I need ideas on how to turn this tiny part

implmex · Jun 28, 2019

Good morning All:
Here is a question for all you turners out there, especially those with micro turning and subspindle experience.
I have a tiny turned cup to process plan and quote in Ti6Al4V titanium; the customer wants quotes on up to 1000 parts per run.
A section view of a Solidworks model is attached below.

The part is 3mm diameter and 1 mm tall.
The wall thickness is 0.1mm (0.0039").

There are no tolerances stated...we are negotiating those but it looks like it will be +/- 0.001" for diameter and parallelism of the flat back face.
No cutoff tab is allowed so it will be 2 Ops.
Assume we can put 0.0015" max rads in the corners.

What machine would you choose?
How would you go about it?
What would you charge to make these in lots of 1000?
I'll likely farm this out...1000 of these at a time on a Prodigy gang chucker sounds more like pain than pleasure to me...especially chucking the part for Op #2

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

Milland · Jun 28, 2019

Bah, that's a stamping op, no turning needed. Getcherself a nice press and some .004" Ti sheet and go to town!

(Almost not kidding, I bet this could be done as a stamped part within needed tolerances).

Booze Daily · Jun 28, 2019

Probably medical. 6AL4V ELI is only available in round.

Swiss?

Conrad Hoffman · Jun 28, 2019

Seems like a Swiss turn part.

npolanosky · Jun 28, 2019

Yeah, swiss for sure.

litlerob1 · Jun 28, 2019

For the quantity, I'd say Swiss CNC also.

But I've built very similar parts on the Hardinge/Omni machines. I've got two, so front facing, need attending for the 2nd op. But I bet I could complete 1000 in 15 hours or less. First op would be bar fed, obviously. Then you just need to try and keep up loading and handling the second op.

R

avto762 · Jun 28, 2019

Agreed, absolutely a swiss part. We've been having fun with some similar size OD and wall thickness parts lately. That one will be good practice on how gentle you can get the sub to clamp....

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litlerob1 · Jun 28, 2019

avto762 said:
Agreed, absolutely a swiss part. We've been having fun with some similar size OD and wall thickness parts lately. That one will be good practice on how gentle you can get the sub to clamp....

Sent from my LG-M150 using Tapatalk

Uhhhh, pretty sure he's going to end up with a plug. Or use a mandrel and hold the ID.

implmex · Jun 28, 2019

Hi again All:
So would you try to clamp the part in the sub in a collet or would you clamp it onto an expanding mandrel?

I'm assuming you'd turn the cup, back turn the step, push the part onto the mandrel (or into the collet) on the sub, part off between the main and the sub with both synched, then back turn the face on the sub and eject the part.

Is this a reasonable process flow? (I have zero Swiss experience)
What kind of cycle time do you think is reasonable?
How parallel do you think you can get the flat faces?

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

Winterfalke · Jun 28, 2019

We turned many parts that small on the swiss machines, I watched our swiss guy set up a run for .010 thick washers turned out of ti with a dome on them, he was holding them by .008 in the sub to face the back. Now I'm not any sort of swissturn expert, but I would suggest rough face, rough turn the OD if necessary, finish the OD and face with an edgebreak between, spot, drill, bore, then turn the step for the backside boss. Pick up in the sub and part off, then finish face the small boss and break the edges. I would hope you could get the faces flat and parallel to a tenth or two.

TeachMePlease · Jun 28, 2019

implmex said:
Hi again All:
So would you try to clamp the part in the sub in a collet or would you clamp it onto an expanding mandrel?

I'm assuming you'd turn the cup, back turn the step, push the part onto the mandrel (or into the collet) on the sub, part off between the main and the sub with both synched, then back turn the face on the sub and eject the part.

Is this a reasonable process flow? (I have zero Swiss experience)
What kind of cycle time do you think is reasonable?
How parallel do you think you can get the flat faces?

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

Cycle time on that? 30ish seconds, depending on what kind of tooling you use for finishing the ID.

I'd drill for rough material removal, finish with a Horn boring bar (provided one is available with the correct radius, but it probably is), use a pickoff collet as an expanding mandrel (so you'd feed in with the collet closed, open it up for the expanding mandrel effect), part off, then do the back profile on the sub side, probably also with a Horn boring bar. It could also PROBABLY be done with a standard pickoff clamping on the OD... But I'm gonna be honest, while I've done lots of small parts, I've never picked off on something with a .004" wall thickness... Come to think of it, I don't know that the spring pressure alone from the sub collet wouldn't distort that part all over the place.

LockNut · Jun 28, 2019

If you finish the step on the back, then part, you can swallow the part and clamp over the bottom wall. Less chance to crush. Then face the overall. Done.
We used to do the back side point of bone screws and part with a very sharp 45 degree insert. No sub work needed. No tit. Just make sure that tool is on center or a .001 or two above.

Paul

implmex · Jun 28, 2019

Hi again All:
Thank you all very much for that great information; it confirms how I would approach it, and I love hearing how others with different expertise from mine would handle a particular machining challenge.
This forum has been terrific for that; I've gained a lot from it and I appreciate it hugely!

So the consensus is that it's a 2 Op part for most of you other than Milland who advocates for making a stamping die and LockNut who feels it can be back faced to within a whisker and then parted off with a pointy tool.

Paul, I've done exactly what you describe on lots of smallish parts; my biggest problem has often been losing so many into the chip pan.
I've tried vacuuming them into a tube as they come off the bar, and haven't been super successful.
Typically I suck mostly cutting oil and chips into the vacuum tube, even if I time the suck with something like a PIAB.

Catching them in a parts catcher has been pretty hopeless too...the smallest parts I've made are typically so light they just fly all over the machine enclosure when they pop off the bar.
These parts are going to be featherweight parts...do you have any tricks to keep them where they belong so I can find them again once the machine stops?
I was thinking subspindle as much for the ability to retrieve them as anything else.
Popping them from the sub into a bucket was kind of how I envisioned it.

But I'm not going to make these in production anyway...I just have to prototype them for now.

Moving on to stamping them per Milland's recommendation.
I'm having a hard time envisioning how they can be trimmed at the rim.
I can see blanking them with tabs, drawing them in a couple of stations, but then I get mentally stuck at the trim because everything is so damned small.
Any ideas on how to trim, or were you thinking to blank them to proper size without tabs and form them in the same hit?

Do you think you can make the draw without tearing the bottom off the part...that sharp corner has me worried and even with a 0.0015" rad, it's still awfully sharp.
So although it's attractive as a concept, I'd be worried about how much it will take to iron out the details.
However it would sure make production quick.

Turning them seems safe by comparison...worst case it doesn't work but I haven't lost a whole die build.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

LockNut · Jun 28, 2019

implmex said:
Hi again All:
Thank you all very much for that great information; it confirms how I would approach it, and I love hearing how others with different expertise from mine would handle a particular machining challenge.
This forum has been terrific for that; I've gained a lot from it and I appreciate it hugely!

So the consensus is that it's a 2 Op part for most of you other than Milland who advocates for making a stamping die and LockNut who feels it can be back faced to within a whisker and then parted off with a pointy tool.

Paul, I've done exactly what you describe on lots of smallish parts; my biggest problem has often been losing so many into the chip pan.
I've tried vacuuming them into a tube as they come off the bar, and haven't been super successful.
Typically I suck mostly cutting oil and chips into the vacuum tube, even if I time the suck with something like a PIAB.

Catching them in a parts catcher has been pretty hopeless too...the smallest parts I've made are typically so light they just fly all over the machine enclosure when they pop off the bar.
These parts are going to be featherweight parts...do you have any tricks to keep them where they belong so I can find them again once the machine stops?
I was thinking subspindle as much for the ability to retrieve them as anything else.
Popping them from the sub into a bucket was kind of how I envisioned it.

But I'm not going to make these in production anyway...I just have to prototype them for now.

Moving on to stamping them per Milland's recommendation.
I'm having a hard time envisioning how they can be trimmed at the rim.
I can see blanking them with tabs, drawing them in a couple of stations, but then I get mentally stuck at the trim because everything is so damned small.
Any ideas on how to trim, or were you thinking to blank them to proper size without tabs and form them in the same hit?

Do you think you can make the draw without tearing the bottom off the part...that sharp corner has me worried and even with a 0.0015" rad, it's still awfully sharp.
So although it's attractive as a concept, I'd be worried about how much it will take to iron out the details.
However it would sure make production quick.

Turning them seems safe by comparison...worst case it doesn't work but I haven't lost a whole die build.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

Marcus,
You can sync the sub to the main. Another thing we used to do for small screws was have a vacuum tube come through the back of the sub, bring the sub up to the part at part off, or just over the part and suck the part through the sub into a container. We specialized in small part production with NO hand loading or unloading. All air assist for loading and unloading. Swiss crew machines, chuckers, gang lathes. Whatever. Some were simple, like above, some were pretty elaborate. The idea was no human intervention in the process. Put parts in a loader, remove parts from a finish bin.

Paul

litlerob1 · Jun 28, 2019

Second thought Marcus.....I know it's a bad idea-me thinking.

Either way the 2nd op is going to be a bitch. But you could generate the whole part on a single spindle-minus the small hub where your part-off tit would be. So Turn the whole thing including the back side and the OD of the small hub, in the First operation. Then burn it off the bar.

R

implmex · Jun 28, 2019

Hi litlerob1:
Yeah I floated that idea past my head too and then I went NAAAAHHH!

The problem is the customer will need thousands per run.
Parting off and back turning takes seconds as you know.
Wiring takes minutes and I will have to clamp every part so it doesn't float away in the worktank.
I might do it for the first twenty or so to get parts in the guy's hands (this is a part of a product still in development so they want a few trial parts RIGHT NOW).
For production someone is going to have to solve the second Op problem but thankfully it's not going to be me.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

Delw · Jun 29, 2019

implmex said:
Catching them in a parts catcher has been pretty hopeless too...the smallest parts I've made are typically so light they just fly all over the machine enclosure when they pop off the bar.
These parts are going to be featherweight parts...do you have any tricks to keep them where they belong so I can find them again once the machine stops?

On a coolant machine its kinda hard, on a oil machine its a little easier. on our citizen we had to make some modifications simple stupid ones to catch small light parts Like the ones you describe.
1st we have to turn the oil pressure down to just a steady flow, the angles of the lines need to be pointed on the back side of the part towards the part tray. then where the tray flows into the bucket we stuck some shim stock the width of the tray and about 4" in length to going into the bucket.
we made a bucket out of delrin we had drilled .020-.025 holes about an inch off the bottom. the bottom has a few .025 holes as well.

the chips will clog the holes on the bottom but will still strain the oils. the shim stock keeps the parts from getting under the lip of the tray ie acts as a slide so to speak. we loose a few but not as many as we used to. the bucket is 4" tall 8" long so it does fill and overflow out the top.
the parts are kinda like a step pin .010 dia on the front for about .025 in length then .020 dia to about .050 OAL.

2 oil lines i have hitting the rotary bushing with big tips for flow running down the bushing , 2 other lines I have big tips on them again for flow pushing from the non cutoff side to the cut off side. the weight of the oil keeps the cut off tool from flinging the parts. basically its just a dribble with alot of flow.
.

sounds kinda weird and trivial but it works.

1st ran the pins on our miyano with coolant even adjusted pressure so its just a dribble, made 1000 pins found less than 500, I had screens everywhere ie window screen, matter of fact 2 years later I still find a part here and there in that machine.

I havent ran much titanium but the cut off tools we use will leave a tit small enough to hit the back side of the pins with 320 grit and it takes the tit off fine. I have one of those very small key less drill chucks to hold the part to sand the tit off square.Obvisouly the drill chuck wont work on your part. finger tip should be fine if you can sand the tit off of titanium.

Delw

implmex · Jun 29, 2019

Hi Delw:
That information is priceless!
Thank you so much for your willingness to share it!
It's the experience driven tidbits like those that enable others to avoid the pain of having to figure it all out ourselves, so my profound appreciation to all who've shared their knowledge!

I will start playing with my cutting oil nozzles.
With luck, maybe I can single Op them and just "nip the tit" as you and Paul describe.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

Zahnrad Kopf · Jun 29, 2019

In a rush so haven’t read every post, but it’s definitely Swiss. I see this as a sub job for the OD ops running second. Turn the cupped ID, transfer onto a mandrel, plumbed for a nice, stout vacuum, part in unison, then turn the outside bits while on the vacc mandrel. Parts catching could be easier that way, too. Position the part over a bin/catcher and then push it off the mandrel after removing the vacuum.

Ox · Jun 29, 2019

I have ran a small Ti part, don't recall what it looked like anymore, but I used a live saw with taper to cut off to avoid the tit. (angled like a cut off insert)
I don't recall how perfect it was or not, but I'm sure that it was pretty decent. (little to no tool pressure trying to break the part off, and no strings)
Depending on how perfect you would need the back side, it might require running them accrost some emery or whatnot by hand quick?

You guys go ahead and re-chuck that part.
Please post a vid or at least let us know how it went. :ack2:

BTW - you don't need a swiss for this either.

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Think Snow Eh!
Ox

I need ideas on how to turn this tiny part

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