Featured Article: Eurostyling the Sprite™
Pro/ENGINEER software is a powerful tool in the development of entire product lines,
producing new designs in timely and cost effective ways. Nilfisk-Advance of Plymouth, Minnesota, presented RFA with such a project
– a family of wet-dry vacuums for the commercial floor care industry.
Nilfisk-Advance was formed in 1994 by the merger of Denmark’s Nilfisk and America’s Advance Machine Company. Their goal was to develop new products for customers on both sides of the Atlantic. They asked RFA to assist them in the development of a five- and eight-gallon wet/dry vacuum called the Sprite™ that would satisfy American and European needs. The initial demand for the new Sprite™ came from European customers, who wanted a machine that was easy to clean and dry after use.
Teamwork was important from the start.
Following the concepting phase, industrial designers created the exterior shape and appearance, while Advance and RFA worked together on the functional design. RFA’s project manager received a list of well-defined specifications, based on input from both manufacturing and marketing at Nilfisk. This was important because a short time frame did not allow them to go through the design process more than once.
Two significant design features of the product line are the rotomolded double-wall tank and the injection molded head assembly. The competition uses single-wall tanks, which provide either easy-to-clean interiors or eye-pleasing exteriors, but not both.
The power head is comprised of three main injection molded parts that support the motor and fan, house an air filter and sound suppression material, and channel cooling air for the motor and working (vacuum) air through the head assembly. The working air is channeled from the tank through the fan and exhausted under the top cover. A complex series of air channels are created when the three main molded housings are assembled. The unique power head design resulted in reduced part count providing easy assembly and servicing.
The design of both the double-wall tank and the unique power head benefited from the use of Pro/E. RFA used Master Model Merge technique to create the outside shape of the wet/dry vacuum based on the industrial designer’s styling requirements and set up a parametric interface between the mating parts. With this modeling technique, RFA was able to refine the design and respond to styling changes quickly throughout the design phase.
The combination of solid modeling and rapid prototyping shortened the product development cycle.
Solid modeling provided precise part fit, while rapid prototyping both validated the model and allowed early testing. When styling changes were requested mid-stream, RFA could make them very quickly, and the inner mating parts would regenerate and still fit perfectly. “Pretesting with the stereolithography parts really saved us a lot of time,” said Advance’s Design Engineer, “two, maybe three months.” He praised RFA’s work, saying, “RFA did a number of iterations. I’d review the designs with my people and then tell RFA, ‘This is what Nilfisk wants and this is what Advance can do.’ RFA would redesign it to meet both criteria.” Good liaison work by engineers at both Nilfisk-Advance and RFA kept all the people involved in the project well informed so everyone was able to provide input at the appropriate times.
Another challenge for RFA and Advance was to communicate with Nilfisk in Denmark. Videoconferences involved RFA, Advance’s engineers and manufacturing personnel, Nilfisk’s marketing and styling personnel, plus suppliers. This project proved distance is not a barrier to successful engineering projects.