Rooster's Revenge

In October of 1991, I was part of a six-person task force that was given six months to revolutionize stamping die architectures for automotive tools. We had to scrap 75 years of history and re-invent how dies were designed and built.

The goal? Save 30% of tooling costs.

It took me four months to convince management that hard metric was the way forward. I had three arguments to support my views. Keep in mind this was 1991 and not 2001:

Product data is hard metric. The tools should be too.

The business will become global by the end of the century. The rest of the world uses the metric system for measurement.

Globally sourced metric components are 30% cheaper than their inch equivalents.

The team did not see a correlation between units of measure on product design to die design. Shot down.

The team did not think, at the time, that tools running in North America would be built in China or Korea. Shot down.

Save 30% on components? That is a significant savings toward our goal. Roughly 30% of the tool bill was components. This means we can save 9% of the tool bill on just components. We are almost one-third of the way home. Sold.

Truth is, the metric system is so damn easy to use. It is based on the number “ten”. There is no “five thousandths and one tenth” or “fifty millionths” talk. No. It is 0.001 millimeters. Simple.

I have personally converted several “mom and pop” die shops to metric. And they have not looked back.

If you are still using inch, go cold turkey and start using metric today.

My dear friend Eric Kam does a great job conveying stamping simulation “geek speak” with his blog.

There has been much talk recently in the industry and online about forming simulation feasibility versus validation.

Reams of paper documents and terabytes of data have been generated by the PhD crowd about this topic.

From the trenches, let me boil it down to its core.

Simply stated, think of feasibility as “make it work”.

Validation can then be defined as “does it work”.

Plain and simple …

I was nervously waiting in the K1 lobby at the historic Fisher Body Headquarters building on July 21, 1986. I was an overwhelmed 19 year old kid that could not believe I was standing in a building that John DeLorean once ruled.

See, it was my first day at General Motors as an apprentice on the die engineering apprenticeship. Over 20,000 people took a test that year. Only 12 people off the street got this coveted opportunity.

At 6:45 AM, Chris Colley comes walking down the steps from the second floor. “Are you here for the die engineering apprenticeship program?” he asks me with an expressionless face. I manage to say the word “yes”.

“Follow me”, was his only response.

We walked through the engineering space. The biggest room I had ever seen. Bay after bay of eight foot height vertical drafting boards that had to be 30 or 40 yards long.

The lighting was very bright, like a stadium. It was as loud as a stadium filled with rowdy sports fans. Between the 500+ people, high ceilings, glass windows on two sides, and tile floors, there was nothing to soak up the sound.

And no smoke eaters to soak up the thick haze of cigarette smoke in the air.

To an impressionable 19 year old kid from Detroit, it was intimidating.

As we made our way to a conference room, I look at the die drawings on these vertical boards. My first thought was that this was an endless sea of intersecting lines. My second thought was I am in over my head. Way over my head.

Chris introduces two journeyman trainers to the group of 13 apprentices (one was an existing GM employee). We were about to embark on a nine month boot camp to begin our 7,328 hour apprenticeship on engineering dies. The two trainers were going to take us from knowing nothing to designing dies on our own so we can function in the smoke-filled drafting room.

“My name is Ronny. You WILL call me Ronny!”, the first trainer barks to us. The second trainer, Boettcher (rhymes with poacher), is off to the side with a giant “the cat ate the mouse” grin on his face.

At this point, the experience is a cross between Full Metal Jacket and Deliverance. It is only 7:05 AM, and I am forcing back the urge to vomit.

“I am not Ron. That makes me sound like a pimp. And don’t call me Ronald. My mother calls me Ronald and I hate it”, he says, “It’s Ronny. And that is rule number one.”

He continues, “Rule number two is find out what they don’t like and give ‘em plenty of it.”

Now, I am confused. He hates being called Ronald, so do we call him Ronny or Ronald? Is this a test? Why did I quit my job to come here?

“Rule number three is you are pukes. Worthless apprentice pukes.”

I think, that is convenient because I feel like I am going to puke all over your expensive cowboy boots. And I know you won’t like that either.

That was 23 years ago today.

The program was a great experience and I do not regret a single minute of it.

The best part for me is the tight-knit group of wonderful people I hired in with. After all these years, we still stay in touch.

Happy anniversary to this blessed group : Chris, Larry, John, Doug, Ian, Kris, Grant, Terry, Anne, Danno, Gaspare, and Frank.

The main pad in a die with die mount cams must hold the stamping in place on the lower tool during the press downstroke before the cam steels make initial contact.

On the press upstroke, the main pad must hold the stamping on the lower tool until the cam steels clear the stamping.

The simplest way to ensure the proper timing of the main pad when die mount cams are present is to calculate the main pad travel.

The equation for main pad travel with die mount cams is:

• Tpad = ESM + {[Tdcs • cos(α - β)] / sin α }

where:

• Tpad = main pad travel (mm)
• ESM = engineered safety margin (mm)
• Tdcs = die mount cam steel travel (mm)
• α = driver angle from vertical (degrees)
• β = work angle from horizontal (degrees)

NOTE: if there are multiple die mount cams, then calculate for all and use the greatest result for the main pad travel. Also, if the direct cutting or forming requires more travel than the die mount cam(s), then the direct operation will drive the main pad travel.

For example, assume a die mount cam has cam steels with a work travel of 12 mm. The upper driver angle is 60° from vertical. The work angle is 10° from horizontal. The engineered safety margin on the main pad is a minimum of 5 mm. The direct steels have 10 mm work travel.

The required main pad travel for this die is:

• Tpad = ESM + {[Tdcs • cos(α - β)] / sin α }
• Tpad = 5 + {[12 • cos(60° - 10°)] / sin 60°}
• Tpad = 5 + {[12 • cos 50°] / sin 60°}
• Tpad = 5 + (7.71 / 0.866)
• Tpad = 5 + 8.903
• Tpad = 13.903
• Tpad = 14 mm minimum

This tool requires a minimum main pad travel of 14 mm so the die operates properly with the die mount cam. Since the direct steels have only 10 mm work travel, the 16 mm minimum main pad travel will work fine.

The main pad in a die with aerial cams must hold the stamping in place on the lower tool during the press downstroke before the cam steels make initial contact.

On the press upstroke, the main pad must hold the stamping on the lower tool until the cam steels clear the stamping.

The simplest way to ensure the proper timing of the main pad when aerial cams are present is to calculate the main pad travel.

The equation for main pad travel with aerial cams is:

• Tpad = ESM + {[Tacs • sin(α + β)] / cos α }

where:

• Tpad = main pad travel (mm)
• ESM = engineered safety margin (mm)
• Tacs = aerial cam steel travel (mm)
• α = upper driver angle from horizontal (degrees)
• β = work angle from horizontal (degrees)

NOTE: if there are multiple aerial cams, then calculate for all and use the greatest result for the main pad travel. Also, if the direct cutting or forming requires more travel than the aerial cam(s), then the direct operation will drive the main pad travel.

For example, assume an aerial cam has cam steels with a work travel of 12 mm. The upper driver angle is 30° from horizontal. The work angle is 20° from horizontal. The engineered safety margin on the main pad is a minimum of 5 mm. The direct steels have 10 mm work travel.

The required main pad travel for this die is:

• Tpad = ESM + {[Tacs • sin(α + β)] / cos α }
• Tpad = 5 + {[12 • sin(30° + 20°)] / cos 30°}
• Tpad = 5 + {[12 • sin50°] / cos 30°}
• Tpad = 5 + (9.19 / 0.866)
• Tpad = 5 + 10.61
• Tpad = 15.61
• Tpad = 16 mm minimum

This tool requires a minimum main pad travel of 16 mm so the die operates properly with the aerial cam. Since the direct steels have only 10 mm work travel, the 16 mm minimum main pad travel will work fine.