die for pressing steel sheet into U shape

[Runner4404spd]

i need to make a die to stamp a flat peice of steel about .050 thick into a U shape. i need these done consistently and will need quite a few of them. these individual Us then get welded togeter.

basically i need the die to have a flat bottom about 1" wide and then have a radius in the corners of .25" and then go up the sides about 1.25 inches. the lenght of the die is about 10-12" long.

i figure that i will need a female and male die to form this, what i don't know about is the spring back of the steel and how to start with making the die. i can bend these by hand but i need consistent uniform results. i would like this to be able to be used in my 20 ton hydraulic press.

[vladdy]

I was involved in something similar to this a few years back, they used a three part die with upper follow or squeeze rollers..
the male top push die was relieved on the sides and the follow rollers would over-bend the sides slightly to achieve a straight side after spring back..
they also had a lower die follower that applied pressure with a hydraulic accumulator to achieve a flat bottom surface as without it there was tendancy to round the bottom flat while bending..
that die set _mostly- worked ok with the exception that occasionally it would gall a little and then pull one side resulting in unequal finished arm length..

afterwards they went to a hossfeld style manual bender with a shop made die, and finished it with a hammer die that was basically two notches at a slight inward angle that compensated for the springback, and a flat top surface to get the proper flat on the center, basically push it down into the notches and smack it with a hammer, surprisingly effective...

enjoy..

[scubanick]

this is probably kinda what you want im guessing
i would try to "coin" the radius in the bottom
to set the material to try to avoid springback

[NC Cams]

A real nice die material to use would be O6 tool steel. It machines very nicely, and when heat treated propgerly, will easily hold a 60-62Hrc.

AND, due to the graphitic nature of the steel, generally speaking, it will pretty much be impervious to galling. It should also have low friction while sliding over the metal thus making it a nice material for deep draw dies. It is not that expensive either.

Be sure to find someone who knows how to H/T it, preferrably in an inert atmophere or neutral salt. Double temper at LEAST, triple is better. TO really prevent distortion, stress relieve at 1250 for 1.5 hour min per 1" thickness and furnace cool if possible prior to austenitize, Q & T.

[schiada96]

Originally Posted by Runner4404spd i need to make a die to stamp a flat peice of steel about .050 thick into a U shape. i need these done consistently and will need quite a few of them. these individual Us then get welded togeter. basically i need the die to have a flat bottom about 1" wide and then have a radius in the corners of .25" and then go up the sides about 1.25 inches. the lenght of the die is about 10-12" long. i figure that i will need a female and male die to form this, what i don't know about is the spring back of the steel and how to start with making the die. i can bend these by hand but i need consistent uniform results. i would like this to be able to be used in my 20 ton hydraulic press.

How many is quite a few? A die to form a U shape as stated would cost 15 to 18 hundred. You could have a sheetmetal house with a press brake and gooseneck die form them.

[scubanick]

did ya build or buy anything to do this with yet

Originally Posted by Runner4404spd i need to make a die to stamp a flat peice of steel about .050 thick into a U shape. i need these done consistently and will need quite a few of them. these individual Us then get welded togeter. basically i need the die to have a flat bottom about 1" wide and then have a radius in the corners of .25" and then go up the sides about 1.25 inches. the lenght of the die is about 10-12" long. i figure that i will need a female and male die to form this, what i don't know about is the spring back of the steel and how to start with making the die. i can bend these by hand but i need consistent uniform results. i would like this to be able to be used in my 20 ton hydraulic press.

[Runner4404spd]

no i haven't made anything yet. since this is just thin sheetmetal, someone else suggested i use oak, to make a die. realistically i probably won't need more than 32 of these.

[scubanick]

oak huh...hmmm
let me know how that turns out

[dimaker]

not a complicated part however for the quantities youve listed a press brake form would probably be better. to acccuractly for a part like this you really need a spring loaded form pad. the spring pressure on this form pad requires a geat deal of pressure (calculated by the bending pressure). in addition adjustment is often needed to dial in part.

[parttime]

press brake sounds like the way to go. If you can find a place locally with a turret press, they can trim the parts to size and form for you.

[Zumba]

This is easily doable on your 20 ton press. Buy the book, "Fundamentals of Press Brake Tooling" from Amazon for about $60, and it should give you all the info you need.

Bending the U in a single press won't be easy as it's difficult to counteract spring back. It'll be much easier to do this with a regular 90 degree die in two presses (which will of course be less than 90 degrees). The book should tell you how much exactly. You'll need a gooseneck die of course, and it'll be offset from center a bit. Not difficult by any means though.

As for materials, on a short run with light weight materials, you can probably get by with plain old A36 hot rolled. 4140 prehard would be better though. Tool steel, probably overboard.

[Kevin Taylor]

RR440 Have the local sheetmetal shop bend one or two part's long enough to cut what you need out of then weld . Are you trying to make a rectangle tube ? I made runner's for a intake manafold with one seam four bend's made a push clevis for my press and a bit that would fit in the confine of the finished part made the bit out of hotroled bar with a radis and cut a grove in 1 1/2 Aluminum for the female with the corect R tool ID. R+mat thickness = Grove R. I kept machining the grove untill the bend was corect when it bottemed out Drilled a series of holes in the edges of the plate to put pin's in for back stop's I think I tryed four times to get the part wright after doing a lot of math calculations to try to save material Good Luck Kevin