Small Plate Straightening Machine?

Nerdlinger · Dec 3, 2020

I have a small plate that gets punched out of .134" thick 1050 strip. The part is about the size of your hand. It comes out of the press slightly dished-shaped...mabye .020" bow on a surface plate/indicator. It would be super duper if there was a machine we could feed these parts into and have them come out within maybe .005" flatness. I'm picturing a big plate straightening machine only smaller, where there's alternating rollers above and below the part that become progressively closer together to almost cold-rolling the material thinner and you would feed the parts through like you would a thickness planer in a wood shop? Does anyone know if there is anything like that out there? Thank you!

michiganbuck · Dec 3, 2020

A simple bench arbor press likely could be set up to push the part to better than .005

Airpower press would also do the job.
Palmgren Air Operated Bench Press - 9661604 - Penn Tool Co., Inc

likely run 300 to 800 an hour with a simple set up.

DDoug · Dec 3, 2020

Nerdlinger said:
I have a small plate that gets punched out of .134" thick 1050 strip. The part is about the size of your hand. It comes out of the press slightly dished-shaped...mabye .020" bow on a surface plate/indicator. It would be super duper if there was a machine we could feed these parts into and have them come out within maybe .005" flatness. I'm picturing a big plate straightening machine only smaller, where there's alternating rollers above and below the part that become progressively closer together to almost cold-rolling the material thinner and you would feed the parts through like you would a thickness planer in a wood shop? Does anyone know if there is anything like that out there? Thank you!

Yup, I bought one....for a friend.

It is an "Uncoiler" to feed a punch press, and it can hold a large roll of material 6" wide max.

It feeds into a series of upper and lower rollers, total length of this part of the machine is maybe 12"-16" long. These are set to flatten the material
just before it goes in the punch press.

Nerdlinger · Dec 3, 2020

michiganbuck said:
A simple bench arbor press likely could be set up to push the part to better than .005

Airpower press would also do the job.
Palmgren Air Operated Bench Press - 9661604 - Penn Tool Co., Inc

likely run 300 to 800 an hour with a simple set up.

Would you just put the part on some blocks and smash em all to the same point (like setting a stop on a manual drill press)? I’m not sure the parts are consistently off by the same amount for that to work. Like some might be off by .020” and some might be off by .010”. But maybe I can just split the difference?

Nerdlinger · Dec 3, 2020

digger doug said:
Yup, I bought one....for a friend.

It is an "Uncoiler" to feed a punch press, and it can hold a large roll of material 6" wide max.

It feeds into a series of upper and lower rollers, total length of this part of the machine is maybe 12"-16" long. These are set to flatten the material
just before it goes in the punch press.

Yeah, that’s about what I was thinking! I actually tried this with our coil feeder for our punch presses but it didn’t work....but maybe there’s one better-suited for my exact application. Or maybe I need to try harder with the one we already have. Thanks!

fciron · Dec 3, 2020

If the distorting is from the punching operation it might be corrected by changing any crown or shear in the punch.

Strostkovy · Dec 3, 2020

Can you curl the material the other way before punching?

gbent · Dec 4, 2020

If your part is getting distorted in the punching process, fix the punching process.

DDoug · Dec 4, 2020

gbent said:
If your part is getting distorted in the punching process, fix the punching process.

Yup, increase the stripper pressure would be the easiest place to start.

michiganbuck · Dec 4, 2020

Nerdlinger said:
Would you just put the part on some blocks and smash em all to the same point (like setting a stop on a manual drill press)? I’m not sure the parts are consistently off by the same amount for that to work. Like some might be off by .020” and some might be off by .010”. But maybe I can just split the difference?

Good to check that they are close to the same. The material would need to be constant for the amount of dish to be consistent. A manual drill press would not be suitable. A homemade swing arm could likely do the job. The part would need a fixture to push into, it would be tweaked until the desired change was made.
*A photo or sketch of the part would help.

A homemade swing arm likely would work.

Coining a part can sometimes make better but that is a progressive die and I don't you seem to not wish to go to that expense.

boslab · Dec 4, 2020

Laser it out, I’m told less distortion if pack cut, though all the plate I’ve cut is 10-16mm, with no real tolerance on flatness better punches, tighter punch to die clearance and a brutal stripper, I mean silly big springs seemed to work with Ali the punch is displacing metal I think, perhaps jig drilling might be a better way to go?
Mark

Nerdlinger · Dec 4, 2020

Strostkovy said:
Can you curl the material the other way before punching?

It might be possible...we buy it in 12' strips. Thanks!

Nerdlinger · Dec 4, 2020

gbent said:
If your part is getting distorted in the punching process, fix the punching process.

Touche'! The punch used to be a "V" shaped taper punch because the 100 ton press we have was the biggest one we had at the time the die was made(or so the story goes) Now we have a 250 ton press so I talked to the two tool and die makers we have (pretty good, experienced chaps) and we decided to take the taper out of the punch and make it "flat." It got a little better but not much. Maybe there is more we can do there, though, so I'll give it another go there. Thanks for the "wake up" call!

Nerdlinger · Dec 4, 2020

digger doug said:
Yup, increase the stripper pressure would be the easiest place to start.

yeah, I imagine the "buckling" of the part from the shear on the periphery must be overcoming the pressure pad hold down force. So maybe we just need some stronger springs in there. Thanks!

michiganbuck · Dec 4, 2020

QT: [slightly dished-shaped] concave or convex to the punch?

Nerdlinger · Dec 4, 2020

michiganbuck said:
QT: [slightly dished-shaped] concave or convex to the punch?

The part is convex relative to the punch. In addition to the outside periphery of the part being cut there are holes on the inside of the part being cut at the same time, so it is a compound die that results in the part having a common burr side all done in one shot. There is a large hole in the center of the part and it sure looks like the part is actually more "V" shaped instead of "bowed." (With the large kidney bean feature being the bottom of the "V".) I will look into the actual "shape" of the part more closely. To be continued...

Strostkovy · Dec 4, 2020

I'm no expert, but is it possibly the part could be distorted in the ejecting process? I.E., is the retracting punch pulling the part into a bow shape?

michiganbuck · Dec 5, 2020

Strostkovy said:
I'm no expert, but is it possible the part could be distorted in the ejecting process? I.E., is the retracting punch pulling the part into a bow shape?

Could need a more solid stripper.

Did the part ever come out flatter, like when the punches were new/sharp?

Does the set up/die have a spring or plate stripper?

gbent · Dec 5, 2020

I see a very uneven radius around the blank. Post a picture of the exit side, it tells a more complete story.

rogertoolmaker · Dec 5, 2020

I am going make an assumption that your stamping the part in a plain blanking die. A compound die may solve your problem. We really need more information about your stamping process and requirements.

Roger

Small Plate Straightening Machine?

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