| 摘要 |
Buttons or similar objects with buffalo horn (eccentrically spiral) pattern are produced by slicing cross-sections from a multicoloured bar. - This bar is produced from a spirally patterned original bar, by squeezing it longitudinally through a tube in which a vane revolves about an axis perpendicular to the pipe axis. - The vane presses the material in layers from its upstream to its downstream side. - Suitable materials are e.g. polyester and polystyrene.
|
