Additive Manufacturing – A new industrial revolution?

You name it and 3D Printing will manufacture-it-all. From a pin to a piano, 3D printing has been one of the most rapidly emerging and eagerly followed applications of Inkjet and deposition technology. The latest additions include a House, a Kidney, a gun, 3D printed meals and so much more.

3D printing is the broader term for tool-less manufacturing methods which enable to manufacture components from digital data layer upon layer. This tool-less production method changes the approach to manufacturing profoundly and thus allows completely new design freedom. Additive Manufacturing is the process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies. The most common additive manufacturing methods utilize this layered approach, but other geometries are also possible.

There are many reasons for the success of this technology and the great interest it has aroused. Potentials for a reduction of costs in stock-keeping and logistics are just a prelude. However, 3D printing also gives many causes for controversial discussions with regard to subjects like copyright and protection of intellectual property. In many cases, 3D printing is already an excellent method to accelerate development processes and to satisfy special wishes. Special applications, too, like light-weight construction and space-saving, compact designs are promising fields of activity for the additive manufacturing methods. Design engineers who combine the traditional engineering know-how with the design options of 3D printing are ahead of the game when it comes to optimising the performance of assembly modules.

There are various sub-technologies which constitute additive manufacturing or 3D Printing

Classification of additive manufacturing:

1) Selective Laser Sintering (SLS) and Selective Laser Melting (SLM)

In SLM & SLS the metal or plastic powder is melted by the energy of a laser beam or E-Beam and the required parts are built up. The powder which is not melted is removed after finishing the laser process.

Materials: Plastics (SLS), Metal (SLM).

Applications: With this technology prototypes and small batches of parts are produced. It is also used to repair and to build up material. Production of tools is a future application under development for this technology.

2) Fused Deposit Modeling (FDM)

In this process, a plastic or wax material is extruded through a nozzle that traces the part’s cross sectional geometry layer by layer. The build material is usually supplied in filament form, but some setups utilize plastic pellets fed from a hopper instead. The nozzle contains resistive heaters that keep the plastic at a temperature just above its melting point so that it flows easily through the nozzle and forms the layer. The plastic hardens immediately after flowing from the nozzle and bonds to the layer below.

Materials: ABS, polyamide, polycarbonate, polyethylene, polypropylene, and investment casting wax.

Applications: Form/fit testing, Functional testing, Rapid tooling patterns, Small detailed parts,Presentation models, Patient and food applications, High heat applications

3) Stereolithografie/Digital Light Processing

SLA uses a UV laser to trace out successive cross-sections of a three-dimensional object in a vat of liquid photosensitive polymer. As the laser traces the layer, the polymer solidifies and the excess areas are left as liquid. The platform is lowered by a distance equal to the layer thickness, and a subsequent layer is formed on top of the previously completed layers. This process of tracing and smoothing is repeated until the build is complete. Once complete, the part is elevated above the vat and drained. Excess polymer is swabbed or rinsed away from the surfaces.

Materials: Thermoplastics (Elastomers)

Application: Form/fit testing, Functional testing, Rapid tooling patterns, Snap fits, Very detailed parts, Presentation models, High heat applications

4) Laminated Object Manufacturing (LOM)

Parts are produced by stacking, bonding, and cutting layers of sheet material on top of the previous one. A laser cuts the outline of the part into each layer. After each cut is completed, the platform lowers by a depth equal to the sheet thickness and another sheet is advanced on top of the previously deposited layers.

Materials: Thermoplastics such as PVC; Paper; Composites (Ferrous metals; Non-ferrous metals; Ceramics)

Applications: Form/fit testing, Less detailed parts, Rapid tooling patterns

5) Photopolymer Inkjet Printing (PIP)

PIP is an additive process that combines the techniques used in Inkjet Printing and Stereolithography. The method of building each layer is similar to Inkjet Printing, in that it uses an array of inkjet print heads to deposit tiny drops of build material and support material to form each layer of a part. However, as in Stereolithography, the build material is a liquid acrylate-based photopolymer that is cured by a UV lamp after each layer is deposited. The advantages of this process are very good accuracy and surface finishes. However, the feature detail and material properties are not quite as good as Stereolithography.

Materials: Thermoplastics such as Acrylic (Elastomers)

Application: Form/fit testing, Very detailed parts, Rapid tooling patterns, Presentation models, Jewelry and fine items

6) 3D Printing

The process is similar to the Selective Laser Sintering (SLS) process, but instead of using a laser to sinter the material, an ink-jet printing head deposits a liquid adhesive that binds the material. Material options, which include metal or ceramic powders, are somewhat limited but are inexpensive relative to other additive processes. 3D Printing offers the advantage of fast build speeds, typically 2-4 layers per minute. However, the accuracy, surface finish, and part strength are not quite as good as some other additive processes. 3D Printing is typically used for the rapid prototyping of conceptual models

Materials: Ferrous metals such as Stainless steel; Non-ferrous metals such as Bronze; Elastomers; Composites; Ceramics

Applications: Concept models, Limited functional testing, Architectural & landscape models, Color industrial design models, Consumer goods & packaging

Additive manufacturing due to the shear scale of materials being used and the applications being targeted has surely brought upon a new industrial revolution and is threatening to change the way we manufacture or do business !

References

http://www.custompartnet.com

http://am.vdma.org