Process for producing a high density by high velocity compacting

Abstract

A method of producing a body from a particulate or solid material comprises filling a precompacting mould with the material, optionally vibrating the mould, pre-compacting the material and compressing it by at least one stroke with high kinetic energy in order to cause coalescence or high density of the material.

Description

[0001] The invention concerns a method of producing a body by coalescence or compaction to higher density. STATE OF THE ART [0002] In WO-A1-9700751, an impact machine and a method of cutting rods with the machine is described. The document also describes a method of deforming a metal body. The method utilises the machine described in the document and is characterised in that preferably metallic material either in solid form or in the form of powder such as grains, pellets and the like, is fixed preferably at the end of a mould, holder or the like and that the material is subjected to adiabatic coalescence by a striking unit such as an impact ram, the motion of the ram being effected by a liquid. The machine is thoroughly described in the WO document. [0003] In WO-A1-9700751, shaping of components, such as spheres, is described. A metal powder is supplied to a tool divided in two parts, and the powder is supplied through a connecting tube. The metal powder has preferably been gas-ato...

AI Technical Summary

Benefits of technology

[0011] The object of the present invention is to achieve a low cost process for efficient production of products from a particulate material or a solid material by coalescence or compaction to a higher density. These products may be both medical devices such as medical implants or bone cement in orthopaedic surgery, instruments, such as surgical knives, or diagnostic equipment, or non medical devices such as ball bearings, cutting tools, sinks, baths, displays, glazing (especially aircraft), lenses and light covers. Another object is to achieve a product of the described type.

[0015] The method according to the invention may utilise hydraulics in the percussion machine, which may be constructed on the same principle as the machine utilised in WO-A1-9700751 and SE 9803956-3. When using pure hydraulic means in the machine, the striking unit or units can be given such movement as to, upon impact with the material to be compressed, emit sufficient energy at sufficient speed for coalescence to be achieved. This coalescence may be adiabatic. A stroke is carried out quickly and for some materials the wave in the material decay in between 5 and 15 milliseconds. The use of hydraulic may also give a better sequence control and lower running costs compared to the use of compressed air.

Problems solved by technology

The strokes according to the method described in WO-A1-9700751, give a locally very high temperature increase in the material, which can lead to phase changes in the material during the heating or cooling.

It has now been found that the machine according to these documents does not work so well.

For example, the time intervals between the strokes, which they mention, are not possible to attain.

Also, the rebounding strokes have proved to result in cracking of the material.

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