Rapid prototyping services fabricate prototype parts from three-dimensional (3D) computer-aided design (CAD) drawings. These physical models can convey more complete information about a product early in the development cycle compared to virtual models. Although conventional prototyping may take weeks or even months, rapid prototyping services can offer turnaround times of just several days. Parts can be tested early to identify problem areas requiring design iteration. By guiding a product from concept to market quickly and inexpensively, rapid prototyping services can help customers remain competitive while controlling costs.

Rapid prototyping services make use of equipment often referred to as 3D printers or additive manufacturing equipment that build parts by adding material layer by layer. Computer numerical control (CNC) machining equipment is common in rapid prototyping, cutting away material from a block to form a part.

Types of Rapid Prototyping Services

There are a variety of 3D printing technologies utilized by rapid prototyping services to fabricate objects, including:

Fused deposition modeling (FDM) is a type of extrusion in which filaments of a material such as thermoplastic are heated and dispensed from a nozzle to form layers of the final object. The material hardens immediately after extrusion. FDM techniques are slow for many object geometries, but are quiet and reliable.

Robocasting or direct ink writing (DIW) is similar to FDM in that a material is dispensed from a nozzle to form layers, but is different in that the "ink" is often a ceramic slurry that requires the final object to undergo a sintering process to achieve mechanical strength.

Stereolithography (SLA) builds object layers by focusing an ultraviolet laser onto a photopolymer resin in the desired pattern; the resin solidifies due to its photosensitivity. SLA provides high accuracy and great surface finish in the finished product.

Digital light processing (DLP) differs from SLA in that the light source is a more conventional lamp instead of a laser. The light is reflected off a deformable mirror device (DMD) or through a liquid crystal panel to expose the photopolymer from below. DLP requires a smaller volume of photopolymer than SLA, and is capable of faster operation because an entire layer is exposed at once.

Powder bed techniques include powder bed and inkjet head 3D printing (3DP), electron-beam melting (EBM), selective laser melting (SLM), selective heat sintering (SHS), selective laser sintering (SLS), and direct metal laser sintering (DMLS).

Laser sintering is a powder bed method similar to stereolithography. A laser is focused on a bed of powder material, fusing the powder in the desired pattern one layer at a time. Laser sintering allows material properties useful for real engineering applications, although the equipment required is typically complex and costly.

Laminated object manufacturing (LOM) cuts cross sections of the desired object out of a web material such as paper and layering each section with a plastic coating in between acting as a bonding agent.

Selective deposition lamination (SDL) is a lamination method similar to the LOM method. It involves carefully depositing adhesive in higher densities in the areas that will become the part, and much lower densities in areas that will only serve as support. This allows rapid removal of supporting material post-production.

Electron beam freeform fabrication (EBF) utilizes an electron beam to melt a metal wire and deposit the material on a metallic substrate that solidifies immediately. EBF reduces the need for surface finishing by creating objects that are very close to the final desired shape.

Image credit:

Proto Labs, Inc.