Grinding a crankshaft is an art in itself, as the demands made on this essential component found in every engine are huge: ever longer runtimes demand the highest precision in their manufacture. The radii not only have to be perfectly round, but the bearing surfaces have to be of perfect quality, too. In short: every surface of this pivotal engine component allows for only the tightest tolerances, otherwise there is no guarantee that the engine will run smoothly.

The Devil is in the Details

One can easily imagine that grinding radii and surfaces using a combination machining process faces its own problems. For instance, grinding the radii requires a number of passes, as the shaft can only take a certain amount of pressure before it “bends;” whereas the pressure exerted when grinding the surfaces is not an issue, as it works in an axial direction. These varying pressure and pass requirements are evident on the wear patterns of the grinding wheel.

Diagonal Grinding Offers a Solution

Taking this problem into consideration, it would be easy to assume that two separate grinding processes may be the solution. That, however, would be detrimental to the cycle time. The engineers from EMAG have addressed this problem and developed the “diagonal grinding” method, a process where both bearing seats and shoulder surfaces are ground in a multi-stage process. Complex, integrated diagonal grinding is achieved by controlling grinding speeds and axis movements with pinpoint accuracy, for which the EMAG PB Series modular machine system was developed.

This technology offers savings in both time and costs (e.g. through a reduction in the grinding wheel wear) and leads to lower component costs, providing a decisively competitive edge in, above all, large batch production of crankshafts.