The 3-D Printing Process
No matter which approach a 3-D printer uses, the overall printing process is generally the same. In their book "Additive Manufacturing Technologies: Rapid Prototyping to Direct Digital Manufacturing," Ian Gibson, David W. Rosen and Brent Stucker list the following eight steps in the generic AM process:
- Step 1: CAD -- Produce a 3-D model using computer-aided design (CAD) software. The software may provide some hint as to the structural integrity you can expect in the finished product, too, using scientific data about certain materials to create virtual simulations of how the object will behave under certain conditions.
- Step 2: Conversion to STL -- Convert the CAD drawing to the STL format. STL, which is an acronym for standard tessellation language, is a file format developed for 3D Systems in 1987 for use by its stereolithography apparatus (SLA) machines [source: RapidToday.com]. Most 3-D printers can use STL files in addition to some proprietary file types such as ZPR by Z Corporation and ObjDF by Objet Geometries.
- Step 3: Transfer to AM Machine and STL File Manipulation -- A user copies the STL file to the computer that controls the 3-D printer. There, the user can designate the size and orientation for printing. This is similar to the way you would set up a 2-D printout to print 2-sided or in landscape versus portrait orientation.
- Step 4: Machine Setup -- Each machine has its own requirements for how to prepare for a new print job. This includes refilling the polymers, binders and other consumables the printer will use. It also covers adding a tray to serve as a foundation or adding the material to build temporary water-soluble supports.
- Step 5: Build -- Let the machine do its thing; the build process is mostly automatic. Each layer is usually about 0.1 mm thick, though it can be much thinner or thicker [source: Wohlers]. Depending on the object's size, the machine and the materials used, this process could take hours or even days to complete. Be sure to check on the machine periodically to make sure there are no errors.
- Step 6: Removal -- Remove the printed object (or multiple objects in some cases) from the machine. Be sure to take any safety precautions to avoid injury such as wearing gloves to protect yourself from hot surfaces or toxic chemicals.
- Step 7: Postprocessing -- Many 3-D printers will require some amount of post-processing for the printed object. This could include brushing off any remaining powder or bathing the printed object to remove water-soluble supports. The new print may be weak during this step since some materials require time to cure, so caution might be necessary to ensure that it doesn't break or fall apart.
- Step 8: Application -- Make use of the newly printed object or objects.