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Stamper performs subassembly superbly

Everything goes in together

Diemasters President and CEO Virgil DeLay pulls the company together and conducts business with the mastery of a maestro. You can almost see the baton in his hand.

In one of Diemasters’ lobby display cases are a variety of tiny, wafer-thin, stamped parts smaller and thinner than a fingernail—made of materials like 0.002-inch-thick beryllium, gold, and copper and some with tolerances of 50 millionths. They are what President and CEO Virgil DeLay calls “stamp-and-ship” parts.

“This is how we started,” DeLay said of the Elk Grove Village, Ill., stamping manufacturer. “We were the traditional high-speed, high-tolerance stamper. We competed well, but as electronic OEMs moved away, all of a sudden we were fighting freight costs and increasingly complicated logistics. That started our growth strategy of value-added and assembly work—and that’s been successful for us.”

Today, 70 percent of the company’s topline revenue is from assembly work, he added (see Figure 1).

The assemblies are a metaphoric representation of the company itself. Products are diverse in every way possible—size, type, market, materials, complexity. So is the staff. One is in a chorus that sings entirely in Swedish. Another is a competitive race car driver. They are drawn from various industry segments, backgrounds, and positions. Yet they are all joined in an orchestration of commonality of purpose and timing.

While Diemasters’ success is the result of a concerted effort, DeLay is definitely the maestro, keeping the band on cue.

Assemblies

“Assembly work” can mean a five-part subassembly for the lawn and garden segment or it can mean a 231-component machine, such as a microfilm reader the company produces (see Figure 2.) Helping customers solve problems and create opportunities via engineering assemblies is central to how the company obtains and retains this segment of the business. And it is a recurring chorus.

Automatic Choke Assembly. “One of the products we manufacture and assemble is a thermostat we jointly developed with our customer [see Automatic Choke Assembly sidebar]. There was a bit of a technical challenge that we had to solve,” DeLay said.

“You go out and set the choke on your lawn mower, you start it, you begin mowing your lawn. Your neighbor comes out and you want to visit, so you turn it off. Five minutes later, you choke it again and now it’s flooded. In your owner’s manual and on the deck there are warnings about that, but you do it anyway. Finally you say to the lawn mower OEM, ‘Fix that.’ So our OEM customer asked us to work with them to engineer a solution to apply to their new engine platform, along with the need to retrofit existing engine production.”

Collaboratively, Diemasters and the company’s engineers devised a five-piece assembly that is essentially a simple thermostat that functions as an automatic choke. It includes a shaft with a bimetal spring and three stampings.

“Now while the motor runs, heat travels to the muffler through the bimetal spring, enabling the spring to relax the choke. Problem solved; no more flooding your lawn mower,” DeLay said. The company manufactures 1.5 million of them a year.

Figure 1
Assemblies have emerged as the largest revenue source for the stamping manufacturer.

Detent Lever Assembly. The company performed problem-solving engineering on another assembly, a detent lever assembly (DLA) (see Shifter sidebar). “In 2004, 2005 Ford and GM got together to design a new transmission, the X22-platform, six-speed transmission—first time Ford and GM ever took on a program like that. It was a joint venture.

“So when you are in your vehicle, whether your shifter is on the steering column or the floor, when you shift it and feel it drop into first, second, third, it is this part mechanically and electronically activating the transmission,”DeLay said.

Diemasters ships 2 million of the highly engineered assemblies a year to a plant in central Mexico where it is overmolded.

Automating Assemblies

Diemasters builds its own automation in-house. One of the assemblies the company built was for the DLA (see Figure 3).

The operator introduces three components—two machine parts and a stamping—into an orbital riveting machine where they’re joined and 100 percent inspected by a vision system. There’s also a physical check on the automation that redundantly measures the hole positions. If the part is good, it goes on a conveyor and enters the wash system, where it is washed, dried, and a rust inhibitor is applied. An operator does one last check, packs the product, and then it goes out the door. If there is any problem, the date code is not inscribed on the part and it is dropped in a “lock” box. If two or more happen in a row, the operation shuts down.

“When we originally went to cost the job, this total system cost well over a million dollars. When our piece-part price was where we needed it to be after amortizing for the equipment, it wasn’t competitive for the customer. So we built this in-house for less. You can see by the weld marks, it’s not commercially ‘pretty,’ but it works at a high-confidence level. We aim to break even on the automation as we make our profit on part production,” DeLay said.

The company’s productivity system forces an evaluation of which type of automation is needed. “A lot of companies will send a part to an outside automation house with the quantity needed and the rate and say, ‘Have at it.’ Well, you have to look beyond that,” DeLay said. “How stable is the process? If the customer does not have a stable design, full automation will bankrupt you on design changes. On this design, we knew there were several changes coming, but we needed to have a piece-part price that was acceptable, so we had to have some automation.”

So with semiautomation, Diemasters can make design and engineering changes for its customer that are affordable. Other assemblies with a mature design lend themselves to full automated assembly, he said.

Diversification

“We make everything from welch plugs to washers to clips to complicated assemblies. We’re big into small engines, so we’re doing everything from intake and exhaust levers to fuel tanks for the lawn and garden segment,” DeLay said.

“Everything from …” seems to be the catchphrase there, because Diemasters’ product line is wildly varying in size, complexity, material, and market.

Figure 2
Diemasters fully assembles a 231-part microfilm machine comprising metal formed parts made in-house and some outsourced components.

The company’s core competency dictates which projects it accepts or pursues, DeLay said. “And our core competency is tooling and engineering for the metal forming industry.”

“Tooling and engineering” may sound like a very broad theme, but to DeLay and his team, it’s sufficiently definitive for determining which projects the company can take on. Tiny electrical contacts that are so small you can hold 1,000 of them in the palm of your hand? Sure. An 8-foot-diameter intake for a land-based gas turbine vessel large enough to stand in? Sure, they can do that too. Single stampings, complex, fully assembled machines? Bring them on. Take your seat. Everything has a place in DeLay’s band, as long as it fits within the company’s core competency—problem-solving via engineering and tooling expertise.

The company designs dies in-house but usually outsources the die builds. “Having said that, in 2014, half of the 24 tools we designed, we built in-house,” DeLay said. Why? “Those 12 tools had a complexity such that we wanted to learn. If we can learn something from the construction of the tool, or if there is something proprietary we’re trying to protect, we’ll build it in-house.”

Since taking over the leadership of the company in 2001, DeLay not only expanded the company’s product offerings into assemblies, but also kept an eye on market diversity.

“One of our deep concerns was not so much the customer concentration but the product concentration,” DeLay said. “Life in this industry—in the middle of Chicago—is about diversity. When automotive is down, medical is up. And vice versa. Today automotive is leading the charge. In 2008 to 2009, lawn and garden was leading the charge. Diversity is really a big part of what has kept us humming.”

Diemasters Productivity System Pulls It All Together

In a lobby display case at the plant is a custom-made sculpture composed of 25 or so welded-together metal stamped components that the company has formed over the years. They were made to go into an assembly. They look as though they have been thrown haphazardly and stuck together midair. It is aptly named “Goesintos!” (see Figure 4).

It would be a mistake to assume that the randomness of the sculpture represents the stamping manufacturer’s mode of operation. It does not. In fact, it is the antithesis of the company’s meticulous, masterfully planned system of operation.

DeLay and staff members devised their own Diemasters Productivity System that rivals the Toyota Production System—complete with the initialism DPS—and bound it in a 219-page handbook and training manual (see Figure 5). The productivity system comprises what DeLay considers the most useful and relevant aspects of Six Sigma, lean, the theory of constraints, and several other disciplines, standards, and best practices for Diemasters’ operations.

“LISSTs stands for lean manufacturing, inherent simplicity, safety first, Six Sigma, and TS16949,” DeLay explained. “Lean manufacturing is our culture; inherent simplicity from the theory of constraints is our infrastructure; safety first is our promise to our employees; Six Sigma is our set of problem-solving tools; and the TS16949 quality system is our customer focus,” DeLay said.

Bottleneck Blasters. DeLay said that the theory of constraints is simply finding and eliminating bottlenecks. “We need to find the bottleneck, then elevate or manage the constraint. If there’s a quality problem, that’s a bottleneck. If there’s an efficiency problem, that creates a bottleneck. There are a whole bunch of optimization techniques that we look at before we even get to Six Sigma.

Bill Curtis, vice president of engineering, described the complex thermostat assembly, its functions and forming challenges, and how Diemasters addressed them.

Six Sigma. DeLay said the company uses the Six Sigma tools just as they are designed. “We don’t add or subtract anything. Where we vary is when and how we use them.”

Pull System Flow. “You’ve probably heard folks talk about a pull system,” DeLay continued. “We’re a multimillion-dollar company with industry-low inventory. The way we do that is our product flow, he said.

DeLay composed the work flow system so that the product “moves on its own,” figuratively, via triggers that prompt someone to move product. “That is how we ensure there is a pull system happening rather than a push. Our product flow chart shows how that works for all our different kinds of products through departments and through the plant. We place the product flow chart all around the plant.”

The pull system benefits the company’s customers, he said. “We have customers that will place an order at the first of the month and have a major change on the fifth of the month.” Being able to control the work-in-progress (WIP) minimizes the pain the customer feels as a result of design changes, he said.

Zero-Defect PPM. The quality aspects of the DPS are fine-tuned. The company has produced 3 million parts with zero defects for a customer for three consecutive years, DeLay said. “We’re their only supplier of significance that can say that.” He added that overall, the company achieves single-digit-defects PPM.

Value

DeLay advised re-evaluating core competencies and operating systems to make sure they are valuable and relevant. “I think most companies get the brightest folks they can, usually centered around their core competency, in our case, stamping. So they get the best toolmakers, the best operators, the best ERP system. Their customers usually have some type of quality system requirements or procedures that they want you to follow. That is really what designs most companies’ operating systems. It’s kind of hodgepodged together. Too often, over time you end up developing even more procedures to satisfy missed customer requirements that are addressed through corrective actions and not by system controls—but the way they are being implemented … are they really adding value to your organization?”

Orbital Riveting

Orbital riveting is a cold-forming process using a peen tool held at a fixed angle to create a sweeping line of pressure around the part, progressively forming the material with each rotation. This process reduces the amount of forming force required by 80 percent on a standard press.

—Orbitform

Automatic Choke Assembly

Bill Curtis, vice president of engineering, described the complex thermostat assembly, its functions and forming challenges, and how Diemasters addressed them.

“This is a thermostat assembly that works as an automatic engine choke for a small engine used in the lawn and garden industry. It’s composed of three stampings: a thick plate part; a deep-drawn cup; and the lever, which has some definite geometry that has to be dimensionally maintained.

“The lever has a couple of key areas that relate to the function of the part. The surface is actually a cam that rides on the linkage of the carburetor. The shaft, which is hooked to a bimetal spring, has to be fastened to the lever, and we have to end up with true positional tolerances from cam profile to true position of this part.

“The part is somewhat delicate; it has a very fragile point designed in at the top of the assembly that allows for hand adjustment after it is fastened to the engine. We have to be able to stamp this part with its weak point, yet hold it intact so it can be checked for true position from hole to cam profile after being stamped and packaged and held in inventory until it is ready for assembly. It’s a common part—not the hardest part in the world—but as you can see, it has nearly all types of forming: ribbing, offsetting, and draws. The lever is made of preplated cold-rolled steel.

“The deep-drawn housing, which holds the bimetal spring and cap assembly, is made of aluminum for its heat conductivity. Aluminum soaks up heat and dissipates it more quickly than steel. The housing, which is sandwiched between the engine block and the muffler, absorbs the heat and transfers it to the bimetal spring, which then acts upon the shaft, which acts upon the lever. That’s what creates the movement.

“This plate piece doesn’t look real difficult, but it’s thick, 3000 series aluminum, and we draw it 21⁄2 times while holding an ID [inner diameter] of ± half a thousandth inch. That’s very difficult. The raw material’s elongation, tensile strength, and heat come into play. We have a lot of adjustability designed into these draw stations. We gather and draw this material in five different stations. Then we size it and burnish it in a few more stations to create an inner diameter that not only is held close, but fits with the part. There are true position and perpendicularity tolerances that we hold in all directions to allow for the smooth operation of the part. “The challenge was being able to produce this shape without an exploding-cigar effect, meaning blowing out the bottom of a draw that looks like a cigar load just went off. Drawing it creates a lot of heat, so we’ve got a cooling vent inside the punch. We mounted a cold-air gun like the ones used in CNC machining to cool end mills. We mounted one on top of the tool and pointed it at the punch itself to dissipate heat for cooling. We float the punch, meaning … say this wall thickness varies a bit as it is presented to the station. For true position, we stamp the pilot hole. We control the location of that. Then we put a pilot on the punch so it catches the hole for true position, but we float the punch so we don’t have to iron out little variations in wall thickness and create more heat for nothing. We let the true position come from the pilot hole, and then we float this draw punch so that pressure and heat are evenly distributed.

“When we first started manufacturing this, the part would be down to almost nothing on one side and high on another side five minutes after we started. So we went through all the steps using the tools in the Diemasters Productivity System to determine why it reacted as it did and ways to counteract it. These two drawn areas are the hardest parts of the whole assembly.

“The next biggest challenges come from material variations from lot to lot of raw material. Material variation really wreaks havoc when you start the tool up. Right now we have an average of 98 percent first time die-in, meaning that when the tool is put into the press for the first time, it runs and makes parts 98 percent of the time. It’s done quite well.

“For the attachment mechanism, though some of our assemblies are welded or ring staked, this assembly is orbital riveted. Most are. We think it’s more consistent than impact riveting or swaging, where you’ve got to rely on the base raw material, even with its elongation and tensile changes. Impact riveting is a one-hit thing; you have only one shot to get it right. The results of the orbital riveting process aren’t as dependent on the raw material because it gets the material to flow out as it goes around—not just one quick hit. It’s just a more consistent and robust process.”

(Note: To see a video version of this, visit www.thefabricator.com and read the article online.)

Shifter

Bill Curtis, vice president of engineering, described the detent lever assembly, its functions and forming challenges, and how Diemasters addressed them.

“This detent lever assembly, also called DLA, controls the valve body. When you get in your car and you grab the shifting mechanism and it goes click-click-click, that’s actually these teeth being rolled across a spring-loaded roller inside the transmission.

Shifting Mechanism

“Some of the challenges with this custom-designed, HSLA [high-strength, low-alloy] part … you look at these other assemblies—way more complicated, right? But from the pin to all of the holes, tolerances are closer than 0.001 inch. So all of a sudden this becomes supertechnical.

“We do the joining on our orbital riveting machines. There are tight positional tolerances from the pin to the teeth to the keys. When you rivet it, this stamping wants to bulge out. You can see how the stamping itself is raised by the pressure of it.

“During orbital riveting, this part wants to walk because of the pressure created and the different cross-sectional areas on the part. So we had to develop corner radii that would clear the sharp corner on the shaft and coordinate it with the orbital riveting pressure and time to create it.

“So when we started the project, we did the riveting and moved the material slightly so the part would end up in true position. It was the development of corner radii, rivet pressure, and timing.

“The true positioning of the teeth to the holes and to the keyed hole is crucial. The stations in the tool have to be piloted and controlled so that the various features in the part are in true position to each other.

“For assembly, we insert a pin. Again, the hole position has to be such that it clears the inside shoulder radius of the pin. We have to do a good orbital riveting job on the back side of the pin so it is contained and cannot spin. So the edge of the part is positioned upon the shaft, which is double-keyed and then riveted into place, while holding true position to the teeth, pin, holes, and the keyway on the shaft itself. All that has to be within true positioning of very tight tolerances.

“During the assembly process, this part goes around the table twice and is hit with two riveters. First the pin is put in upside down, with the plate on top of it, the operator hits the button and it’s attached. Then the one that’s already riveted presents. You take the one, put the shaft down, put the assembly on top of the shaft, put the pin in the plate, and hit the button to attach the second piece.”

(Note: To see a video version of this, visit www.thefabricator.com and read the article online.)

About the Author

Kate Bachman

Contributing editor

815-381-1302

Kate Bachman is a contributing editor for The FABRICATOR editor. Bachman has more than 20 years of experience as a writer and editor in the manufacturing and other industries.