ALGOR SUPPORTS DESIGN OPTIMIZATION AND CREATIVITY AT BLACK & DECKER

Creativity is the key requirement for design engineers at Black & Decker. Because the company produces such a wide variety of consumer products, the capabilities of both the engineers and their design engineering software are tested on a daily basis. At Black & Decker Canada Inc., located in Brockville, Ontario, that challenge is met by a team of engineers, headed by Colin Overy, Manager - Product Development, with the help of Algor design and analysis software.

Colin Overy, Manager - Product Development (left) and Richard P. Rosa, Design Engineer, are pictured with optimized wheel design used for a revolutionary new Black & Decker lawnmower. Note stress analysis model on computer screen.

Design and Analysis Integrated

Mr. Overy has taken full advantage of Algor software's integration of design and analysis capabilities on desktop computers. In his words: "Algor allows FEA to become a process to be used by capable engineers and technologists on an as-needed basis. We have found it to be complimentary to, but not a substitute for, sound engineering judgment and innovative design."

Design Techniques

Black & Decker engineers use a number of techniques in the creation of models. "One technique we use is to import various elevations from a company-standard CAD system into Superdraw and construct the model there," says Mr. Overy. "We see modeling as the real challenge. A few minutes spent planning the model construction technique can save hours later." Algor software has been used in the design of a large number of Black & Decker products. The photos and descriptions below are just a few examples of the innovative use of Algor software at Black & Decker Canada.

A Mower on the Cutting Edge

One of the most innovative products Black & Decker has introduced recently is the cordless electric lawnmower. The new mower is designed to greatly reduce the amount of air and noise pollution that is created by standard gasoline-powered mowers. A gasoline-powered lawnmower creates more air pollution in 30 minutes than does a typical automobile driving the 200-mile distance between Washington, DC and Philadelphia. The new cordless mower is also nearly half as noisy as a gasoline-powered model.

The new Black & Decker cordless electric mower is the first of its kind. It produces less pollution and noise than gasoline-powered mowers.

The Blade

Several components of the new mower were designed and analyzed with Algor software, including the patented cutting blade. "The blade rotates at 3,600 rpm," says Mr. Overy. Algor software was used to confirm blade deflection and maximum stresses. The deflection was confirmed by actual measurement and stresses by a strain gauge telemetry system. The analysis data were used to verify infinite fatigue life design criteria. Correlation and confidence in the analysis was so good that deflection and strain gauge testing of a subsequent new mulching blade design was considered unnecessary."

A light-shaded rendering of the cordless mower blade. This complex model was constructed to study deflection behavior.

The Wheel

Algor software also played a part in a needed redesign of the mower's wheels. According to Mr. Richard Rosa, Design Engineer for Lawnmower Product Development, "Field trials of the new cordless mower revealed a problem with wheel durability just after production began. Unforeseen lateral loading was occurring when cutting parallel to slopes, in conjunction with impact loading. The Algor analysis showed elastic deflection closely duplicating the permanent deflection seen in the failed part.

"The fix," continues Mr. Rosa, "was a small circular rib (later to become known as the "Rosa rib"). This was modeled and a new analysis showed acceptable deflection and stress levels. The production mold was modified overnight and production resumed in a day or two. The confidence in the Algor analysis reduced the problem to a short production delay and all the funds spent on the software were recovered ten times over!"

This stress analysis rendering shows the lawnmower wheel with the added ring.

The Wheel Bracket

"In this case," says Mr. Overy, "the analysis of a new concept in lawnmower height adjustment, using a unique wheel bracket, indicated changes were needed to reduce stresses. The use of Algor software eliminated at least one, and probably three prototyping steps. Again," he continues, "the cost effectiveness of the software was appreciated."

Design optimization of the lawnmower's unique wheel bracket with Algor software eliminated costly prototypes.

Coffee Carafe

"This component," says Mr. Overy, "Is a liner for a coffee maker carafe. Algor software was used to model the liner and perform analyses of structural stresses due to vacuum and thermal loads. In addition, the effects of changing the glass to a type with lower thermal expansion properties were evaluated. The volume capacity of new liner configurations was also calculated using Algor."

The Dustbuster

The Black & Decker design team has used Algor's fluid flow analysis processor to investigate flow patterns associated with new Dustbuster designs. "The data allowed many configurations to be evaluated initially, and the better ones were selected for subsequent prototyping and analysis," says Mr. Overy. "Full color plots, showing pressure and velocity, were created in Superview for discussion and reporting purposes." Unfortunately, we cannot show any photos of the analyses, because the details are confidential.

Algor in the Future

Mr. Overy and his team plan to continue finding creative ways to use Algor software. In his words: "We will continue to utilize Algor software as we expand our analytical work. I foresee using Algor for advanced conceptual design and analysis, in-depth analysis, design optimization and investigating what-if situations. Algor features we appreciate include the family-style related formats of the different programs, and the added features and speed improvements included in the latest release."