Help with stamping die design

DYNAMIC TOOL 1 · Apr 17, 2017

Hello everyone,
Looking for a little help designing the die to make this attached part. I know the material will move when the "U" shape is formed. Trying to figure out how to make the part with out snapping off the punches. Any ideas ???
Thanks Dave.

magneticanomaly · Apr 17, 2017

Two hits, two stations in the dieset. Or, trough is formed first by heavily spring-loaded punch, then it collapses to allow shorter piercing punches to engage.

cvairwerks · Apr 17, 2017

Not a tool and die guy by any means, but a blanking die, then a two station die. Blank the part, 1st station forms the "u", second station pierces the holes on each end. At the 5k quantity per year, I don't think a progressive die would price out to make it a profitable job., although, at a little over 6500 feet of coil stock it might.

Rewt · Apr 17, 2017

You can also use a heavily springed stipper to do something similar to what magnetic said. Hardened insert in the stripper forms part, located punches follow at whatever interval works for you.

DYNAMIC TOOL 1 · Apr 17, 2017

2 stage . something like this.

SIP6A · Apr 17, 2017

Do you have any interest in a Tool & Die shop building you a die then running the parts?

Todd
[email protected]

KilrB · Apr 17, 2017

1. Are you running these from coil or sheet?

2. What kind/size press are you running them in?

My suggestion is similar to cvairwerks.

Run it from coil.

Two dies.

First die punches the holes and parts-off the blank to length.

Second die forms the channel.

Note that the first die should punch the trailing hole of one part and the leading hole of the next, and part-off between them.

This allows for a shorter die block and eliminates the need to get the distance between holes just right to allow for the draw-in of the channel.

It will also allow you to change the over-all part length without having to make a new die.

DYNAMIC TOOL 1 · Apr 17, 2017

I tried bending the form with a heavy spring but it just collapsed the spring. Maybe I need 4 springs?

KilrB · Apr 17, 2017

DYNAMIC TOOL 1 said:
I tried bending the form with a heavy spring but it just collapsed the spring. Maybe I need 4 springs?

No, you need a punch and die manufactured to form that feature at that location in that material at that thickness ...

DYNAMIC TOOL 1 · Apr 17, 2017

I made a punch and die to form the "U" shape. Then tried to form it with a heavy spring in a vise , but the spring just collapsed. It only bent the material slightly.

KilrB · Apr 17, 2017

DYNAMIC TOOL 1 said:
I made a punch and die to form the "U" shape. Then tried to form it with a heavy spring in a vise , but the spring just collapsed. It only bent the material slightly.

Please explain.

Do you not have a press of some kind to do this in?

Where are/were you locating the spring, over the punch, under the die?

If so, get rid of the spring and apply pressure directly to the punch and die.

Now ... how are you keeping the rest of the part "flat" while you form the channel?

A spring-loaded pressure pad with a channel for the part would work.

Have you put corner radii in your die so that it allows your material to flow into the die?

DYNAMIC TOOL 1 · Apr 17, 2017

I do not have a press to run the die.
I had 1 heavy duty spring under the die in a large vise.
When I remove the spring I can form the part no problem. The rest of the part stays straight.
There are small radius on the corners of the die.
The punches and form die will all be in a die set, once I have the design figured out.

What exactly is a spring loaded pressure pad??
Is it a stripper plate with a channel "U" shape form on it, and spring loaded?

jscpm · Apr 17, 2017

I would suggest having the die made professionally. The hours you will burn trying to figure it out are not worth it.

If I were designing this die, I would make a single-stage, triple-action die. You have 3 operations: drawing, punching and cutoff/shearing. A single die can do all 3 in order. As the block descends, first it draws the bend, then the punches pierce the blank, finally the shear descends. So, you have a triple block which is staggered, with the drawing block in the center, the punching block around it, and a shearing block to one side. Putting all this together would take a lot of work, especially for someone who has never done it before. Best leave it to a die maker.

UPDATE

I read your post more carefully and it says something about vises. Get professional help.

KilrB · Apr 17, 2017

DYNAMIC TOOL 1 said:
I do not have a press to run the die.
I had 1 heavy duty spring under the die in a large vise.
When I remove the spring I can form the part no problem. The rest of the part stays straight.
There are small radius on the corners of the die.
The punches and form die will all be in a die set, once I have the design figured out.

What exactly is a spring loaded pressure pad??
Is it a stripper plate with a channel "U" shape form on it, and spring loaded?

So, how do you envision this working?

1. Nothing anyone here has suggested is going to fit or work in your vise.

2. Unless these are very expensive parts you will never recoup what you spend on a progressive or single-stage, triple-action die at only 5000 pcs a year.

3. A spring-loaded pressure pad can have many forms and functions. As I picture it for you application it would have a channel only slightly deeper and wider than your part to allow it (the part) to slip, but not kick up, when the form punch passes through it and forms the part.

If you are planning this as a DIY project I suggest you search these forums for a "suggested reading" list ...

AD Design · Apr 17, 2017

I was a tool and die maker for over 25 years and I have to say that if you don't have a press of some sort it's not going to easy or consistent trying to make those parts in a vise. The others have given you some good suggestions, I even have a few to contribute, but without a proper stamping die it's going to be more struggle than work. Your parts will likely not be consistent and it will likely be for nothing. As a suggestion, if you do manage to create the "trough" without the part deforming you can always set a stop in the mill and put the hole in as a secondary operation. Not much fun if it's a large run batch. Otherwise, get a few quotes from a shop for running these. Not trying to discourage you, just don't want to encourage you to waste a lot of time/money for poor results. On the other hand, this would be an excellent example to learn what die design should be.

DYNAMIC TOOL 1 · Apr 17, 2017

Sorry, the die will be ran in a press , coil feed stock.
I am building the die for someone. I`m just not sure of the design because the material will move when the "u " is formed.

Can I spring load a punch to form the "U"

Or preform like attached die design?

KilrB · Apr 17, 2017

DYNAMIC TOOL 1 said:
Sorry, the die will be ran in a press , coil feed stock.
I am building the die for someone. I`m just not sure of the design because the material will move when the "u " is formed.

Can I spring load a punch to form the "U"

Or preform like attached die design?

View attachment 196480

Oooh boy ...

In that case I suggest you go back and re-read jscpm's post (#13) ... and good luck.

(edit)

For cost and manufacturing reasons, you might also see if your customer is open to a two die solution.

Like AD, I do not want to discourage you from learning Tool & Die.

Too few in this country are taking up the challenge these days.

That you made an, apparently, functional form punch and die is commendable.

... but you done jumped in the deep end son.

(more edit)

Still more to consider ...

While your sketch could be used as the barest of bones start to building your die, just how big is the press it is going to run in?

With a formed length of 14-3/4" and a developed length of around 14.89" you are looking at a die set around 32"-36" long as you have it sketched.

That better be a big press ...

I couldn't even guess at you open and shut heights as of yet.

With no press of your own, how are you going to prove this die before delivery?

TDegenhart · Apr 17, 2017

As a young design engineer, I always though a one hit die would do the job. All nicely staged. Then I got around real dies and die makers.

If you do not or cannot justify a progressive die, then the only practical way that I see is a two die approach. Feeding from coil stock has no advantage, actually I would prefer to use pre cut strips. Tolerance on length is wide open.

Two ways of doing this, two totally separate dies and a die set with two stations. I would prefer the two station, one die set approach.

You will need a die set with leader pins in order to maintain punch alignment. The dies are, a form die for the "U" which uses a simple stop and guide pins, and a second die that uses the form for locating. Strippers would be urethane sleeves on the punches and urethane blocks on the form side. For stripping the formed strip, I would use a slot underneath the strip for a tool if needed.

Operation: locate a strip in the form station against the stop pin. Close the press. The punch will draw material from both ends. Open the press, remove the now formed part and position it in pierce station. There will need to be a punch in the pierce station to maintain alignment. Reload the form station. When the press opens, the urethane sleeves will strip the part from the punches.

Tom

jscpm · Apr 17, 2017

If we are going to get into the nitty gritty of this design, one thing I should mention is that the way you have it in the drawing is problematic because of the sharp edges of the U-shape. If you actually wanted to produce this shape for real, you would have to make a bending die, not a drawing die, and that would be MUCH more complicated (=expensive) because it involves a rolling action. If you want to draw it, you will need to redesign it so the U has a rounded shoulder. The die maker will explain all this.

SIP6A · Apr 17, 2017

You need to find somebody that has actually built a die to give you a hand. It's obvious from your post that you have never done anything like this. Your die needs to be designed by a competent die designer. People can be killed by die designed and built by hobbyists

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