Method of and appartus for producing a compression product

Apparatus for producing a product by compression of material comprising:

• a hollow die;
• an elastically compressible lining for the die;
• means for compressing the lining to provide in the die a compressed lining of reduced internal size;
• means for compressing material in the interior of the lining when inside the die, and
• means for releasing the lining at least partially from the die to produce an increase in the internal size of the lining to allow removal of the compressed product from the lining,
• in which the lining is a continuous lining for the interior of the die, and the lining has when uncompressed, an external size greater than the internal size of the die,
• the means for compressing the lining comprising means for forcing the elastically compressible lining into the die to compress the lining by a smooth, continuous, elastic deformation of the bulk material of the lining, so as to reduce the internal size of the lining while maintaining the accuracy of the internal shape of the lining.

A method of producing a product by compression of material, comprising the steps of:

• providing in a hollow die a core to form a required opening in the final product;
• compressing product material in the die around the core to produce a compressed product;
• and
• after the compression of the product material, removing the compressed product from the die and from the core;
• in which the method includes expanding elastically the external size of the core and compressing the product material in the die around the expanded core, and, after the compression of the product material, reducing the external size of the core to assist removal of the compressed product from the core,
• the core being continuous around its external surface, and the exterior of the core being expanded by a smooth continuous elastic deformation so as to increase the external size of the core while maintaining the accuracy of the external shape of the core.

A method of producing a product by compression of material, comprising the steps of:

• providing in a hollow die a compressed sleeve which is elastically compressed so as to reduce the internal size of the sleeve relative to the internal size before compression,
• inserting into the compressed sleeve a material to be compressed,
• compressing the material in the sleeve to produce a compressed product,
• releasing the sleeve at least partially from the die to produce an increase in the internal size of the sleeve, and
• removing the compressed product from the sleeve,
• in which the interior surface of the die and the exterior surface of the sleeve are both tapered, and the method includes the step of inserting the tapered sleeve into the tapered die and compressing the sleeve by the effect of the tapered surfaces before the compression of the product material in the sleeve, to produce a selectable compression of the lining depending upon the extent of insertion of the sleeve into the die, whereby the increase in internal size of the lining on release of the lining from the die can be selected in relation to the expected increase in external size of the product on release from the die.

Apparatus for producing a product by compression of material comprising:

• a hollow die;
• an elastically compressible lining for the die;
• means for compressing the sleeve to provide in the die a compressed sleeve of reduced internal size;
• means for compressing material in the interior of the sleeve when inside the die, and
• means for releasing the sleeve at least partially from the die to produce an increase in the internal size of the sleeve to allow removal of the compressed product from the sleeve;
• in which the interior surface of the die and the exterior surface of the sleeve are both tapered, and the means for compressing the sleeve comprises means for forcing the sleeve into the die independently of the means for compressing the product material in the interior of the sleeve, to produce a selectable compression of the lining depending upon the extent of insertion of the sleeve into the die, whereby the increase in internal size of the lining on release of the lining from the die can be selected in relation to the expected increase in external size of the product on release from the die.