Rapid Prototyping Technologies

Over the past 25 years or so, several rapid prototyping (RP) technologies and methods have emerged — all based on the additive manufacturing concept. Rapid prototyping technologies and machines differ in terms of size, part accuracy, time of build, surface finish and cost. Because of these great variations, rapid prototyping technologies should be considered in light of the needs of the applications being targeted.

The following provides short descriptions of the major rapid prototyping technologies and methods, and their RP advantages.

Fused Deposition Modeling (FDM) Technology

Fused Deposition Modeling offers a layered manufacturing process in which a thin bead of molten plastic is extruded through a computer-controlled nozzle, and deposited layer-by-layer on a base to build up the desired form.

FDM Technology is the only additive manufacturing method that uses production-grade thermoplastics which can endure high heat, caustic chemicals, sterilization and intense mechanical stresses. This offers RP benefits for applications such as tough mechanical testing, manufacturing tooling, custom end-use parts and low-volume manufacturing. FDM is a relatively inexpensive RP process, and is clean, quiet and office-friendly.

PolyJet Technology

PolyJet rapid prototyping is based on a similar principle to that used in inkjet document printing, except instead of jetting drops of ink onto paper, the rapid prototyping method works by jetting layers of liquid photopolymer onto a build tray. Layers are cured by UV light and build up one at a time to create a 3D model, prototype or part.

PolyJet rapid prototyping offers significant RP advantages as it provides superior quality and speed, with a very wide versatility of materials. Pioneered by Stratasys (then Objet), PolyJet-based 3D printers can print 16-micron layers with a high accuracy of up to 0.1mm. Prototypes can be printed using a range of materials offering different properties — from rubber to rigid, from transparent to opaque and from standard to engineering plastics. Objet has also introduced a range of more than 100 materials with the ability to combine these to produce advanced composite materials and to specify up to 14 separate materials properties in a single printed model or prototype.

Other Rapid Prototyping Technologies

Selective Laser

Sintering Selective Laser Sintering uses a high-power laser to fuse 3D parts from powdered materials. Compared with other rapid prototyping methods, this technology can produce parts from a relatively wide range of materials, such as plastic, metal, ceramic, or glass.

Stereolithography

Stereolithography works by curing liquid photopolymers when exposed to ultraviolet light. This technology provides a good surface finish and is suitable for conceptual and presentation designs.

Rapid Prototyping Technologies — Summary:

Selective laser sintering (SLS)

Thermoplastics, metals powders

Fused Deposition Modeling (FDM)

Thermoplastics

Stereolithography (SLA)

Photopolymer

PolyJet

Photopolymer and composite photopolymers