Comparative life cycle inventory of CNC machining and powder bed fusion additive manufacturing: Comparative assessment of the materials and energy flow for three metal components manufactured by CNC machining and powder bed fusion

Juan Silva

Research output: ThesisMaster's thesis

Abstract

This thesis work aims to produce a life cycle inventory (LCI) in the comparison between one method from advanced manufacturing (AM) and one method from conventional manufacturing (CM). For the AM, a powder bed fusion laser beam (PBF-LB) has been utilized, and for CM, CNC-mill and CNC-lathe has been uti-lized. The comparative assessment was performed for the manufacturing phase of three different metal components. Two of the components are commercial prod-ucts from SEW-Eurodrive Oy and Proventia Oy. The third component is a spur gear optimized and designed by the author for AM and a solid gear for CNC-machining. Most of the components were manufactured from stainless steel 316L, but the SEW component manufactured with CNC was made of 11SMn30+C. The three components have been 3D printed with an SLM 125 HL. For post-processing, EDM was utilized to separate the build plates and CNC for the final operations. Similarly, the three components were manufactured with a CNC mill, and the SEW part was also made with a CNC lathe. The experiments performed in this thesis aim to replicate a real-life manufacturing scenario while measuring the input values. Hence, efforts have been made to reproduce the functional character-istic of the components, such as tolerances, thread sizes and surface roughness. These experiments aimed for accurate measurements of the consumables, such as argon gas and raw material waste. Energy meter devices were installed in all the machines to obtain electricity consumption during the operations and stand-by procedures. The results for the energy consumption were higher for the PBF than the CNC machining in all the components. The Proventia and SEW components manufactured with CNC-mill had higher material waste than those manufactured with PBF. The finished part weight from the optimized gear manufactured in PBF was 40% lighter than the solid gear manufactured with CNC-mill. The waste for the optimized gear manufactured with PBF was 69% greater than the solid gear made with CNC-mill. Both required almost the same total raw material input. The Proventia part was manufactured twice in PBF with a 30 µm and 50 µm layer thickness. The 50 µm layer thickness component consumed 10% less energy and argon gas and generated 16% less waste. The SLM 125 HL consumed 1.145 kg of argon gas to fill the chamber before printing. This SLM machine has a single laser and consumed an average of 2.3 kWh during the utilization of the laser and 1.35 kWh when the laser was not melting. The material waste of the filters and sieving from the SLM process were higher than expected.
Original languageEnglish
QualificationMaster Degree
Awarding Institution
  • Aalto University
Supervisors/Advisors
  • Ekman, Kalevi, Supervisor, External person
  • Reijonen, Joni, Advisor
Award date29 Dec 2022
Place of PublicationEspoo
Publisher
Publication statusPublished - 23 Jan 2023
MoE publication typeG2 Master's thesis, polytechnic Master's thesis

Keywords

  • life cycle inventory
  • additive manufacturing
  • powder bed fusion
  • laser beam
  • CNC-machining

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