Exton, Pa. — Attendees at the second day of Boy Machinery Inc.'s April 9-11 open house — a day dedicated to thermoplastic molding — got a dose of good news about high-tech molding, resin drying and injection molds.
Then they heard from Bill Hartwick. You could call him Mr. Dirty Jobs, like that TV show — only it's all plastics machinery, all the time for the Canadian troubleshooter.
Hartwick's presentation was on preventive maintenance. But his slide show depicted on gory detail what happens if you never do any maintenance, let along change the hydraulic oil.
"The things you learn from your mistakes is where you really learn, said Hartwick, technical director of Filter Specialties Co., a field services firm in Milton, Ontario.
Hartwick said the definition of "preventive maintenance" is to perform the work while the equipment is still operating, so you don't have a catastrophic failure. He showed what could happen, posting a series of slides depicting aging machines in a state of entropy and decay. It's his personal collection of common mistakes by companies that fail to keep up with maintenance.
"People are creatures of habit," he said. "If we could make them have the right habits, this is a good thing."
Hartwick suggested starting simple. List things you want to check. Set up a schedule. Create work instructions. First write it down manually, then create a computer system, he said.
He gave some basic advice: Properly align the barrel, adjusting it to make sure the nozzle is centered so that plastic doesn't leak at the nozzle. Inspect the check ring for wear. Buy parts only from the original equipment manufacturer; not from the aftermarket. Check hydraulic fluid. Clean the filters. Check belts. Check tie bar stretch.
"Just the simple term, 'know your machine.' Because you're counting on it every day," Hartwick said. It's easy to take short cuts or just put off maintenance. "It looks simple to do these repairs, and it's not rocket science. but you gotta pay attention," he said.
Steve Corcoran, national sales manager of Dri-Air Industries Inc. delivered a drying 101 presentation. Not all resins have to be dried, but some resins are hygroscopic, and absorb moisture, like ABS and nylon.
If moisture is not properly removed, that can cause problems in molded parts like visible color changes, splay marks and striations, Corcoran said.
Dri-Air, of East Windsor, Conn., makes dryers.
Screw designer Michael Durina said the MDP screw tip from his company, MD Plastics Inc., has the lowest pressure drop in the industry. The Min-Shut automatic shutoff nozzle tip prevents drooling and stringing, he said.
The new Inject-EX injection unit uses a stationary screw and plunger assembly. Md Plastics President Durina said the arrangement is very precise, addressing what he said are several deficiencies of the reciprocating screw.
Md Plastics is based in Columbiana, Ohio.
