Slow Cooker...Fast Prototypes Take The Heat Off

Service Detail from 3 Dimensional Services

Slow Cooker...Fast Prototypes Take The Heat Off -Image

With the deadline for new product introductions approaching, Coleman® turns up the heat for slow cooker prototypes-rapid prototyping specialist fuels a fast response

There are two types of people enjoying the out-of-doors…those primitive survivalists who want only the barest of essentials…and those that want all the comforts of home-away from home. For both, and all the varying degrees in between, the Coleman® Company, Inc., has been the premier outdoor outfitter and sports equipment supplier for nearly 100 years. Coleman products are used throughout the world by pup tenters and self-contained RVers, backpackers, hunting enthusiasts, backyard barbecuers, and game-time tailgaters. And, while Coleman knows more than anyone on how to equip people for the great outdoors, when it boils down to precious little time to prepare new products for introduction expositions, their product managers often seek assistance from companies that specialize in prototype builds.

For Coleman, one specialist has been 3-Dimensional Services, of Rochester Hills, MI, a rapid prototype firm that specializes in design, engineering and analysis, in-house tool construction, and complete build of first off parts and low to medium volume production runs. Their use of advanced process methods, manufacturing technologies and staff talents means prototype parts are typically provided up to 70% faster than conventional prototype shops are able to offer.

And so it was recently that, with the exhibit looming when buyers for retail outlets would be previewing the newest products for placement on their stores' shelves for 2006, Coleman brought one of its latest design ideas to the rapid prototyper. The new product was to be called the RoadTripTM Heat 'N Serve Slow Cooker, a home-style, six-quart crock-pot appliance capable of portable use fueled by a disposable 16.4 oz propane cylinder. The slow cooker was designed to be compact yet stylish, and engineered to be efficient-up to 10 hours of slow cook time on a low heat setting-for flavorful simmering of soups, chili, and stews, to slow cook a variety of meats, plus to heat pre-cooked recipes and meals.

To be ready for the show, Coleman asked that six prototype slow cookers be prepared from their design, which was furnished via CAD data files. For 3-Dimensional Services' role in the prototype build, the firm was to produce four different parts, including the deep-draw forming of the removable stainless steel food vessel, plus the stamping of the outer housing, the burner support plate, and the appliance base-all fabricated from cold rolled steel-as well as assembly welding these three components.

From the time they were given the design file, through the machining of the dies and stamping or forming of parts, to delivery of the six sets of four parts, 3-Dimensional Services required just three weeks. The fast response was due in part to the company's CAD-to-CAM machining program generation, high speed machining of stamping dies, hydraulic press forming, both 3-axis and 5-axis laser trimming, and precision weld operations-all provided by the in-house capabilities of 3-Dimensional.

The fast turnaround from 3-Dimensional also meant that Coleman had plenty of time to finish coat the parts plus complete the necessary assembly work such as adding handles, attaching the housing and burner support to the base, mounting the burner, and preparing the glass lid. The valuable time saved allowed the slow cooker prototypes to be ready on time for the show, and are now being stocked in retail outlets. Importantly, the prototype services offered by 3-Dimensional also helped Coleman shorten its development time from concept to product by incorporating production-like tooling designs and process methods into the build procedures.

According to Steve Kelly, 3-Dimensional Services' Sales Engineer for the Coleman slow cooker prototype project, the application presented some unique challenges for the firm. "First, the shape of the food vessel was elliptical," says Kelly, "measuring approximately 14" x 6" and, from a stamping aspect, that's a particularly difficult shape to form when drawing materials. If adequate measures are not taken, it's very easy to crimp and wrinkle the material. Then too, the 8" depth of the draw was critical to the outcome of producing quality parts, and the fact that the vessel was made from stainless steel all contributed to a tough stamping challenge, considering the time constraints on the project."

"For this application, the appearance of the food vessel was critical. Usually our prototypes are used by engineers to evaluate performance characteristics and to verify parts for clearances and fits and dimensions. Few times, however, are the prototypes used as a substitute for actual products, needing to impress potential buyers. Knowing this in advance, our staff produced the stamping tools to not only generate this level of finish but to also accurately demonstrate production intent. In the end, the project went smoothly and the necessary surfaces, even the draw flow lines were smooth," notes Kelly.

To form the stainless steel food pan, the first step in the process was trimming accurately sized blanks using a 3-axis laser cutting system. The second stage was the construction of three die sets-a pre-draw, draw and redraw tool. Within each tool set was three pieces-the punch, the die and a draw ring. The draw ring was critical to the quality outcome of the forming process in that it eliminates wrinkles in the material and promotes a smooth feed and even flow of the stock through each stage of the draw process. The forming operations of the food vessel and stamping processes of the other three components were completed on a 500-ton press.

After the stamping and forming operations, the company used 5axis laser systems to perform a final trim around the contours of the parts, an especially important procedure for the food vessels rim.

Another important factor to the fast, three-week response, according to Mr. Kelly, is 3-Dimensional Services' use of aluminum alloys to fabricate the tools and dies for prototype stamping and forming operations. "We've tested various aluminum alloys and have found one that holds up well for short runs," he remarks, "while the speeds at which it can be machined helps to reduce machining times by 50% or more as compared to some tool steels. Coupled with today's high speed CNC machining centers and their capabilities for programming complex tool paths, we were able to turn out tools fast yet capable of producing the required surface finishes."

Equally critical to 3-Dimensional's fast production of the slow cooker components is the fact that the company possesses its own wide array of stamping presses from 60 ton up to a 7000 ton unit, plus the necessary laser cutting systems (16 in all) for cutting and sizing the blanks, trimming the formed pieces after stamping-all in-house technologies so that control and timing of the entire process remains in-house.

"In just three weeks, not only did the Coleman team have the parts they needed to successfully display the Heat 'N Serve Slow Cooker at the trade show," relates Kelly, "they had the tooling data and designs, proven for their manufacturing-intent, that would help speed up the fabrication of production tooling and assure fast startup for the slow cooker. Within a few months after the prototypes were completed, RoadTrip slow cookers were in full production. That kind of smooth and fast product launch is a result of not only the fast turnaround of the prototypes, but also from the high level of confidence in the tested tool deigns and the manufacturing processes to go forward to success."

3-Dimensional Services has redefined prototyping-the ability to manufacture complete, production-like prototype parts in a rapid time frame. The company, along with its subsidiaries Urgent Plastic Services and Urgent Design & Manufacture, provide prototype services for virtually all process disciplines including laser cutting and welding, machining, stamping, hydroforming and tube bending, injection molding, vibration welding, castings, RIM tooling, rapid modeling, high definition stamping of exotic alloys, and assembly.