EuroWire July 2021

Technology News

Wire and cable surface defect detection Measuring devices based on non-contact laser measurement for geometric moni- toring of wire and cable have been avail- able for many years. The measurement of the outer diameter, the calculation of the ovality, and the detection of shape defects such as lumps and necks are part of the classical measurements. As diameters become smaller and speeds increase, many devices are limited in performance by their technology.

second. Scratches, die marks or defects such as impurities, bubbles or particles on the insulation are displayed on PC software for analysis and characterisation. The system works like a “ring camera” around the circumference of the cylindrical object. The image is analysed in real time by algorithms in order to provide defect information such as length, width, surface and location. It allows the operator to identify and isolate the causes, and generates alarms according to the customer’s parameters. SQM was developed to focus on very fine dimensions: wire diameter from 2,000μm down to 20μm. The technology is suited to detecting and characterising defects on metal wires with a reflective surface (such as steel, copper, gold and silver); drawn products and certain extruded products; and enamelled wires, plated wires and some insulated wires. Cersa-MCI www.cersa-mci.com

The inspection of the surface appearance and detection of surface defects on cylindricalproductsduringproductionpre- sent an even greater technical challenge. Measuring techniques and equipment do exist, but they are often either dedicated to offline measurement of samples, or for in-line measurement at diameters of several millimetres or even centimetres, and at low speeds. There has previously been a lack of equipment capable of detecting defects that may appear on the surface of wire, cable or tube during the drawing

▲ Cersa’s SQM surface defect detection instrument

or extrusion process, particularly for products with very small diameters and at high speeds. Demand frommanufacturers for zero-defect production and minimal scrap has led Cersa to fill this gap by developing a new measuring device. The SQM is a patented instrument developed to meet the need for continuous monitoring of the surface quality of fine wire, cable or tube. It offers high-resolution and real-time surface defect detection with 200,000 images per

Complete rod preparation portfolio for advanced wire cleaning

Lämneå Bruk’s rod preparation portfolio includes five machines designed for continuous, in-line mechanical descaling of wire rod. Mechanical descaling is an environmen- tally friendly method of rod cleaning, so the machines have a minimal environ- mental footprint and facilitate efficient, space-saving in-line rod cleaning for wire prepared for the next production steps. The descaling system consists of a four- or six-sheave scale breaker, a four-pair brushing unit, a new sandpaper descaling machine, a water jet and the Candocoat cleaning and coating machine. The reversed bending descaler, suitable for low-high carbon rod preparation, is available in two sizes for wire diameters from 5.5 to 12mm. The design is equipped with bending rollers with solid carbide steel placed at the centre, eliminating the need to change the entire roll. The mechanical brushing system is fitted with an intelligent brush pressure detection system for improved cleaning results and extended brush lifetime.

The high-pressure water jet is a compact descaling system that uses only water, without any chemicals in the cleaning process. As no wearing occurs while cleaning the rod, the result is consistent wire quality. The cleaning and coating machine removes scales from carbon steel and stainless steel wires in a three-step process: loose particles are removed from the surface with hot water, the lubricant carrier applies a wet coating, and the rod is dried. The most recent launch in Lämneå Bruk’s rod preparation portfolio is the second generation of the descaling sandpaper machine. The machine has one or two 300mm-wide sanding belts, with rod wire guide rollers and integrated line speed feedback to avoid the risk of over-sanding if the line stops. The device is also equipped with features such as belt tracking control, synchronisation to line speed, and individual drives for each flyer and sand belt to allow full rpm flexibility. Lämnea Bruk’s sandpaper descaling machine is suitable for low- to high-carbon and stainless steel wire.

The rod preparation equipment is manufactured entirely in the company’s ownworkshop in Sweden, and is designed, manufactured and tested according to European safety standards. Lämneå Bruk AB www.lamnea.se

▲ The new sandpaper descaling machine

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July 2021