Preventive Maintenance with a 3D Printing Option

Additive manufacturing (AM) technology, or 3D printing as it is otherwise known, has been developing rapidly. Among other things, it enables on-demand printing of spare parts via local 3D printing hubs. This theoretically eliminates the need for firms to keep spare parts inventory, even though such printed parts may not be as reliable as regular spare parts. To investigate this trade-off we develop two age-based preventive maintenance policies in which on-demand printed parts are used to protect against long system downtime. In the first policy the printed parts are only used temporarily, i.e., until a regular spare part arrives, while in the second policy the printed parts are subject to their own age-based preventive maintenance threshold. These printing policies are benchmarked against a common age-based preventive maintenance policy for which a regular part is held on stock. We find that the printing policies outperform this benchmark in terms of costs in many cases, but not in all. Specifically, on-demand printing should be used in a preventive maintenance setting when holding costs and direct failure costs are high. We furthermore find only small difference in performance between the two printing policies. These parts should be subjected to a preventive maintenance threshold only when printed parts are expected to last for a significant amount of time (i.e., several times the magnitude of the regular spare part lead time).