Rapid Prototyping: What is it?

Rapid prototyping – literally “fast prototype construction” – refers to processes used to quickly produce prototypes, functional models, and initial small-batch components with low tooling costs. The goal is to test geometry, fit, function, and sometimes even material behavior before investing in expensive production tooling (e.g., for injection molding or extrusion).

In elastomer and sealing technology, rapid prototyping is particularly suitable for seals, O-rings, profile cross-sections, molded parts, and injection-molded parts. Design, assembly, and sealing performance can be tested on the actual component without the need for production tooling.

Typical Rapid Prototyping Processes

Rapid prototyping encompasses various manufacturing technologies – primarily from additive manufacturing, supplemented by fast tooling and cutting processes:

• 3D printing (additive manufacturing)
  Layer-by-layer construction of the component directly from CAD data. Depending on the process (FDM, SLS, SLA/DLP), thermoplastic polymers, photoresins, metals, or elastic, silicone-like materials are used. In sealing technology, this allows for the production of elastic prototypes with defined hardnesses (e.g., in the range of 35–65 Shore A), wall thicknesses from approximately 0.5–0.6 mm, and complex geometries – such as sealing lips, membranes, or profile seals up to several hundred millimeters in length.
• Selective Laser Sintering (SLS)
  Powder-formed material is locally melted with a laser and built up layer by layer. The process is suitable for robust functional prototypes with complex internal geometries, such as housings, support components, or technical molded parts that are later combined with elastomer seals.
• Stereolithography (SLA/DLP)
  A liquid, light-sensitive resin is cured layer by layer in a bath. Very fine details, smooth surfaces, and optically high-quality models are possible. Useful, for example, for visible parts or precise master models from which silicone molds for vacuum casting are later produced. Vacuum casting: A silicone mold is created from a master model (e.g., 3D-printed). Polyurethane or silicone systems are then poured into this mold under vacuum. This produces small-batch prototypes with a series-production-like appearance, feel, and mechanical properties – for example, for handle parts, housing components, or elastic molded parts. Subtractive processes (e.g., waterjet cutting, milling): Flat gaskets or profile patterns are cut out of sheet or panel material with precise contours. This is particularly interesting when near-series production materials (e.g., fiber seals, rubber sheets, PTFE films) need to be tested before a die is manufactured. Rapid prototyping is often complemented by 3D scanning and reverse engineering: Existing sample parts or components are optically measured, reconstructed as an STL or CAD data set, and then manufactured using the appropriate rapid prototyping process. Benefits in seal and molded part development Rapid prototyping enables, among other things, the following in the development of seals, profiles, and molded parts: Early installation and functional testing on the actual product Component
• Fast iteration loops for cross-sectional geometries, sealing lips, snap-in and plug-in areas
• Detection of collision points, tolerance problems, and assembly limits
• Realistic sampling for trials and customer tests
• Significant reduction in development time, tooling costs, and project risk

Important: Prototypes made from rapid prototyping materials are not always material-identical to the later series production. Especially with elastic seals and technical elastomers, tensile strength, compression set, media resistance, and aging behavior can differ. For the final approval of critical applications, sampling using near-series or identical materials and tools is therefore required. Synonyms / related terms: rapid prototyping, prototype manufacturing, additive prototyping, rapid tooling, rapid manufacturing.