How 3D Metal Moulding Works?

1

Feedstock

Feedstock can be bought as a readymade solution through a Catamold system or mixed in-house. Each way brings different benefits, so the choice of what to use will depend on the client’s requirements.

The Catamold system can be beneficial for larger parts with thicker sections or where a quicker cycle time is required whereas mixing in-house can achieve a more bespoke finish.

Fine metal powders are mixed with organic binders which provides visibly improved surface finishes, tighter tolerances and better densities. A wider choice of materials can be used, providing more options for customers. Blending feedstock in-house also allows the powder to binder ratio to be tailored which controls the shrinkage rate - this means a range of materials can be moulded using the same tool if required.

2

Moulding

A custom made tool is fitted into a standard moulding machine and the feedstock is injection moulded into it to produce a net shaped 'Green' component. Correctly producing the initial tool is just as critical as using the right feedstock, as the quality of the finished part will depend on both.

3

Removing the binding agent

Once moulded, the 'Green' component is transferred to a debind oven where the binding agent is removed either thermally or using solvent. Once ‘debound’ the parts are very brittle and porous as only one binder remains, at this stage parts are referred to as 'Brown' components.

4

Sintering

The final stage of the 3D Metal Moulding process is to sinter the ‘Brown’ part in a controlled atmosphere. Temperatures are taken to just below the material’s melting point, allowing menisci to form between the particles. Controlled, uniform shrinkage of on average 17% occurs at this stage and the component densifies to its finished size, shape and tolerance parameters.

When sintering is complete, the high density 'White' component has equivalent properties to wrought materials and can be heat treated, polished, plated or welded.

5

Post sintering operations

If required, secondary operations such as heat treatment, plating, polishing and welding can take place.

The industry standard working tolerance is +/- 0.5% of a dimension - this can be improved through secondary operations or tooling development if required.