3D printing, or rapid prototyping, is the method of creating a physical replica of your CAD model. In order to effectively create a prototype, you’ll need to make sure your CAD draft is going to produce a quality result.
The common file format for a rapid prototype is .STL. It converts the CAD data into a list of x, y and z coordinate triplets that describe a connected set of triangular facet that are sliced by the printing software in order to create layers that can be printed.
Note that if you have problems converting your design, it could be an indication that the CAD data is not correct or corrupt.
Most Commonly Used 3D CAD Software File TypesThe CAD format must be converted using a resolution that works for the design. If it’s too low, it will not produce a smooth surface, which can affect the quality of the product. On the other hand, too high of a resolution will slow down the process because of the size of the file. You should work to find a resolution that takes into consideration both outcomes to ensure a smooth surface finish without too much time devoted to processing. After the CAD model is converted, it’s important to make sure the spaces in between any surfaces are closed, or “watertight.” If there are open spaces, printing may not turn out as expected because the geometry is not recognized by the computer. If your design is plastic and has holes that help connect parts, you will need to factor in that plastic expands and contracts when it’s heated and cooled. The dimensions related to this need to be adjusted or the parts may not fit properly. If your design has internal materials, they can be more difficult to print. When you’re in the designing process, it’s important to consider the layer by layer manufacturing process and its limits. If your design has layers, it will need rafts and supports, which are needed to build the product. Designs that are hollow are also difficult to print because the inside materials are hard to remove once the product is printed. Designs with multiple parts that require assembly will need to be printed with tolerances that accommodate each part to ensure that they will fit together. Tolerance values based on conventional manufacturing processes must be adjusted to between +/- 0.15” – 0.20.” You’ll want to be sure to balance part density and strength. 3D printing uses honeycomb structure to provide stability in thin walls, but you’ll still want to make sure the wall-thickness is not under 1.5mm. Anything under that can result in weak walls that can become damaged when you try to remove internal support materials. A thickness of at least 1.5mm on areas over 50mm is recommended. The model is built based on vertex normal, so make sure that all surfaces of the model have the normals pointed in the right direction. If it contains inverted normal, the 3D printer won’t be able to determine what is the inside and what is the outside of the model.
