Precision assembly includes molded part and extruded silicone

A precision assembly is helping ease incontinence and other medical problems caused by a variety of gynecologic conditions, including prolapse.

Engineers at MedPlast (Elkhorn, WI) developed a new approach to a product called pessary balloons that includes a molded part, a check ball and a glued-on silicone extrusion.

MedPlast design includes glued-on silicone extrusion.

The recently developed assembly is latex-free. Previous designs had been 100% latex, but medical device manufacturers globally are moving away from latex because it contains proteins that can cause an allergic reaction.

Silicone has become the preferred replacement in pessary applications, while in other devices elastomers and other polymers are used. Silicone, however, can be difficult to manufacture.

Poor tear resistance

"The silicone offers poor tear resistance compared to natural rubber," says Bernie Stritzke, vice president and general manager of MedPlast's facility in Elkhorn. "The balloon section of the multi-piece product is thin, and has to be stretched and there are difficult de-molding transitions," he said, noting that the company made a special part to de-mold without over-extending the piece. "It's a process that requires great finesse."

MedPlast uses the new approach in a product tradenamed Inflat-o-Ball for CooperSurgical.

"The Inflat-o-Ball pessary is a unique device designed to manage complicated pelvic prolapse cases," says Robert Auerbach, MD, senior vice-president and chief medical officer of CooperSurgical. "Being able to provide this product without latex is an important advancement in patient care, as many patients using the product are exposed for extended periods of time, making those with latex allergies unable to receive this therapy. The new silicone-based product eliminates this problem. Now this device is available to all in need,"

Many pessaries are removed at night.

The MedPlast facility in  Elkhorn focuses on elastomeric processing, including liquid injection molding, compression molding, transfer molding, multicomponent molding, and most recently, silicone extrusion.

Formed more than three years ago, MedPlast now operates five plants in the United States with a growing focus on medical, which  now represent more than 80% of total revenues. The company operates approximately 220 injection molding machines. About 70% are 50 to 250 tons of clamping force.