However, it is not just such presses which employ Berndorf’s belts today but the decorative laminate business is taking an increasing share of the company’s production; and not just in smooth-surfaced belts. Until relatively recently, embossed decorative surfaces were only produced using engraved press plates in single- or multi-opening presses. Laminate flooring has been a major driver in the transfer of this technology to continuous presses employing textured stainless steel belts. Significantly, in 2000, Berndorf Band took over the German company Hueck Engraving, a specialist maker of smooth and embossed press plates, and started producing embossed stainless steel endless belts for the laminating of panels with decorative papers for laminate flooring and furniture.Berndorf Band also produces stainless steel transport and process belts for a variety of industries including the food and chemical sectors. Gernot Binder, director of belt production and services, took us through the production process. This begins with inspection of the stainless steel strip as it arrives from the steel mill. The steel is then levelled in a roller process to achieve optimal flatness and straight tracking. The levelling machine has its two end heads mounted on rails so that all lengths of belt can be accommodated, up to 250m. The embryonic belt is edge-trimmed simultaneously in the levelling machine for the accurate longitudinal welding required to make the wider belts demanded by the panel industry. This is then carried out in a TIG welding process (Tungsten Inert Gas). After welding the belt is made into a roll, followed by heat treatment in a specially designed chamber. This improves the belt’s tensile strength and durability. Next comes simultaneous two-sided wet grinding of the belt until the weld is invisible and the surface meets the required specification. Berndorf recently installed an automatic surface inspection and thickness measuring system on the grinding line, designed to increase production speed. This, like all the machinery in the factory, was designed in-house.
The final step is the preparation of the ends of the belt which will later be welded at the customer’s factory to form an endless belt for the continuous press. This preparation process is automated to ensure the endless belts run straight and true in the press. The belts are then rolled onto wooden drums and packaged ready for shipment. Andy Holzinger, director of business development, then showed us to a separate production hall where the belts for laminating are produced, after longitudinal welding in the main factory. These belts, unlike those intended for raw board manufacture, are joined into a continuous loop before being textured. There is another important difference here too. The longitudinal weld is spiral, which means it has no cross-weld when the completed loop is made and this avoids a potential weak spot where the longitudinal and cross welds meet, explained Mr Holzinger. This system is patented by Berndorf.
"We can produce wood grain effect, or any structure the customer wants," said Mr Holzinger. "We work from a customer’s sample and our designers replicate it on the belt surface." The belt production process starts in a similar way to that for raw board belts, but as a loop, with levelling, welding and grinding. Then the decorative pattern is printed onto the belt’s surface in what Berndorf says is a unique process. Chemical etching is carried out by spraying the chemicals onto the belt in a closed room, with most structures having more than one component to them, so the belts are printed and etched twice. Various depths of structure can be offered. The finished belt is then chrome-plated to give it a hard surface, polished to achieve the required level of glossiness for that design, and packaged as a loop on a steel frame inside special steel-framed wooden crates.
Service is an important part of the supply of such high-value products as stainless steel belts. For instance, laminate flooring decors have a wear-resistant surface (usually containing aluminium oxide) and this is abrasive to the belt. Thus Berndorf can re-polish the belts to restore the required level of glossiness. All belts can be serviced, refurbished or repaired here, regardless of who the original manufacturer was or whether or not the belts have a structured surface. The Service Centre incorporates service, training and research and development. "We carry out 550 to 600 service jobs a year for our customers, from welding a cracked belt to installing a new one," said Gerold Wimmer, technician for customer services. "It requires a lot of equipment and skilled people." Berndorf Band has 26 service centres around the world, equipped with all the required tools, and is in the process of setting up a further two, in India and Bulgaria. "We train our own people on a regular basis on manual belt repairs, re-training our service specialists from all over the world every two years. They then receive a certificate," said Mr Wimmer.
Training facilities include an old production machine with the belt running as in a continuous press. Customers’ staff are also trained at the Berndorf centre so that they can make emergency repairs and various repair tools are available for clients to purchase. Berndorf has offered a belt patching tool since 1997, but this has been continually developed and has now reached generation three. The tool cuts out a circular section of belt containing a crack or dent and welds in a replacement. Patching Tool 3000 has halved the repair time of generation two and is also half the weight, enabling it to be operated by one person instead of two. The magnetic clamping of the second version is replaced by pneumatic. Like the mark two, the 3000 also employs two-sided welding, not available on the 1997 version. This is claimed to give a much better, less stressed, repair.
During running in a continuous press, the belt is subjected to heat and mechanical stresses and develops tensions as a result, which cause ‘cupping’, or curvature of the belt across its width. The shot-peening device offered by Berndorf fires very small steel balls onto the outside of the belt, within a traversing cup which captures the balls for recycling. This process flattens the belt and can be done during panel production. The expensive alternatives to this are to stop the press, remove the belt, turn it inside out and put it back – or replace the belt entirely. Most of the damage to belts in continuous presses occurs on the edges and Berndorf offers another tool to maintain the edges and thus prolong belt life. A set of selected hand tools and processing machines for minor repairs is also offered. The customers can thus choose whether to carry out their own repairs, having been trained by Berndorf, or to call in a Berndorf service person from their local Service Centre.
Mr Holzinger said that demand is high from all market sectors for the company’s belts and Berndorf is thus building production capacity on its existing site to enable it to fulfil future market demands.
