September 2010- When stainless steel outer panels for appliances became the hottest trend for home kitchens, appliance manufacturers had to respond to the increase in consumer demand.

GE, Shelton, Conn., one of the world's largest appliance makers, turned to 3-Dimensional Services Group, Rochester Hills, Mich., to help develop the products. The 3-Dimensional Services Group consists of 3-Dimensional Services, Urgent Plastic Services and Urgent Design & Manufacturing. These companies provide rapid prototyping and low-volume production, including laser processing, injection molding, stamping, machining, robotic and manual welding, waterjet, hydroforming, tube bending, vibration welding, casting and pattern fabrication, RIM tooling, SLA and LOM rapid modeling and assembly.

The company specializes in design, engineering and analysis, in-house tool construction and prototype parts, along with low- to medium-volume product runs. It typically can provide a prototype up to 70 percent faster than conventionally equipped prototype shops.

"When GE contacted us, they said they needed to make a new line of refrigerators with stainless steel outer doors to meet market demand," says Steve Kelly, senior sales engineer for 3-Dimensional. "GE had to move fast to get these new models into the stores by spring to take advantage of this major sales opportunity. Our part in the process had to be done fast, and it had to be done right."

In an eight-week window, 3-Dimensional had to create three stainless steel outer-panel doors--two French and one freezer--for five new French-door refrigerator models. Approximately 250 three-door sets were required for each of the five models. Along with the use of stainless steel, some models required doors formed from smooth, prepainted, cold-rolled steel and others from textured, prepainted, cold-rolled steel. Therefore, the company would be working with different material thicknesses, ranging from 0.024 in. to 0.032 in.

A Class-A finish
The company had to create tooling for its four hydraulic presses, ranging from 400 tons to 1,600 tons, to make the new parts. It has presses ranging from 20 tons to 7,000 tons, which allow it to handle everything from simple bends to complex tooling. But this project presented another challenge.

Because these models would be used for consumer in-home testing and as sales display models, "these parts had to have a Class-A finish, free of scratches or blemishes of any kind," says Mike Baranowski, 3-Dimensional program quality assurance manager.

"[GE] wanted the highest-quality prototype parts we could produce," he continues. The company created tooling with steel inserts to ensure optimum part definition. Multiple die sets for each of the five models were required and finished in approximately four weeks. The tooling was polished meticulously for a superior finish, and the parts were protected with plastic sheeting during forming.

The company used its 3- and 5-axis lasers to trim the metal before stamping. Its focus on quality resulted in a three-stage process of visual inspection, dimensional accuracy, using a coordinate measuring machine, and a fixture inspection using check fixtures created by 3-Dimensional.

"The challenge didn't consist merely of making the doors. The challenge consisted of making the doors, the check fixtures, and designing and manufacturing the packaging, and doing it all in eight weeks to help GE re-energize its product line. That was the big story," says Baranowski. FFJ