Rubber
Prototyping
Wayne Rubber supports product development programs with two distinct prototyping paths: 3D printed rubber-like parts for early-stage fit and form verification, and single-cavity prototype molds that produce parts in the actual production compound. Both paths are available at Wayne Rubber’s Wixom, Michigan facility, and both can be engaged before any commitment to production tooling.
Two Paths, Two Purposes
No single prototyping method answers every question in rubber product development. Wayne Rubber offers two complementary approaches that serve different stages of the development process. Understanding which path answers the question you are currently asking is the first step in using prototyping effectively.
Wayne Rubber produces 3D printed rubber-like prototype parts in-house using flexible filament materials. These parts are produced without tooling from your CAD file, typically within days. The primary purpose is fit, form, and assembly verification: confirming that the part geometry works in the mating hardware before any tooling investment is made.
- Lead timeDays, not weeks . no tooling required
- Best forGeometry verification, assembly clearance checks, early design iteration
- MaterialFlexible rubber-like filament . not a production elastomer
- What it cannot doValidate compression set, fluid resistance, tensile strength, or any physical property that depends on the true production compound
- Tooling costNone . print directly from CAD file
- IterationsFast and low-cost . revise the CAD and reprint the same day
Wayne Rubber produces single-cavity prototype molds that compress, transfer, or injection mold parts in the actual compound specified for production. The primary purpose is material and functional validation: confirming that the chosen elastomer performs as required in the application before committing to a multi-cavity production tool.
- Lead timeTypically 2-4 weeks including tooling fabrication and initial production run
- Best forCompound validation, functional testing, customer approval samples, regulatory submission samples
- MaterialThe actual production compound in the specified elastomer family and durometer
- What it providesTrue physical properties: Shore A hardness, tensile strength, compression set, fluid resistance, and dimensional conformance to the drawing
- Tooling costSignificantly lower than production tooling . single cavity, aluminum or soft steel construction
- Path to productionThe prototype mold can be used for low-volume production while production tooling is being fabricated, or additional cavities can be added to the prototype mold frame to scale volume
The Case for Prototyping in Rubber Product Development
The argument for skipping the prototyping step in rubber product development is always some version of the same logic: the design looks right in CAD, the compound is a standard catalog grade, and the application is not that different from a previous program. The argument against skipping is the cost distribution of where errors get caught. A design error caught during 3D print review costs a CAD revision. The same error caught after production tooling is machined costs tooling rework, schedule delay, and the complete scrap of any parts already produced. A compound selection error caught during prototype functional testing costs a compound change and a short prototype run. The same error caught in field returns costs warranty claims, customer relationship damage, and potential liability. Prototyping is not a cost. It is where the cost of errors is minimized.
The compound selection decision in rubber product development is consequential and not always reversible within a program timeline. A production tool designed for a 70 Shore A NBR compound cannot simply be used with a 60 Shore A EPDM compound if the NBR turns out to be incompatible with the service fluid. The part geometry may need to change to account for the different durometer, which means the tooling needs to change. A single-cavity prototype run in the candidate compound, tested under actual application conditions, identifies this incompatibility before production tooling is ordered. The cost of the prototype run and any required compound change is a small fraction of the cost of a production tooling rework driven by a compound error discovered after the fact. See the elastomer selection guide for the full framework on matching compounds to application conditions.
3D printed rubber-like parts look like rubber and feel like rubber at ambient conditions. They do not behave like rubber under the conditions that matter for sealing and gasketing applications. A 3D printed part cannot tell you the compression set behavior of the compound after sustained load at the operating temperature, because the 3D printing material is not the compound. It cannot tell you whether the part will maintain sealing contact force after 10,000 thermal cycles, or whether it will swell in the service fluid, or whether it will crack in ozone-rich outdoor exposure. These properties can only be validated with a part made from the actual production compound, molded by the actual production process. The single-cavity prototype mold produces exactly that part.
Rubber part geometry interacts with mold design in ways that are not always apparent from the CAD model. Draft angles that appear adequate in CAD may cause tearing during part removal. Wall sections that look sufficient in 3D may trap air and create voids during molding. A cross-section radius that works at 70 Shore A may be too stiff at the actual installation clearance when the durometer is confirmed. These issues are discovered and corrected during the prototype phase at the cost of a tooling revision on a single-cavity prototype mold. Discovered after a multi-cavity production tool is machined, the same corrections require rework on every cavity and potentially the runner and gating system as well. Prototype tooling changes are faster, cheaper, and less disruptive than production tooling changes at every stage of the program.
Many OEM programs require customer-approved samples before production tooling is ordered. Regulated programs in medical, food processing, aerospace, and defense require submission samples from the actual production compound and process as part of the qualification package. A 3D printed part satisfies neither of these requirements. The single-cavity prototype mold produces submission-quality samples in the actual production compound, with full material certification and physical property test data, which is exactly what a formal approval or regulatory submission requires. Starting with a prototype mold rather than building the full production tool first means the approval process runs in parallel with production tooling lead time rather than after it.
The conventional product development sequence is: finalize design, order production tooling, wait for tooling (4-12 weeks), run initial production samples, validate, find problems, rework tooling, re-run, validate again. The prototyping sequence is: run 3D prints while the design is still being iterated, finalize design, order single-cavity prototype mold (2-4 weeks), run validation with prototype parts while production tooling is simultaneously being ordered and machined, arrive at production tooling first article with known-good design and compound. The prototyping path does not add time to the program. It runs qualification activities in parallel with tooling lead time and eliminates the rework loops that extend timelines when problems are found after production tooling is received.
Choosing the Right Prototyping Approach for Each Question
Each prototyping method answers specific development questions well and cannot answer others at all. Use this table to match the method to the question being asked at each stage of the program.
| Development question | 3D Printed part | Single-cavity mold |
|---|---|---|
| Does the part fit the mating hardware? | Yes : best tool for assembly verification | Yes : with dimensional accuracy of a molded part |
| Does the geometry work for the application? | Yes : fast iteration at low cost | Yes : with production-representative geometry |
| Is the compound compatible with the service fluid? | No : 3D printed material is not the production compound | Yes : test actual compound in actual fluid per ASTM D471 |
| Will the part seal at the required compression? | No : 3D printed material does not have production compound properties | Yes : validate sealing contact stress with actual durometer and geometry |
| What is the compression set after service exposure? | No : not testable with 3D printed material | Yes : ASTM D395 Method B on molded specimens from actual compound |
| Will the part survive the operating temperature? | No : 3D printed material thermal properties differ significantly | Yes : heat aging per ASTM D573 on actual compound |
| Does the design need tooling-driven revision? | Partial : identifies gross geometry issues only | Yes : identifies all molding-process-dependent issues |
| Can I submit this for customer or regulatory approval? | No : not a production-equivalent part | Yes : with material certification and physical property test reports |
| How quickly can I get first parts? | Fastest : days, no tooling required | 2-4 weeks including tooling fabrication |
| What is the cost to iterate the design? | Lowest : revise CAD and reprint | Tooling revision required : still significantly cheaper than production tooling rework |
Wayne Rubber’s Prototyping Process
From Prototype to Production at Wayne Rubber
Ready to Start a Prototype Program?
Share your CAD file or drawing and describe the application. Wayne Rubber will recommend the prototyping path, confirm the compound, and quote the 3D printed parts and single-cavity prototype mold for your program.