OEMs that source thermoformed parts expect to receive high quality within tolerance of the part's specified dimensions. Thermoforming presents special challenges because of the expansion and contraction the plastic undergoes as it is heated and cooled, and also because many panels, housings, and enclosures are designed with soft features, and few sharp angles or flat surfaces. Factors such as heat, humidity, and variances in the raw stock make the task of consistently meeting specifications throughout a long production run of thermoformed panels or components an ongoing challenge.

At Kintz Plastics Inc, meeting spec is more than a challenge; it is an opportunity to create added value for its OEM partners. As an ISO 9001:2000 registered manufacturer, Kintz takes its commitment to quality seriously, using a multipronged approach to the continuing challenge of insuring that every part it produces meets spec. (Shown here, a trained operator uses the Faro Arm, described below, to touch a part at several critical points, quickly determining how close that part is to spec.) Here are some guidelines to maintaining quality.

• Finished Part Inspection: Although inspecting finished parts is neither smart nor efficient, many thermoformers and other fabricators still use this outdated practice. When a defect is found in a finished part at the end of the production process, the damage has already been done! The part is either shipped to the customer anyway, or tossed away, and neither option benefits either the customer or the reputation of the thermoformer.


• Continuous Part Inspection: Inspect parts for adherence to the customer's specs and cosmetic standards at multiple phases through thermoforming and through all post-thermoforming processes, such as trimming, painting, screen printing, fabrication, and assembly. The earlier a problem is spotted, the quicker and easier it is to fix. Also, spotting variances from spec within the production process reduces delays in shipping finished parts, improving on-time delivery performance.


• Twin Sheet Is a Special Challenge: In a twin-sheet thermoformed part, warping and distortion of the two-sided panel can occur as the two sides of the twin-sheet structure are joined and each side cools and contracts. A combination of smart tooling design, excellent engineering, and continuous inspection is used by Kintz to produce twin-sheet panels that consistently meet specifications.

In addition to an experienced staff and its Quality Assurance practices, Kintz uses two pieces of highly sophisticated equipment to verify part dimensions.

• Faro Arm: A portable device that can be deployed at any location in the manufacturing complex, the Faro Arm touches thermoformed parts at various points to quickly and accurately determine its physical dimensions to within ± 0.008 in. over a 6 ft distance.


• Coordinate Measuring Machine (CMM): Parts are placed on the bed of the CMM, which measures multiple dimensions of the part and produces hard copy documentation. The CMM can detail a part to repeatability within 1 micron and accuracy within 3.5 microns. A slab of solid granite is used for the bed because only granite produces a hard, perfectly flat base that will not warp and does not contract or expand with changes in heat or humidity. (Pictured, a part is placed on the granite bed of the CMM, which examines it with a Renishaw ruby-tipped probe by taking points and recording the part's dimensions as it continues to check the part.)


• Reverse Engineering Capabilities: The Faro Arm and CMM enable Kintz to accurately and efficiently reverse engineer any part, component, or panel to determine its exact dimensions. This is especially helpful when OEMs upgrade from sheet metal, fiberglass, or other materials to thermoformed plastic.