Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Tool manufacture using spray forming techniques

The manufacture of tools and dies using spray forming techniques (MUST) is a direct, net shape manufacturing process that can produce steel tools and dies in a fraction of the time and at a fraction of the cost of the more conventional processes.
Research has been carried out to further develop the production of tools and dies by the simultaneous spray peening (SSP) process. A hybrid process is also being devised in which an electroformed shell is first made, onto the back of which an SSP deposit of tool steel is formed. This gives further advantages of detailed replication and ease of parting from the pattern.

A series of prescreening trials were carried out to evaluate the relative importance of a wide range of spray forming variables.
Spray strategy, spray metal selection, substrate material, and bonding conditions to electroformed shells were isolated as areas which needed further study.

A fundamental study of the MUST process involved:
assessing the mechanical properties of spray deposited materials using a range of process variables;
residual stress measurements in spray formed deposits;
investigating potential backing materials for the process.

A number of inserts were manufactured and tested in a plastic injection machine, a high pressure die casting machine and a press forming machine. Various levels of success were achieved with some applications such as plastic injection mouldings showing a great deal of promise, while high pressure die casting showed some problems.

With respect to developing the process steps the following work was carried out:
development of castable ceramic former materials;
development of spray strategies for spraying metal into complex shaped formers containing cavities;
designing preproduction equipment.

A number of plastic injection dies were produced for demonstration purposes. Further work will be required to ensure the accurate reproduction of larger sizes.

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