Method of forming an article

Abstract

A method of making an article includes determining the greatest dimension of an article along a selected axis, and manufacturing a first part of the article between an end and a face lying in the laterally extending plane containing the dimension. The method further includes placing the article on the support of direct layer deposition (DLD) apparatus with the face upwards, and forming the remaining part of the article using the DLD apparatus.

Description

BACKGROUND AND SUMMARY[0001]This invention relates to a method of forming an article.[0002]The laser sintering / melting of powdered materials to form solid parts is now well known, though the forming of nominally 100% dense metal parts by a practical process is relatively new.[0003]In particular there are commercial powder bed ‘Selective Laser Sintering’ / ‘Selective Laser Melting’ (SLS / SLM) machines such as the M270 produced by Electron Optical Systems (EOS) M270 and the Realizer II marketed by MCP. These take metal powders under an inert atmosphere and direct a CO2 or fibre laser onto a layer of powder.[0004]There are other similar powder bed machines and somewhat related processes such as ‘Direct Laser Fabrication’ (blown powder). Generically a point source of energy such as a laser or electron beam is selectively applied to a layer of powder and a 3D part built up layer wise from a ‘slicing’ of a design file. The heat from the point source melts or sinters the particulates to form ...

AI Technical Summary

Benefits of technology

[0005]The term Direct Layer Deposition (DLD) can be used to describe all such processes and we will here describe only the powder bed SLS / SLM process. In the powder bed systems, powder is fused at a single plane and the object thus built is formed from a cycle of selectively sintered / melted powder at the upper surface of the powder bed, stepping the powder bed and part built object down by one layer and recoating powder across the surface of the bed and part-built object. This way objects are built up in layers and the built part is surrounded by the powder bed. Extremely accurate building is possible with good surface finishes.

[0035]a) Firmly, to avoid intolerable movement induced by the thermal stress of the SLS / SLM process,

Problems solved by technology

By their very nature these supports are not part of the desired geometry and therefore need to be designed, built and removed.

This is both time consuming and requires skill thereby adding delay and cost.

A further problem is that the geometry of the part may be such that it is difficult or impossible to locate support structures that can be removed—thereby limiting the geometries that can be made by the DLD process.

Whilst useful this process is time consuming and the second part made by welding is not (near) net shape and subsequent working such as cutting and gauging is required.

There are therefore 3 layers and two interfaces in this system being the two parts and the bonding system and thereby it is more prone to failure.

Also there are geometric limits to moulding processes and materials limitations dictated by the moulding process.

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