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  • Repeatability to 1.3 microns
  • Vector velocity to 50 m/min.
  • Thermal compensation

CMMs Give Automotive Wheel Maker Added Control

Dunlop Topy Wheels, located in Coventry, England, needed a way to maintain better control of pressworking operations of center-disc production for its steel automotive wheels. To solve this problem, Dunlop turned to LK Metrology Systems Inc. (LK MSI) and its coordinate measuring machines (CMMs).

 According to Dunlop Topy Quality Manager John Sonnenstein, a major advantage of the CMMs is that they allow added dimensional checks on the center discs. "With the CMMs, we're not limited to inspections at the beginning of every batch run," Sonnenstein notes. "We have time to carry out additional checks, as well as do the same hourly checks of safety-critical parameters that we did before."

 The LK MSI CMMs offer another important advantage. In contrast to the go/no-go measurement results of the feeler and plug gages, they provide absolute dimensional measurements. Coupled with LK MSI's Quality Analyst software, this allows Dunlop Topy to generate statistical process control charts. "We now have the ability to trend our results and predict if and when parameters will drift out of tolerance," explains Sonnenstein. "That gives us better overall control of our pressworking operations."

 Currently, Dunlop Topy is using LK MSI programming software to write CMM programs for all 40 of its wheel disc variations in production. The LK MSI software employs graphical representations or icons in place of text, making programming easier and eliminating the need for specialized programming skills.

 Two of the LK MSI CMMs used by Dunlop Topy are state-of-the-art G90 models. One of these CMMs is installed in an inspection room next to the main press shop where three Clearing multi-stage mechanical power presses produce the majority of the company's center discs. For parts inspection, the shift inspector retrieves the first-off part from every production batch and one part an hour from each of the three presses thereafter. Following the setup of each part on the CMM and startup of the measuring cycle, the inspector is immediately free to go to a different press to collect another sample. By the time he or she returns to the CMM, the five- to 10-minute inspection of the preceding part has been completed and the next part can be set up on the CMM table.

 A second LK MSI CMM--an older G80 model--works alongside the G90C to support 24-hour manufacturing operations in the main press shop. Though 10 years old, the G80 machine has been upgraded by LK MSI with the same user-friendly control system software as the G90C. In addition, a second G90C CMM is stationed in Dunlop Topy's heavy pressworking shop where it's used to perform identical checks on four large disc variations.

 LK MSI's G90C range of bridge-type, vertical-spindle CMMs offer cost-effective, high-precision capabilities for use in a production-floor environment. These advanced CMMs incorporate state-of-the-art design features that contribute to enhanced performance and reliability, including an extremely lightweight spindle with integral pneumatic counterbalance and a cast ceramic Y-beam using a sophisticated steel-belt drive system.

 Throughout their construction, the G90C CMMs make maximum use of low-mass, high-stiffness materials, yielding price affordability along with performance characteristics typical of much more costly units. These machines, for example, combine vector velocities of 50 m/min (33 in./sec) with repeatability to within 1.3 microns (0.00005 in.). Other features include air bearings and ceramic guideways for precision and stability.

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