Rapid prototyping uses 3D computer-aided design (CAD) and manufacturing processes to rapidly develop 3D parts or components for R&D and product testing. Rapid prototyping is typically performed through additive manufacturing, allowing designers to develop multiple iterations of a prototype without the additional cost or time associated with traditional manufacturing and design techniques.
What are the different types of rapid prototyping?
Prototype fidelity (i.e., how closely the prototype fits the final product) varies from project to project, ranging from low to high fidelity.
What is low-fidelity prototyping?
We refer to low fidelity when a prototype loosely matches the final product. Prototypes can test overall fit or functionality without optimizing weight, manufacturability, or surface finish design. Prototypes can also be used to test designs only in critical areas of concern to designers or to create scaled-down versions of the final product. One advantage of low-fidelity prototypes is that they typically require less time to print.
What is higher fidelity prototyping?
We refer to higher fidelity when the prototype closely matches the final product, including geometry, tolerances, and material properties. Prototypes with higher fidelity typically take longer to print and have higher associated costs.
What is the correct fidelity of your prototype?
The level of fidelity that applies to a given design iteration depends on the overall project goals, the design’s maturity, and the designer’s interest. Determining the appropriate level of fidelity in rapid prototyping can save time in the design process and optimize resource allocation.
Different prototype attributes, such as geometry, material properties, fit, and surface finish, can be considered at different fidelity levels for individual iterations. These considerations affect the overall fidelity of the prototype.
What are the most common rapid prototyping processes?
Rapid prototyping uses additive manufacturing to create test parts, models, or assemblies. However, depending on available resources and the designer’s needs, other more traditional manufacturing processes such as milling, grinding, or casting may be used.
Common prototyping processes fall into five groups.
(1) Light curing
(2) Powder bed melting
(3) Material extrusion
(4) Jetting
(5) Binder spraying
Detailed information on each process is provided below. To overview these rapid prototyping processes, learn more about additive manufacturing technologies.
Various processes for 3d printing
Stereolithography (SLA)
Parts with very high dimensional accuracy and intricate detail can be produced. However, they are often brittle, and their mechanical properties may degrade over time, making the parts unsuitable for functional prototyping. The process is best suited for rapidly prototyping design geometries and proof-of-concept of part interfaces. It is also suitable for details in the early stages of design and when mechanical properties are not a primary design focus.
Direct Light Processing (DLP)
Direct Light Processing (DLP) is similar to SLA, with the main differences being the level of detail and material properties. Parts produced using DLP do not have the same intricate detail as SLA but have the same or greater dimensional accuracy and part strength as traditional injection molded parts. Therefore, DLP is best suited for rapid prototyping and proof-of-concept of design geometry when the design focuses on overall geometry rather than specific details or when mechanical properties are a priority.
CDLP
Like DLP, continuous DLP (CDLP) produces parts that do not have the same level of detail as SLA but have the same or greater dimensional accuracy and part strength as traditional injection molded parts. Therefore, CDLP is best suited for rapid prototyping and proof-of-concept of design geometry when the design focuses on overall geometry rather than specific details or when mechanical performance is a design priority.
Powder Bed Fusion
Powder bed fusion (PBF) technology produces substantial parts using a heat source that induces melting by sintering or melting between plastic or metal powder particles one layer at a time. The main variations of the PBF process depend on the different energy sources (e.g., laser or electron beam) and powders (plastic or metal).
Selective Laser Sintering (SLS)
Selective laser sintering (SLS) uses granular thermoplastic polymer materials. Since SLS parts are printed using multiple layers, small variations may occur between parts. Therefore, SLS may be less effective for prototypes with complex details or small tolerances. Smooth surface finishes can also be achieved when using post-processing. SLS is best suited for rapid prototyping when part geometry or overall fit and function is a design priority. If post-processing is feasible, SLS may also benefit marketing or proof-of-concept prototyping.
Selective Laser Melting (SLM) and Direct Metal Laser Sintering (DMLS)
Selective laser melting (SLM) and direct metal laser sintering (DMLS) can be used for various metallic materials that typically require post-processing for surface finish. Therefore, these processes are best suited for rapid prototyping when material properties are a design priority. They can be cost-effective if part surface finish is not an issue.
Electron Beam Melting (EBM)
Electron beams melting (EBM), like SLM and DMLS, is best suited for rapid prototyping when material properties are a design priority and can be cost-effective if part surface finish is not an issue. The main difference is that EBM has limited material applications (titanium or chrome cobalt alloys). However, it may be the most appropriate option for specialty industries that require these materials (e.g., aerospace and medical fields).
Multi-Jet Fusion (MJF)
Multi-Jet Fusion (MJF) is similar to SLS but with shorter cooling and post-processing times and finer precision and detail. An in-depth comparison of SLS and MJF processes can be found by Wuhan cyber 3D Technology here. Like SLS, MJF is best suited for rapid prototyping when part geometry or overall fit and function is a design priority and can also be used to support higher levels of detail or tighter tolerances than SLS.
Fused Deposition Modeling (FDM)
Fused Deposition Modeling (FDM) is a very versatile process for a wide range of thermoplastic materials with short production cycles. One drawback is that FDM’s dimensional accuracy and resolution are lower than other additive manufacturing processes.FDM is best suited for early prototyping when part geometry or overall fit and function is the design focus. It is also best suited when the final part is made of materials similar to the prototype but without concern for details such as functionality or reliability testing.
Material jetting is considered one of the most accurate 3D printing techniques for various colors and surface finishes. However, material properties are not suitable for functional prototypes. Material jetting is best suited for rapid prototyping when part geometry or fit is a design priority and part strength is not required. It is also best suited when material properties, such as proof-of-concept or marketing prototypes, are not a concern.