[Xconnect]

Trying to machine this profile in 3/4"x3/4" CRS, 24" long. Problem is after 1st side is machined, part looks like a banana and must be pressed back into shape to do the 2nd side. Angle on each side is 20deg. Any ideas? I'm very close to making my own machine with a spindle on each side and machine them both at once. More on that later if needed. Still thinking there has to be a way to do this simply.

Greg

[RICHARD ZASTROW]

CRS is full of mechanical stress from the cold rolling process. That's one of the reasons it goes "bananas". How are you holding/fixturing the pieces now?

Dick Z

[Xconnect]

CRS is full of mechanical stress from the cold rolling process. That's one of the reasons it goes "bananas". How are you holding/fixturing the pieces now?

Dick Z

In a jig using the 2 sides (top and bottom on photo) to do the first cut. But I have to take it out to flip it for other side (in another jig). That's when it warps. Once pressed back into shape, it works fine. Trying to avoid that operation. I also don't want to stress relieve before since I have a lot of these to make in the future.

[txcncman]

So, when you take it out after the second operation it does not warp again? Or are you saying at that point, you do not care if it is warped or not?

[Xconnect]

So, when you take it out after the second operation it does not warp again? Or are you saying at that point, you do not care if it is warped or not?

It is. But I can deal with it because it get's inserted (the narrow end) into a straight slot and plug welded from the bottom. This straightens it out.

Greg

[txcncman]

If I were going to run this job, I would set up 3 vises with extra long soft jaws on my mill and run it as in the first picture. Then I would cut some extra long soft jaws to hold and cut it as in the second picture. I would let the vises and my hammer do all the straightening that was needed.

[Xconnect]

If I were going to run this job, I would set up 3 vises with extra long soft jaws on my mill and run it as in the first picture. Then I would cut some extra long soft jaws to hold and cut it as in the second picture. I would let the vises and my hammer do all the straightening that was needed.

Ya, that's how it is setup now (except with a fixturing jig for many bars at once). Problem is I need to do a good 1000 of these at a time. I think I'm gonna build something like this picture. Just need to figure out HP and tooling (thinking 1" or 1-1/4" indexable endmill, APKT or the like, 2 or 3 inserts) to be able to cut everything in one pass (just under 1/4" doc at thickest point). I don't care if I have to go 6ipm at 500RPM. I can make a feeder and have it all automated. I can make it weigh a ton and as rigid as possible. I don't even care about finish, it all gets galvanized after welding anyways. All that's important is angle and repeatability in same batch.

[txcncman]

I think the point was your jig was not working and you had to straighten each piece before proceeding. My solution takes out the straightening step.

If you are going to build a machine, you might want to go horizontal with a finish form tool and with some stock and part guides and feed rollers. Place the bar in one end and it comes out the other finished. Probably want to shoot for the 10 HP range.

[Xconnect]

I think the point was your jig was not working and you had to straighten each piece before proceeding. My solution takes out the straightening step.

If you are going to build a machine, you might want to go horizontal with a finish form tool and with some stock and part guides and feed rollers. Place the bar in one end and it comes out the other finished. Probably want to shoot for the 10 HP range.

Sorry for the confusion. I wanted to see if there was something I was missing and was a way to make this part without it bending between the 2 steps.
As for 10HP, on each spindle? Or 5 on each, 10 total? Seems like an awful lot. Yes, the rollers are actually pictured on the picture (although very feint). Will be using die springs on top and one side to squeeze everything together for positioning. My problem is the 10HP. Will be running it on 550V, but that's still a bear of a motor. I was thinking more 2HP on each spindle (another seperate motor/gearbox for the feed). As I said, don't really care if it goes slow. Trying to limit costs.

[txcncman]

I was referencing 10 HP for the entire machine, power feed rollers and all.

[bad bearings]

You might consider starting with some 7/8" or 1" bar and rough three or four sides before cleaning it up in a second pass.

[fizzissist]

If you're going to consider a special machine... consider sawing, w/ 2 saws opposed at the desired angles, staged with supporting rollers.

Looking to me like you need to stress relieve the mat'l first...
I'm curious why you need CRS as opposed to HRS for this part... nonna my business, of course...but ... (I personally despise HRS, but there's times when it's just plain easier)

...For the quantities you're looking at, you might also consider
Cold Drawn Steel, Cold Drawing, Hot Rolled Steel, Hot Rolling, Hot extruding, Extruded Steel Shapes, Steel Extrusions, Cold Rolling, Cold Forming, Roll Forming Manufacturing Processes

Would be worth a quote.

[bad bearings]

If you're cutting this part on a cnc you might try stress relieving the opposite sides simultaniously by alternating you cut from one side of the stock to the other--in a pattern similar to stitch welding. This way you can relieve the stress gradually along the part with a single cutter without producing large deformations.

[Xconnect]

If you're cutting this part on a cnc you might try stress relieving the opposite sides simultaniously by alternating you cut from one side of the stock to the other--in a pattern similar to stitch welding. This way you can relieve the stress gradually along the part with a single cutter without producing large deformations.

Yes, but how would I hold it? There are no flat sides left for me to clamp and leave the other 2 sides completely exposed for machining.

Greg

[txcncman]

Since you seem to have the time and money to throw at the problem, I still think your idea to make a dedicated machine is best. I think my idea of a single horizontal spindle is better than two. The cutter(s) will cost you though. With 2 tools and 2 spindles at angles, getting it set up after a tool change will be more difficult. With a horizontal and a special cutter, you will only need to set Y and Z.

[Xconnect]

If you're going to consider a special machine... consider sawing, w/ 2 saws opposed at the desired angles, staged with supporting rollers.

Looking to me like you need to stress relieve the mat'l first...
I'm curious why you need CRS as opposed to HRS for this part... nonna my business, of course...but ... (I personally despise HRS, but there's times when it's just plain easier)

...For the quantities you're looking at, you might also consider
Cold Drawn Steel, Cold Drawing, Hot Rolled Steel, Hot Rolling, Hot extruding, Extruded Steel Shapes, Steel Extrusions, Cold Rolling, Cold Forming, Roll Forming Manufacturing Processes

Would be worth a quote.

I need the tensile strength of CRS. As for the sawing, interresting. You thinking circular saws on arbors? I've never actually used those, would you have any references on HP/feed/speed calculations for these? I'll start looking at that now. Thanks.

Greg

[Xconnect]

Since you seem to have the time and money to throw at the problem, I still think your idea to make a dedicated machine is best. I think my idea of a single horizontal spindle is better than two. The cutter(s) will cost you though. With 2 tools and 2 spindles at angles, getting it set up after a tool change will be more difficult. With a horizontal and a special cutter, you will only need to set Y and Z.

Some time and some money. Nothing is infinite I'm afraid. And only because the cost of machining is too high right now, and I figure we could recuperate cost of the machine and design in first few batches. Someone was trying to charge me $2.50 a bar just to stress-relieve ($2500 a batch).

The single tool would obviously be easier to setup, but I'm deathly afraid of seeing it break while being run by whoever is here at the time (we're mostly welders). I'd be way more comfortable with off-the-shelf cutters, even if we do spend more time setting everything up after a change. I'd have to see how long the inserts would last. If they can last for 1000 pieces (2000 feet), I'd be happy. No idea if this is realistic. But one thing we can do is make the setup as rigid as possible (huge spindles, and I have about 1000 tons of tubing and plate in here).

Greg

[txcncman]

Another consideration with dual spindles is cutting direction. Are you going to run one right hand and one left hand tool? With a single tool, you only have to compensate once.

I am off to a meeting now. Will think on this more later.

[Xconnect]

Another consideration with dual spindles is cutting direction. Are you going to run one right hand and one left hand tool? With a single tool, you only have to compensate once.

I am off to a meeting now. Will think on this more later.

If I can find left handed cutters. Otherwise, both right-handed and I'll adjust individually if needed. You foresee a problem even if bar stock is very rigidly held (can't move up or down with cutting force)? I don't really care about have a poor finish. Just need proper angles in finished part.

[rowbare]

This looks like a job they would have used a metal planer for in the past. They would have set up two cutters and cut both sides at once. It might have taken a few passes because the stock is fairly thin.

With that in mind, do you really need to use rotating spindles? What if you set some carbide strips (might even be able to use indexable inserts) at the proper angle in a heavy block of steel. This block would run along some linear rails and be powered by a hydraulic ram. Each pass would shave a strip off the bar. On return, the head would index downward for the next pass.

Something like this would be fairly compact -- about the size of a log splitter. Since it would cut both sides at once, warping shouldn't be much of an issue. You could build rollers into the moving block to keep the bar from lifting etc...

Just some food for thought.

bob