Additive Manufacturing (AM) is becoming more popular each day, and as all disruptive technology, its environmental impacts are still little known. Some authors have been studying and analysing its environmental impacts using Life Cycle Assessment (LCA) that is the most common method for this. This paper presents an experiment performed by using Life Cycle Assessment to identify the environmental hotspot of a start-up that uses 3d-printing technology to print orthotic insoles. The findings suggest that when AM is used by expert users (CAD and 3d-Printing) as a business opportunity to print small plastic products, the Printing process is the most impacting phase regarding environmental impacts. The 3d-printer machine, due to the energy consumption, causes the environmental hotspot and deserves special attention, particularly if environmental arguments have to be associated to the final product.