Wheel truing is defined as act of restoring the cutting face of a grinding wheel by removing the abrasive material from the cutting face and sides of the wheel,so that it will run true with respect to the axis of rotation and produce perfect round or flat work.
It also includes the altering of the cutting face shape to produce special contours.As soon as a fresh wheel is fitted,it becomes necessary to true its face.It also produces concentricity or parallelism of faces.It prepares the wheel to perform a forming operation.
Wheel dressing is defined as the act of improving the cutting action.It can also be described as sharpening operation.It becomes necessary from time to time during the course of working to correct uneven wear and to open up the face of the wheel so as to obtain efficient cutting conditions.
Dressing a wheel does not necessarily true it.The wheel may be out of round or parallel even after dressing as it only removes the outside layer of dulled abrasive grains and the foreign material.
Dressing may be accomplished by using metal crushers,abrasive sticks,abrasive wheels,single-point diamond dresser,single set and matrix diamond dressers,rotary and stationary diamond rolls,and crushing rolls.
Truing is the process of changing the shape of the grinding wheel as it becomes worn from an original shape, owing to the breaking away of the abrasive and bond. This is done to make the wheel true and concentric with the bore, or to change the face contour for form grinding. While The purpose of dressing is to restore the correct cutting action of the wheel. Dressing removes the clogs on the surface of the wheel and the blunt grains of the abrasive, exposing the new sharp abrasive grains of the wheel which can be cut and brought to shape efficiently. Truing and dressing are done with the same tools, but no for the same purpose.
Dressing is not so much important for rough grinding wheels, but you’ll need to always have a true, flat face on your wheel in case you’re doing some precision grinding.