Additive manufacturing is a process of making a three-dimensional solid object of virtually any shape from a digital model. Additive manufacturing is achieved using an additive process, where successive layers of material are laid down in different shapes. Additive manufacturing is also considered distinct from traditional machining techniques, which mostly rely on the removal of material by methods such as cutting or drilling (subtractive processes).
The first working additive manufacturing process was created in 1984 by Chuck Hull of 3D Systems Corp. Since the start of the 21st century there has been a large growth in the sales of these machines, and their price has dropped substantially.
Additive manufacturing technology is used for both prototyping and distributed manufacturing with applications in automotive, aerospace, military, engineering, dental, medical, fashion, footwear, jewelry, eyewear, architecture, construction (AEC), industrial design, education, geographic information systems, food, and many other fields.
What is Additive Manufacturing?
The term additive manufacturing refers to a collection of technologies where materials are selectively accumulated to build, grow, or increase the mass of an object layer-by-layer until a three-dimensional object conforms to its digital model. Objects that are manufactured additively can be found throughout the product life cycle, from pre-production (e.g. rapid prototyping) to full-scale production (e.g. rapid manufacturing), in addition to tooling applications and post-production customization.
The ASTM Committee F42 on Additive Manufacturing Technologies publishes the official terminology standard for the industry. ASTM F2792-12a generically defines seven process classifications for additive manufacturing, specifically Binder Jetting, Directed Energy Deposition, Material Extrusion, Material Jetting, Powder Bed Fusion, Sheet Lamination, and Vat Photopolymerization.
Currently additive manufacturing is frequently referred to as "3D printing," however these two terms illustrate the constantly evolving field of additive manufacturing. READ MORE
Additive manufacturing takes virtual blueprints from computer aided design (CAD) or animation modeling software and "slices" them into digital cross-sections for the machine to successively use during its controlled build process. READ MORE
To perform a build, a prepared file is dispatched to a machine where successive layers are executed as a series of cross sections. READ MORE
Supports are removable or dissolvable upon completion of the build, and are used to support overhanging features during construction. READ MORE
Additive Manufacturing Processes
A number of additive processes are now available. They differ in the way layers are deposited to create parts and in the materials that can be used. Some methods melt or soften material to produce the layers, e.g. selective laser melting (SLM) or direct metal laser sintering (DMLS), selective laser sintering (SLS), fused deposition modeling (FDM), while others cure liquid materials using different sophisticated technologies, e.g. stereolithography (SLA). With laminated object manufacturing (LOM), thin layers are bonded and cut to shape and joined together (e.g. paper, polymer, metal). Each method has its own advantages and drawbacks. The main considerations in selecting a system or process for a given part are based on functional goals. The materials that are joined by these additive manufacturing processes are specialized to perform in the dedicated apparatus on which they are to run. For example; powders to be fused must be capable of absorbing energy, jetted binders must be dispensable and polymers must respond to controlled activation. In general terms, one must select from the material choices that are offered by a given system menu. System manufacturers support the distribution of these materials to their user community.
Like all additive manufacturing processes, binder jetting begins with the processing of a digital geometric model into layers of finite height. The binder jetting machine will selectively bind (glue) one layer of powder at a time, each succeeding layer being swept over the previous one (sweep, bind, sweep, bind, etc.) READ MORE
Directed Energy Deposition (DED) is the ASTM term used to describe a family of additive technologies, which essentially adapt welding techniques to build up material into three-dimensional near net shapes. READ MORE
Fused deposition modeling uses a plastic filament or metal wire that is wound on a coil and unreeled to supply material to an extrusion nozzle, which turns the flow on and off. The nozzle then heats to melt the material. READ MORE
Material jetting uses a number of print heads (similar to a document inkjet printer) to selectively jet build material and support material into place on an xy layer before raising in the z direction to build up the object layer by layer. READ MORE
Photopolymerization is primarily used in stereolithography (SLA) to produce a solid part from a liquid. READ MORE
Powder bed fusion is the selective fusing of materials in a granular bed. The technique fuses parts of the layer, and then moves the working area downwards, adding another layer of granules and repeating the process until the piece has built up. READ MORE
In some printers, paper can be used as the build material, resulting in a lower cost to print.READ MORE