Crankshaft Grinding Process Reduces Cycle Times

Emag’s VTC 315DS vertical grinder is designed for synchronous support grinding of crankshafts, which is said to combine high flexibility and high productivity. In this process, two opposing CBN wheels machine the same point on the workpiece to cancel out axial forces generated in the feeding direction. An NC steady rest that pushes against the workpiece from the direction of the machine base also eliminates tangential forces, ensuring that the part is securely clamped and does not give way under pressure. According to the company, eliminating both axial and tangential forces enables high feed rates, while the use of two grinding wheels reduces cycle time. Additionally, the use of both directional and counter-directional grinding strokes can cancel out forces generated during machining, enabling users to hold the crankshaft between centers with only the momentum created by friction.

The workpiece is secured by a headstock at the top and a tailstock below. Each opposing spindle has a power rating of 30 kW and cutting speeds ranging to 50 m per second. The grinder also includes functions for gap control and automatic balancing. The wheel is loaded into the work spindle vertically via a simple wheel changer, and the wheel receptor features a short taper and flanged contact surface for easier changing. According to the company, the machine’s thermal stability ensures that required tolerances are held. Other features include two measuring sensors for checking part alignment during setup and two integral dressing spindles for simultaneous wheel dressing at 15,000 rpm.