By their nature, microhardness testers are delicate instruments. Extremely light forces (typically from 10 to 1,000 g.) must be accurately applied, and the resultant impressions (some as small as 10 microns) must be precisely measured under high magnification. And so there are a number of problems inherent to all of them.
When people think of microhardness testing, three terms often come to mind: finicky, subjective, and time consuming. In many cases, all three of these connotations are well deserved. Fortunately, advances in computer technology have reduced, if not eliminated, them as issues. In addition, there are the problems of accuracy, repeatability and correlation that are inherent to microhardness testing. However, by using properly maintained and calibrated equipment, trained personnel, and appropriate testing environments, these problems too can be minimized.