Additive manufacturing offers a new way to make objects. First, let’s distinguish the dominant manufacturing technologies. Machining, in the form of milling, cutting, drilling, stamping, and so on makes objects by removing material off of a block of material. Machining is akin to sculpting, removing material in places it is not wanted or needed.
Injection molding takes a liquid form of a material and injects it into a mold where the material conforms to the contours of the mold and solidifies as it cools.
Manufacturing has used these two dominant technologies for about 100 years. They are well known, well-understood, and nearly all designers know how to best work with them when creating a new design.
Additive manufacturing makes parts differently than these two methods. It builds a part one layer at a time—whether the technology uses extrusion, vat photopolymerization, some type of bed fusion, or some type of material jetting—all of these options build a part one layer at a time. It’s this method of building that gives designers amazing freedom when creating an object. Designers don’t have to worry about whether a machining tool can go into a crevice to remove material. Designers don’t have to worry about mold restrictions required with injection molding.
Now let’s look at the ways additive enhances design freedom.
Leightweighting. One of the newer ways additive manufacturing is displaying its design freedom is through lightweighting. A good example of this is how additive has been used to make a bracket. Most brackets have been machined. Thus, brackets often use more material than actually needed to function. If a design uses topology optimization software, though, he/she can examine the bracket and remove any excess material not needed for the bracket to function. This removes weight from the bracket, and usually gives the bracket an organic look. To make this bracket, however, requires a technology that can handle all the open spaces and unusual curves. Only additive manufacturing can make it at a reasonable cost.
Part consolidation. Because additive manufacturing uses multiple degrees of freedom, a part can be made to include multiple assemblies and reduce part count. Without additive manufacturing, you can see that this pipe would require five separate pieces and about 24 fasteners to hold it all together and manage the directional changes. Additive technology makes this one piece. And because it’s all one piece, it helps remove possible weak points, such as the fastening.
Complexity is free. This is a common phrase associated with additive manufacturing. It means developers will not have to pay extra for complexity. Making a part with one curve can cost the same as making a part with a dozen curves. The more complex a design, the more the designer should consider additive manufacturing.
Internal channels. Additive technology easily handles designs with internal channels, such as those often used for cooling. Additive builds in multiple axes simultaneously, so internal features are much easier to build here than with subtractive or injection molding technologies.
Along with internal channels, additive manufacturing can be used to create internal voids or entrapped features that don’t require escape holes. Depending on the design, that can save weight while adding strength and support to a design.
Mimicking nature. Because additive manufacturing handles any geometry, this design freedom makes it easy for engineers to use nature as a design guide. Curves, holes, various geometric shapes are no problem for additive manufacturing.
Another design freedom is the ability to create structures with varying porosity. This freedom gives designers new ways to explore cooling options, filters, and catalysts in unusual ways.
Many are now exploring the ways additive technology can enable meta-materials, constructs of one or more materials to obtain specific properties and characteristics. In addition, designers can instill such properties in specific areas of a design. Meta-materials may be able to accomplish functions not possible with traditional materials and traditional design.
Thus, additive manufacturing gives design engineers a new tool to use to develop designs, objects, and parts not obtainable by other methods.