Process Encyclopaedia

Sintering and HIPing

Overview

There are 2 main types of sintering: with pressure (hot pressing or pressure sintering) and without pressure (pressureless sintering). A variant used for 3D shapes is called hot isostatic pressing (HIPing) Much of the research in powder processing is to obtain good quality powder, as this helps to achieve a good quality component.

Materials and shapes

Mostly used for small (<2kg) components. Dominant method of producing ceramic components. For non-HIPing, sides must be parallel to allow ejection of part. HIPing can work with complex 3D shapes. Very good dimensional accuracy (near net-shape process) with 100% material utilisation.

Economics

The machinery is expensive, and can cost well over £100,000 for HIPing. The dies are dedicated, expensive (£5,000+) and need to be replaced after about ten thousand uses. They can take several weeks to manufacture, so prototype testing is slow. The production rate is dominated by the sintering stage and is therefore quite slow (2-20 per hour). Because there is little competition, can be economic for small batches (1,000+) - although still not cheap!

Typical products

cutting tool tips, spark plugs, electrical insulators