Additive Manufacturing: Post Processing Methods and Challenges

Additive Manufacturing (AM) has shown great potential for efficient realization of complicated microdevices fabricated with higher freedom of design and made from a wide variety of materials suiting to their specific target functionalities. Capability of generation of components with reduced weights, higher part consolidation, greater customization offered along with minimal waste generation are its advantages over conventional manufacturing processes. The AM built parts, however, need to undergo relevant post processing techniques to render them fit for their end product application. The paper attempts to classify the post processing techniques and emphasize their applicability to specific AM methods, generalized procedure as well as the recent improvements undergone. The post processing techniques have been categorised as methods for support material removal, surface texture improvements, thermal and non-thermal post processing and aesthetic improvements. The main challenges to the expansion of additive manufacturing have been discussed which highlight the future, scope of improvement and research required in the area of appropriate tool path development and product quality with regards to surface roughness, resolution and porosity levels in the built part.

Design for Additive Manufacturing: A Systematic Review

The last few decades have seen rapid growth in additive manufacturing (AM) technologies. AM has implemented a novel method of production in design, manufacture, and delivery to end-users. Accordingly, AM technologies have given great flexibility in design for building complex components, highly customized products, effective waste minimization, high material variety, and sustainable products. This review paper addresses the evolution of engineering design to take advantage of the opportunities provided by AM and its applications. It discusses issues related to the design of cellular and support structures, build orientation, part consolidation and assembly, materials, part complexity, and product sustainability.

A Part Consolidation Design Method for Additive Manufacturing based on Product Disassembly Complexity

Parts with complex geometry have been divided into multiple parts due to manufacturing constraints of conventional manufacturing. However, since additive manufacturing (AM) is able to fabricate 3D objects in a layer-by-layer manner, design for AM has been researched to explore AM design benefits and alleviate manufacturing constraints of AM. To explore more AM design benefits, part consolidation has been researched for consolidating multiple parts into fewer number of parts at the manufacturing stage of product lifecycle. However, these studies have been less considered product recovery and maintenance at end-of-life stage. Consolidated parts for the manufacturing stage would not be beneficial at end-of-life stage and lead to unnecessary waste of materials during maintenance. Therefore, in this research, a design method is proposed to consolidate parts for considering maintenance and product recovery at the end-of-life stage by extending a modular identification method. Single part complexity index (SCCI) is introduced to measure part and interface complexities simultaneously. Parts with high SCCI values are grouped into modules that are candidates for part consolidation. Then the product disassembly complexity (PDC) can be used to measure disassembly complexity of a product before and after part consolidation. A case study is performed to demonstrate the usefulness of the proposed design method. The proposed method contributes to guiding how to consolidate parts for enhancing product recovery.

Comparing mechanical properties of impact modified polypropylene-copolymer (IMPP) from injection molding (IM) and fused layer modeling (FLM) processes

Purpose The purpose of this study was to produce dimensionally accurate and reliable fused layer modeling (FLM) feedstock composed of an impact modified polypropylene matrix, compounded with a cellulose nanofiber (CNF) reinforcement and coupled by a maleic anhydride coupling agent to produce comparable mechanical properties in comparison to the industry-standard method of injection molding (IM). Design/methodology/approach A spray dried CNF (SDCNF) was compounded with the polymer matrix using a masterbatch method. The composite was diluted with neat polymer and extruded into a filament and then printed into standardized mechanical testing samples. For comparison, the filament was chopped and standardized samples were produced with IM. Findings A loss in mechanical properties of up to 30% was observed in FLM samples. If normalized to reflect improved density from a part consolidation method, losses are reduced to 15% or show improvements in the neat polymer matrix. Originality/value Limited research has been done on producing FLM feedstock, reporting mechanical property results based on standardized testing and comparing the same material with IM.