The use of a portable measurement device is helping Global Glass Inc. reduce development time for vehicle accessories such as running boards, ground effect kits and spoilers.

By allowing company engineers to capture the surface outlines of cars, trucks and RVs for use in CAD/CAM software, the device has changed accessory development from an error-prone manual process to a more accurate electronic one. Greater accuracy means less rework to address fit and finish problems and consequently, faster cycle times. The company recently developed a 1/5 scale model of a Ford truck and new running board 60% faster than previously possible.

Based in Elkhart, IN, Global Glass employs 100 people and has three production plants. The company's main business consists of making fiberglass exterior parts for RV manufacturers, but there's also an injection molding division that uses a proprietary plastic molding process to produce vehicle accessories. These products are purchased by van converters and truck outfitters.

The accessories division's main challenge can be summed up with the phrase: too many vehicles, too little time. "With the number of vehicles and models on the market, we can't supply accessories fast enough," says Ted Filley, CNC programmer at Global Glass.

To help meet this demand, the company purchased a measurement device called a FaroArm from Faro Technologies Inc. "By letting us create our own surface data for the vehicles, the FaroArm lets us move more of the process onto the computer and CNC router," Filley explains. "The accuracy of this approach prevents a lot of rework and helps us develop products faster."

Auto and RV manufacturers use computer-aided design (CAD) or computer-aided industrial design (CAID) software to create the proprietary surface designs of their vehicles. As a result, Global Glass must buy, rent, or borrow a vehicle to design an accessory for it. Often someone from the company must go to Detroit to get access to a vehicle prior to its public release.

Previously, the first step in designing an accessory was the creation of a "splash" mold of the area where the accessory would fit. The splash mold was a light, fiberglass mold that served as a temporary duplicate that Global Glass could take back to its own facilities. To protect the vehicle, the area to be molded was completely covered with masking tape but even so, some manufacturers were "not thrilled about the messy process," Filley explains. The process of masking the vehicle and making the splash mold took approximately two days.

The splash mold served as the guide for the pattern maker who created a wooden model of the accessory. Sample molded parts were made from the pattern and installed on the vehicle to check for fit and finish. If they fit, a mold tool was created, but only after the part dimensions were adjusted manually for the shrinkage that occurs during the molding of Metton, the material used to make the finished product.

Getting to the point where they had a good mold could take Global Glass six months. To reduce that, they needed a way to eliminate the errors involved in going from the splash pattern off the vehicle to the wooden model, mold, and part. By moving the process to the computer, the company can now design an accessory on-screen as a digital model, then transfer the data to a CAM package that produces toolpaths for a CNC machine. This machine can produce a scale model of the accessory or even the actual pattern, holding much tighter tolerances than possible by hand. If the design is in question, it is used to cut a full-scale part out of foam. This prototype part is then mounted on the vehicle for final design approval.

To move from a manual to a digital process, it was necessary to get the shape of vehicles into the computer so accessories could be designed around them. One method for doing this, called a coordinate measuring machine (CMM), was ruled out because the device was too large to take on trips to Detroit, too expensive, and not able to handle the large size of most vehicles.

In contrast, the Bronze 8-foot FaroArm met Global Glass' requirements for portability and a large working envelope. It has a measurement envelope of 8 feet and can be used to digitize vehicles of any size. The user simply indicates three points on the vehicle as references points to tell the FaroArm where it is in 3D space. He then moves the arm to a new location and realigns it to the reference points on the vehicle.

The new, digital accessory development process at Global Glass can be illustrated by a recent project, a running board for a Ford truck. Only one side of the truck was digitized, which was an improvement over the earlier practice that required making a splash molds for each side of the vehicle. Since the truck was basically symmetrical, the CAM software's "mirror" function was used to create the second side instantly.

The captured points were transferred to the SurfCAM software from Surfware Inc. and turned into a surface model of the vehicle. The running board was then designed alongside the surface model of the truck. With SurfCAM, the design data was converted into CNC toolpaths that were used to cut a one-fifth scale model of the truck and running board for management approval. According to Filley, development time needed to get to this stage was reduced by 60 percent compared to the old, manual process.

Although the time required for digitizing versus making a splash mold are about the same (two days), the greater accuracy afforded by the digital approach will mean much less rework on mold tools. That will mean a faster development cycle, which will significantly increase the number of accessories Global Glass can produce each year.

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