Control of starter ring gears

KLS Ljubno is important producer of rings for engine flywheels (starter ring gears, mass rings, signal rings). Company is located in Slovenia and supplies to major automotive suppliers globally.

At KLS Ljubno they believe quality is a sales argument. They strive towards products deliveries of high quality, without claims and on time. Their production processes are planned and developed in accordance with high degree of reliability. The share of delivered poor-quality products is very low. These are mainly detected during manufacturing and are not delivered to customers. Consequently their quality ranking with customers is less than 5 ppm and recently.

Even if the share of poor-quality products is very low, the client insists that all such products have to be detected during manufacturing process, so reliable, 100% inline quality control was required.

Our challenge

Designing inline inspection and measurement cell using machine vision technology for starter rings and other rings for engine flywheels. Cpk required was > 2, ensuring tolerances in the range of 0,01 mm (for some measurements even 0,05mm). To reach this in rough industrial environment the holistic system approach to compensate effects of physical environment was developed and included in the solution.

Features

• Standalone, inline machine vision solution for optical inspection of starter rings, performing:
  • dimensional measurement (diameter, radial thickness, circularity, excentricity, radial runout),
  • detection of edge burrs and swarfs,
  • measurements of chamfer edge profile,
  • measurement of gear tooth chamfer,
  • inspection of tooth shape,
  • surface inspection;
  • detection of cracks on inner ring surface,
  • detection of imprints and other irregularities.
• Number of optical measuring sites: 3.
• Cycle time: inline (8s)
• Tolerances:
  • tolerances of inner ring diameter: ± 0,05 mm (with diameters ranging from 160 mm – 400 mm),
  • tolerances of outer ring diameter (toothed): ± 0,2 mm,
  • Ring (axial) thickness: ± 0,025 mm,
  • tolerances for circularity, excentricity, radial run out: 0,25 mm.
• Repeatability < 6%.

Benefits

With this approach, client did succeed in reducing defect rate below 5 ppm. For three consecutive years they have reached "6 sigma" at ppm and less than two claims per million delivered products. Till today, client has implemented 28 such machines on their production lines.