Seven Injection Units Speed Toothbrush Production

It’s interesting that simple day-to-day products often have the most complex molds. One example is toothbrushes.

A German moldmaker, Zahoransky Formenbau , says it has developed  the first-ever seven-component mold ever built. It was developed for Schiffer Dental Care Products, also of Germany.

The 16-fold injection mold has two injection stations and one loading and removal station located outside the tool. Two different materials in the same color are processed in the

3D graphic of various nozzlesfirst station, while two different thermoplastic elastomers (TPEs) are used in the second station. One of these stations is injected in four different colors.

No time-consuming color changes (two hours on average)  are necessary,

“What has been produced during the day can now be in the supermarkets’ storerooms by the evening,” according to a press release from Zahoransky.

The technical challenge was interesting because seven injection units had to be connected to the mold in a tight space. The availability of several material feeds, the different processing temperatures of the various materials and the close spacing between the different nozzles at the same cavity were also factors. Injection molding was done on a six-component machine from Engel. The seventh injection unit from Boy was integrated in the production process.

Mold-Masters supplied a special two-part soldered runner which is unique for Mold-Masters. Instead of having only straight channels, these runners have as many as three melt levels with gentle curves and turns. This allows design freedom because of natural balancing, a uniform thermal profile and a comparatively low construction height. This technology allows two or more melt flow-ways to be integrated into a single runner. The design also allows six (and more) materials and colors in a single runner.

About Doug Smock

Former Chief Editor at Plastics World and Senior Technical Editor Design News

Consumer Goods, Design, Elastomers, Europe, Injection Molding , ,

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