Help making die to form this part

As usual I get a job with no dimensions hardly,no drawing,no engineering,etc.
I have a pic I am enclosing to show basically how the finished part should look.
The material is 304 SS .035 thick
The basic shape will be lasered out
Now I have been tasked with the job of how to form this piece from the flat lasered out part to what the drawing looks like
At this time quantity of parts to be formed is 100 pieces,with more possible in future
They the customer want this so their employees (figure that out) can do the forming easily
I have zero experience making forming dies,but close to 20 years machining experience,so making the dies is piece of cake,,engineering and design is where I need the help
What material for die ?
Use oil while forming ?
What shape and clearances ? (this is not a precision part)
Is this doable with a big Dake arbor press or a 50 ton hydraulic press or even a kurt mill vise ?Obviously the fastest way is desired
Out of my wheelhouse on this one
Thanks guys

Forming low production formed blank

jrmach said:

As usual I get a job with no dimensions hardly,no drawing,no engineering,etc.
I have a pic I am enclosing to show basically how the finished part should look.
The material is 304 SS .035 thick
The basic shape will be lasered out
Now I have been tasked with the job of how to form this piece from the flat lasered out part to what the drawing looks like
At this time quantity of parts to be formed is 100 pieces,with more possible in future
They the customer want this so their employees (figure that out) can do the forming easily
I have zero experience making forming dies,but close to 20 years machining experience,so making the dies is piece of cake,,engineering and design is where I need the help
What material for die ?
Use oil while forming ?
What shape and clearances ? (this is not a precision part)
Is this doable with a big Dake arbor press or a 50 ton hydraulic press or even a kurt mill vise ?Obviously the fastest way is desired
Out of my wheelhouse on this one
Thanks guysView attachment 268857

Click to expand...

The cost of a form die may be prohibitive for limited requirements. The forming could be done with low cost standard press brake tooling.

Roger

rogertoolmaker said:

The cost of a form die may be prohibitive for limited requirements. The forming could be done with low cost standard press brake tooling.

Roger

Click to expand...

I am making the form die
How to make is my question
and yes brake tool option I have stated to customer,but they would like something faster and less labor intensive

Jrmach,

4140 HT, 4142 HT, P20 steels would work. All are considered pre-hard so Rock C is about 25-30, readily machinable with standard end mills. Once machined, no further heat treat is required.

Make a male and female die, I would use the 50T hydraulic for those quantities, provided the press can give you the control.

Springback would be my major concern, and some experimenting with the dies might be in order.

Chuck
Burbank, CA

typical terrible print [2]90 degree bends [2] 45 degree bends ? typically you need to over bend due to spring back trial and error so if trying to bend in 1 shot all bends . also you may find variations in sheet to sheet as to over bend necessary. drawing need dimensions and tolerances high and low limits on lengths and angles

jrmach said:

I am making the form die
How to make is my question
and yes brake tool option I have stated to customer,but they would like something faster and less labor intensive

Click to expand...

If you have a die set, and a 50 ton hydraulic press you should be fine.

I would form the part upside down from the view you have. The two outside wings probably should have spring pressure holding them flat, but it's possible to do it solid. It will just be difficult to get the part off the bottom form when the operation is completed.

The top will require a spring pad in the middle section, pretty stout springs at that. you will want a good amount of preload on them also.

You will need to allow for spring back on all four form edges. I would construct the die with very small inside radii, adjusting as you go this way, you can avoid much of the spring back that S.S. will have.

A2 should be fine for this project.

probably the easiest way is this sort of die in a press brake with appropriate stops to locate the flat part on the die:
View attachment 268858

if they don't have a press brake, arbor press might work, 5-10t range would be sufficient to form each Z bend for that part, maybe use one of those diy kits as a basis for the tool holder, put both dies side by side, so you could make the right angle Z bend, then flip the part and use the other die to form the wide angle Z (at least it looks to me that the right Z in the drawing is not a right angle one)
View attachment 268860

Solidworks (and Fusion360) have sheet metal drawing options, including generating flat patterns, but expect some trial and error, bend radius of your dies will have to be accounted for in the software (K-factor value), larger bend radius - shorter distance between bend center lines, and the opposite of course

with a 1mm+ bend radius, I'd say you could make the first 100 parts with soft dies

I think this what your asking.
Mount the form tool in a die set.
Make two form blocks; each end of the part with a spring pad between the form blocks. As mentioned spring back is a concern. Design the form die so the punch can be set hard on the Die radii. It may still me necessary to heal the punch at the radii to eliminate the spring back. The spring pad should bottom on the die shoe. Two 3/4" dia. blue Danley springs in spring pockets drilled into the die shoe. If your going to the expense of building a die; I would use O1 tool steel and heat treat 60-62Rc and grind. A lessor hardness will scorer the die in short order and soon the P&D will be in poor condition. Make the punch with .035 material thickness between the form punch and the and die blocks. Make the form pad CRS.

Roger

Ask the customer if you can have a small gusset at each of the forms. That will help with spring back. Also a pilot hole in middle for controlling side-side movement.

Tom

I failed to anwser one of your questions

rogertoolmaker said:

I think this what your asking.
Mount the form tool in a die set.
Make two form blocks; each end of the part with a spring pad between the form blocks. As mentioned spring back is a concern. Design the form die so the punch can be set hard on the Die radii. It may still me necessary to heal the punch at the radii to eliminate the spring back. The spring pad should bottom on the die shoe. Two 3/4" dia. blue Danley springs in spring pockets drilled into the die shoe. If your going to the expense of building a die; I would use O1 tool steel and heat treat 60-62Rc and grind. A lessor hardness will scorer the die in short order and soon the P&D will be in poor condition. Make the punch with .035 material thickness between the form punch and the and die blocks. Make the form pad CRS.

Roger

Click to expand...

Liquid friction is always less than solid friction. When forming use oil by all means. The form radii should be the same as the material thickness or less, but not less than .015 radius. Your 50 ton press is way more than adequate.

If you have questions about die design, I may be able to help you.

Roger

Roger, are you thinking of a one stage or two stage die?

Tom

Form the part in one stroke of the press in one station.

Roger

Hi jrmach:
I have made a fair number of simple bent parts similar to this and I've usually had the best success for these simple parts making rough and dirty individual bending jigs instead of making press tooling, especially if the customer was supposed to run it and had no proper facilities to do so.
Attached is a couple of pictures of a rude and dirty tube bending jig for 1/8" OD heavy wall tube where I had to get the bends within a 10 thou of nominal for the centerlines of the bent legs.
It's patterned on a bog standard roller bender, and you may find something like this works best for your application too.

To keep it simple, I'd consider making two benders; one for the first pair of bends and one for the second pair of bends.
If you make them adjustable as I did with mine you can noodle about with them until everything is just right then hand them off to the customer and let them have at it.
The nice thing about doing it this way is that you don't need anything fancy and you don't need much of a design.
Look at commercially available sheet metal folding benders for inspiration.

You should be able to make something for a thousand bucks or so and I'll bet they can run 100 parts in a morning without breaking a sweat.
If they need better than that, they'll have to spend more and you'll have to fuck around more to make something that works on the first try, but for a hundred parts I'd keep it as simple as possible.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

I agree that building a die for 100 parts should never fly. Unless it is the only way. I am just trying to answer his concerns about a form die. It will help him decide what to do. It all depends on the customers desires.

Nice forming jigs.

Roger

It would take two hits, but what about a "Z" form die? Form one side, then the other.

Tom

Questions/Answers

I agree with what others have already posted. What may not be clear (to me anyway) is whether the company you're making this for understand what the cost will be for what their expectations are. As already stated, making a die for this will be expensive for only 100 parts. It will also have built in issues with adjustment because spring-back from one sheet to the next can/will be different. Since all the parts are pre-cut a change can occur in the middle of the run and the bends can/will be inconsistent. If this is acceptable to the company (bend tolerance needs to be stated) then this may not be a problem that needs to be addressed. A die can be designed to be easily adjustable to compensate for different mechanical properties in material but this adds a lot more expense. If the company is ok with expense then it's not much of an issue. A bending jig would be a LOT less expensive to build but this may not satisfy the customer stated wish for something "faster and less labor intensive". The customer may not fully understand the Time=Money equation and the old adage of "You get what you pay for". This is understandable if it's office types you're dealing with, I don't understand cost accounting very well for the same reasons. If possible, try to communicate that:

1) All parts cut from the same sheet are to bundled together (if using a forming die)
2) A bending jig will be the lowest cost but will be subject to more labor and the quality of labor
3) A far better drawing with tolerance limits, angles, and dimensions will be required (by you?)
4) A cap limit to cost needs to be set. This should drive the decision of bending jig or die
5) Somebody is going to need to adjust the die or bending jig stops to be fool proof unless bend tolerances don't mean much.
6) All pre-cut parts need to be oriented with the bend going ACROSS the grain rather than WITH the grain. This will affect the sheet layout and the laser outfit will do the layout for efficiency NOT grain orientation. Bending along the grain runs a good risk of developing cracks at the bend(s). You may already know this but thought it worth mentioning.

There's plenty of advice to be had from experienced members (besides me) here on the board. Any lack of experience you have with dies or bending shouldn't be a problem for you. Do post when/what you can. I've had jobs like this too where the customer sends just a photo or a stick-figure drawing on a napkin with insufficient dimensions. They need to be educated a bit, make sure you charge them for hand holding if that's what this comes to. Hope this was of some help.

Die with two hits.

TDegenhart said:

It would take two hits, but what about a "Z" form die? Form one side, then the other.

Tom

Click to expand...

You can make this work with proper gaging. As previously stated form across the grain. It looks like you have all the information to decide what to do.

Roger

Its .035" thick stainless less than 1/2" wide. You could do this with 3d printed tooling off a cheap plastic extrusion printer. I agree though given the 90 deg leg it will be easier in 2 hits. Printed correctly will easily handle several hundred bends, and if it wears out super cheap to print another set.

The only reason I can see that it wouldnt work from 3d printed is if the bend radius has to be really tight or tolerances are tight, but if allowed say .1" no problem. Given the back of the napkin drawing I would aSSume low tolerances but it does need to be asked.

JP Machining- I'd be interested in hearing what material would be used for 3D printing that would hold up to forming pressures and the abrasion. Two companies I contracted for used 3D printing. One used it for mock-up fitment of castings, the other used it for complex shaped feed ramp transitions. In both instances my opinion was "nicely made toys". I've zero experience with using a 3D printer to generate useful tooling. I try to read threads on the sub-forum but still have the opinion, perhaps mistakenly so, that additive manufacturing still either isn't capable and/or cost effective to employ as an option. If you have experience with using this for tooling I could stand to be educated here.

https://www.practicalmachinist.com/...s-brake-tooling-does-work-355995/#post3249851

While it does have its limitations, another reason why I said 2 hits for this part. It can work quite well. The dies I printed in the above link have made several hundred bends now and other than being dirty on the ends they still look and function like they did when new. I have done some smaller ones as well bending stuff like 20ga stainless with a 1/2" bottom V die and they hold up well. The only one I have had fail so far has tried to do a hem die for 22ga steel, just too much compression force.

Some people look at the time it takes to print the larger dies and think its not worth it, but most printers once they get started on a print dont really need any further attention so basically free, other than cost of filament (maybe $20 per kg) and elec to run printer. I havent done any multibend dies as of yet but have seen many others that have with good success as well as what Wilson and other die makers are now offering. A better printer than can handle nylon filament and maybe even some carbon fiber in it will make much better form tools than the PLA that I use but it works too. I'm already researching building a newer printer than could do this for me.

For this part I envision 2 sets of Z bend dies (offset dies), would probably need a die set to put them in to work in an arbor press but if done right easily changeable for other dies down the road.