Portable surface roughness testers, sometimes known as profilometers or stylus profilers, are primarily designed for two-dimensional testing of machined, ground or polished metal and non-metallic surfaces. These instruments trace the surface profile by moving a skidded contact-type diamond stylus in a straight line across a surface while measuring the vertical movement of stylus with respect to linear distance. Surface roughness parameters are then calculated according to ISO standards.
Years ago, surface roughness was judged by inspectors who checked surfaces visually or used one of their fingernails as a stylus. Today, a handheld electronic surface roughness tester can easily provide accurate characterization of a surface. Typically, a testing unit consists of (1) a sensor (stylus), (2) a transducer, (3) a controlled traversing mechanism, and (4) a microprocessor. The transducer converts the stylus motion into an electronic signal which is analyzed by the microprocessor and converted into numeric parameter or also possibly a graphical profile.
Portable surface roughness testers are widely used in manufacturing operations, incoming inspection departments and laboratories. The most commonly-used surface roughness measurement parameter is Ra, average roughness. Another commonly-used parameter, Rz, indicates the average peak-to-valley distance.
Surface roughness measuring procedures, general terminology, definitions of parameters and data filtering methods are available in ASME B46.1 and ISO 4287 and ISO 4288.
PortableTesters.com LLC offers four portable surface roughness testers, two basic models, TR100 Plus and R6000, and two advanced models, TR200 and R7000.