Video: The HardFinisher from Praewema

The German machine tool builder Praewema presented its new HardFinisher technology at the recent International Manufacturing Technology Show (IMTS) in Chicago. In the video above, you’ll see the twin-spindle HardFinisher perform the complete machining of workpieces with internal or external gears.

In grinding operations, the standard approach to machining these parts has always involved passing them through two independent machine tools; one for grinding the bore and the face, and the other for grinding the gears. The HardFinisher is designed to perform both operations on a single machine, the company says.

In the initial phase, or the “first clamping,” the bore and face of the workpiece is machined, involving either grinding, hard turning, or a combination of both. Gear flanks are machined in the second phase. Continuous-generated grinding or honing utilizing a dressable ceramic tool can be performed on workpieces with external gears. The grinding wheel is balanced automatically by a dynamic system that is integrated into the spindle, the company says. Depending on the batch size, either a universal diamond dressing disc or a diamond-coated dressed gear can be used. Workpieces with internal gears are machined with gear-shaped, diamond-coated tools.

Various automation systems can be integrated due to the unit’s vertical‚ pickup design, with the spindles handling both loading and unloading of the workpieces. A single spindle can be used, or both simultaneously, and measurement devices can be mounted in-line. Robots and/or conveyor systems can easily be attached as well.