Speakers explain technology behind all-electric blow molding

Pittsburgh — Officials of two machinery makers that make all-electric blow molding presses touted the technology during presentations at the Society of Plastics Engineers' Annual Blow Molding Conference in Pittsburgh.

Italian machinery maker Magic MP SpA is selling the third generation of its all-electric blow molding machine, said Celestino Spiga, area manager. He said Magic began making all-electrics about 20 years ago. Company leaders found that the fully electric blow molders were more repeatable and precise than hydraulic machines, removing the variables of oil temperature and viscosity.

"The basic concept came from our customers," Spiga said. "They, from the beginning, were looking for all-electric because it is cleaner and no oil." At first, the presses went into cosmetic and clean room pharmaceutical package, all-electrics have spread to a wide range of markets, he said.

He explained the technology behind Magic's all-electric extrusion blow molders, which uses rack-and-pinion transmission. Electric motors run the two key axes of motion: clamp movement and the blow pin operation. The all-electric blow molders use 30 percent less energy than hydraulic presses, Spiga said.

Magic, based in Monza, Italy, has produced more than a thousand fully electric blow molding machines since it began making them in 1997, Spiga said. The company makes more than 100 machines a year — every one of them all-electric.

Magic is setting up a North American operation in Canton, Mich., run by Celestino Spiga's son, Pietro Spiga.

Another speaker, Thorsten Bung, director of sales at Germany-based Hesta Blasformtechnik GmbH & Co. KG, put the energy savings of all-electrics at 50 percent over hydraulics. The machines also run cleaner and quieter.

Fully electric blow molders also are more flexible. "You don't have to run at full clamping force, and that's an advantage," Bung said.

He said that hydraulics do have some advantages. Maintenance people and operators are familiar with hydraulic power. Hydraulics are universal, so it's easier to upgrade a press than it is with all-electric, Bung said.

Also, machinery companies are using servo-driven hydraulics to cut energy use.

Bung's advice? Go for all-electric for medical clean room molding. Hydraulic is the technology for large accumulator-head machines, but he said a blow molder could look for a development partner to add electric capability.

All-electric blow molding presses reduce long-term energy costs, but you pay more upfront for the machine and need to spend money for employee training, Bung said.

Hesta is based in Göppingen, Germany.