Using CNC Lathe as Metal Rod Bender. Do/Don't?

I'm looking at a 500 piece job that is a 3/16 Diameter 1018 CR rod 5" long with a 1" long 90 degree bend on one end. There is also a small cross drilled thru hole that needs to maintain orientation with the bend. 1/8" radius on the bend ID. Considering a "Wiping" type bend. I'd like to bend the short end. I figure I might be able to devise a way to grab the bent end with the 2nd spindle and hold it for cross drilling, cutoff and maybe even parts catcher delivery.

I was thinking of doing this on my dual spindle C axis bar fed Mori lathe. (SL200-SMC) Either with machined steel 3 jaws or perhaps using a 3J collet chuck. (Which I don't have yet.) Thinking it's possible to get completed parts off the machine.

My question is has anyone done something like this? I can't imagine bending a 3/16 rod would be hard on the machine but that's really my main question. Would it be? Anyone have an idea of the tonnage for something like this? I actually care more about the machine then some major time saving, but if it can do it in it's sleep and not cry about it, why not? I'm sure building a hand operated bending rig would be simple enough, but 500 times anything manually is not my goal in life.

I think the machine has a servo torque sensor safety system. Not sure if the forces would be great enough to alarm out or not. Or if a fast or slow move would be best.

Experience anyone? Words of wisdom?

Dave

I can't speak to using a lathe for bending but 500 pieces wouldn't take an hour with a manual bender and a little hustle. One of these would work great for what you wanted to do. You could have them bent before you got the machine set up.
Model 1A Bender | Manual/Hand Operated Machines | Di-Acro(R)

Without a proper mandrel, I doubt you would be able to achieve the type of bend/consistent you're looking for.

Though, this could perhaps be machined into one of the jaws, and using a 2 axis "bend" movement to follow the same radius of the "mandrel" but offset the material...

This should be doable id think. if you do this on the sub, you dont need to get creative with the workholding to partoff, etc.

I think it would do it fine as long as you don't crash it.

You'll have to machine the inside radius and the radius of the punch will bear on the tonnage- The smaller the radius the higher the tonnage.

One thing to consider is you could program the bend as an X and Z move. Instead of a wiping move, have the punch make contact and move in an arc. If you do it this way you can even overbend so you can actually get a 90.

If it's just a straight wiper action you won't get to 90.

It will probably work better the faster you go too. Like 50-100 IPM.

I did this on my mill with a bunch of 5/32 stainless rods and it worked great, I wouldnt hesitate to do 3/16. My parts had a 90 degree bend and a 45 degree bend and they both turned out great. You can easily adjust the angle and every part is exactly the same. I just used the shank of a cracked off 3/8 endmill to push on it. Didnt even leave the marks that manual benders do as the spindle rolled over the part instead of sliding.

If you need 90 degrees you will need to bend a little past that to allow for spring back. I ground a slight relief on a parallel and bent against that, the relief allowing me to go a little past 90 degrees.

welderboyjk said:

I can't speak to using a lathe for bending but 500 pieces wouldn't take an hour with a manual bender and a little hustle. One of these would work great for what you wanted to do. You could have them bent before you got the machine set up.Model 1A Bender | Manual/Hand Operated Machines | Di-Acro(R

Click to expand...

Welderboy that's sure a nice bender, but too costly for this job and would seldom get used again. I'm a machine shop that other then one big repeat fabrication job I have, I do very little fab work except for that which comes with something else. Not what I like.

sirAIG said:

- this could perhaps be machined into one of the jaws, and using a 2 axis "bend" movement to follow the same radius of the "mandrel" but offset the material...

This should be doable id think. if you do this on the sub, you dont need to get creative with the workholding to partoff, etc.

Click to expand...

Yes I planned on machining the jaws for bending. Also my turret takes 1" tooling so figured to take a square stick of cold rolled and machine some kind of punch. I like the idea of a two axis sweeping move and I really like your idea of bending at the sub spindle side. That's the problem with working alone. One person can't think of everything and for whatever reason I hadn't thought of that. Really solves a problem. A couple actually. Thank you.

Garwood said:

I think it would do it fine as long as you don't crash it.

You'll have to machine the inside radius and the radius of the punch will bear on the tonnage- The smaller the radius the higher the tonnage.

One thing to consider is you could program the bend as an X and Z move. Instead of a wiping move, have the punch make contact and move in an arc. If you do it this way you can even overbend so you can actually get a 90.

If it's just a straight wiper action you won't get to 90.

It will probably work better the faster you go too. Like 50-100 IPM.

Click to expand...

All good info. Thank you.

mmurray70 said:

I did this on my mill with a bunch of 5/32 stainless rods and it worked great, I wouldn't hesitate to do 3/16. My parts had a 90 degree bend and a 45 degree bend and they both turned out great.

Click to expand...

Nice to hear of others making extra use out of all that CNC controlled weight.

I guess unless I hear a definitive "hold your horses you're going to wreck something," sounds like I should be good to go. Will take a few trys I'm sure, but advances in technique seldom come easy.

Dave

Never bent rod, but pressed in thousands of 1" OD by 3/4" ID bronze bushings with the lathe. No noticeable harm came of it.