FOBOHA develops fully electric stack turning mold

As part of its drive to boost presence in medical markets, German moldmaking specialist FOBOHA now offers complex stack turning and cube molds that are totally operated with electric servo drives.

The all-electric design of a complete unit will be shown at the Ferromatik Milacron stand at the Fakuma show in the Friedrichshafen Exhibition Center Oct. 16 to 20.

"As the all-electric injection molding machines are increasingly becoming the standard in the market, FOBOHA's engineers have searched for solutions of how to make stack turning and cube molds entirely without hydraulic drives," the company stated in a press release. "One special challenge was the issue of how to integrate the necessary servo drives into the mold."

All drives (axes) of the new design-from the ejector via the reversing unit to the handling unit-are fitted with electric motors.

Processors in medical, pharmaceutical, and food processing fields have been pushing for all-electric molds to maintain the cleanliness and precision they have achieved in all-electric injection molding machines. They are also less expensive to operate.

A 4x8+8 mold producing a polypropylene cap sealing system for bottles will be shown  at Fakuma. Photo-sensitive additives can be stored and protected in a dark chamber in the cap. Once the cap is opened for the first time, the additive enters the bottle. "Separating the flavoring substances before use not only improves the aroma, but also prolongs minimum shelf life," according to FOBOHA.

The two parts in the cap are manufactured using a cube mold. The assembly also includes a lid for subsequently resealing the powder chamber.

Eight upper and eight lower parts are injected in the mold parting lines. Slide bars used to demold the outer thread and the non-tamper seal are on the nozzle side.

When both units finish resin injection, the central block is turned 90°. The lower parts are connected to the upper parts on both exposed sides when the next injection phase begins.

This is accomplished through an interested piece of engineering by FOBOHA.  The eight upper parts are removed through a proprietary handling device, which then moves the parts  sideways to the lower part and then reconnects them. The assembled parts are demolded with a servo-driven ejector system. Sixteen mounted sealing caps are made per cycle. Cycle time including assembly of the 2 x 8 parts is 7.5 seconds

"The cavity-assigned assembly of the individual parts guarantees an optimum degree of assembly precision and substantially enhances the quality of the assembly part," says FOBOHA. "The cap sealing system can also be made with greater economic efficiency. Owing to the cube engineering, the cycle time is at least 30% shorter that in injection processes using conventional molds."

Footprint is another benefit because it uses just one molding machine and does not require a dedicated automatic assembly unit.

FOBOHA is part of Adval Tech, which operates under the names AWM, Omni, QSCH, Styner+Bienz and Teuscher. Adval Tech (Niederwangen, Switzerland) acquired FOBOHA (Haslach, Germany) in 2003.

FOBOHA says it has more than  400 stack turning production systems since  the launch of the technology in 1996.