Surface quality characterization of textile-reinforced thermoplastics

To allow cost effective mass production of reinforced thermoplastics for vi sible parts, in-situ a surface quality with "Class-A" standard must be achi eved. Furthermore, after the application of varnish, an appearance (gloss, waviness, color) similar to that of the traditional metal component is requ ired. Porosity and fiber readout are the common surface defects. Fiber read out results from the significantly higher volume shrinkage of the thermopla stic resin (higher CLTE) in comparison to that of the reinforcement during the cooling process in production combined with the uneven distribution of resin and fibers. While glass mat reinforced thermoplastic (GMT) parts show a disorderly readout influenced (among other factors) by fiber length, pro cessing and fiber content of the semi-finished material, the fabric reinfor ced thermoplastics (organic sheets) suffer from a regular print-through-a d isplay of the textile reinforcement. Modern tools of measurement enable one to quantify gloss, roughness, and waviness of the surfaces. Thus parameter s significantly influencing the surface characteristics can be identified. This leads to the development of procedures for improving the surface quali ty.