bending 1/4 A36

[plazmabob]

I'm using a hydraulic press, setup with European punch and a 2 inch v die. I'm trying to bend 3 inch wide channel. The trouble is that when I make th first break the material bows in the opposite direction the punch is traveling. In other words, the bent material is raised up off of the die nearly a half inch in the center, but the bend is 90 deg. all the length. What can I do to prevent this?

 

[stanweld]

Was the steel strip/flat bar originally purchased as coiled product?

 

[berkshire]

plazmabob (Industrial)
If the bend is still there after you put the second bend on your channel, it would indicate that the material has uneven tension in the stock. with more material in the outside edges of the material.
This is common with the first couple of strips if you are shearing stock off a sheet, and depends upon how well the material was stretch straightened in the first place.
If you are buying strip you need to talk to your supplier.
You can also try using a bigger radius on your top die.
B.E.