Hong Kong-based Welltec Machinery Ltd. has introduced an injection press that uses a proprietary chemical foaming system it claims can cut manufacturing costs and part weight significantly in applications that include auto parts, furniture and consumer products.
The HyperFoam system, introduced at Chinaplas in Guangzhou, was developed by Welltec, a subsidiary of Hong Kong's Cosmos Machinery Ltd., and its Hong Kong partner, additives maker CVI Modern Technology Development Ltd. The system can trim part weight 10-30 percent, lower cycle time, reduce clamping force needed by about 50 percent and cut power consumption by 30 percent, the firms claim.
The project represents cooperation stretching across three continents. Swiss auxiliary equipment firms Herzog AG Degersheim of Wolfertswil and Sulzer Chemtech Ltd. of Winterthur supplied the equipment; and U.S. consultants Michael Caropreso of Caropreso Associates in Chester, Mass., and Michael Reedy of Reedy International Corp. in Keyport, N.J., helped to develop the system.
Welltec General Manager Raymond Li said the company sees the process as an alternative to foam molding systems such as the MuCell process from Trexel Inc., and this year expects to sell about 25 machines outfitted with HyperFoam. It wants to develop versions for smaller parts.
Li pointed out that Trexel has targeted MuCell mostly for use in high-volume, small, thin-wall applications using engineering thermoplastics. The Welltec machine can run commodity materials and be used to make large, thick-wall parts. The sample part they exhibited at Chinaplas was a hefty chopping board, with thicknesses in some sections up to 14 millimeters, or more than half an inch. ``This is a niche market, of course, but we see this as high potential,'' Li said in a May 21 interview at Chinaplas. He said the competitive price for the HyperFoam injection machine offers ``a much lower admission fee'' for getting into the specialized foaming business. He suggested an export price of about US$90,000 for a press with 260 metric tons of clamping force, a 450-tonne barrel and platform, and a 3½-pound shot size.
Welltec said the technology uses carbon dioxide gas injected into the mold cavity at high speeds - up to 400mm per second - to create a honeycomblike foam structure.
It requires a specially adapted chemical foaming agent developed by Reedy, a nitrogen injection accumulator and static mixer from Sulzer, and a high-pressure, hydraulic-driven shut-off nozzle from Herzog.
Caropreso provided technical assistance with mold design and a gas counterpressure module to improve the swirled surface finish that is common to foam technologies.
The unique aspect of the technology is getting the press, the auxiliary equipment and the chemical blowing agent to work together, said Joseph Hui, CVI business development manager. The process, which works with commodity thermoplastics, has a patent pending in China, he said.
The firms involved said the technology has potentially wide application with wood-plastic composites, and in automotive, for developing stiff, lightweight and sound-insulating parts. The machine can save capital costs by allowing a smaller press to do the work of much larger injection machines. They claim users could see a one- to two-year payback on their investment in resin savings alone, not counting any energy savings and the like.
Reedy said that tool design is fundamental to the success of the system, and that the technology will require educating mold makers in Asia so they become familiar with it. Initial plans call for marketing the press in China, but Welltec said it is willing to export the unit. The parties said they have no plans to license the technology.