Cost-Efficient Low-Volume Production Through Additive Manufacturing

Abstract

Additive manufacturing, commonly known as 3D Printing, is a production method of rising popularity. The method works by adding layers of material, in contrast to subtracting, which is the dominating method today. The objective of this thesis has been to evaluate the cost-efficiency of producing relatively complex parts through additive manufacturing, compared to subtractive methods with production volumes less than 20 units. Initial findings narrow the additive methods down from seven, to two methods (Selective Laser Sintering/Melting and Fused Filament Fabrication) which are found best fit for end use parts. Data is gathered by acquiring price quotes from manufacturing companies for two plastic and two aluminium parts, through subtractive and additive methods. In order to look for intersections found at intermediate production volumes, the companies were asked to give price for 1, 5 and 20 units of the same item. Compared to subtractive methods, additive manufacturing processes are found to exhibit less cost-decrease per additional unit produced. The cost of producing a 150gram plastic part through the additive process was found to be between a quarter, and half the cost of the subtractive machining processes. In comparison, for a 15 gram part, additive manufacturing was found to be even more cost-efficient, with prices ranging between 10% and 20% of the alternative. The metal additive manufacturing process was found to be 15% cheaper than the subtractive at producing one single small part (100gram), whereas in contrast, it was 50% more expensive when producing 20 units. For manufacturing larger parts (500gram), it was found to be between 75 and 150% more expensive than the subtractive machining. As such this thesis complements existing literature on when to choose an additive process over the subtractive, and shows that whilst plastic additive processes are very cost-efficient for low volumes, metal additive manufacturing still has a way to go before becoming the natural choice for low-volume production