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Technical Report
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Power play in the Allgäu Region

The success story of Epp Industrietechnik comes down to this succinct common denominator, i.e. the new markets being explored by offering complete processing of metal and plastic parts, including designer finishes and polishing.

Epp now stands for the complete CNCprocessing of the aforementioned metal and plastic parts, for 5-axis simultaneous milling of prototypes and complex components, as well as for the production of components, assemblies and devices for a variety of industries. The processing portfolio based on CNC machines comprises all cutting and milling processes as well as robot-aided grinding and polishing, while surface treatments are also taken care of in-house, i.e. micro-deburring and vibratory grinding. The certified component and system supplier Epp Industrietechnik really offers its customers a complete one-stop service, consistently based on the use of new technologies.

Exploration of a new technology...

An example of this is the robotised grinding and polishing system recently acquired by SHL Automatisierungstechnik AG. SHL is among he world's leaders in grinding and polishing a variety of components using industrial robots. The grinding and polishing machines are entirely developed and produced in-house and SHL acts as a system integrator, always using in-house products, with the exception of the robots. The same principle applied in the case of Epp, which was all about very precise grinding and polishing of customised components made from aluminium profiles. What appeared to be rather mundane at first, turned out to be a challenge in practice, both for Epp Industrietechnik as the manufacturer and for SHL Automatisierungstechnik AG as the systems supplier. The grinding of aluminium and other light metals results in problems such as dust and dirt pollution as well as the risk of explosions caused by flying sparks, possibly resulting from a torn belt or contact between the grinding belt and the steel components. The grinding and polishing machines manufactured by SHL can therefore optionally also be equipped as Ex-protected and TÜV-certified versions, which of course were also used for Epp's new grinding and polishing system. As though this were not enough of a challenge, the specially designed operating panels had to be accurately milled to their final dimensions and provided with a perfect designer cut (aluminium made to look like stainless steel) without undergoing any kind of change due to the very strict tolerances specified.

Interactive development of a process solution

Ultimately, a grinding process was developed in close cooperation between Epp's production skills and SHL's application technology; this process is now being used for the serial production of between 50 000 and 80 000 custom-made operating panels per year from milled aluminium profiles. For time reasons, the grinding processes were optimised and adapted in parallel to the construction of the system at the SHL technology centre in Böttingen.

The robotised grinding system planned, constructed, installed, programmed and commissioned by SHL mainly consists of an SHL FKS 250/450 aluminium open-belt and contact roll grinding machine, an SHL P550 aluminium grinding system, a KUKA KR 60/3 6-axis industrial robot, a conveyor belt for removing the finished components, a component-supply system via a palleting/multiple storage system, all associated safety devices, including a safety barrier and access door, the system controls, the software and a range of grinding accessories (contact discs, grinding belts, finishing wheel). The FKS grinding machine, the P550 grinding system and the high-powered extractor system deserve a special mention. Both the FKS open-belt and contact roll grinding machine and the P550 grinding system have grinding belts and/or finishing wheels made from suitable materials that will not create sparks; in addition, they are fully encapsulated.

The extractor system is controlled via ventilation flaps and efficiently removes the loose particles created during processing (grinding and finishing work). The encapsulated design and direct extraction system ensure that there are hardly any residues that could result in process interruptions.

Using standard components to construct individual robotised grinding systems

The requirements given below show that supposedly simple milled components made from aluminium profiles are quite complex in practice. The parts must be accurately and reproducibly milled to a thickness of 1/100 mm, as the switch elements mounted behind them will react to the slightest touch. This means that if the thickness tolerances and thus the residual thickness of the material in the milled areas falls below a certain value, this would result in functional problems and the components in question would have to be regarded as rejects.

The development of a reproducible grinding process that will combine minimal metal removal with the designer finish "aluminium with a stainless steel appearance". In addition, about 20 different types and variants of decorative and operating panels had to be taken into account, based on five different extruded aluminium profiles. The problem was jointly solved and the ideal combination of designer polish and adherence to the specified dimensions was achieved. For Epp Industrietechnik, the acceptance of this special order for the complete creation of decorative and operating panels signified the exploration of another entirely new type of technology. According to Daniel Epp and Hans J. Ihsen, who have taken on this responsibility, this project has allowed them to round off and extend their processing /service portfolio very well, as it means that both existing and potential clients in the fields of consumer goods/white goods, the automotive industry and aviation, as well as their suppliers, can be offered advanced grinding, polishing and surface-finishing services on a one-stop basis.