3D 打印技术

Characterization and evaluation of a PMMA-based 3D printing process

Abstract

Purpose – The purpose of this paper is to characterize and evaluate a new 3D-printing process based on Poly(methyl methacrylate) (PMMA).

Design/methodology/approach – A benchmark part and standard parts were designed, printed by a 3D-printer and characterized.

Findings–3D printed PMMA parts have a tensile strength of 2.91 MPa and a modulus of elasticity of 223 MPa. The mechanical properties can be improved by infiltrations with epoxy (tensile strength: 26.6 MPa, modulus of elasticity: 1,190 MPa). The surface quality of the parts can be improved by infiltration with wax for usage as lost models. The minimum feature size is 0.3 mm.

Research limitations/implications–The PMMA-based 3D printing process can be used for manufacturing concept models, functional parts and lost models for investment casting.

Originality/value – This is the first paper investigating a PMMA-based 3D printing process. Keywords Mechanical properties of materials, Surface properties of materials, Thermoplastic polymers, 3D printing, Poly(methyl methacrylate),

Benchmarking, Infiltration, Shrinkage, Surface roughness

Paper type Research pape

1. Introduction

Three-dimensional (3D) printing is an example of additive manufacturing or of solid free for m f abri cation technology.Powdered materials are deposited in layer s and selectively joined with binder from an ink-jet print head (Sachs et al.,1992). In recent years 3D pr inting came to the foreg round as a very competitive process in ter ms of cost and speed. Sales of these machines have increased significantly compared to other additive manufacturing equipment (Wohlers, 2009). There are several 3D printing machines on the market that work with different materials. The par ts can be mainly used for rapid prototyping and rapid tooling applications. Recently, several research g roups have utilized the 3D-printing technique for biomedical applications like the manufacturing of custom-made scaffolds for tissue engineering (Gbureck et al., 2008;Suwanprateeb et al. , 2009; Warnke et al., 2010).

A relatively new 3D printing process developed by the Voxeljet Technology GmbH (Augsburg , Ger many) is based on a poly(methyl methacrylate) (PMMA) polymer blend. The resulting plastic par ts can be used for concept models,functional models or lost models for investment casting. In order to improve the mechanical properties or the surface quality the printed par ts can be infiltrated.

The mechanical proper ties , surface characteristic and accuracy of additive manufactured models are of great importance for the application i n the field of rapid prototyping , rapid tooling and rapid manufacturing. Previous studies investigated and evaluated technical proper ties of parts made by 3D printing processes based on starch and plaster(Dimitrov an d va n Wijck , 2006) an d other additive manufacturing technologies. In order to characterize the technical proper ties appropriate test and benchmark parts are needed. Several studies (Juster and Childs, 1994; Ippolito et al. ,1995; Reeves and Cobb, 1996; Shellabear, 1999; Mahesh et al. ,2004; Suwanprateeb, 2007) have proposed geometric benchmark or test par ts for comparative evaluation of additive

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