Post-Processing
9.1 Introduction
AM parts also require post-processing to enhance surface finishing and mechanical properties. For metals, the dimensional precision of additive processes is not yet adequate to produce a component that can reach tight tolerances without further processing. Many AM processes need post-processing to prepare the component for its intended shape, fit, and function after partial construction. Depending upon the AM procedure, the explanation for post-processing varies. This chapter will concentrate on post-processing techniques for convenience purposes which are used to enhance components or address AM limitations. These include:
- • Support material removal
- • Surface texture improvements
- • Accuracy improvements
- • Asthetic improvements
- • Easy to use as a pattern
- • Improvements to properties using non-thermal techniques
- • Enhancements in property using thermal techniques
There are a number of process parameters that can be varied to influence the physical, mechanical, thermal properties, cost, speed, and quality of an AM component. The combination of process parameters coupled with post-processing directly influences the microstructure (e.g. grain size, porosity, cracking density), and mechanical properties, such as tensile, fatigue, and creep properties.
The willingness of numerous AM professionals to conduct post-processing is one of the most distinguishing characteristics of competitive service providers. Companies that can effectively and accurately post-process parts to the customer’s specifications will often charge a premium for their services, whereas companies that compete solely on price can compromise post-processing quality in order to reduce costs.
Support Material Removal
Support removal is the most common type of post-processing in AM. Help materials can be loosely divided into two categories:
- (a) Material that surrounds the part as a naturally occurring by-product of the construction process (natural supports) and
- (b) Rigid structures that are designed and built to support, restrain, or attach the part that is being built to the building platform (synthetic supports)
