Persico SpA is rolling out the next generation of its fully automated Leonardo rotational molding machines, which use electricity for heating and cooling the molds directly, instead of oil.
The Italian company conducted extensive research and development before making the change, said company official Sergio Zilioli, in a presentation May 7 at the Society of Plastics Engineers' rotomolding TopCon in Cleveland.
“We found out that with electrical resistance applied to the molds, we get a benefit that we can't get with oil,” said Zilioli, Persico sales manager for the United States and Brazil.
The machinery maker in Nembro, Italy, currently is building two of the new electric machines for customers in Germany, one each for Italy and France, he said. Persico is in “deep discussion” with customers in the U.S. and Brazil, he added.
Leonardo is a major innovation for rotomolding. Instead of cycling a turning mold through an oven, then a cooling station before manual part removal, Leonardo heats and cools the mold right at the mold surface. Initially, the machines used heated and chilled oil pumped through channels machined in the mold — and Zilioli said Persico has installed five of these machines that use oil heating and cooling in the United States and two in Australia and 35 in Europe, mostly in Italy.
The machines are highly automated, loading the resin, loading the mold with resin, opening and closing the mold and removing parts. The mold is held under vacuum to remove bubbles and pinholes.
But now, Persico uses a series of resistors applied directly to the mold surface, for heating and cooling.
At the SPE Rotomolding Division's conference, Zilioli gave a case study of a Finnish maker of organic waste composters and dry toilets that purchased a Leonardo to make 15,000 bodies and lids a year.
Persico installed a fully automatic, turnkey system: a Leonardo machine and molds, robots, and equipment that automatically applies a sealing gasket. Persico engineers incorporated the customer's existing machine to foam the hollow parts with polyurethane insulation into the manufacturing cell. The total investment was about 2 million euros ($2.5 million), he said.
“It was a big project for the customer. They were previously buying the parts from a custom molder, and they decided to bring inside the production of the parts with the highest volumes,” Zilioli said. “But they decided to approach it in a different way — not with a conventional machine but with a Leonardo, because this company is very sensitive to the environment, from the product line and also from the company policy.”
The efficient electric mold technology reduces energy savings, he said. Also, there is no need to pre-heat any oil, or change oil.
The customer in Finland, who Zilioli did not identify, also is building a wind turbine next to its factory to power the Leonardo and the plant's lighting.
The bodies of the composter and toilets remain on the bottom of the mold once it's opened. A robot moves the parts into a cooling station. Later, a robot moves them to the automated foaming area.
After his speech, Zilioli said Persico will still make oil machines for existing customers, but officials are pushing the electric molds as the second-generation Leonardos.