Development of 3D printer for functionally graded material using fused deposition modelling method

3D printing employed in additive manufacturing, converts digital data based on a computer-aided design (CAD) model into an object by adding material layer by layer. Unlike subtractive manufacturing, complex geometries can be printed with minimal wastage. The additive manufacturing process for 3D printers features several types of technology ranging from fused deposition modelling (FDM), laser sintering, stereolithography and laser melting to binder jetting and others. However, these technologies are limited to process one material at a time, which poses a challenge to print functionally graded material (FGM). This difficulty can be overcome by offering a unique solution which is proposed in this paper - by applying FDM customized with an extrusion screw to incorporate mixing and blending of the polymer matrix and filler as a continuous process during printing. The intent of this technique is to ease the production of FGMs (which vary in mechanical, electrical and texture gradually over volume) by incorporating additional filler into the polymer matrix during printing. Therefore, it could enable users to design and produce FGMs in a single printing process. A unique controllable mixer design is embedded in the printer to allow users to process and mix up bi-materials by varying the mixing ratio of two materials as required during the printing process. Through programmable logic controller (PLC), the printer is able to map the variation in material properties and control the mixing ratio required to achieve functionally graded 3D material.