As mentioned in an earlier post, 3D Printing, while as amazing and exciting process, is best utilized in specific contexts. As Matthias Holweg wrote in the Harvard Business Review:
“The simple fact of the matter is the economics of 3D printing now and for the foreseeable future make it an unfeasible way to produce the vast majority of parts manufactured today. So instead of looking at it as a substitute for existing manufacturing, we should look to new areas where it can exploit its unique capabilities to complement traditional manufacturing processes.”
To illustrate this, take the ubiquitous child hood toy of budding engineers: the Lego brick. The classic 8 stud brick, if printed using ABS filament on a hobby 3D printer, would take about 15 minutes to produce and cost a dollar or two in raw material. Compare this, if you would, to the same design being produced on Lego’s high volume commercial injection molding machines populating the workshop floor in Billund, Denmark. This factory produces around 2 million bricks per hour, breaking down to just .017 seconds per brick, with an approximate raw material cost of $0.02.
The graph below can help visualize the trade-off between 3D printing and many traditional fabrication methods. Many methods (such as injection molding) have a very high set-up cost due to the need for custom tools and process development. If this cost is applied to a single part, you end up with a 6 figure plastic brick. As the volume of parts increase, that cost is spread out over those parts.
If you're thinking about using 3D printing, think carefully about how many you will need to make, and out of what materials. The per part price between a plastic injection molded part and a plastic 3D printed part get really close when you're between 100 and 1000 parts. Also, always look carefully at what you actually need in a part. 3D printing is a great tool for experimental design, but if you can answer a question with a Popsicle stick and a rubber band, that's even better.