Product creator Satellite Industries Inc. of Plymouth, Minn., adopted a blind-rib technology in blow molding large plastic panels for its latest portable toilet.
``We found a blow molding process that made a rib inside a wall without a dimple or dent,'' Ron Holmstadt, director of product engineering, said by telephone. Hidden rib supports create smoother walls in the Maxim 3000 than in earlier models.
Previously, a vendor vacuum formed sidewalls and the single-wall roof. The door and frame assemblies were blow molded.
Blow molding ``yields nearly finished parts right out of the mold for good cost efficiency,'' and high-molecular-weight high density polyethylene ``has superb impact and stress-crack resistance and has high production capacity,'' Holmstadt said.
Satellite handles sales and marketing, design and logistics. The firm's first plastic portable toilet, introduced in 1972, was made of vacuum formed sheet stock with metal or wood reinforcements. Over time, the other materials deteriorated, so Satellite replaced them with plastic.
By 1998, operators renting portable toilets were asking for easy cleaning, an ergonomic floor and a sleek look.
Satellite built on longtime vendor Chilton Products' experience in blow molding the doors. Graham Group and Brera Capital Partners LLC co-own Chilton's parent, Western Industries Inc.
The Chilton, Wis., molder worked in 1982 with Satellite to create ``arguably the largest blow molded flat panel to date,'' Holmstadt said. The 46-inch-by-84-inch part became the door and frame assembly for the Tufway model.
The Maxim 3000 called for 11 major blow molded parts with minimal bumps or ledges and easily cleaned surfaces inside and out.
Leisure Inc., doing business as Leisure Product Solutions in Chanhassen, Minn., did design work, sculpted foam models and formed some parts, said Paul Pilosi, Leisure vice president.
Satellite teamed up with Hobson Mould Works Inc. for mold building, which cost more than $1 million, and selected four blow molders in Wisconsin, Illinois and Minnesota to make the parts.
Hobson introduced the blind-rib technology in mid-1999. Financial problems, however, led Hobson to close in May 2001.
Holmstadt said the blind-rib technology was relatively new in the United States - starting with some automotive spoilers - but had been used in Japan for several years on parts much smaller than Satellite's.
Blind ribs ``wouldn't be possible in a single-wall, vacuum formed design or conventional tack-off-type blow molding,'' he said.
In taking ``a big leap of faith,'' Satellite ordered an expensive, complicated mold to make a 44-inch-by-77-inch sidewall, he said. ``The gamble was successful and the finished Maxim 3000 uses the process in the three sidewalls and door.'' Other blow molded parts include the roof, urinal, hand-wash tank, base runners, waste tank, vent pipe and, for flushing models, the water tank.
The product debuted in November 2000 and has achieved good sales, Holmstadt said.
Satellite applied in mid-2000 for patent protection on the blind-rib technology for portable toilets.