Think of the many businesses that need dies and punches to produce parts. The giants of metalworking manufacturing: automotive, aerospace, industrial equipment, and consumer products, come quickly to mind. Expand that focus to cover the millions of parts and products made by injection molding, thermoforming, or other plastics-production methods, and the vital role of production dies becomes obvious.

Worldwide, spending on tooling is in the hundreds of billions of dollars, experts say. “If we can capture 10% of that amount, that would be a good thing,” says Joe Szuba, group leader for rapid tools at the Manufacturing Systems department of Ford’s Scientific Research Laboratory (Dearborn, MI).

They just might. Ford is now licensing companies to produce dies, punches, and other tools by a thermal-spray process it developed by which a ceramic master of the working die surface is spray-coated with molten wire, then backfilled with epoxy to create a working die. According to Ford, such dies can hold production tolerances and be delivered in a fraction of the time and cost required for conventional dies. No machining, no heat-treating, no chips.

For more than a century, dies, punches, and tools continue to be made by the subtractive method; working from a casting or block of steel and chipping away until you achieve the desired net shape. The evolutionary improvements of ballnut leadscrews, carbide tools, EDM, numerical control and CNC, up through high-speed and five-axis machining, all have had the same goal: make chips faster.

Ford’s thermal spray technology turns diemaking into an additive process. The spray-coating know-how came to Ford via its acquisition of a small UK-based company, Sprayform Holdings, in the early ’90s. How it works is that the part master can come from REN boards, stereolithography models, silicone rubber, or plaster. The part is cast in ceramic and frozen. Once the part master is separated from the ceramic mold, the mold is dried in an oven prior to spray-coating. “Once the ceramic is on the model, freezing it sets up a crystalline structure on the surface, almost like ice crystals,” says Kevin Regan, Ford research engineer. Subsequent baking drives the water out, but leaves minuscule voids in the crystals’ place. “Once we’re all done, that gives the steel something to bite into.”

Although the ceramic is frozen, then baked, it is never fired in the sense of traditional ceramic processing. The result is a low-cost process that accurately replicates the pattern with excellent surface and thermal shock properties in the ceramic mold.

Metal spray deposition happens courtesy of an industrial robot with four spray guns mounted on the end of the arm. In 1998, the spray cell could handle a die surface of 18 × 18" (457 × 457 mm). Last year, the company doubled the size of die surface possible through the process to 36 × 36" (914 × 914 mm), and the goal is to have it working on 96 × 96" surfaces (2438 × 2438 mm) by 2004.

The original goals of acquiring and developing the technology were to slash die development time while not sacrificing die durability or accuracy, Szuba says. The Ford research team started small, attempting to develop a die for a rotor blade for torque converters. The die was delivered to the press in four weeks versus the 16 to 20 weeks a conventional die would have required, and was subsequently used for a prototype run of 16,000 parts. The parts were so good that the same die was then used for a production run of 750,000 blades, many of which are on the road in vehicles today. Another spray-formed die for a latch reinforcement for the Ford Focus is still in service in a Ford stamping plant in Valencia, Spain.

Dies from the spray-form process aren't just for prototypes, but are holding up well in production runs.

Thermal-spray deposition of metal to make tooling is not a new process, but the reason it’s not more popular is that the resulting die is prone to cracks and other surface imperfections. Mainly, these are due to differing rates of thermal expansion of coating and substrate, as well as a lack of overall process control. Ford’s process solves that problem by using a PC-based thermal compensation software program that talks to a programmable logic controller in the spray cell, along with a number of heat-sensing devices, including an infrared camera. According to Richard Allor, Ford technical specialist, the program can follow a recipe, capture data while spraying, and make real-time process adjustments, all in a closed-loop system. The algorithm is a distributed parameter control system, meaning two distributed variables, temperature and the thickness of the metal being deposited, are being controlled simultaneously. “Spray forming is generally considered to be more like spray coating; no one thinks we can spray more than 0.0005" [0.0127 mm] at a time,” Allor says. Ford’s system can spray in bulk, up to three inches (76.2 mm) at a time.

The process has proven so robust that Ford’s research team can deliver prototype parts from spray-formed dies in as little as six days, from master model to stamping press, depending on part configuration. “In one case, the part designers wanted a design change,” Allor says. “We determined it was faster to make a new tool than to weld and hand-work the design change into the existing tool.”

Following spraying, excess ceramic is removed from the metal shell, and the steel die face is ready to be backfilled, trimmed, and mounted in a press for stamping. Backfilling is usually accomplished with epoxy material, with chunks of old dies thrown in.

The Ford research team quickly realized the bigger bang for the buck lay in making dies for larger parts. The group was challenged by the Vehicle Operations division to create a die for the inner hood of the Mercury Mountaineer, and began looking to the outside world for help. “From day one, the team did not sit there and hoard the technology, acting like they were the only ones who knew what was going on in the world,” says Bill Powers, former vice president of research at Ford. “They were very aggressive in going outside to universities and other companies to find out what was being done worldwide in this technology; to learn about it, incorporate it, and even buy it.”

The main challenge was that the spray cell was too small to spray the inner hood die in a single section, so the die was divided into 12 sections. Since the pieces of this puzzle had to fit precisely together, Ford chose abrasive waterjet technology from Flow International (Kent, WA) for trimming the die pieces, which were then taken to Troy Tooling Technologies (Troy, MI) for being fitted together into a die “nest.” Backfilling the nest with epoxy and chunks of old dies brought the die face up to the proper height, as well as making the working die strong and heavy enough for production stamping. That the die stood up well enough for production “was the turning point that got everybody’s attention about this technology,” Szuba says. The Inner Hood Project, as it was known within Ford, proved this rapid tooling technology could reduce both timelines and costs.

This posed another problem for the automaker. Ford designs and builds automobiles, not production tooling. “We tried to fit this technology into current die designs and construction methods, and we became master tool makers as a result,” says Joe Szuba. “This technology works, but too many hurdles were continually presenting themselves. Now that it’s developed, we needed to shift our strategy to commercializing it.”

Basically, Ford’s goal is to get the technology into the hands of vendors that make tools. “Our role is to develop the design and construction methods for tool-using industries,” says Szuba. “Our licensees, the vendors who are directly connected to production tooling, will find more ways to adapt and advance the technology than we ever could.”

Ford’s first commercial licensee is Praxair Surface Technologies (Indianapolis, IN), which not only conducts a large volume of surface-enhancing business for aerospace, automotive, and other manufacturing industries, but also sells thermal spray coating equipment through one of its companies, Tafa Inc. (Concord, NH).

“The first thing that struck us about it was that it had the potential to be revolutionary,” says Steve Wichmanowski, director of marketing, Praxair Surface Technologies. Praxair’s joint development agreement with Ford to advance this technology is already paying dividends. Working together with Ford, the Praxair team recently completed a 50” (1270 mm) door panel tool, and plans are to develop more tools not only for Ford, but for other customers. Atlas Tool (Roseville, MI), among the world’s leading independent stamping die manufacturers, is the second Ford licensee for this technology.

In September, Ford also licensed The American Tooling Center (Grass Lake, MI), and Ceradyne (Costa Mesa, CA) to further use and develop the spray forming technology.

What does Ford see as the benefits. “Although we’ve been developing this technology for only the past two and a half years, we see ourselves as out of the concept stage of this technology and into its implementation, demonstrated by the tools we’ve made,” Szuba says. “On average, we are 30% better in cost and in time, and in some instances we’ve demonstrated 50% improvement.”

Szuba likens spray-formed tooling to Texas Instruments entering the calculating machine business against National Cash Register. “NCR was a giant company that dominated its industry, making mechanical machines for calculating numbers,” Szuba explains. “Texas Instruments designed a digital system to accomplish the same task electronically, and then designed and developed a printer to display the results. The big difference was the speed and resulting low cost of the TI machines. They changed the adding machine business with the force of a lightning bolt. This is our lightning bolt.”