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Quality control

Quality control. 100% inspection and defect detection. Why need for 100% inspection. Customer demand Increase productivity Reduce Waste Leverage for Procuring new contracts Greater confidence of defect free supply Management information aiding quality and production processes.

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Quality control

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  1. Quality control 100% inspection and defect detection

  2. Why need for 100% inspection • Customer demand • Increase productivity • Reduce Waste • Leverage for Procuring new contracts • Greater confidence of defect free supply • Management information aiding quality and production processes

  3. Web inspection Systems • Eyeballing • Revolving mirrors • Strobes • Video Camera web viewers • Digital Camera web viewers • Active Camera systems • TRUE 100% Inspection

  4. What is TRUE 100% inspection? “Inspecting 100% of the web 100% of the time” • Beware Term often misused! • Continuous not sampling inspection • No speed limitations

  5. System expectations/performance • What is max. web width to inspect? • What is minimum size of defect to be detected? • What is maximum inspection speed required? • What type of substrates? • Special inks/foil/embossing?

  6. Technical overview

  7. Image Acquisition Large, unwieldy camera cases. Difficult to fit on machine! Limited resolution, reduces chances of spotting small defects. Complex sensor requirements

  8. How it works Area scan • Relies on overlapping images to cover whole web • Frame-rate of camera determines inspection speed • Fork sensor to trigger capture, encoder for position • Strobe or high intensity illumination to cover area Linescan • Image “streamed” continuously line by line • Line rate of camera determines inspection speed • Encoder provides all necessary positional information • Single line of illumination

  9. What can we detect?-Pixels, linerates etc. System performance depends upon the camera pixel resolution and speed. Pixels are the elements that make up an image. The speed is quoted as Linerate (Khz) for Linescan cameras and Framerate (Hz) for areascan cameras. Example “We want to detect a missing/broken character in 8pt text, over a web width of 350mm and running speeds of 120m/min” Physical size of text = 3mm x 2 mm

  10. Web width=350mm Requires 3500 pixels across web for above. Inspect at 120m/min = 2000mm/sec, to achieve 10 pixels/mm Linerate = 20,000/sec (20KHz) 4096 Pixel (4K), 20Khz linerate camera required. Areascan equivalent, assume 4Kx4K pixel (16Meg), frame every 400mm required. At 120m/min = 5 frames/sec Web width=350mm Requires 1750 pixels across web for above. Inspect at 120m/min = 2000mm/sec, to achieve 5 pixels/mm Linerate = 10,000/sec (10KHz) 2048 Pixel (2K), 10Khz linerate camera required. Areascan equivalent, assume 2Kx2K pixel (4Meg), frame every 200mm required. At 120m/min = 10 frames/sec

  11. Colour Versus Monochrome Colour systems are perceived to be more desirable but, there are compromises to be made

  12. Why is it in Black and white?? • This is not a web viewing device • Currently colour linescan cameras limited by speed and resolution.(42m/min max for given example) • Colour cameras are expensive • Extra data requires faster/dedicated processing-more expense! • Monochrome will detect most colour related defects • Very sensitive setup and installation

  13. Production and management data • Roll mapping of defects • Optional customisation of report data/structure • Defect quantities, position, size • Web meterage good/bad • Full networking capabilities • Transfer of roll map info for rewind (when used on press) • Machine speed, time start/stop, etc

  14. Demonstration

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