Heraeus Carbon Infra-Red Oven Improves Powder Coating Flexibility and Quality at SFS Intec
A three-zone, carbon infra-red medium wave oven from Heraeus Noblelight is helping SFS Intec to improve the flexibility and quality of its powder coating operations.
A three-zone, carbon infra-red medium wave oven from Heraeus Noblelight is helping SFS Intec to improve the flexibility and quality of its powder coating operations. It has allowed the Leeds-based company to change powder curing from a continuous to a batch operation, so that it can now respond more quickly to customer requirements for corrosion-resistant screws and fasteners. In addition, the new pyrometer-controlled oven delivers a more consistent coating quality, is much more energy-efficient than the previous powder coating curing installation and requires considerably less space.
SFS Intec is part of a Swiss-owned international group, which is involved in a range of activities, from the manufacture of solar fastenings to hinge systems. The Leeds site, which has produced fasteners for over 100 years, today develops and manufactures stamped parts and supplies multifunctional thread rolling screws and sub-assemblies for use in the construction industry. It has the resource to offer architects, designers consulting engineers and contractors a proven commitment to effective technical solutions and efficient and responsive service.
Screw fasteners for the construction industry represent an important product line at SFS Intec. The heads of these screws must be coated to resist corrosion in use and the powder coating was formerly cured using an electrically-heated oven, through which the screws were passed continuously on a conveyor belt. However, this was very energy-intensive, as the oven had first to be heated up to temperature and then held at that curing temperature for some time. More importantly, this continuous operation lacked flexibility as it could not respond quickly to changes in colour or to customer demands for fast delivery of limited numbers of screws, as often happens in the construction sector, especially in the closing stages of a construction contract.
To solve both of these problems, SFS Intec contacted Heraeus, who designed, manufactured and installed a carbon infra-red medium wave curing system. This is a three-zone oven with seven 4kW medium wave infra-red emitters in each zone. Medium wave radiation is readily absorbed by powder coatings and allows rapid and efficient curing.
In operation, trays of coated screws are now manually loaded into a selected zone and the emitters are switched on. The curing temperature of 180°C, monitored by an integral pyrometer, is achieved in a matter of seconds, rather than the 30 minutes or so required by the previous system, and a digital timer is then set to determine the time that the screws need to be held at the curing temperature. All three zones are individually loaded and controlled so that three different batches of screws can be cured simultaneously, if required.
“We very much pride ourselves on the quality of our customer service,” says Bob Mrozik, the technical services manager at SFS, “and the new batch processing with the infra-red oven now means we have improved this service by being able to respond more quickly to last minute customer requests – and often provide a next-day service. In addition, we have found that the pyrometer control of the product surface temperature, as opposed to merely controlling the oven air temperature, as was previously the case, has given a much more consistent quality cure.”
Heraeus specialises in the production and application of high quality energy sources covering the electro-magnetic spectrum from ultraviolet to infra-red. It has over 40 years’ experience in infra-red technology and offers the expertise, products and systems to provide efficient and effective solutions to drying, heating and curing problems throughout industry.