TPT January 2019

T E CHNOLOG Y

Infrared for curing speciality coatings

There is also no immediate control of the surface temperature of the part. Consequently, Whitford decided to investigate the use of infrared curing technologies and evaluated this technology at Hereaus Noblelight. The tests were carried out on two specific Xylan products: Xylan 1070 and Xylan 1424. The results suggest that infrared curing can provide similar processing benefits for other coatings in the Xylan 1000 and 1400 series. The experiments carried out at Heraeus were designed to address a range of variables, including lamp type, cure profile, and physical properties of the cured coating on flat panels and complex geometry components. Various wavelengths of infrared were used, including carbon medium wave, fast response medium wave, medium wave and short wave. All wavelengths proved to be a suitable alternative for curing Xylan coatings. A particular benefit was shown in the curing of large metal mass components, as infrared heats only the surface of the substrate, with a reasonable degree of penetration, so there is no need to heat the entire metal mass to the part metal temperature (PMT), as is the case with convection ovens. This may provide significant savings in processing and oven dwell times. Gareth Berry, in charge of the investi- gation for Whitford, stated, “The inves- tigations carried out at Hereaus give Xylan applicators a viable alternative to convection oven curing, which could have cost- and time-saving benefits.” Heraeus specialises in the production and application of high quality energy sources covering the electro-magnetic spectrum from ultraviolet to infrared. It has over 40 years’ experience in infrared technology and offers expertise, products and systems to provide solutions to drying, heating and curing problems throughout industry.

A SERIES of comprehensive tests carried out at the Heraeus Noblelight applications centre in Neston, Wirral, UK, in conjunction with Whitford Ltd, have demonstrated that Whitford’s Xylan ® coatings are capable of being cured more quickly with infrared than by using conventional, large footprint, hot air convection ovens. Specifically, infrared offers the benefits of reduced process times and energy costs. Investigations are currently ongoing for using infrared heating in the coating repair market in the offshore and chemical processing sectors. Whitford, based in Cheshire, UK, manufactures a large line of high performance fluoropolymer coatings and sol-gel ‘ceramic’ non-stick coatings. Applications include the coating of cookware and bakeware, small electrical devices and manufactured parts used in the aerospace, automotive, chemical processing and textiles sectors. The company’s Xylan range of coatings offer corrosion- and chemical-resistance, and sub-sea visibility, making them suitable for use in the offshore industry. Xylan coatings are dry-film lubricants, combined in a matrix with the latest high-temperature organic polymers. The result is a plastic alloy, known as “an extreme performance coating” that offers low friction, and chemical-, corrosion- and wear-resistance, as well as being resistant against sunlight and salt water. It can perform in a wide range of temperatures (-250°C to 285°C), and is very pliable and machinable, allowing multiple coats to be applied and then milled to specification. The coating can be applied to a wide range of parts, from flat panels to complex geometry components, such as nuts and bolts, to facilitate removal after prolonged use in extreme conditions. Whitford supplies Xylan to coaters/ap- plicators, who then apply the coating to multiple components. The Xylan range provides adhesion to most metals. How- ever, most of the coatings in the range require curing at elevated temperatures. Conventionally, this has been carried out using convection ovens, which can be energy- and time-consuming, as the whole mass of the part to be cured must be heated to the cure temperature.

Heraeus Noblelight Ltd – UK Fax: +44 151 353 2719 Website: www.heraeus.com Whitford Ltd – UK Email: salesws@whitfordww.com Website: www.whitfordww.com

49

www.read-tpt.com

JANUARY 2019