By Mark Cotteleer, Research Director, Deloitte Services LP
An interesting study by researchers at Michigan Technological University examined the return on investment (ROI) of 3D printing at home.(1) The study focused on a commonly used additive manufacturing (AM) device (RepRap) that creates plastic parts using an extrusion-based process.(2)

To conduct the study, the researchers selected 20 objects, including shower curtain rings, a garlic press, a spoon rest, and a stand for a tablet computer, which are available on a popular website that provides open source designs for AM,(3) and they checked online shopping services to obtain price information for comparable items.(4)

The researchers calculated the total cost of production (materials, energy, machine cost) for each of their additively manufactured items and compared those costs to the comparable item’s purchase price. They assumed only the production of those 20 items during each year of AM device operation.

The total energy and materials cost of these 20 items came to $18.11, compared with retail prices of $312.03–1,943.83.(5) The researchers used these values to compute payback periods for the AM device between four months (when using the higher retail prices) and two years (when using the lower retail prices). ROIs were estimated using both a three-year and a five-year lifetime for the AM device.(6) Using the lower retail prices as a comparison, ROI ranged between 20–40 percent. ROI for the higher retail price comparison exceeded 200 percent for both three- and five-year lifetimes.

The researchers conclude that additive manufacturing of simple plastic components already represents an attractive financial trade-off for US households. With as little as a single day’s printing of simple household items, the designs, which are among the more than 100,000 available for free download, more than justify the cost of the device. As these devices continue to improve in quality, availability, and cost, home use of AM may very well become a mass-market application of the technology.

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1 B. T. Wittbrodt et al., “Life-cycle economic analysis of distributed manufacturing with open-source 3-D printers,” Mechatronics 23, no. 6 (2013): pp. 713–726.
2 The specific machine used for the study was a Prusa Mendel RepRap machine, with an estimated cost (for 2013) of approximately $575.
3 To see the selection from which the researchers chose, go to http://www.thingiverse.com/
4 The author takes pains to note that shipping costs, particularly for low-value items, often represent a substantial portion of total costs. Nonetheless, shipping costs have been excluded in the interest of conservatism in the results.
5 In an effort to be conservative, the researchers also incorporate a 20 percent “print failure rate” to account for circumstances where an object needs to be recreated due to quality issues.
6 The machine life is important because it determines the period over which the cost of the AM device itself must be amortized. In this case, the authors note that the expected machine life is much longer than three years, particularly in light of the fact that the RepRap is capable of printing out approximately 57 percent of its own replacement parts.