This paper addresses critical issues related to the structural design of a micro-factory housing a mobile 3D printing system for plastic recycling. Rather than a simple comparison, it quantifies the “modification penalty”, the structural and economic cost of retrofitting a repurposed ISO shipping container (ISCC) versus deploying a purpose-built cold-formed steel (CFS) volumetric structure. Finite Element Analysis of a standard 20-foot shipping container revealed a serviceability failure in its roof under standard imposed loads. Concurrently, an initial analysis of an equivalent CFS structure also indicated non-compliance, with significant floor and roof deflections. Both platforms were subsequently redesigned with structural reinforcements to achieve full compliance with Australian Standards. The comparative evaluation moves beyond static analysis to incorporate critical performance metrics. While the CFS structure proved to be 575 kg lighter with a lifespan 300–400% longer, the modified ISCC was 47% cheaper in initial capital outlay (7161 vs. 13, 549). However, when considering the totality of performance factors, specifically the ISCC’s inherent vulnerability to resonance (8–18 Hz), which overlaps with transport frequencies, and the logistical burden of losing CSC certification upon modification, the CFS platform is conclusively identified as the superior engineering solution. Its design flexibility, predictable performance, and amenability to purpose-built optimization make it a more reliable and operationally secure platform for this specialized application.
Cunzolo et al. (Mon,) studied this question.