Validating Additive Manufacturing in 5 Steps
A printed part may function well but still be unsuitable for mass production. Anyone seeking to validate additive manufacturing must therefore examine more than just the dimensional accuracy and appearance of an initial prototype. The decisive factor is whether the material, machine, build process, post-processing, and inspection consistently deliver the required component performance under defined conditions.
For industrial applications, validation is not a single acceptance test, but a controlled process from the initial requirement to the approved production chain. Its scope depends on the risk: A mounting fixture with a limited service life requires different types of verification than a safety-critical aerospace component, a medical device, or a production part with defined media resistance. The following five steps provide a robust basis for decision-making.
Validating additive manufacturing begins with the requirements
1. Define the component’s function, operational limits, and test criteria
The starting point is not the printing technology, but the actual function of the component. What loads are static, dynamic, or impact-related? What temperatures, media, UV exposure, or cleaning cycles are involved? Are electrical properties, leak tightness, flame retardancy, or biocompatibility relevant? Equally important are production volume, planned service life, delivery windows, and the consequences of a failure.
These requirements are translated into testable characteristics. These include critical dimensions and tolerances, permissible distortions, surface areas relevant to function, and mechanical parameters. For a housing, for example, snap hooks, sealing grooves, and threaded inserts may be more critical than visible surfaces. For a fixture, positioning accuracy, rigidity, and wear are the primary concerns. Without this prioritization, it is easy to end up with a test plan that generates a lot of data but does not support a release decision.
The interface with the assembly also falls within this phase. A component may pass an individual test but fail during assembly because tolerance chains, screw tightening torques, or thermal expansion were not taken into account. Therefore, design, quality, production, and purchasing should jointly define the acceptance criteria. This prevents a prototype from being evaluated retrospectively against requirements that were never documented at the start of the project.
2. Select the Process, Material, and Design as a Process Package
The material designation alone is not sufficient. A PA12 component produced using the powder bed process behaves differently from filament-printed nylon, even if the chemical composition is similar. Orientation within the build volume, layer structure, moisture absorption, energy input, support structures, and post-processing all influence the resulting properties. Therefore, it is always the combination of geometry, material, process, and process window that is validated.
For high-strength nylon production parts, powder 3D printing often offers advantages in terms of production volume, design freedom, and reproducibility. Filament-based processes can be cost-effective for large fixtures, mounts, or tooling applications, provided that anisotropic properties and surface requirements are taken into account during design. Resin-based processes are suitable for, among other things, high-resolution components, casting patterns, anatomical models, or specific functional materials. The appropriate choice does not depend on a general quality ranking, but rather on the prioritized requirements.
In this phase, the CAD model is adapted for manufacturing. Wall thicknesses, radii, debinding openings, support structures, part orientation, and the tolerance strategy are specifically evaluated. Design for Additive Manufacturing does not mean designing as complexly as possible. It means using complexity where it reduces assembly effort, integrates function, or lowers a risk associated with conventional manufacturing.
At the same time, limitations should be openly addressed. Very tight tolerances, high-gloss visible surfaces, or load-critical threads are often achievable but require defined post-processing, suitable measurement strategies, or hybrid manufacturing steps. A sound decision identifies these additional steps early on, rather than discovering them only after the first batch of rejects.
The 5 Steps to Validated Additive Manufacturing
3. Produce reference parts using a risk-based inspection plan
The first reference part is not merely a visual sample. It serves to verify the key technical assumptions under production-like conditions. This includes a documented build job specifying the material batch, machine, parameter version, build volume position, orientation, and post-processing route. This is the only way to ensure that results can be traced and reproduced later.
The test plan focuses on the critical features identified during the requirements phase. Depending on the application, it may include dimensional inspection, 3D scanning or CT scanning, tensile, bending, and impact tests, leak testing, thermal aging, media storage, or assembly tests. For components with snap-fit connections, repeated actuation is often more informative than a single tensile test. For fluid-carrying components, leak tightness after thermal cycling may be more important than the visual surface finish.
Reference parts should not be selected solely based on an ideal installation position. If the geometry or quantity warrants it, various positions and orientations are examined. This reveals whether the quality variation falls within the intended production window. Particularly for functionally critical parts, the question is not only whether a prototype meets the requirement, but also how large a gap exists between actual performance and the minimum requirement.
4. Validate the pilot series under real-world conditions
A successful reference part confirms feasibility but does not yet guarantee a production-ready supply chain. The pilot series is used to verify whether multiple components and multiple production runs achieve the same quality targets. Typical production conditions are deliberately incorporated into this process: varying production run assignments, material changes within the approval rules, defined post-processing, packaging, and transportation.
This is also when it becomes clear whether the inspection method itself is suitable. A measurement system must be able to reliably distinguish the required tolerance. Test equipment, measurement strategy, fixturing, and evaluation are therefore coordinated. If a measurement produces more variation than the permissible process range, no reliable approval can be derived from the data.
Clear acceptance criteria are required for the pilot series. These include, for example, permissible dimensional deviations, minimum values for mechanical tests, documented surface conditions, and rules for rework. Deviations are not merely sorted out but evaluated: Is this an isolated case, a design weakness, or a process-related cause? This differentiation determines whether parameters, the design, or the test plan need to be adjusted.
The pilot phase is also the right time to evaluate economic metrics. Cycle time, scrap rate, rework effort, lot size, and lead time determine whether a technically suitable solution is also viable at the target production volume. For small production runs, a higher unit price may be acceptable if no tooling is required and changes can still be implemented quickly. As volumes increase, however, a combination of additive manufacturing and downstream automation may become a viable option.
5. Establish Process Approval, Documentation, and Change Management
Once series production is approved, the validated configuration is finalized. At a minimum, the following must be documented: material and approved batches, processes, machine class, relevant parameters, orientation, post-processing, inspection characteristics, inspection frequencies, and approval criteria. Depending on the industry, traceability, first-article inspection reports, certificates of conformity, or customer-specific documentation may also be required.
Managing changes is essential. A new material lot, a software version, a different machine, or a change in color can affect the component. Not every change requires a complete revalidation. However, it must be evaluated through a regulated change control procedure. This evaluation determines whether documents need to be updated, comparison parts inspected, or a new pilot run required.
Ongoing production also requires monitoring. Appropriate measures include defined incoming goods and in-process inspections, random sampling based on risk class, and the evaluation of customer complaints and process data. For stable, well-understood repeat parts, the inspection effort can be reduced. For new geometries, safety-critical applications, or process changes, it should be increased again. Quality assurance thus remains application-specific and cost-effective, rather than measuring as much as possible across the board.
Validation is a supply chain decision
Technical approval of a component is only complete if its supply can also be planned. This includes available machine capacity, qualified alternative processes, documented material supply, packaging requirements, and realistic delivery times. Anyone integrating additive manufacturing into a mass-production supply chain should also define how CAD revisions, orders, and approvals are managed digitally.
PartsToGo guides you through this process—from application verification through reference parts and pilot runs to repeatable production. The appropriate level of validation is not determined by a standard template, but rather by the function, risk, quantity, and verification requirements of the specific component.
The most sensible next step is therefore not a blanket material comparison, but a structured review of an actual CAD model along with its operating conditions. Once critical features and acceptance criteria are clear, a 3D printing trial becomes the basis for a well-informed industrial manufacturing decision.
