| 摘要 |
Metal clad plastic articles, e.g. high production dies capable of forming ferrous sheet material having a thickness in excess of 0,03 inch are made by providing a thin uniform coating of a metallic wetting material on a mould surface, spray depositing a metallic shell over the coating, and pressure casting against the coated mould a resin compound, e.g. epoxy resin, containing a high proportion of inorganic reinforcing fibres, e.g. glass fibres or steel wool. The metallic shell, which ultimately forms the operating surface of the die, may be of bronze or a steel such as stainless steel. A suitable metallic wetting material comprises, for example, metallic zinc or aluminium sprayed directly on a primary coating of a parting and wetting material such as polyvinyl alcohol. The metallic wetting material should be non-ferrous, non-inflammable, have a lower melting point than the metal to be applied subsequently and may include tin, lead, or Babbitt metal in addition to the above examples. The casting resin should be maintained under a pressure of at least 25 p.s.i. until it has set. The thickness of the metallic shell should be at least 0,03 inch at areas of the die where severe wear is anticipated. |
