WCA January 2012

Technology news

The non-contact laser makers to accurately mark

sequential applications. Manufacturers are realising productivity gains with this technology by significantly reducing measurement errors and improving process control. This article gives an inside look. real measurement challenges during production application, mechanical contact-type encoders face a number of challenges in wire and cable production processes. First, mechanical encoders must contact the wire or cable in order to measure the length and speed of product during production. These measurements are indirect measurements, relying on the physical contact between the mechanical encoder wheel and the product’s surface. Length is calculated from the amount of rotation of the contact wheel. However, contact encoders by their very nature have several fundamental flaws that make them prone to measurement errors. Contact encoders are subject to slippage and calibration changes caused by variations in the diameter of the contact wheel due to dirt build-up or wear. Since the contact encoder is a mechanical device, it also experiences mechanical component failure from time to time – requiring repair and re-calibration. printing Contact encoders face Depending on the

Manufacturers today face a number of production challenges based around productivity, quality and cost reduction. At the centre of this challenge, is the ability for manufacturers to accurately measure the length and speed of wire and cable in order to better control sequential printing or marking operations.

▲ ▲ LaserSpeed non-contact length and speed encoder

Traditionally, manufacturing plants have used mechanical type encoders, such as contact rotary encoders or tachometers, to measure the length and speed of wire and cable during production in order to control the sequential printing on products. The outer coatings of cables are typically marked with details including product length in the form of metre or footage marks, manufacturer’s name, product and operating information. Wires may indicate special numbering or coding for identification purposes. Customers rely on the accurate spacing of this information to ensure the manufacturer delivers the exact amount of product as specified. Customers also rely on the accuracy of this information to perform critical tasks, such as laying the correct amount or length of wire or cable without needing to re-measure it. But contact encoders are prone to mechanical and calibration problems which result in costly measurement errors. As such, wire and cable manufacturers are looking to non-contact measurement methods such as the LaserSpeed encoder from Beta LaserMike to accurately measure the length and speed of product during

The measurement error of mechanical systems will also change with production conditions, requiring the line operator to continuously check the spacing of the print and then recalibrate the contact encoder to keep the marks within specification. Product length and speed inaccuracies may be as much as 2%, or even greater, depending on the

▲ ▲ Contact method is prone to measurement errors

application.

Products such as CAT, CV, power, telephone, and other types of cables are very expensive to produce, and manufacturers produce millions of feet or metres of wire and cable product monthly. A two per cent measurement inaccuracy on this large amount of

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Wire & Cable ASIA – January/February 2012