PATCO modular tooling from Prototype Systems replaces conventional dedicated fixtures.

PATCO modular tooling from Prototype Systems (Sterling Heights, MI) replaces conventional dedicated fixtures with reusable components that position and hold prototype parts to coordinated location points in a functionally repeatable mode. The DaimlerChrysler Tech Center in Auburn Hills, MI, has been using this method for more than 7 years. "We have saved 40 percent on every prototype design and build program," says Richard Moore, supervisor of body in white assembly tooling and gauges for prototype vehicle operations at the DaimlerChrysler Tech Center.

From an engineering perspective, tooling repeatability, tolerances, flexibility and changeover are strong benefits. "Our old method was not stable. We shot the tooling to the floor and poured plastic around the legs to lock everything in place, where it stayed for 22 weeks during the build portion and another 10 months while in use," says Moore. In contrast, modular tooling is portable, easily disassembled, stored and reassembled. The setup always matches the original fixturing. Assembly tolerances using the tooling meet all customer criteria. Setup is straightforward, requiring a day for training. Changeover is fast and flexible. It takes only a few hours instead of weeks.

DaimlerChrysler is one of the most active users of the modular tooling methods. Many first and second tier suppliers are also pursuing these methods to realize these tooling advantages, as well as achieve compatibility with their customers' methods. Additionally, fabricators from other industries, such as aerospace, farm and recreational equipment, boating and test labs, are evaluating the benefits of modular tooling.

The modular tooling uses a selection of manual clamps (210-U, 503, 603-R, 21006), upgraded special clamps and automated clamps (82P locating pin clamps and 82L automated power clamps) from De-Sta-Co Industries (Madison Heights, MI).

The base is cast aluminum with a 1.25 inch-thick top and integrated ribbing. This provides structural strength and maintains flatness. A prebored grid-available in 50-millimeter holes or 2-inch holes-is laid out across the base top. Along with the system's componentry, this key innovation assures flexibility, accuracy and repeatability, making all geometric dimensioning and tolerancing location points accessible.

To reduce the need and cost for weldments, standard cast aluminum components provide orientation and support for workholding templates. The components can be either upright or angular, in 10-degree increments. They are fastened to the base using two 16-millimeter shoulder bolts. Components come with a matrix of attachment holes that allows a 12.5-millimeter step over to attain any location on the base. This feature minimizes the complexity of the fixture, resulting in additional savings during the design and build process.

The system's overriding benefit is time savings. "A before-and-after snapshot of our build operations," states Moore, "shows 22 weeks conventional and only 8 to 10 weeks using modular tooling." With over 300 bases plus components in inventory, PATCO is the standard for all build prototypes throughout the corporation.

In terms of benefits, a close second is cost savings. Because the tooling is reusable, it's a one-time investment. It does not cost any more than traditional prototype build fixtures, which makes the system affordable. Even low-volume parts can be run cost-effectively. "Wasted dollars for us were tons of conventionally built fixtures that were stored in warehouses, fields and parking lots, never looked at again and eventually thrown out," observes Moore. "That was a huge cost of doing business until we committed to the modular method."

The most dramatic benefit is optimized operational capability resulting from the huge amount of time saved. "To be honest, conventional means can yield, at the maximum, three prototype vehicles in a 12-month period. We're doing seven full vehicles from the ground up. We're getting the design job done and are faster to market because of this tooling," states Moore.

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