EuroWire May 2016

Technical article

• Since the camera is looking at the surface, water droplets/grease/dust particles will be detected as defects by the system. Generally, this can be fixed with a well-placed air wipe. Alternatively, the system sensitivity can be decreased, which may result in some of the smaller defects passing through the filter 3.4 Test Results The wrap defect inspection system is a modified version of the surface inspection system that is used in numerous production lines around the world to detect surface defects on wire and cable. Some samples images of defects and wrap measurements can be seen in Figures 1 to 6 . 4 Conclusions With a wrap defect inspection system, imperfections in the wrapped cable surface will be detected and the cable will be wrapped correctly, to show overlap distance and angle. The system provides several benefits: • Suitable for any type of wrapped wire/ cable and convoluted armouring • Ensure the customer will not get defective products, improving customer relationship and confidence • Reduce rework and eliminate cable waste resulting in material cost and labour cost • Assist in internal improvement to production process to reduce defects • Ensure cable overlap n Paper courtesy of the 64 th IWCS Technical Symposium, Atlanta, Georgia, USA, November 2015

An advanced algorithm is used to process the images for cable wrap inspection. A typical algorithm is capable of detecting surface and wrapping defects such as scratches, holes, uneven wrapping, incorrect wrapping angle, tape peeling and tape tears. The algorithm requires analysis of the pixels of the image and grouping them for further interpretation. If a defect is detected, an alarm will notify the operator and an error report is saved to the on-going data log. The defect will also show up on the display for operators to clarify. 3.2 Improving Quality Assurance Suitable for any type of products : Since the surface defect detection system with accurate diameter measurement uses machine vision, it can be used to inspect the surface for many types of wrapped products or convoluted profiles. It is the most thorough method of detecting wrapping and surface flaws available and the advanced algorithm can help classify the type of defects accordingly. Reduced defects : The system can provide the operator with a view of current surface images as well as both the most recent defects with defect dimensions and the current cable diameter. This continuous stream of real-time information – especially failure data – allows the operator to isolate the causes of wrap imperfections. Identifying when and how a defect occurs will allow the technical staff to learn the root cause of defects and reduce their occurrence. Quality assurance : The system will continuously monitor the wrapping of the cable for both overlap distance and wrapping angle, and the measurements can be recorded for later analysis. Images of wrapping and surface defects are captured and saved to a hard disk for use in quality reports. The wrap inspector system’s display makes it easy for engineering and production supervisors to examine potential defects without having to see the defect on the actual cable itself. Defect images are saved together with location information allowing operators to quickly find and eliminate defects before they reach customers or fail in the field. 3.3 Limitations There are a few limitations to the wrap defect inspection system: • Sometimes significantly different wrapping types will require adjustment to the optical setup or software changes

▲ ▲ Figure 1 : Uneven wrapping

▲ ▲ Figure 2 : Surface blemishes

▲ ▲ Figure 3 : Tape peeling

▲ ▲ Figure 4 : Tape wrinkle

▲ ▲ Figure 5 : Armour puckering

▲ ▲ Figure 6 : Discolouration

The frame rate is synchronised with an encoder and speed algorithm. The lighting varies depending on the application. The factors in consideration are the reflectivity of the material, surface profile, colour, line speed and camera type. To ensure consistency in the images, the setup features an enclosure to prevent ambient lighting, outside particles, etc from affecting the results. Vibration of the cable is minimised by cable guides, preventing images from being out of focus.

Craig Girdwood and Andrew McCloskey Taymer International Inc Markham, Ontario Canada Tel : +1 905 479 2614 Email : craig.girdwood@taymer.com Website : www.taymer.com

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May 2016