By installing a Carbon Infrared (CIR) system to pre-heat acoustic soundproofing sheets prior to molding, Faurecia has significantly reduced production cycle times and virtually eliminated maintenance costs and machine down-time on one of its major molding machines.Faurecia is a world leader in the supply of automotive equipment and its Washington, Tyne and Wear, U.K. plant produces acoustic products for vehicle interiors and luggage compartments. Essentially, many of these products are produced by molding a thick sheet of PE-EVA (polyethylene ethylene vinyl acetate) to the required shape and then applying a layer of polyurethane foam to impart the sound-deadening properties.
An essential part of the molding process is the pre-heating of the PE-EVA sheet. Some of the molding machines at Faurecia apply this preheat before the sheet is dropped into the mould for forming and one such machine has recently up-graded its pre-heat system to incorporate Heraeus medium wave emitters.
However, one of the molding machines at the Washington factory, relies on heating the PE-EVA blank while it is actually in the mould. This heat was previously delivered by medium wave infrared foil heaters, which were proving expensive to maintain. Moreover, the slowness of the heating operation, which also involved pre-heating the blanks with large hot water radiators, was starting to create a production bottleneck.
In an effort to rectify this situation, Faurecia contacted infrared specialists Heraeus Noblelight, who investigated the possibilities of retrofitting a more modern, more efficient infrared system to meet the current requirements of the molding machine.
Initial on-site trials immediately established that carbon infrared emitters could eliminate the need for pre-heating, as they provided a 16% increase in heat-up rates. Consequently, it was possible to dispense with the hot water radiators and associated stands and create valuable new floor space. It also proved possible to retrofit the new carbon infrared system using many of the existing electrical supply connections of the old system, as well as the existing control panel and pyrometer.
In operation, the blank sheets are now heated in the mould, without any pre-heat, by means of a 104 kW carbon medium wave cassette, which carries 26,4 kW twin tube emitters, arranged in 13 zones. The emitters are switched on when the sheet is dropped into the mould and switched off by the pyrometer, on achieving a pre-set temperature. Switch on/switch off times are less than one second.
Since installation, it has been found that cycle times have been reduced by 20 seconds and there are energy savings of 9 kW/h because of the elimination of the pre-heating alone. Furthermore, maintenance costs and duties have been cut dramatically, as the twin tube emitters are proving much more durable than the original foil heaters and any infrequent change-over involves minimum downtime.
