Advanced vision systems for Quality Control in glass

Advanced vision systems for Quality Control in glass manufacturing Robert Mortensen, Sales Manager, JLI vision a/s AFGM Conference in Chiang Mai 2007

Agenda 1. General tech. considerations 2. Glass tubing 3. Tableware 4. Container Glass 5. Final remarks AFGM Conference in Chiang Mai 2007

Technical considerations Components that make up a vision system: § Engineering and software § Cameras § Lighting § Mechanical design § Integration and support AFGM Conference in Chiang Mai 2007

Technical considerations (cont. ) § Cameras: § § Chip type (e. g. Matrix, line-scan, CCD, CMOS) Resolution Pixel-sensitivity of chip Exposure time § Examples of exposure time ( linescan): Std camera……………… Advanced cameras…… JLI second gen. ………… § Lighting: § § 1/19000 sec 1/30000 sec 1/58000 sec Structured lighting Arranging the lighting itself Light source Mechanical Design: § § Choice of physical components Physical constraints on production floor Power supply Line speed and stability AFGM Conference in Chiang Mai 2007

Technical considerations (cont. ) § Integration: § Running in the system § Calibration and adjustment of tolerances § Surveillance: § § § Software based monitoring system Measures e. g. temp. , voltage, fan RPM, HD conditions Training: § § User training both on-site and long distance Optimal use and first line support AFGM Conference in Chiang Mai 2007

Glass tubing § § § Optimal design is 100% circular with even wall thickness and defect free Diameter versus line-speed: diameter x speed = constant Exposure time § Speed up to 12 m/ sec § defects down to. 02 mm § § Motion blur – rule: max movement 1 pixel pr. sec. Light source Centering Depth of field: critical for front- and back-end inspection AFGM Conference in Chiang Mai 2007

Glass tubing (cont) Examples of windows for tube-end inspection: Figure 1 – Window Dimensions § Figure 2 – Window Region of Interest Defects – stones, knots and airlines § Stones are inclusins, typically refractory material § Knots are lumps from badly dissolved glass § Airlines is air trapped in pockets at the mandrel AFGM Conference in Chiang Mai 2007

Glass tubing (cont) Figure 3: Examples of thin airlines from the JLI Offline system § Mode of detection § Stones and knots are found by detecting black inclusions refractory material § Knots are lumps from badly dissolved glass § Airlines, down to 3 micro meters, are detected using high resolution CCD cameras and a very power full light source. § Clusters of faults can be detected in a predefined area § 100% defect-free tubes § Main challenge is very thin airlines § JLI developed Off-line system to cover this market AFGM Conference in Chiang Mai 2007

Tableware § Market caracterised by large number of different models – especially stemware has a complicated range of shapes. § § Different forms and sizes – issue with diffraction § The Dynamic Light Box – JLI Vision inspection demands different and often complicated masks § Uses background lightning with pattern composed of light/shadow § Enhances the type of defect that needed to be highlighted § Defects like mould rings, waves and cracks can only be detected in this way § Specific patterns are syncronised with production to achieve max. Intensity § Geometry measurement – bright uniform background with mask following the profile of the glass. Accuracy is 0. 1 mm AFGM Conference in Chiang Mai 2007

Tableware (continued) § Dynamic Light Box (cont. ) § Easy to install, reliable, and very adaptable solution to detect and measure geometry § Principle shown below Figure 4: The Dynamic Light Box AFGM Conference in Chiang Mai 2007

Container Glass § Both hot- and cold-end inspection § Handling restriction in hot-end § Dimensions measured with an accuracy down to 0. 1 mm § Wall thickness measurement by tight control of measurement loop. Accuracy 0. 01 mm § Change in production parameters shows up on dimensions § Efficient way of monitoring production, e. g. via trend graphs Figure 5: Birdswing detected by backlightning AFGM Conference in Chiang Mai 2007

Final remarks The glass industry has many challenging inspection applications and it is always a challenge to provide practical solution to this market segment. Even highly automated glass-factories need continued surveillance in order to maintain their high quality level. A vision system provide you with the following advantages : § § More accurate and stable quality control Continued 100% inspection Improved production flow Fast feedback from production and automatic data logging In order to keep a high and consistent standard of their products in todays marketplace our customers have acknowledged that investing in advanced vision technology may be the only viable way AFGM Conference in Chiang Mai 2007

Khob Khun Krub Tee Hai Kawm Ruam Mue (Thank you for your attention ) AFGM Conference in Chiang Mai 2007