Polymer additive manufacturing for spare part production : technological potential for use in the norwegian Armed Forces

Polymer AM is a production technology that has gained popularity in recent years. The method requires little manual labor, physical space, raw materials and tooling during production. It enables the production of complex shapes at a low cost and it integrates well with digital engineering tools. The project aimed at investigating the feasibility of using polymer AM for spare part production with the goal of reducing spare parts obsolescence. A literature review was conducted aiming to investigate the main mechanical behaviors and characteristics of printed parts with a focus on fused filament fabrication. The possibility of on-demand, on-site production and digital value chains was also covered. The material behavior of select materials was investigated using tensile testing, dynamic mechanical analysis and short term tensile creep testing. Additionally, a case study was conducted where an obsolete part for a land vehicle was redesigned for polymer AM. It was then produced as a metal-polymer hybrid design using fused filament fabrication. This demonstrated the potentials and possible issues of the technology using the theory and laboratory data found. However, it was identified that material quality of produced parts can be inferior to that of traditional manufacturing methods. This was mainly attributed to defects such as lack of fusion and voids. Together with strong anisotropy, characterizing part performance can be difficult, limiting the applicability for demanding engineering purposes. Through the holistic approach combining theoretical, experimental and practical work, several aspects of AM for spare part production was investigated. It was found that the technology is promising for spare part production, but should be considered as an addition to existing production capacities and there is a need for systematizing the implementation and quality assurance of the technology.