GROB–High Tech for the Automotive Industry

Process safety and optimization are the driving forces behind GROB innovations such as the GROB motor spindle with chip-in-spindle monitoring, a new linear motor and G-modules with greater rigidity and damping. These are innovations which continue to prove the leadership of GROB technology.

Mindelheim/Hanover. With technically new developments and advancements in existing products, GROB-WERKE continue to impressively demonstrate their technological leadership in the machine tool industry. The latest example is the chip-in-spindle (SiS) monitoring system developed by GROB which contributes significantly to increasing process reliability especially in large-scale manufacturing in the automotive industry. After an automatic tool change, this system queries the tool interface precisely for the presence of chips. During the GROB SiS check, sensors in the spindle nose detect and assess asymmetrical distortions of the tool clamping position caused by chips. The resulting information is transmitted via high-frequency radio signals to the machine controller which then indicates the faulty tool change. The power supply to the sensors in the spindle nose is provided by one stationary and one rotating induction coil per sensor. The spindle is tested while stationary directly after the tool is clamped. Simultaneously to this, the feed axes move to the new machining position. The system reliably detects chips which, at a distance of 150 mm to the contact face of the HSK-A63 tool mount, cause a change of tool concentricity of just 0.01 mm. It is irrelevant whether the chips lie in the area of the tool taper or the contact face. Since this chip-in-spindle detection is unrelated to cycle time, and does not require preparation in the machine’s operating area, the system provides a good enhancement to increase process reliability during automatic tool changes.

Coating cylinder running surfaces of modern combustion engines is an advancement in the automotive industry to reduce engine fuel consumption while increasing their wear resistance. For machine tool manufacturers like GROB, this development represents new challenges in machining applications. The first step is to roughen the aluminum cylinder contact surface. One possible method is to use a so-called bonding tool. These tools have PKD cutting edges which create 0.15 mm x 0.15 grooves and which must be reliably checked for breaks and wear. In this regard GROB is working on a camera-based application adapted to the harsh environmental conditions of a machine tool. After the 0.4 mm thick hard material layer has been welded to the cylinder running surface, the next step is machining the layer with a geometrically defined cutting edge. Because of the chromium component of the hard material layer, such machining makes the highest demands on both the machine and the tool. GROB has met this challenge with extensive test series and initial customer applications.

In order to successfully meet such machining tasks in the future, G-modules are under continuous development with respect to rigidity and damping, and the capacity for static and dynamic rigidity measurement and subsequent computer simulation is being significantly expanded.

Shortening downtime is a significant cost factor in large-scale production in the automo-tive industry. Here GROB engineers are making continuous improvements in reducing downtimes during tool changes and tool provision. Influential factors include process optimization, increasing the dynamics of working axes and the potentials of new generations of controllers. GROB has been able to make dynamic improvements in machine loading. Thus, an innovative linear motor was integrated into the new GROB linear portal which can move both carriages with 7.5 m/s2 at 450 m/min. Noteworthy: no magnetic material is contained in the iron reaction rail of the secondary section. Since the coils and magnets are located in the primary section, the linear motor is suitable for open and unenclosed drive applications with long travel distances. This linear motor allowed the implementation of a highly-dynamic and non-wearing drive application in the GROB linear portal. 

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