| 摘要 |
<p>Grooves are made in fusible material, e.g. thermoplastic esp. plastics foam, by melting-off excess material to leave a groove. The melting step is effected continuously, according the desired cross-section of the intended groove. Used in mfr. of plastics-foam wall coverings which are to be provided, at least in selected zones, with longitudinal grooves to enable them to be smoothly bent around protruding corners. The process is less expensive than grooving by machining and there is no risk of injury to operative. Pref. the excess material (i.e. the material filling the space where the intended groove will extend) is melted off along the conour of the cross-section of the groove whilst the unfused excess core is severed.</p> |
