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Dual spindle lathe...........what kinda speed we talkin' here?

david n

Diamond
Joined
Apr 13, 2007
Location
Pillager, MN
So I just love to hear from a salesman or even some folks here on PM...............spending others' money and telling you that you need a mill/turn, or 5 axis, or dual spindle/3 turret lathe, or...............:rolleyes5:.........this is not practical here......................So..............

Work load keeps creeping up and up and up....................over the past few years one customer's order numbers have gone from 250/yr-500/yr-1000/yr + and that's 20-30 different part numbers in various quantities. Some stuff lends itself to a dual spindle lathe................but will it make parts faster?

One example................

Currently making 3 parts. 2.250"Ø x .709"-1.181" long 6061. Very similar, just length varies. All told 5k+ parts a year. Right now they are turned and dropped off the lathe in under 30 seconds/part. One bar runs for 30 minutes(time for me do do other things). Next they go into the mill in two double vises................Qty 4 in vise one for side one and flip qty 4 in vise two. 4 finished parts/cycle start. Nine through holes 8 and 9mm......................three grooves with a 3/8 BNEM on each side and nine holes chamfered each side. Load/unload and machine is under 4 minutes. Hired hand runs these. Looking to add 2 more doubles...........or just finally bite the bullet and build a fixture with Mitee Bites to hold 20-30 parts.

So I have about just under 1.5 minutes into each part..............even with handling.

So how fast will dual spindle live tooled lathe run?

Turn side one. Drill. Mill. Chamfer.........................Grab/pull with Sub. Part. Drill. Mill. Chamfer side two. Drop it the bucket.

The thing that has me head scratchin' is it will turn the part just as fast as I am right now, but it's only milling one side at a time.................when it's milling, it ain't turning. And in the mill, one tool change covers multiple parts.......................and the mill is running all out.......pushin' feeds pretty hard and 10k RPMs on all tools...................I don't think 4-6k RPM live tools will keep up to what I'm doing now.

So cost would be a factor too................dual spindle live tool.....eh. Spendy, but "doable" for a good return on these parts. But no way in heck is a mill/turn or dual spindle/dual turret in the cards. I'm thinkin' I'm going to have a few brands run these parts for me and see what kinda numbers they come up with. Any input?
 
We have numerous dual spindle C and Y axis machines. For us they are great. Your described parts could easily be made on a dual spindle machine. You would eliminate a huge chunk of your labor cost not having to hand load them in a mill. Get creative and you can have both spindles working at the same time. So what if your cycle time does go up? As long as you have enough time in the day to get the work done. Sounds like a perfect lights out job.
 
You may not end up with a faster time per part the way you're evaluating it, but you would free up the mill to do other work and if you had a part catcher and a bar feeder it could run and run and run. Even if it took 2.5 minutes per part, you have finished parts coming out of the machine while you're making sales, eating lunch, sleeping, etc and they are complete all in one go.

If you can run the mill on other work and you don't have to think about the lathe while doing so, I'd say that's a win.
 
As mentioned above, it's not about reducing cycle time per se (although modern spiffy sub-spindle live-tooled lathes are pretty fast). Rather, you eliminate a handling step or two, you get more consistent parts since there's no chance of putting it in the mill vise wrong, you free up the mill to make other parts, and you don't need a human sitting in front of the mill loading and unloading.

Do you have room for a bar magazine and a parts collector? If so, you could run the machine overnight.

Also (and this is intangible) when word gets out that you have a modern spiffy sub-spindle live-tooled lathe, it's likely that you will get other work for it.

If I got that one particular giant order back that I lost in 2017, I would probably get me a Doosan sub-spindle live tooled lathe.

Regards.
 
Just to echo what everyone else is saying, we have moved parts from a single spindle to single turret lathe to a twin spindle three turret lathe. Cycle times went up a little. Maybe 25%. But profit margins at least doubled. Having a guy load a bar in the machine once an hour while keeping 2 other machines going was great for business.
 
It doesn't sound like you will end up with much of a net savings.



Just to echo what everyone else is saying, we have moved parts from a single spindle to single turret lathe to a twin spindle three turret lathe. Cycle times went up a little. Maybe 25%. But profit margins at least doubled. Having a guy load a bar in the machine once an hour while keeping 2 other machines going was great for business.


And only cost $450,000 for the privilage.



High volume parts are seldom ran on "one and done" machines.
Depending on the part - but it's not usually cost effective for big runs.


With that said - I like mine!


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

Think Snow Eh!
Ox
 
Worth adding my experience of live tooled lathes, you don't get the tool life you do in a mill if you start to get aggressive but that's in steel. that said you also don't lose parts because a bit of swaf in a vice jaw etc.

At 5K a year running lights out assuming no stoppages that's only 1 part per 1 hour 40 minutes or so, hence if nearly fully automated the cycle time should be easy to get under to make the annual total at least. Even if it took you 5 minutes a part, it kinda would not matter, still be only running during day shift when it could be supervised and be making you money with near zero operator time input. Instead of putting a bar in the lathe once ever 30 minutes, you end up putting a bar in just a few times a day. Once running stable it sounds like a ideal lights out job though to me, hence may have a lot more value in freeing the time during the day to make something not so easily automated?

Your only going to gain from the spend though if you want the time - no longer need the operator etc or can put other work on the mills or the other lathe assuming your not replacing the lathe with this one?

I don't see a move like this on a part like this directly saving you money or even possibly turning a profit on the reduced labour by the time savings alone assuming the labor savings are going to be swallowed up by the machine cost in the first year or 2. I see it more side ways kinda move that opens a gap in other machinery frees time that if you can then use you get to make some significantly better money with. Or lets you get rid of a pain in the ass employee etc.
 
Looking to add 2 more doubles...........

Be careful with that thinking. This:
20170621_160722.jpg
Will ruin your day when its time to change to the next set-up.

My thinking: the fewer times you (or whoever) has to handle the parts, the better!
But, your in territory I am not good at. Figuring your acceptable ROI, and sticking to the plan.
 
Be careful with that thinking. This:
View attachment 246117
Will ruin your day when its time to change to the next set-up.

My thinking: the fewer times you (or whoever) has to handle the parts, the better!
But, your in territory I am not good at. Figuring your acceptable ROI, and sticking to the plan.

Set up times can kill you. There are a number of things you can do to reduce that time. Quick change tooling such as Capto is one. Off center Y axis machining will allow you to utilize multiple tools per station. In theory, a single turret, dual spindle, 16 position lathe could hold 64 tools. Probably not practical for 99% of users, but possible .
 
One the parts I was using as my example is usually 1000 pc order a few times a year. Machine time for both a lathe and a mill is around 25 hrs combined. That's setup, run, tear down. 1/3 lathe and 2/3 mill. The lathe gets ahead of the mill right quick. As most of these parts do............That leaves my lathe open for the next job that might be only 1 op turn part or a part that doesn't need live tools/second spindle. If I have a fancy dual spindle live tool lathe that take 32-35 hours to turn/mill that 1st part complete, I sit twiddlin' my thumbs to get 'er done. The one op part sits in limbo waitin'......................

For just one customer I have 35 different part numbers of turned items.........qty's range from 250 to 2500 pcs ordered 2-5 times a year. A bunch can be done in one in a 2 axis lathe. I guess I'll have to sit down and do some figgerin' and see how the work flow would pan out. There's only so many hrs in a day and X amount of parts need to be made in that time. If done-in-one takes too long, it creates a bottleneck...........
 
Another element (not sure if it's been pointed out) is that when you need very close Orientation for Positional stuff, it's pretty hard to beat a Lathe with a pick off spindle. Strange shapes can be Milled into soft jaws.

And if you have 2 Spindles AND 2 Turrets then you can be working on both sides at once (let alone the 3 Turrets). It is not as fast chip to chip. But it makes up for it other ways, only the person whose hands are on the parts knows.

BTW, I really dislike when people say "set-up is expensive", nothing personal, but it's only expensive when cheap ass people quote the job for less set-up time than is required. I had a boss that would cut my quotes on set-up, then bitch about how long they took. All the while never told us that he was knocking 25% off when he would submit the RFQ. Set-up time is billable time.<that is a Period. Talk to the guys who run Swiss CNC all day, their set-ups take upwards of 50 hours sometimes, ALL billable time.

R
 
Have you estimated what it would do for you to make a fixture? If you've got common parts I just can't see how a vise is useful. Vises are general purpose. There are options out there that work as pallet systems so you can load parts outside the machine onto a pallet while the machine is running, then when parts finish swap the pallets, start machine while you're unloading the finished parts. Have you considered how just doing some relatively CHEAP fixtures would benefit you?
 
Set up times can kill you. There are a number of things you can do to reduce that time. Quick change tooling such as Capto is one. Off center Y axis machining will allow you to utilize multiple tools per station. In theory, a single turret, dual spindle, 16 position lathe could hold 64 tools. Probably not practical for 99% of users, but possible .

Don't post the picture... don't post the picture....

Fuck, couldn't help myself:

ydRXE6Y.jpg
 
There's only so many hrs in a day and X amount of parts need to be made in that time. If done-in-one takes too long, it creates a bottleneck...........

Done-in-one running at night, over lunch break, etc., is definitely faster than the machines sitting there not doing anything.

Regards.

Mike
 
I can’t even imagine the money in live tooling that thing has in that turret. Probably more than my two CNC’s together.
 
Even if it takes a bit longer for cycle time, the big thing is that it should be able to do it while you sleep. Have it do the 1000+pc orders that make it worth the set up, and run the other smaller qty's the regular way on the other machines.
Add up the price(less material) of all the large enough QTY orders that you'd plan on running on it in a year. If its around 3X the yearly cost/overhead of the machine, might be worth it. Assuming time and keeping up with increasing demand really is a big issue that can't be solved for way less $ and risk.
There are some people working really hard to screw up the economy in the US and Canada. I'm glad I bought my new toy last year cause it wouldn't be happening this year.
 
I can’t even imagine the money in live tooling that thing has in that turret. Probably more than my two CNC’s together.

It was originally for an NZ 2000, in 2004ish. The machine at the time was 500k, all the holders are MD (not cheap), they were about 100k. But that's just one of the Turrets.

R
 








 
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