| 摘要 |
<p>Cold forming sheet or sheets of thermoplastic material at temperatures below its softening point, pref. at ambient temp. by compressing the slab to a thickness suitable for driving into a convergent wedge-shaped cavity which pref. diverges in width sufficiently to accommodate the material displaced by further compression. Subsequently the sheet material may be supported over a mould cavity with the peripheral sheet covered by a plunger guide block separated from the mould level by spacers at least as thick as the blank sheet. A plunger passing through the guide block deforms the centre of the blank into the mould cavity, drawing additional material as necessary from between the mould and guide blocks. Suitable for forming laminate sheet materials with biaxial, multiaxial or pref. uniaxial overlay pattern, esp. where the blank was initially roller compressed (by about 50%) in one direction and subsequently forced into the mould normal to the rolling direction. The mouldings can be rapidly formed and immediately ejected and usually have improved stress crack and impact resistance compared with hot moulded components.</p> |
