One of the technologies that will enable broad access to space is 3D printing and rapid prototyping in general. Friday we will cover the use of 3D printing specifically in rockets (mostly DMLS), but today lets just cover the basics of 3D printing.
At heart, 3D printing is manufacturing a component by adding material instead of subtracting material. Instead of removing material by machining away from a brick of material, small pieces of material are fused together to create a solid part. Most 3D printing works layer by layer by adding the material in one layer then stepping up to the next layer and continuing until the end of the file. The most common sorts of 3D printing are fusing filament, sintering, and stereolithography.
Filament Fusing – also know as FDM (Fused Deposition Modeling) – This uses a small filament which is extruded and heated to a liquid, then positioned drip by drip in the right location. Most DIY printers use this and, in general, it is great for prototyping as it is usually cheaper but with with some ridges and layer marks.
Sintering – also know as SLS (Selective Laser Sintering) – This uses a high powered laser to fuse powdered material together. A version of this called DMLS is used for metals. This is great for plastic prototypes and low volume production of all sorts. The main issues are cost for large volumes and getting the powder out of enclosed areas.
Stereolithography – This uses a laser to polymerize a photosensitive liquid. This works very well for surface finish and general build quality, but it is a brittle material so it is only used for fit check and models.
3D printing is a great technology for complex parts in low volumes. Since that is a great definition for rockets in general, we are going to use a fair bit of 3D printing in our designs.