James Hendry is considered the father of gas-assisted injection molding, a major technological advance, but one plagued by nasty legal battles. Hendry started developing the principles of gas-assisted molding in the late 1970s. He was trying to solve the problem of the swirly surface finish of structural foam parts, while working at Ex-Cell-O Corp. Gas-assisted molding works by pumping gas, usually nitrogen, inside the mold. The gas produces hollow parts by pushing the melted plastic out against the mold. Gas-assist can cut resin costs and eliminate weld lines and sink marks. Because it's a low-pressure process, it avoids molded-in stresses, and allows processors to use smaller-tonnage machines.
Gas-assisted molding has grown, especially in large automotive and business machine parts. But most industry observers agree that adoption of the technology has been retarded by lawsuits and threats of lawsuits, most often made by Michael Ladney, the sometimes acidic owner of Gain Technologies Inc.
Hendry agrees the legal noise has impeded the technology. No question about it, he said. It hurt a lot of people.
Gain has clashed repeatedly and very publicly with its arch-rival, Cinpres Gas Injection Ltd. They sued each other in the United States and Europe. At a conference, Ladney once remarked: Until Cinpres is knocked out, it's a fight to the death.
Hendry, who holds more than 20 patents covering internal gas-assisted molding, has been employed by both Cinpres and Gain. (That's like saying you played football for Ohio State and Michigan.) He also worked for Asahi Kasei Corp., Lear Corp., Ford Motor Co. and Sajar Plastics Inc.
In a world without fear of lawsuits, what percentage of U.S. injection molding companies would be using gas-assist today? Hendry thinks as many as 50 percent.
But as Hendry prepares to join the Plastics Hall of Fame, the 88-year-old inventor hopes the industry remembers him for contributions to technology, not legal maneuvering.
Well, I wasn't the one who started the lawsuits, he said. I was the tennis ball in hand. If you work for someone and he sues someone, then you've got to go with it, right? You've got to have some loyalty to the person who gives you a paycheck every week. It's up to you to obey the commands.
Despite his legendary status, Hendry has worked for other people nearly his entire career. He did start his own small company in Detroit in 1981, KMMCO Structural Foam, to sell an early gas-molding process called Smooth Surface Technology. But the severe recession of the early 1980s killed that dream, and KMMCO went bankrupt.
Back then, there was no Gain or Cinpres. In better times, KMMCO could have been the big player in gas-assisted molding.
Hendry remains active as a plastics consultant today, even as he pushes 90. In September, he's flying to Japan to give an external-gas presentation at Asahi Kasei.
Hendry discussed his 71-year career in an interview at his house in Brooksville, Fla., near Tampa. On his kitchen table, he organized a pile of sample parts, photographs and a book describing his more than 95 patents.
Steve Ham, a consultant in gas-assisted molding, nominated Hendry for the Plastics Hall of Fame. Without Hendry's quest to inject gas into the injection mold, there probably never would have been a gas-assist industry, he said.
Praising his innovative and bold approach to the processing mechanics, Ham said Hendry's current work in external gas-assist, which uses gas pushing on the part's outer surface, is perhaps his greatest invention.
Although best known for gas-assisted injection molding, Hendry played a key role in developing the two-stage injection molding machine, structural foam molding and PVC molding.
He's a walking history book whose plastics working life began in the compression molding era, back in 1938. During World War II he worked on major military plastics projects at Electric Autolite and Pro-phy-lac-tic Brush Co.
Born a coal miner's son
He was born in Scotland, the youngest of 12 children. When he was toddler, the family moved to West Virginia. His father, a coal miner, died from cancer when Hendry was just 8.
When one of his sisters married a man from Detroit, the whole family moved there. Hendry went to work right after high school. He took a job at Burroughs Adding Machine Co. in 1938, compression molding handles and cases for its adding machines. Then he became an apprentice mold designer.
Burroughs had a reputation for never laying off anyone during the Great Depression. People worked a few days a week so the company could maintain full employment. It was a great company to work for, he said.
During World War II, the government halted car production to gear up for war production. Hendry went to Electric Autolite in Bay City, Mich., as a mold designer. The swing-over came very quickly, and the government practically picked you out and said, 'You're gonna do this, you're gonna do that,' he recalled.
Autolite made metal-clad phenolic distributor caps for U.S. Army Jeeps so they could run through deep water. Other wartime products included parts for the proximity fuze and torpedoes.
Hendry left Autolite in 1944 to work at Pro-phy-lac-tic Brush in Florence, Ky. Before the war, and afterward, Pro was known for its toothbrushes, hairbrushes and combs. Hendry worked on a plastic aircraft battery case. Pro had purchased what back then was considered a huge injection molding press, a 350-ton Lester with a 32-ounce shot.
But even the Lester was not big enough to mold the large battery case, developed as two pieces that were glued together. So Hendry and the engineers at Pro developed a two-stage machine, using a patent that Pro's owner, Lambert Co., had purchased from Quick Point Pencil Co. in St. Louis. Hendry said the patent called for a fixed extruder screw to feed resin into a shooting pot, then a piston to inject it into the mold.
We had to change things around considerably to make the damn thing work. [Quick Pencil] had never reduced it to practice. We did, Hendry said.
The shot-pot doubled the Lester's shot size, to 64 ounces. Pro-phy-lac-tic Brush displayed the acrylic battery case at the first NPE, in 1946, held in New York City.
Intrigued, Hendry left Pro and joined his brother John, who had a small machine shop in Detroit. They built a two-stage molding machine. At a chance meeting, Hendry met the owner of Jackson & Church Co. The large company in Saginaw, Mich., made lots of things, Hendry said, such as brick machinery, woodworking equipment and furnaces but not plastics machinery.
The owner came down to Detroit to see the prototype machine. They signed a contract. Hendry would be in charge of building the machines and would earn a commission on the sale of each one.
He worked for Jackson & Church from 1947-59. Hendry developed a number of major two-stage innovations, and earned his first patents. An early Jackson & Church press was the first to successfully mold unplasticized PVC, according to the book Plastics History U.S.A.
That machine was the foundation for Tube Turns Plastics, a joint venture that made injection molded pipe fittings and valves from PVC.
Origins of gas-assist
Hendry became vice president of equipment for Borg Warner Corp.'s Marbon Chemical Division in Parkersburg, W.Va., where he worked for 1959-70. While at Marbon, he picked up more patents, many dealing with heating and plasticizing for structural foam.
His push into gas-assisted history started at Ex-Cell-O Corp.'s structural foam business in Athens, Tenn. Hendry worked there in the 1970s for the whole decade. As president of the Plastics Components Division, he designed structural foam molding machines and set up a custom molding plant.
Ex-Cell-O worked closely with big players IBM Corp., Xerox Corp. and Burroughs Corp. and Hendry earned even more patents, for things like a nozzle shut-off valve and closed-cell foam molding. Structural foam molding was growing rapidly, along with the market for business equipment and large computer workstations.
An early use of gas-assisted injected molding came when Ex-Cell-O needed a way to turn out parts with a smooth surface finish. That was a big challenge, because the structural foam workstations and other very large parts had to be finished and painted, which resulted in costly scrap.
If we could come up with an idea of how to make a smooth surface, we'd have been home free, he said. But Hendry said he decided to leave Ex-Cell-O in 1981 when the company, then under new ownership, nixed his idea to flash-heat the structural foam mold with steam and then shoot in the plastic. He said that idea, never commercialized, provides a smooth surface finish.
Hendry said company officials also rejected a proposal by joint venture Asahi-Dow Ltd. to swap Asahi's gas-assisted molding patent in Japan for the steam invention.
That led Hendry to return to Detroit and start KMMCO. The company folded in just two years, but it did enjoy some successes, including what Hendry claims is the first commercialized gas-assist application.
Sensormatic Corp., a security systems firm, designed a gate with an alarm for retail checkout areas. Molds were built specifically for KMMCO's SST process. The part was perfect, Hendry recalls with nostalgia: Inside these swinging doors, they had wires running all in the inside. So it had to be hollow, and it had to have ribs inside to direct the wires. It was beautiful, full of ribs and bosses. And we gassed the whole part. Gorgeous parts.
Hendry got a call one day from Terry Pearson from a British company called Peerless Foam Molding. They talked about a licensing agreement, but then KMMCO closed down in 1983. Hendry said his firm was a victim of the recession.
Meanwhile, Peerless started Cinpres as a separate company to promote gas-assist.
Ladney, who was well-known in Detroit for founding Detroit Plastics Molding Co., created Gain Technologies. Hendry said Ladney tried to forge a licensing agreement with Cinpres, but it fell apart.
It was the late '80s. The patent wars, the nastiness, had begun.
I wish that had never happened, Hendry said.