DUSSELDORF, GERMANY - Extruder manufacturer Davis-Standard will begin making machines to extrusion blow mold PET bottles using ``hand-over-hand'' technology through a joint venture with Sabel Plastechs Inc. of Cincinnati. The machines combine a type of pipe extrusion with blow molding.
Frank Kennedy, industry manager for Davis-Standard's Blow Molding Systems, said the technology will compete against injection stretch blow molding of PET and extrusion blow molding of PVC in select markets, such as small-sized bottles for cosmetics, toiletries, foods, liquor, detergent and health-care and medical products. The machine, a Sabel 820 Extrusion Blow Molding System, can produce small PET containers at a rate of 1,400-2,800 per hour.
Benefits include a small investment in tooling and no leaking hydraulic oil, since the system is entirely electric- and pneumatic-powered. The technology was invented by Samuel Belcher, president of Sabel Plastics.
The ``hand-over-hand'' blow molding system is not entirely new to plastics. In the mid-1960s, Owens-Illinois tried to extrude Maxwell House coffee jars from PVC pipe, but the project ended because PVC could not offer enough barrier protection, the paper said.
The new machine ``uses existing technology, only in a new way,'' Kennedy said.
Extrusion blow molding PET is a change for Davis-Standard, Kennedy said. Through its Davis-Standard/Sterling unit in Edison, N.J., the company has traditionally made larger, accumulator-head blow molders.
Kennedy described how the Sabel 820 works at Plastics High Performance Packaging in Dusseldorf. He said a 11/2-inch Davis-Standard extruder moves PET through a small-pipe die and a vacuum sizing tank. Two sections of the clamping mechanism, with molds inside, leapfrog over each other and grab the pipe. A needle inflates the containers.