Understanding the procedures and mechanisms of dressing grinding wheels is critical to obtaining optimum performance in grinding. The available dressing methods are numerous and confusing — even the basic terminology varies from one manual or paper to another. For the purposes of this discussion, the following terms will be used:
• Truing: Creating a round wheel concentric to the axis of wheel rotation, and generating, if necessary, a particular profile on the wheel face. It is also to clean out any metal embedded or “loaded” in the wheel face. A further function is to obtain a new set of sharp cutting edges on the grains at the cutting surfaces.
• Conditioning: Preferential removal of bond from around the abrasive grits.
• Dressing: Truing the wheel and conditioning the surface sufficient for the wheel to cut at the required performance level.
Many people use the term dressing to mean conditioning, but with most of the high-production grinding occurring today, truing and conditioning are simultaneous processes and are referred to in combination as dressing. In Europe, conditioning can mean dressing or truing, sharpening can mean conditioning, and profiling can be used for truing [Pricken 1999].
All wheels require dressing with the exception of electroplated wheels, although even here they may be occasionally trued initially 10 to 20 pm or occasionally conditioned lightly with a dressing stick to remove loaded metal. The focus of this chapter, however, is on bonded wheels, especially vitrified. These bonds are popular because their porous, crushable bonds allow dressing in a single automatic operation.
Dressing processes for conventional wheels can be divided into two distinct classes:
• Dressing with stationary diamond tools
• Dressing with rotary diamond truers that offer much longer tool life The simplest to begin with are stationary tool processes.