Rooster's Revenge

Here is a note from my long-time die guy pal Pete Ulintz. Y’all know Pete; he took over the Tooling by Design column I used to write in MetalForming magazine. I am sure most of you have heard Pete speak at PMA events or have visited his website ToolingByDesign.com.

This is his note:

Tim,

I like your blog regarding restrike operations. I have another “rant” idea for you: Many times I see cam pierce stations added to progressive dies having straight forward bending operations (no drawing or stretching) because people are afraid the development will be lost if the form wears or the die radii changes, or an incorrect “adjustment” is made during production. Obviously, this adds cost and complexity to the tooling but some companies and individuals subscribe to this “just-in-case” approach regardless of the short term and long term costs. Your thoughts?

Pete

 I agree completely with Pete. More and more, stampers are adding unnecessary operations, like restrikes and cams, to their process because they are scared. Planning for every “what if” scenario becomes cost prohibitive after a while and all the while flying in the face of so-called “Lean” initiatives.

It is funny to me. Back 20 years ago, I believe you would get your ass kicked for adding cams that you don’t need. Today, you get your ass kicked for assuming the die shop is not capable of getting the job done right.

For me, the best design is the simplest design that works.

Why is it that, when I either process a stamping or setup a formability simulation for any company in any industry on any continent, I get some proprietary commodity code for a material specification from the customer?

Commodity codes suck, and I will tell you why: they are completely useless.

Every company that needs sheet steel to manufacture products buys the same steel from the same material manufacturers. Commodity codes are a reference to an existing material that the company will purchase.

Die engineers need material properties to do their job effectively. It takes longer to cross-reference some bullshit commodity code to something meaningful than it does to do the job itself.

Here is an idea: create a universally-recognized generic smart code for each material. By smart I mean include the abbreviation for the material type and grade plus the tensile strength.

So, instead of a commodity code like SPX28975AFU, I would have S-DP-500 for Dual Phase Steel with a tensile strength of 500 MPa.

From there, I not only know generally what the material is, I can also get the material properties I need without guessing.

Here is my Top 5 list of words that I feel are over-used in the die engineering community. In order,

1. Robust

2. Optimize

3. Checklist

4. Benchmark

5. Psychobeotch

Yes, psychobeotch is all the rage. While hearing “robust” makes me taste vomit, “psychobeotch” gives me a Fatal Attraction tingle.

The discussion on the validity of restrike dies continues with a comment from Eric Kam that I would like to post here instead of comments due to length:

It seems to me that the reason that the restrike is more appealing and rational than the trim line correction…

by creating an adjustment point closer to the final destination (the conveyor belts and the racks) they are able to affect the “illusion” of control over some of the variation. To address the initial form or flange die may require the definition of a different tip angle, or inclusion of a CAM that was not originally part of that planned operation. Additionally, fudging a “calibration” hit or tweaking the restrike may have far less negative impact on the overall behavior of the panel.

I am not defending it, but I can see the safety-blanket-like appeal of using the purpose-built restrike die as a control point. A tool that if the attempt at re-cutting or shimming or welding up or just plain hard hitting the tool away from original design intent will not have as broad or potentially negative impact on larger portions of the product. severely mess with the restrike and you are not messing with the product.

Similar to the concept of double draw beads used in large panel draws. We know that square lock beads can effectively lock out all material flow, and that grinding on those square beads can affect all gradients of restraint until the bead is gone. However, we still see double draw beads and the significantly larger blanks that they require in production. Why? Because if I have to make adjustments to the material flow, it feels like we can safely grind and weld on one of the two drawbeads without drastically altering the die. While grinding on the ONLY drawbead feels more risky.

Rational yes, but still an illusion of control.

What folks need to be able to do more effectively during their engineering of the PROCESS and all the tools in the entire process, is to meaningfully evaluate not just what the die does in the best/worst/nominal cases that they might be simulating as their standard. But they need to consider what happens when the world changes slightly around them-as it will. In springback there is no Best or Worst case.

Different is Different. And when it comes to springback any difference can end up being wrong. The restrike die just gives us one more bite at the apple to fix what we could not stabilize in the initial hit and when it appears to fix the problem at buy-off via tweaking, it actually becomes a bit of a self-fulfilling prophecy. We will prove by having it that we needed it. Vicious cycle, the only good news is that we might get paid to make the restrike die, so I don’t foresee the world doing away with them.

Good points, Eric. But with Obama now wanting more aggressive CAFE standards in the next 20 years, the only profitable way to stamp automotive vehicles is to get away from the unnecessary bells and whistles like restrike dies and just-in-case cam operations.

It seems as though stampers that are running anything but 1008-1010 steel want restrike dies for flanges. This is flawed.

Restrike, or spank, dies are intended to sharpen feature lines and plussed radii. Radii that is too sharp to be formed home in the draw or form operation.

Somewhere along the way, it became acceptable then fashionable to use restrike operations to compensate for springback coming out of flange dies.

If you need to compensate for flange springback, do it in the flange die. In other words, if the flange die does not work, fix the flange die.

I mean, if the trim die did not get the developed trim within tolerance, you would not add another trim die to retrim after the first trim would you?

Hell no. I believe they would take away your Journeyman’s card for something like that.

You would rework the trim steels until the developed trim works. The same rational thinking goes for flange dies. Too much springback in the flange die? Rework the flange die to fix the problem right where it starts.

Dan Grieshaber gave a presentation titled Lightweighting Automotive Body: Enablers and Manufacturing Challenges at the Great Designs in Steel 2010 event.

As I have mentioned before, I genuinely thought Dan did a fabulous job of presenting. His slide presentation was generally good. He spoke freely without notes or a script. Dan was relaxed and knew his topic cold. This was evident during the question and answer period.

To set the stage for the talk, the entire event centered around how the automotive industry can continue to manufacture vehicle bodies out of steel and achieve the federally-mandated Corporate Average Fuel Economy (CAFE) of 30 Miles per Gallon for cars by 2016. This is a 40% increase from where we are today.

Dan spoke about three key enablers:

1. increase the use of Advanced High Strength Steels by a factor of 3X;

2. scallop trimlines on non-Class A panels;

3. use alternate processes such as stretch forming for rail-type parts that would otherwise be stamped with form and flange dies.

We are still in the infancy stage of using AHSS. This is evident when Dan mentioned his dies have to be cut 3, 4, 5, and sometimes 7 times to compensate for springback.

I began to cringe when he added that dimensional requirements for auto bodies will get tighter. This is the beginning of the manufacturing challenges Dan spoke of.

What makes this worse? Basically this: the material definitions used in formability simulation and springback analysis software sucks. In fact, the springback analysis software itself pretty much sucks.

How does all this come together? It is simple: To achieve lightweight cars, we will have heavyweight dies.

The dies will be heavier with full inserts made of premium materials and expensive surface treatments.

Die costs will at least double, if not triple, as a result.

And everyone will be happy if the dies are cut only 2 or 3 times instead of 6 or 7. Everyone except for the consumer that will have to wait an extra year to buy that new car and pay a hell of alot more than they should for a vehicle that will save them a measily $350 a year in fuel costs.

Before I start blogging on the takeaways I got from individual presentations at the Great Designs in Steel 2010 event last week, I would first like to share some high level thoughts on the topic.

The overall theme was this: future automobile designs must be stronger for Federal safety requirements and lighter to meet CAFE demands. To meet these objectives and still use steel as the base material for the vehicle structure, sheet steel will continue to become more complex to form.

I get the safety thing. But lightening the vehicle through product design and the forthcoming super advanced high strength steels to meet CAFE standards is misguided.

Why? Because it will take longer to get a new vehicle on the road, the materials will cost more, and the dies that stamp the parts will cost 2X. From the consumers’ standpoint, they will be paying a premium for the vehicle to save pennies in fuel costs.

This whole thing is politically motivated and economically irrational.

To put this into perspective: the fuel efficiency of our vehicles is the best in the history of automobiles. And, gas is relatively cheap. People pay $50 a gallon for coffee brewed at Starbucks and only $3 a gallon for gasoline. That is nearly 17-to-1 more to get you going in the morning versus getting your car or truck going.

Let’s do some simple math. Say a vehicle that costs $24,000 and gets 25 MPG gets redesigned so it gets 50 MPG at a sticker price of $48,000. The average person drives 10,000 miles a year and keeps the vehicle for 4 years.

We are getting twice the fuel ecomony at twice the vehicle cost.

The savings in fuel is 800 gallons of gas. At $3 a gallon, we saved a whopping $2,400. In other words, to get twice the fuel economy, we had to pay 10X that for the vehicle.

Now, let’s say that cars will run on Starbucks coffee. At $50 a gallon for a white mocha, we are going to save $40,000 over 4 years.

Where is the breakeven? For the super high strength steel vehicle to be economically rational, gas would have to be $30 a gallon.

But the agenda is not about rational economics. It is about conserving fuel (at any cost) and continuing to use sheet steel for automobiles.

If the agenda is really to be eco-friendly, then we need to find a viable alternative energy source (batteries are not it) and perhaps a new material for automobile bodies.

I say, let rational economics guide the decisions.

For those that need a bandwagon to ride, start a campaign to reduce the cost of coffee. Paying $50 a gallon is ridiculous.

Gotta go now. I have to pay $1 in gas to drive 10 miles to buy a white mocha at $50 a gallon.

Today was the annual Great Designs in Steel 2010 event.

I have much to say about this day long event in a day or two …

It was fun seeing my faithful friends and fans of my former MetalForming magazine column and this blog. I genuinely had a great time chatting with everyone.

In particular, I have been thinking of my old pal Gary. Much to my surprise, he was there AND recognized me after all this time.

I had a side bet with my die guy pal Bob that Dan Grieshaber would rock the house today. He did not disappoint. Dan’s presentation was by far the best of the day. I told him afterwards it was fabulous. Now, Bob owes me lunch.

The event organizers did a great job of keeping the program on-time. It finished three minutes early. To me, that is incredible.

Most of the presentations, in my opinion, were horrifically delivered. The message was not clear or crisp. And Dan’s presentation aside, I could not read a single slide because I can’t read light blue 12 point font on a bright white background from 40 yards without a sniper scope and dark sunglasses.

Seriously.

All in all it was good. And connecting with the faithful few made it even sweeter.

Today is Cinco de Mayo Eve – like New Year’s Eve.

The weather in the midwest is fabulous. I have visions of double vision. Laying back in a lounge chair with a drink in my hand; soaking up the sun.

If you are working way too hard or are having a difficult time focusing on work because you have been working too hard, then have a drink on me.

Tell your boss that Timmy said it was ok. If your boss is your spouse, please don’t mention my name. It will be our secret.

I have been experimenting, developing, testing, and using solid modeling technology since 1989.

If you are not using parametric and associative solid modeling to engineer dies, then you are not really playing at the same level in the same game as the rest of us.

An acquaintance of mine, Ray Proeber, is a huge solid modeling evangelist for die design.

Check out his company, Accurate Die Design. They are industry experts that provide 3D software, training, and support to the tool, die, and stamping industries.

Their software of choice? SolidWorks.

I personally feel SolidWorks has the best user experience in the game. Of course, they are owned by Dassault Systems – the same company that makes Catia.

In my opinion, there is Catia for high end modeling and surfacing, SolidWorks for everything else, and then nothing else.

Give Ray a call … you will be glad you did.