Thermoforming Key To Water-Massage Unit

When engineers at Kintz Plastics took on the challenge of designing a cover for a new water-massage machine, they quickly discovered a myriad of challenges. The cover had to be lightweight, durable, attractive, and watertight. And no wonder.

The Aqua Massage Dry Water Massage uses 36 computer-controlled water jets to produce a finger-tip-like massage that relieves muscle stiffness and tension. Users can customize their massage by adjusting water pressure, temperature, and pulsating frequency.

But customers also had to lie inside the box-like massage machine. That meant that the cover would have to be transparent to eliminate any chance of claustrophobia. For safety reasons, it had to open and close easily. It had to form a water-tight seal-and be attractive, since it is a consumer product.

Kintz and Aqua engineers worked together on the design and decided to use a 0.187-inch thick acrylic for the material. Further, they decided that the size of the cover made thermoforming a practical process choice: They believed that thermoforming would be faster, and less expensive than injection molding. The thermoforming process formed the flat sheets into the required shape in a single process.

After thermoforming, the process called for holes to be drilled at defined points around the perimeter where Kintz inserted screws, washers, and nuts so the unit would be ready for final assembly at Aqua's manufacturing plant.