Peitzmeier from Gütersloh, which specializes in the construction of grinding machines, has developed a system, the Omni-Grind Twin 3100 AC, with which customers from the metalworking industry can grind and polish workpieces fully automatically. One of the users of such a grinding system is a Dutch company that processes stainless steel washbasins. Before the system was commissioned in 2016, those responsible placed some unusual demands on the grinding machine: The three-tonne system was to grind 40,000 stainless steel washbasins per year in the fully automated expansion stage and proceed with particular care, as the washbasins are made of thin sheet metal that is only one millimeter thick. The tool must therefore never grind in one place for too long, otherwise the workpiece will be damaged.

Peitzmeier had to adapt the sanding machine to meet these requirements. The heavy sanding tool, which is normally mounted on a double-stranded U-rail, had to make way for a lighter tool that can be aligned with absolute precision on just one guide rail. The previous guide system was unsuitable for this. Peitzmeier went in search of a manufacturer of suitable guide rails and found what they were looking for at Hepcomotion.

Movements in the range of hundredths of a millimeter
Peitzmeier opted for the GV3 linear guide system. The system consists of precision-ground guide rails and a carriage equipped with special rollers. The rollers have so-called V-groove bearings, which engage with their notches from above and below in the tapered rails and, thanks to low friction, enable movements in the range of hundredths of a millimeter - at a maximum speed of eight meters per second. At the same time, the guide rails have sufficient rigidity to withstand the contact pressure of the grinding tool. Peitzmeier was looking for this combination of precision and resistance to elastic deformation. The low-noise operation of the system proved to be a further advantage.

The rollers of the GV3 guide system have so-called V-groove bearings, which enable movements in the range of hundredths of a millimeter. (Image: Hepco Motion)

Modularity reduces installation height
In addition to the precision and resilience of the linear guide system, the space-saving design also saves space. The GV3 system has a modular design; the rollers were purchased separately and mounted directly on the adapter plate of the grinding tool. By dispensing with the remaining components of the carriage, it was possible to save almost 40 percent of the installation height and still achieve a high load-bearing capacity. The Hepco guide system is suitable for use in harsh environments as it is self-cleaning and therefore protected against rapid wear. The V-groove bearings simply wipe deposits off the rail, ensuring smooth and reliable operation.

The special feature is the modular design
Three washbasins are transported to the processing table in the sanding machine via a feed belt. There, the basins are clamped by pneumatic cylinders and fed to the sanding belt with the table feed, which moves in a trapezoidal circulation system. The sanding tool, which moves horizontally on the guide system between the feet of the machine, then presses the sanding belt with a roller onto the surface of the workpiece to achieve the desired sanding effect. The precise alignment of the sanding tool ensures that the machine never sands in one place for too long. A second guide rail with a polishing module is located behind the sanding tool.

The entire machine is made from laser-cut components; all screw-on surfaces and screw-on holes can be integrated directly into the basic machine with little effort - for example, a second guide rail for a deburring module or a rounding module. pb