Back to 3D Printing
Advantages of 3D Powder Printing
- Objects with negative space and undercuts can be printed out.
- Due to the pressure of the surrounding powder in the print bed, no printed support structures are necessary.
- Voids created by shelling parts must have access to the outside so that unused powder can be retrieved.
How 3D Powder Printing Works
- First, the 3D Printer spreads a thin layer of powder.
- Second, an
ink-jet printhead sprays binder throughout the cross-section of the part
- The build piston then drops down, making room for the
next layer, and the process is repeated.
- After the print, loose powder is dusted and cleaned from the finished part.
- The resulting material is very brittle with no tensile strength.
This must be considered during the modeling process.
- The printing
quality depends on the 3D powder print machine's layer thickness, which is set at 0.004 inch intervals.
- Deformation of the form is possible, depending on the geometry of the
part and its orientation.
- 3D printed objects can be finished by sanding, using filler, applying primer, epoxying, and painting.
- Epoxy Infusion for 3D Prints
General File Preparation Guidelines
- Only surfaces that form a closed object can be 3D
printed. The closed surface/polysurface model must be converted into a solid
object, which is described by the *.STL file.
- Create surfaces with no gaps (trim, etc.).
- Unify the Surface Normals of each object. Normals should be pointing toward the exterior (non-printed space) of the object.
- Wall thickness (dependent on the geometry): For parts with thin walls, normal engineering practices of adding ribs for
support, creating fillets, reinforcing edges, and/or minimizing spans
should be used.
- Wall thickness should not be less than 1/8 inch.
- Reduce cost: Parts should be shelled and have the voids connected to the outside so that we may reclaim and recycle the powder.
- Fitting parts: Very thin or spindly parts should be
constructed from a different material as they are vulnerable to break.
- When parts are designed to connect to a 3D printed model, the 3D
printed model should incorporate a mating socket or groove. Users must
offset mating walls negative 0.010 inch per occurrence, (the part
expands by this amount during the printing process).
- Scale: Be aware of the scale and units of the CAD model.
Application-Specific File Preparation Instructions
The RPC only accepts the file format ZBD for 3D Powder Printing. ZBD files are created by importing STL or VRML files into the ZPrint software, available on all DAAP CGC PC machines. The STL or stereolithography format is a list of the triangular surfaces that
describe a computer generated solid model. Information on how to export an STL file from your application can be found using the links below:
ZPrint HelpWhy ZBD Instead of STL?
| Importing CAD to ZPrint
| ZPrint Operations
| Creating Group Builds in ZPrint