What Is Rapid Prototyping?

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by Stephen Gould
February 16, 2022
By Stephen Gould
February 16, 2022

Rapid prototyping makes it possible to efficiently evaluate a product before manufacturing. Seeing and touching working prototypes allows you to make faster, more informed decisions that will help you beat competitors to market with the best possible product. Our prototyping services include CAD tables, 3D printing, thermoforming, and injection molding.

Rapid prototyping refers to a variety of manufacturing techniques for quickly fabricating a physical product, part, or assembly using 3D computer aided design (CAD). Key to the process is additive manufacturing, which is more commonly referred to as 3D printing. The manufacturing technology “prints” layer-upon-layer of material, creating a working prototype before your eyes. Prototypes aid visualization, design, and development of the manufacturing process in advance of production.

Prototypes are typically referred to as either low or high fidelity. Low fidelity prototypes are less refined and are used primarily for testing product functionality. A higher fidelity prototype will have a close physical resemblance to the desired final product to better evaluate it’s visual appearance and emotional impact on the customer.

The earliest rapid prototyping methods became available during the 1980s in the automotive industry. 3D printing quickly rose to prominence thanks to its affordability and speed.Today, rapid prototyping techniques are widely used across numerous  industries and applications and can even be used to manufacture production-quality parts in small quantities, enabling cost savings in comparison to a usual low quantity manufacturing run.

This guide summarizes common rapid prototyping processes and outlines the advantages of a rapid prototyping phase in design and manufacturing.

The Rapid Prototyping Process

Additive manufacturing is the most common rapid prototyping approach, but other technologies are also used, including casting, molding and high-speed machining.

Conventional manufacturing processes are commonly used alongside rapid prototyping methods. These include:

  • Subtractive manufacturing: creating a prototype by grinding, turning, or milling a block of material

  • Compressive manufacturing: forcing liquid material into a desired product shape and solidifying it into a mold or cast

Common Types of Rapid Prototyping

Prototypes can be made in many ways. An experienced product designer will be able to determine which method or technology is best for your product. Common rapid prototyping methods include the following.

Stereolithography (SLA) is the first successful method for commercial 3D printing. Stereolithography uses a bath of photosensitive liquid that is solidified layer-by-layer using ultraviolet light controlled by computers.

  • Advantages

    Good for producing parts with intricate geometries and excellent surface finishes

    Relatively low cost

  • Drawbacks

    Not as strong as prototypes made from engineering-grade resins

    Less ideal for functional testing

Selective Laser Sintering (SLS) tools are used in both metal and plastic prototypes. SLS 3D printed products are composed via a powder bed to build a prototype one layer at a time. A computer-controlled laser draws onto a hotbed of nylon-based powder from the bottom up, lightly sintering (fusing) the powder until it is solid. After each layer, a roller lays a fresh layer of powder on top of the bed, and the process repeats.

  • Advantages

    Fast and accurate printing

    Strong and durable for functional testing

    Relatively low cost

  • Drawbacks

    Rough surface finish and lack of fine details due to limited resin choice

    Material cannot be recycled

    Post-processing can be difficult

Selective Laser Melting (SLM) process is favored for the complex, high fidelity prototyping frequently employed in aerospace, automotive, defense, and medical equipment industries. SLM 3D printing processes use a laser or electron beam to melt fine metal powders and build prototypes layer-by-layer.

  • Advantages

    Wide range of metals available

    Ability to create complex shapes and internal features at a much cheaper price than traditional manufacturing

    No tooling necessary which reduces lead times

    Ability to produce multiple parts simultaneously

  • Drawbacks

    Expensive, especially if parts aren’t optimized for the process

    Specialized skills and knowledge needed

    Rough surface finish

    Require significant post-processing

Laminated Object Manufacturing (LOM) is a low cost, low fidelity process in which plastic, metal, and ceramic materials cut by laser beams or other devices are assembled layer-by-layer to create the CAD design. Each layer is delivered and bonded on top of the previous one until complete parts are made.

  • Advantages

    Quick and inexpensive, especially for large parts

    No support structures necessary

  • Drawbacks

    Parts are delicate and can absorb moisture

    Poor surface finish

    Not ideal for parts with internal structures and undercuts

Digital Light Processing (DLP) is similar to SLA in that it also involves the polymerization of resins that are cured by a light source. Instead of a laser, DLP uses UV light from a projector.

  • Advantages

    Quicker and cheaper than SLA

    Less waste due to using a shallower vat of resin

  • Drawbacks

    Sacrifices accuracy for speed

    Unpleasant odor

Binder Jetting allows for multiple parts to be printed at once. This process is performed by using nozzles to spray liquid binding agents that join powder particles into one layer. Powder is added layer-by-layer, spread by a roller, and then a binder added. The layering of powder and binder creates the prototype, which is cured in an oven to burn off the binding agent and fuse the powder into a single part.

  • Advantages

    Good for very large sizes

    High speed processing

    Well suited for printing colors

  • Drawbacks

    Less accurate

    Rough surface finish

Cost Factors for Rapid Prototyping

The cost of rapid prototyping can vary greatly depending on a size, scope, and complexity of your project. Typical cost factors include:

  • Physical size of the part

    Quantity

    Machining method

    Surface finishing

  • Volume of material used

    Labor costs

    Amount of post-processing required

Design Better with Rapid Prototyping

Stephen Gould’s team of experts is well-versed in a wide range of rapid prototyping technologies and processes. We can leverage our rapid prototyping expertise to help you make crucial decisions about design, materials, assembly, and more, so you can get your products to market faster than your competition.

Contact us today to learn more about our rapid prototyping services.