MAPAL Focuses on Fluid Technology

Fluid technology products are used in a wide range of markets, such as mechanical and plant engineering, energy and environmental technology, automation technology, printing machines, woodworking machines, food and packaging machines, aerospace and shipbuilding. Driven by rising population figures worldwide, particularly agricultural engineering and construction machinery are absolute growth markets.

In an industry analysis, the VDMA confirms the high level of innovation in fluid technology from Germany. In terms of world trade, Germany ranks first, ahead of the USA and China, with an export quota of 60 percent, making it the world's most important supplier in this sector. The foreign production of many German fluid technology companies also enhances market penetration.
The prospect of a comparatively crisis-proof growth industry is by no means the only reason for MAPAL to focus more on fluid technology. The workpiece materials to be machined (cast iron, steel, stainless steels and non-ferrous metals) are ideally suited to the tool manufacturer's product portfolio. Over and above carrying out demanding machining steps, MAPAL can support the entire process worldwide here as a technology partner. "The customers' needs fit our MAPAL DNA," is the analysis of Jochen Schmidt, who heads up the General Machining segment. To him, being a technology partner means understanding both the customers' needs and the actual product and how it functions in the end product.
 

One such end product might be an excavator. Sitting behind a row of levers, the excavator operator becomes a virtuoso at his workplace. He usually operates two or three levers at the same time, not just to move the boom or bucket in one direction, but to implement complex sequences. Since superimposed movements are the rule, joysticks have often found their way into the cabs instead of rows of levers.

Irrespective of whether a lever or a joystick is being used, bringing loads weighing several tonnes to their destination with millimetre precision means that every single movement must be executed very precisely and reliably to ensure perfect interaction. Each lever is connected to a specific valve housing. The more functionalities the machine has, the more of these valves are installed in series. The number of parts that can be moved during excavation corresponds to the number of valve housings installed.

For Jochen Schmidt, manufacturing them is the supreme discipline in the world of hydraulics. For many years, MAPAL's expertise has been in demand for the spool bore in the valve housings. The gap dimension with the slide depends on the accuracy of this bore, which is very narrowly defined in modern hydraulic valves, so that the hydraulic oil can only flow in the required direction. The roundness, straightness and surface finish of this bore are also crucial.

The first machining step takes the varying quality of the cast blanks into account. Since the pre-cast bores are relatively imprecise, a precise pilot bore must first be created in the first ridge. This lays the foundation for creating a good cylindrical form in the subsequent machining steps. Next, a solid carbide tool or, in the case of the larger parts, a tool with indexable inserts passes through the entire bore. What the pilot drill has created for the first ridge is now produced along its entire length. To prevent ring formation in the hollow chambers due to propelled chips, MAPAL ensures a soft cut during machining by using tangential technology. This can eliminate the need for a separate washing cycle in the process.

After this pre-machining, the classic fine boring tool from MAPAL is used, finishing the bore extremely precisely. It has an adjustable cutting edge and guide pads, which prevent the tool from being displaced from ridge to ridge. This produces a high degree of straightness and an exact cylindrical form.
 

The different valve housings have different requirements. The fact that a three-stage honing process is added for some parts after the fine machining of the spool bore shows how high they can be. Since quantities in the sector are increasing and production capacities are often inadequate, honing has become an important issue. The workpiece usually has to be moved to another machine for this, which takes time, drives up costs and sometimes creates a bottleneck in the manufacturing process.

Nonetheless, the bore quality can be improved with the MAPAL fine boring tool under certain circumstances, so that only a single-stage or two-stage honing process is required, or honing can even be dispensed with altogether. In many cases, where three stages are still needed, this process is considerably faster thanks to the good pre-machining. Any time saved pays off here. Although the hydraulics sector is characterised by extremely high component variance, the quantities in series production are in the millions.

MAPAL considers it important to identify and eliminate possible cost drivers. "As a technology partner, we have the product portfolio to be able to design the entire process for the complete component in line with requirements," assures Jochen Schmidt. In addition to the central spool bore, MAPAL also carries out the fine machining for the pressure balance bore and was able to completely replace honing here. With 2 µ for straightness and roundness, high accuracy is also required for this shorter bore.
 

Zur Bearbeitung von Hydraulikbauteilen gehören nicht nur Experten- und Sonderwerkzeuge, sondern unterschiedliche Technologien, die auch mit dem verfügbaren Standardportfolio wirtschaftliche Bearbeitungen möglich machen. Beispiele sind sind das NeoMill-Programm für das Planfräsen, die Tritan-Drill-Reamer, die Bohren und Reiben in einem Arbeitsgang vereinen, oder Tangential-Schruppwerkzeuge (TSW), die bei der Vorbearbeitung von Bohrungen in Ventilgehäusen für die mobile Hydraulik deutliche Einsparungen bei der Hauptzeit und eine signifikante Qualitätsverbesserung liefern.

Die Bauteile sind 500x500 mm große Ventilblöcke aus GGG50, bei denen drei Kolbenbohrungen von beiden Seiten zu bearbeiten sind, wobei das Aufmaß im Durchmesser bis zu 16 mm geht. Die TSW von Mapal erzeugen kurze Reißspäne und verhindern damit, dass Ringe in die Zwischenräume gedrückt werden, die dann mit hohem Aufwand entfernt werden müssen. Pro Bauteil konnte die Eingriffszeit um 15,33 Minuten verkürzt werden. Die Gehäuse des entsprechenden Typs wurden in einer Stückzahl von 500 gefertigt, was insgesamt eine Zeiteinsparung von 128 Stunden bedeutet.

In Zukunft die kompletten Bauteile zu zerspanen, ist für MAPAL ein strategischer Schritt. Gab es früher in der Industrie noch den Zielkonflikt zwischen hoher Produktivität oder möglichst guter Qualität, lässt sich heute beides miteinander prozesssicher vereinbaren.