Push-button precision: General Industry Coverage

Effectively and efficiently grinding workpieces to meet tolerance requirements is no easy task. Machine operators generally don’t perform the calculations for determining optimal grinding parameters because they are too complicated and instead go with the values that worked well in the past or rely on their gut feelings, according to Erhard Kämpf, head of the forms and threads department at grinding machine builder Fritz Studer AG.

“For them, it is often not possible to obtain good results in the desired time and without much optimization effort,” Kämpf said. He explained that the optimization effort involves determining what changes to make if the surface finish or roundness tolerances are not achieved. Those changes cover the dressing speed, infeed speed, spark-out time and rotation ratio of the workpiece and grinding wheel.

Courtesy of Fritz Studer

Having Studer-Technology Integrated software determine the correct grinding parameters relieves grinding machine operators from performing complex calculations.

The operator usually starts with one of these influencing factors, regrinds the workpiece and measures the part again, possibly repeating the time-consuming procedure several times until the tolerances are met. He added that most users underestimate the machining output of a wheel and, therefore, rarely dare to approach the limits of what is possible.

The task is particularly daunting when cylindrical grinding because more than 300 grinding parameters determine the process. Kämpf pointed out that in addition to the material-removal rate, feed rate for roughing, finishing and fine finishing, switching points, spark-out time and traverse speed—the most important parameters—grinding values include ones that are not often considered, such as critical speed, or integer, ratios (incorrect ratios for the number of workpiece and wheel revolutions can cause nonround diameters, such as polygons with varying numbers of lobes), part deflection and tangential force.

A new software package, StuderTechnology Integrated, overcomes this obstacle to higher productivity by performing the calculations to determine the optimal cylindrical grinding parameters based on operator entry of just a few critical process variables, such as the type of grinding wheel, workpiece material (including its hardness), and coolant, according to the company. Studer and its software partner, mcs software ag, developed the software, which is included at no additional charge in Studer grinders with StuderWIN controls.