EuroWire September 2022

Technology News

Infrared curing for silicone

The fire resistance of cables in public buildings, such as airports or hospitals, follows strict guidelines. In the event of a fire, to evacuate all people safely the basic functions of a building must stay intact for as long as possible. Silicone’s high temperature resistance, low smoke emission, zero halogen content and non-toxic substances make it a suitable insulation and jacketing material for cables used in fireproof applications such as elevators or alarm systems. The quality standards that need to be fulfilled for integrity (DIN 4102-12) and insulation (IEC60331, EN50200 and BS6387) are met by each safety cable produced on a Rosendahl silicone line. To make silicone cables resistant against high temperature, they need to be cross-linked. Different processes are available to do this, but hot air or infrared curing are mostly used in new production lines. Rosendahl machines rely on infrared curing, which the company says is more efficient and flexible than other cross-linking methods, with minimum scrap rates and easily controllable parameters. It is up to 15 per cent faster than hot air systems utilising the same floor space, and power consumption during production is around 30 per cent less. An infrared curing section typically consists of three zones. A shock oven “freezes” the silicone surface, enabling the use of support rollers without the silicone sticking. The remaining ovens

Rosendahl’s infrared cross-linking section

are used for gentle cross-linking of the silicone to the desired degree. Each oven is temperature controlled, specified by the line control. Rosendahl’s infrared ovens are optimised for energy efficiency and easy handling. For safety reasons the ovens are designed to open automatically in case of an emergency. To simulate the cross-linking process Rosendahl has developed a mathematical model that provides relatively exact values for the process and production speed. Together with the line control, this ensures product quality with continuous monitoring. Rosendahl now offers different optimised line configurations for safety cables with diameters ranging from 0.25 to 300mm 2 . It also develops optimised extruders with automatic stripe feeding, crossheads and curing ovens.

Rosendahl Nextrom GmbH www.rosendahlnextrom.com

H I GH PREC I S I ON CNC RADIUS DRAW DIE GRINDER

Jiangsu Qunye Electrical Co., Ltd. is a specialized spools manufacturer. We have highlevel workshops and offices, first class equipment lines and complete inspection facilities, advanced management and quality control systems to fulfill all customers’

requirements. We manufacture all kinds of metal and plastic spools and gain a good market share both at home and abroad.

REGRINDING SERVICES AVAILABLE

Basaran Grinder Corp. 100 Laser Ct. Hauppauge, NY 11788 USA +1.631.273.3030 Info@BasaranGrinder.com

37

www.read-eurowire.com

September 2022