Evaluation of gloss meters for measurement of moulded plastics

Three makes of commercial gloss meter, with an incident angle of 60°, have been assessed for use in measurement of the surface of (dough moulding compound) DMC injection mouldings. It has been found that a reduced measurement area is beneficial when quantifying the gloss of defective areas. When local variations of gloss are measured, the average gloss value, together with the standard deviation of a set of adjacent readings, gives a good measure of surface appearance. For DMCs, values of up to 60 gloss units correspond to a poor finish and in the best areas values exceed 80.