EuroWire March 2019

Technical Article

High-Speed Lump and Neck-down Detection with Accurate Diameter

Measurement By Craig Girdwood and Max Fondyga , Taymer International Inc

Abstract Taymer’s lump and neck-down (ZT) detection system with accurate diameter measurement is a tool that allows manufacturers to inspect and record product diameters for high-speed production environments. It is suitable for high-speed applications such as fibre optic cable production on draw towers and wire drawing lines. Due to the extremely high line speeds of these production lines, previous inspection technologies have had difficulty providing sufficient diameter measurement and lump and neck-down detection. The ZT system provides diameter measurement and diameter defect detection along 100 per cent of the product length at speeds up to 3,000m/ min. The system also saves images of all defects, allowing operators and engineers to validate defects. This technology improves the quality of the product and allows manufacturers to prevent defective products from reaching customers. 1 Introduction Increasing Internet traffic and Internet speed are causing a sharp rise in the demand for fibre optic cable. In order to keep up with this demand, manufacturers must produce ever-increasing amounts of fibre. Diameter is a critical factor for fibre, as even small variations can cause structural failure and/or signal loss. There is therefore a need to measure diameter continuously, and detect diameter defects. However, the high production speeds of draw towers – up to several thousand metres a minute – pose a challenge for most current inspection technologies, necessitating innovation.

2 Current diameter measurement techniques and limitations 2.1 Laser inspection gauge A laser gauge is the most common method of inspecting round products for diameter defects. laser/shadow technology to measure diameter very accurately and to classify lumps and/or neck-downs. However, after a defect is reported there is no way of verifying the defect short of a rewind line. This can lead to false positives from dust or water droplets (for example), which result in unnecessary scrapping or rework of product. Additionally, the lower scan rate of most laser gauges allows many small and moderately sized defects to go undetected when product is moving at a high line speed. Laser gauges can also have difficulty measuring the diameter of transparent materials. 2.2 Previous vision systems Previous generations of vision-based diameter systems compensated for several shortfalls of laser gauges. They offered the ability to save images of defects – allowing a reduction in uncorrected false defects and preventing scrapping and rework. However they faced similar difficulties measuring diameter accurately at high speeds, due to processing and resolution limitations. These machines use

Wire drawing is used to produce wire for a wide range of applications including the manufacturing of re-bar, springs, paper clips and, perhaps most importantly, electrical wire. This is also a growing industry, experiencing a similar increase in demand, and requiring comparable diameter inspection to verify that wire produced meets the desired gauge. The speeds of wire drawing applications can meet or even exceed those of draw towers – also up to several thousand metres a minute. specifically designed to measure and record images of diameter defects for these high-speed applications. It can detect diameter defects as small as 1 micron at speeds up to 3,000m/min, and scans 100 per cent of product length at these speeds. The system also saves actual images of all defects that are detected, allowing the engineer or operator to review all defects and improve product quality by understanding and targeting causes of defects. In addition to defect images, the diameter measurements for the entire product run are saved to a database along with a record of any diameter defect information. The defect information includes defect size and location on the product. This allows defects to be isolated quickly by operators after production is completed. Thus the ZT system offers both immediate and long-term benefits, by preventing release of defective product to customers and by improving product quality over time. It is also easily integrated into existing production lines, or incorporated into new ones. The lifetime of the lights can be over 50,000 hours of usage and they are the only consumable parts. Taymer’s ZT technology

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March 2019