that's kinda tight for them. Might be the best bet if there's only ten parts tho.

(Shaper tools do not like to run up against solid metal, guys. Jesus. Altho he could potentially use like a keyseat cutter to put a relief mostly under the keyway. Or sort of halfway mostly).
Standard practice for a blind keyway is to drill a slightly larger hole in the OD where the keyway ends. They could use something like the picture shown. I ran that very machine back in the late 70's. It still sits in that same building to this day, unused, as are all of the other machines.
 

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Standard practice for a blind keyway is to drill a slightly larger hole in the OD where the keyway ends. They could use something like the picture shown.
Ja, if that's acceptable, and there's new ones

slotter.jpg

and 6" pratt & whitneys are not impossible to find, and there's a nice smaller douglas that would do the job and take less space, and there's brand new cnc slotters that might be able to do a synchronized pullout at the end and it wouldn't hurt to know the material but do we get any information ? How many parts !? What does "blind" mean ? Has to be blind, run up to a solid shoulder or can it have an curved exit ? relief groove ? hole drilled through ? some other method of giving the cutter a place to exit ? Basic stuff.

Makes you want to cry. People here have never got a quote before ?

Sorry, '70, but c'mon. You ain't no noobie in junior college with a term project to finish.
 
I should have specified, and have since edited my original post. This is a recurring large quantity thing. It is worth it to purchase a machine to do it. I only gave one example but there are several similar features that we would need to do. We have a RAM but it would take longer than the entire rest of the part. I can get a little relief behind where the cut needs to end as EmGo was asking so the material can shear off.
 
Ja, if that's acceptable, and there's new ones

View attachment 438382

and 6" pratt & whitneys are not impossible to find, and there's a nice smaller douglas that would do the job and take less space, and there's brand new cnc slotters that might be able to do a synchronized pullout at the end and it wouldn't hurt to know the material but do we get any information ? How many parts !?. What does "blind" mean ? Has to be blind, run up to a solid shoulder or can it have an curved exit ? relief groove ? hole drilled through ? some other method of giving the cutter a place to exit ? Basic stuff.

Makes you want to cry. People here have never got a quote before ?
I can't be overly specific with the product and I also don't want to get keyholed into a machine that can ONLY do one thing, because yes I have gotten quotes before and salesman tend to sell you on what THEY have, not what's best for your application. I'm not asking for a quote, just general information to start looking to evaluate.
Quantity will be thousands to tens of thousands a year.
I said blind because I didn't want to waste people's time looking at traditional "pass through" style broaches. I am not going up to a wall per se, but I do need to limit the end point of my stroke in the direction of the broaching. No curved exit but a relief can be added so it's not stopping at a solid wall.
No hole is or can be drilled but there's not a ton of material to be removed.
 
I should have specified, and have since edited my original post.
Sorry, 70 ... it's frustrating that this is such a recurring thing here. Getting all the facts can be like pulling teeth.

It'd be easy to do in a little slotter, and they are available ? But since you said "large quantity" and it's 2024, and you want to do it as a separate op I would personally look into a cnc shaper and a simple robot loader. You could get away with very little manual input that way, the parts should just run and run and run. Predrilling or milling saves a lot of life on a shaping cutter and might be worth experimenting but not necessary for the concept.

If this were a lathe part I'd mention there are slotting attachments for live-spindle lathes. But seems like not.

About "only doing one thing", sorry but cutting keyways is pretty specialized, those machines aren't exactly universal milling, turning and grinding centers :)
 
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If you were to do it in a turning centre you could use one of those high speed broaching heads that work off the driven tools. That way you could also do the undercut in cycle with a groove milling cutter, if you didn't want to turn a full relief or drill a hole.

Should be a very quick cycle.


Edit: Does nobody make an aggregate head similar to this but for a mill? That way you could do it in cycle, but I haven't ever seen such a thing, presumably they don't exist...
 
Edit: Does nobody make an aggregate head similar to this but for a mill? That way you could do it in cycle, but I haven't ever seen such a thing, presumably they don't exist...
Volstro and somebody else used to built lightweight slotting heads for a bridgeport that went in the spindle. You could probably get someone or do it yourself to build something similar but better. They were not very heavy-duty but might work for this ? Then it wouldn't have to be a separate op, either.
 
Is it really going to be less expensive or faster to do it in a second op rather than do it complete in the 5 axis machine?
My impulse is to put the cheapest used 2 axis cnc lathe on the floor and do it in that, would give you power clamping fast operation and easy cut adjustment, even coolant and chip management. Since the spindle is not turning the spindle bearings can be worn out. Possibly robotic loading and unloading.
 
My impulse is to put the cheapest used 2 axis cnc lathe on the floor and do it in that,
Rework an old gear shaper like a 7 or an 8 so it only infeeds (was not uncommon), totally automatic just push 'start', power clamping, much faster cycles than you'd get with a lathe (iirc a 7 runs up to 900 strokes/minute ?) .... but long-term, maybe a custom slotting head on the mill you are now using for the rest of the part would really work the best. Do it all at once.
 
A cheap old Haas or something to just go down, up, over, and repeat?

Are we sure the slot cant go all the way through? Sometimes the designers dont realize how difficult it is to make something they have designed. Good luck!
 
A cheap old Haas or something to just go down, up, over, and repeat?

Are we sure the slot cant go all the way through? Sometimes the designers dont realize how difficult it is to make something they have designed. Good luck!
I'm positive the design is locked.

The vertical shapers look like they would give me what I want. Now I just need to find one that's half decent.
 
The vertical shapers look like they would give me what I want. Now I just need to find one that's half decent.
Those big slotters are slow and run manually. A 7 fellows will run about 400 strokes per minute, an 8 is a little faster - 600 ? a 10-2 (too much money and too big ?) is over a 1,000. If the part is small a 3 is faster than a 7 and much smaller. All of them can be set up to just plunge straight in (takes a special drive arrangement but it's not difficult), and they are all automatic, just push go.

I had a long-running job of some 12t 16/32 pinions, so about 3/4" diameter, cycle time was under a minute and that wasn't pushing it. Biggest problem was changing parts fast enough.
 
Cams makes a slotter that has a automatic cycle From startposition it goed to the beginning of the slot with rapids Then slots to depth an then returns with rapids
But with a stepper motor and some comtrols every shaper can be made to do so

Peter
 
Just buy a cheap Haas and getter done.
Can also be used as a vertical machining center when not being used.
 
Mitts and Merril, maybe a new name by now, makes a cnc slotter/keyseater that is pretty cool. It can ramp out at the bottom of a blind keyway and do all knids of indexing. Only trouble is, they are quite expensive.

Seems like the cool stuff always is.
 








 
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