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What strategy do you think is best for this feature?

alek95

Cast Iron
Joined
Sep 23, 2022
Hi everyone,

I'm programming a new variation for a production part that I do.

Material is 6061 and the machine is Doosan Lynx 2600SY.

Problem is, as most of you already know, these machines are definitely more lathe than mill :crazy:. Even a Haas minimill will outperform the live tools on these things in MMR, precision, and surface finish.

I'm gonna try circular interpolation with an endmill first, but I'm uncertain if I will get the results I need, particularly in hole circularity.

What strategy would you guys try to tackle this? My batch sizes are about 200 parts on this. Has anyone tried a small boring head on a live tool lathe?

how to make this feature.JPG

PS: I don't have access to a real 4/5 axis mill.
 
Is any part of this being processed on a mill or do you have a sub-spindle and Y axis and you're trying to knock out the whole thing in one cycle?

I first posted this saying that was a 1-3/16 spherical joint pocket but it's 0.002" too big. Are they sure they didn't make a mistake on the size? Or do they maybe want a deliberate slip fit with the circlips instead of a tighter fit?
 
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Is any part of this being processed on a mill or do you have a sub-spindle and Y axis and you're trying to knock out the whole thing in one cycle?
Everything I do is barfed, sub-spindle, and Y.
99% of what I do is done in one cycle. Only if it needs a slitting saw or multiple angled live tools, then it will see a mill.

I should add, you need to find out how your client will be inspecting that. Gauge pins? CMM? It will make a difference.
I will have to talk to the QC and engineering department. I don't work for a job shop. Luckily that makes it easier to get information on requirements.

I'm not a lathe guy, but my first instinct would be to see if I can get a custom reamer for a reasonable price and lead time. Of course then you don't have the adjustability of a boring head.
I'm thinking something along these lines, also. I'm not in love with the idea though because I'm already putting 18 tools on the turret for these parts I think. I don't know where I will fit another slot for a live tool :willy_nilly:

Thanks for the comments, guys.
 
Have you looked for a micro boring head with a straight shank? It's gonna be hella expensive but, you'll have it for future work. Casually searching around there are some tiny (and compact length) heads out there.

Edit: here is one that looks interesting.


 
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Honestly I haven't looked into it at all. First time seeing this print was today. I wouldn't even know the first thing about which boring head is good for a BMT lathe.
 
Well, that's where I'd ask them what goes in the hole, is it a 1-3/16" Swivel joint/bearing? cause if so, well it's gonna be loose .002" anyway so interpolation is probably fine.
 
What if you make a special fixture for that part. Maybe a round part, with the contour
of the part and a hole for the Thread to clamp it, so the bore is in the middle of the part.

You need a 2nd operation, but with the power of the lathe and you can make all the
chamfers, recesses with one tool.
 
Yes, I have used boring heads on my live tools before. I prefer D'Andrea over all others, and their smaller modular shank sizes fit in a collet no problem. Should be no problem for that size of a hole in an ER25/32.

Your turret/tool has to be aligned perfectly coaxial to X or you will bore an oval hole, not normally an issue but when you only have a couple of tenths either way it matters.

You should have no problems interpolating the Ø1.262".

However, it seems to me that your turret is going to be really crowded by the time you have enough live tools in there to finish that part...
 
Yes, I have used boring heads on my live tools before. I prefer D'Andrea over all others, and their smaller modular shank sizes fit in a collet no problem. Should be no problem for that size of a hole in an ER25/32.

Your turret/tool has to be aligned perfectly coaxial to X or you will bore an oval hole, not normally an issue but when you only have a couple of tenths either way it matters.

You should have no problems interpolating the Ø1.262".

However, it seems to me that your turret is going to be really crowded by the time you have enough live tools in there to finish that part...
I agree with Gregor . The D"Andrea are my preferred as well so +1 . That is going to be a crowded turret though.
 
I'm not a lathe guy, but my first instinct would be to see if I can get a custom reamer for a reasonable price and lead time. Of course then you don't have the adjustability of a boring head.

Ahem.... https://www.ebay.com/itm/266299524779






Somewhere it is written that these reamers are "never to be used to adjust the size bigger or smaller, only adjust the screw so you can resharpen it to size".

That's a load of shit and I use these things all the time for making oversize holes that I can adjust.
 
I'm curious on that mini boring head in the live tool.. sounds feasible if you have the room!
Looks like a fun little part though, I would like to try it one and done on a mill but I'm sure cycle time would suffer
 
Ahem.... https://www.ebay.com/itm/266299524779






Somewhere it is written that these reamers are "never to be used to adjust the size bigger or smaller, only adjust the screw so you can resharpen it to size".

That's a load of shit and I use these things all the time for making oversize holes that I can adjust.


LOL!

I would agree, but I have found on the very few occassions that I ran with this plan, that I fought dialing into size a cumbersome issue as the tapered set screw threads apparently were NOT very precise at all! A turn of the screw made a whopper of a change. Eventually I think that I got what I wanted, but it seems like it was hunt and peck for a while.

Regardless tho - I am leaning towards a reamer as well. If you don't think that your live tooled machine is good enough to interp that, then I'm not sure that a single point boring head is going to be any better? I guess that it depends on what aspect of the machine that you feel is the Achilles heel of the process? Maybe a "good as new" live head would work? Anything less would Shirley be a lesson in futility eh?

Finding a pocket for a reamer isn't any harder than finding a pocket for a boring head...

It's just 6061. It should ream out good?
Possibly go with a 60* lead-in chamfer on the reamer to help it not go O/S?

I have ran a similar part before, but I was able to interp it, and all was fine.
I don't recall the tols that I had on mine, but it was similar. You would need a new head for milling it as well as you could easily git a tapered hole from tool pressure / short bearings.

I would run that on the lathe as well, but 2 turrets make jobs like that a LOT easier to tool up!


----------------------

I am Ox and I approve this here post!
 
Well, that's where I'd ask them what goes in the hole, is it a 1-3/16" Swivel joint/bearing? cause if so, well it's gonna be loose .002" anyway so interpolation is probably fine.

I'm always surprised at the number of suggestions to query the designer. As a manufacturer, my questions are limited to drawing clarifications and commissions. Unless I'm asked for input. But, a lot does depend on the customer. Since this sounds like an in-house project, querys should be easy, but it depends on how autonomous/arrogant the design team is.

Don't mill this to size. You'll wear your tsil out chasing a barely capable process. Mill it leaving honing stock and finish hone. But you gotta have a honing machine!
 
I couldn't get too excited about a reamer in this situation. I've spent a lot of time and money chasing size on reamers. Harvey is +0"/-.0002" for uncoated reamers, +.0002"/-0" for coated. Lots of other reamers are +.0002"/-0". If your 1.1897" reamer (aiming for midpoint) is +.0002", and you have any runout at all, the hole is oversize. A reamer that big is not going to self-guide, it'll make a hole wherever it wants to. If you game it the other way and get a 1.1895" reamer, and it's a Monday, it'll cut a 1.1894" hole.

If it was a .2505" hole, I'd just try a bunch of different reamers until I found the one that worked, but that big of a reamer is going to be $$$.

I'd figure out some way to use a boring head, either in your turret or as a separate op in a mill in a fixture.

If no on the boring head, I'd try interpolating, IF you had confidence that the turret was practically perfect and you have the backlash under control. One nice thing about interpolating is that, right or wrong, the hole is generally very consistent over 100's of parts.

Regards.

Mike
 
I wouldn't touch a reamer for that, boring head all the way.

There are no cutting forces involved, as long as the live tool still has even a little bit of its preload remaining it will work fine with the boring head.

A premium 2µm boring head in a spindle without play will hit that tolerance all day long no problem.
 
Shock end cap...............I know them well. Prolly made 50k plus of them over the years and prolly 3 times that many rod ends with the same bore features................If'n you gotta drop them one and done in the lathe, I git it. I don't have a y axis sub lathe.........I turn op 1 op 2 and fixture 8 pcs at a time on the 4th, milling all the features, including just good ol' interpolating the bore for the spherical bushing............customer has never had an issue..............but customers vary 'o course. Mosta of those bushes need 'round .001-.002 press................
 
I'm always surprised at the number of suggestions to query the designer. As a manufacturer, my questions are limited to drawing clarifications and commissions. Unless I'm asked for input. But, a lot does depend on the customer. Since this sounds like an in-house project, querys should be easy, but it depends on how autonomous/arrogant the design team is.

Don't mill this to size. You'll wear your tsil out chasing a barely capable process. Mill it leaving honing stock and finish hone. But you gotta have a honing machine!

And as a manufacturer when I can avoid turning a 30 second job into a pain in the ass waste of time and a likely higher scrap rate, and still offer the customer a perfectly fine working part at a cheaper price, I try to do that.
 








 
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