CLEVELAND — Cast aluminum molds remain the most common type for rotational molding, but CNC-machined molds out of a block of aluminum are growing — and are faster to produce, according to industry officials at the SPE Rotational Molding Division's TopCon 2014 here.
Diversified Molds & Castings LLC has added two CNC machines to its factory in Warrensville Heights, Ohio, CEO Vince Costello said. The company had offered machined molds in the past, but sourced them from an outside company, he said at Diversified Mold's booth at the TopCon.
Installed in January, the CNC machines allow the company to improve delivery times, maintain control of projects in-house and control costs, Costello said.
Faster part design is important for rotational molding, which lags other plastics processes in speed to market, several speakers said at the Society of Plastics Engineers conference, held June 1-4 in Cleveland. It starts with the mold. CNC machines can run automatically using CAD drawings. Diversified Mold's engineering department has two sets of SolidWorks 2014.
Also to help with faster delivery, Diversified Mold recently hired Jim Henry as sales and design engineer, to link sales with technical consultation on mold design. Henry has 25 years of experience in mold design, engineering supervisory experience, including 12 years in the rotomolding industry.
Diversified Mold's new CNC machines are a Fryer MC45 metalcutting machine with an envelope of 45 inches by 25 inches by 25 inches. Costello said the company plans to install a larger machine in the next year. The other one is a CNC router, a DMS five-axis moving table unit with an envelope of 60 inches by 120 inches by 48 inches. The router will make machine models and patterns out of wood and blocks of foam.
Diversified Mold & Castings is celebrating its 75th year in business. The company was founded by Vince Costello's grandfather, Luke Beinke, a pattern maker who started an aluminum foundry to make castings. His father, Sam Costello, ran the company from 1966 to 1996, when Vince bought it.
In other news from the Rotomolding TopCon, an executive of Nembro, Italy-based Persico SpA said CNC machines rotational molds now account for 80 percent of the 1,200 molds the company makes a year. The other 20 percent are cast aluminum. Most of the molds are used by customers to make parts for motorcycles, trucks and construction equipment, said Sergio Zilioli, key account manager for Persico North America.
Persico cut its first CNC mold in 2000. Today the company runs 20 CNC machines in-house, with access to 60 more at associated companies. CNC molds typically take three to eight weeks to make, but Zilioli said the company has reduced the time by designing and producing the frame — known as the spider in rotomolding speak — at the same time as the mold gets machined.
Cast aluminum molds have a rougher surface, and need a lot of finishing work. CNC molds, on the other hand, come out much cleaner and require less polishing, Zilioli said
Zilioli said Persico can make large CNC molds — big enough to rotomold an eight-foot-long sailboat.