Creep-feed grinding wheels deliver productivity advantage

Strato-Ultra creep feed grinding wheels can deliver a 30 to 50 per cent productivity advantage over conventional products. The wheels use a high strength bond that allows the amount of vitreous material to be reduced, which in turn allows the abrasive grain content to be lowered. The results are an increase in both pore volume and average distance between individual grains, delivering a creep feed wheel that holds profile better and for longer. In operation, friction is lower due to fewer cutting edges being in contact with the workpiece. There is also less bond material in the contact zone, which can inhibit chip removal and cause additional friction. As a consequence, the amount of heat generated is reduced, forces on the component are lower, and the power drawn by the drive motor is decreased. These benefits improve component quality, both dimensionally and metallurgically, as well as speeding grinding cycle times and resulting in a more efficient and economical machining process. Despite being very porous, the wheels exhibit considerable mechanical strength even for large diameters and wheel widths, allowing relatively high peripheral grinding speeds up to 63 m/s, without the need for additional bore reinforcement. They are especially well suited to VIPER grinding of gas turbine engine components, with or without continuous dressing. Tyrolit continues to recommend that fused aluminium oxide (AlOx) grain is the preferred type for most aerospace and turbine applications. While there can be some benefits from using sintered grain in certain applications, the negative effects of high wheel cost, high diamond roll wear and poor process capability when producing deep profiles, results in a majority of users staying with fused-grain wheel types. The case for fused AlOx grain is further strengthened by Strato-Ultra itself, as the extended wheel life and lower grinding forces allow users to realise most of the benefits normally associated with sintered-grain wheels, without the above disadvantages.