Bulk Molding Compounds Inc. has developed a gas-assist molding technology for its thermoset material, and now is introducing it to processors that otherwise might use thermoplastics.
The system is going into its first commercial application on a handle for a kitchen range, and the firm rolled out the concept during the Society of Automotive Engineers 2003 World Congress, held March 3-6 in Detroit.
BMC is eyeing a number of potential uses, said Len Nunnery, corporate quality director for the West Chicago, Ill., company. The material could be used in mirror housings, decorative spoilers or under-the-hood components where the product's heat tolerance would be beneficial.
And for companies interested in using the gas-assist process, BMC will not request a license fee - as long as they use the company's material.
``We're interested in increasing the use of our product,'' Nunnery said. ``We aren't going to go crazy with the patent process.''
The system places the gas pin at the far end of the mold, with a full shot of the resin pushed into the mold at the start of the cycle. As the material begins to set along the outer edges, the gas blows back the inner core into the nozzle.
The unused material from the inner part then is available for use in the next shot.
In total, the system can reduce the cycle time and material use by a third or more, compared to traditional BMC parts, Nunnery said. That allows BMC to compete for use in structural components that otherwise might use a glass-filled thermoplastic with gas-assist molding.
The process can be adapted for existing presses, he said.
The firm believes the system could see real success in the automotive industry, where parts may need to be painted for external applications or stand up to extreme heat. The hollow core in a gas-assist component also could aid in acoustics applications, or find use in valve covers or other under-the-hood locations.
