1/2" round from 1/2" square with automatic loading

I have a customer who needs to take a 1/2" hot rolled steel square bar, 9" long and turn a 1/2" diameter on one end 2.25" long. I have done a handful in the lathe only to see how the material cuts and I can take the diameter in one shot pretty easily.

I have been looking at those automatic loading chamfering machines as basically a starting point of the basic idea on how to automate this process with very little work needed to be done by a worker. The quantity on this part is around 100k per year so hiring a guy to sit and load a machine for 8-10 hours a day does not appeal to me. In the event the worker were to quit or not show up, I do not want to be the one loading these all day.

Thinking if I had a walking beam or gravity feed to a hydraulic or pneumatic vise and some sort of unloader that would be the ticket. Ideally, just load a bundle of blanks and have them drop in a bin when complete.

The tolerance on the round is tape measure close for length and diameter as well.

I have looked for other companies who make a machine, but have not found one to perfectly suit this need. I may need to build my own machine to do exactly what I need, but wanted to see if other had ideas that may be staring me in the face already.

Due to the nature of that cut I wonder if an axial endmill might work better than turning it.

MaxPrairie said:

I have a customer who needs to take a 1/2" hot rolled steel square bar, 9" long and turn a 1/2" diameter on one end 2.25" long. I have done a handful in the lathe only to see how the material cuts and I can take the diameter in one shot pretty easily.

I have been looking at those automatic loading chamfering machines as basically a starting point of the basic idea on how to automate this process with very little work needed to be done by a worker. The quantity on this part is around 100k per year so hiring a guy to sit and load a machine for 8-10 hours a day does not appeal to me. In the event the worker were to quit or not show up, I do not want to be the one loading these all day.

Thinking if I had a walking beam or gravity feed to a hydraulic or pneumatic vise and some sort of unloader that would be the ticket. Ideally, just load a bundle of blanks and have them drop in a bin when complete.

The tolerance on the round is tape measure close for length and diameter as well.

I have looked for other companies who make a machine, but have not found one to perfectly suit this need. I may need to build my own machine to do exactly what I need, but wanted to see if other had ideas that may be staring me in the face already.

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Why re-invent the wheel ?
Sub this job out to a swiss/browni/acme shop

mhajicek said:

Due to the nature of that cut I wonder if an axial endmill might work better than turning it.

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I plan to pinch turn the diameter to eliminate chatter.

DDoug said:

Why re-invent the wheel ?
Sub this job out to a swiss/browni/acme shop

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I don't know if hot rolled square would feed too nicely through those type machines.

latheman78 said:

I don't know if hot rolled square would feed too nicely through those type machines.

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It would not. Typically you need ground stock for swiss work.

nihilistic said:

It would not. Typically you need ground stock for swiss work.

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Who said anything about feeding during the cut ?

nihilistic said:

It would not. Typically you need ground stock for swiss work.

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I have a Swiss, as long as the stock isn't tapered and within .001 roundness it does ok.
I have gotten hot rolled or prehard and even the 7/8" is .006 out of round, forget about anything with scale on it. I could imagine hot rolled square could also have some twisting in it.

I would suggest the OP go look at the proposed stock that will be used before coming up
with a plan on how to run them. Stock condition could eliminate options.

DDoug said:

Why re-invent the wheel ?
Sub this job out to a swiss/browni/acme sho

Click to expand...

latheman78 said:

I have a Swiss, as long as the stock isn't tapered and within .001 roundness it does ok.
I have gotten hot rolled or prehard and even the 7/8" is .006 out of round, forget about anything with scale on it. I could imagine hot rolled square could also have some twisting in it.

I would suggest the OP go look at the proposed stock that will be used before coming up
with a plan on how to run them. Stock condition could eliminate options.

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I have had the stock for a couple weeks. 1/2" square measures 0.503 and 0.511 which is why I do not want to run in a square collet. I know what I want to do as an intermediate step before full blown automation. I would agree a swiss would have a hard time with these and an acme is not the correct machine. It is a one feature one op part. Unless Doug tells us what is behind his mystery door.

You're not running that stock through a bar fed anything. Saw the stock, and load a bunch into a horizontal to mill around the ends. Or buy the right stock for the job so you can bar feed it.

MaxPrairie said:

I have had the stock for a couple weeks. 1/2" square measures 0.503 and 0.511 which is why I do not want to run in a square collet. I know what I want to do as an intermediate step before full blown automation. I would agree a swiss would have a hard time with these and an acme is not the correct machine. It is a one feature one op part. Unless Doug tells us what is behind his mystery door.

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So you chamfer and use a box tool, and somehow you don't think that is appropriate for any of the above listed machines ?
Miles of HR has been fed thru collets. They make hardened collet pads just for this.

MaxPrairie said:

I have had the stock for a couple weeks. 1/2" square measures 0.503 and 0.511 which is why I do not want to run in a square collet. I know what I want to do as an intermediate step before full blown automation. I would agree a swiss would have a hard time with these and an acme is not the correct machine. It is a one feature one op part. Unless Doug tells us what is behind his mystery door.

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If all the stock is the same size have a collet sparked to that size and digger Doug has the answer, put it through a Brownie.

I am going to third doing the B+S, if you want to get something that will do it pretty much out of the box with minimal setup. With the tolerances you are describing, you could probably find a clapped-out machine for cheap and it will pay for itself in no time.

Are the collets that Brownies use similar to a 5C, 16C or the like? I don't see how it feeds as I bet that stock isn't perfectly straight, pretty sure it will have a few twists here and there.

If the stock is so twisted that it won't feed thru a collet, then I would find a different supplier as that material is just junk. I can't see how a slight twist or bend over the length of a 8 or 12 foot bar would affect performance with wide open tolerance.

Even swiss machines can run with some variation in stock, it's just that the tightness of guide bushing and your tolerances limits how much before you run into problems. If you have +-.005 on your parts it's not as much of an issue as +-.0002 (you get out what you put in basically). We would occasionally get bent bars that would rattle like a SOB in the bar feeder, as long as there's wide enough of a tolerance on part dimensions, we could run them without too much trouble (besides bothering the guy on the machine next to you).

What's wrong with a two jaw chuck and a standard bar feeder? You'd need a square drawtube liner, but trusty cook will make you that for a couple hundred bucks.

I don't know but would a swedging machine be able to do what you want. Oldwrench member has some machines ,maybe he could shed some light on it.
Maybe they are only suitable for tubing?

Doug said:

Wild ass idea...stud weld the round on. There may be machines to automate the process....

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Or friction welding ! Always wanted to try that, too cool for school ...

A few things to consider for automating this. 100K parts per year running a realistic 240 days a year = 417 parts per day. Say you want to tend the cell every few hours to load/unload what ever feeder/storage you have, you need to plan how many parts you will need to have feeder/storage for. If you want a reasonable 12 hours a day of production with 4 hours of unattended running when you go home in the evening. You will need to have part feeder/storage for 139 (417/3) parts for 4 hours of unattended running. 139 parts should be doable without having a massive feeder and storage system. Every four hours you would have to go unload 139 finished pieces and reload 139 parts worth of stock. My guess is this would be a 10-20 minute process. It would also give you some breathing room for tool/insert changes and coolant/chip maintenance. In your 8-10 hours on manned time you should be able to run two 139 piece loads and do the other needed maintenance. Also, 12 hours of running to make 417 parts is about 1.7 minutes per part including load/unload cycle. that should be achievable. If I was tasked to automate this with one shift, five days a week this is how I would approach it. If the 4 hours of unattended run is not possible then the cycle time per part will get a little tighter, but not out of realistic range. If you can run more unattended hours per day you will need more part feeder/storage which adds to cost and floor space, but may be worthwhile.

At my place of employment we have six robot tended lathe cells that I designed and built. They run between 6 to 20 hours a day unattended. We cannot stack finished parts so we had to go with 2500mm reach robots to be able accommodate the needed number of parts. Here is a screenshot of a few of our cells from our security camera. Also a couple of mills with pallet loading robots in the pic