The pre-production stage exists to catch process problems before that point—but only if the sample is made correctly. A sample built on approximate tooling or an undocumented process validates the design, not the production. At CMI, we fabricate pre-production samples on production tooling, follow a defined and documented process, and inspect them against drawing acceptance criteria before approving a single production unit.
Ready to discuss your pre-production program?
Contact CMI’s engineering team to talk through your documentation requirements, quality system needs, and production timeline.
Why Pre-Production Samples Fail to Support Production Approval
Most pre-production problems are not design problems. They are process problems that the sample stage was supposed to catch. When a sample is fabricated on bridge tooling instead of production tooling, it validates the geometry but tells you nothing about whether your production molds will hold dimensions. When the layup sequence and cure cycle are not formally defined and documented, any technician on the floor can run the process differently, and the sample becomes a one-time event rather than a repeatable procedure.
A pre-production sample that supports production approval needs to satisfy three conditions: it must be made with production tooling, it must follow a documented process that any qualified technician can replicate, and it must be inspected against the same acceptance criteria the production parts will be measured against. Meeting all three conditions separates a sample that de-risks production from one that creates false confidence.
CMI’s Pre-Production Sample Process
Production Tooling From the Start
CMI fabricates pre-production samples on production tooling, not bridge or soft tooling. The engineering team that designs the molds works alongside the fabricators throughout the process, which reduces the dimensional translation risk that occurs when tooling is outsourced or managed by a separate team. Because in-house design and engineering govern both the tooling and the sample fabrication, the validity of the sample depends on tooling quality and process fidelity rather than on coordination between separate vendors.
Defined, Documented Process Parameters
Before fabrication begins, the layup sequence, materials, and cure cycle parameters are defined and documented so that any qualified technician can repeat them. This documentation is not a byproduct of the pre-production stage. It is one of its primary deliverables. For programs that move into full production, that documentation becomes the foundation of the production process record and supports ongoing process control through CMI’s manufacturing and assembly quality system.
Inspection Against Drawing Acceptance Criteria
We inspect every pre-production sample against all drawing dimensions and features in the inspection plan. When the program requires it, we perform nondestructive inspection. The delivered documentation package includes dimensional records, material certifications, cure cycle records, and any required nondestructive inspection results. For programs where custom composite engineering is part of the scope, documentation can support design history file assembly.
Commercial Programs vs. Regulated Medical Programs
The pre-production process at CMI is structured differently depending on whether a program falls under standard commercial quality controls or regulated medical device requirements.
- Commercial programs follow standard production quality controls, with dimensional inspection and material traceability scaled to program requirements.
- Regulated medical programs run under an ISO 13485-compliant quality system. CMI confirms validation scope, inspection depth, and documentation at intake based on device classification and the OEM’s quality agreement.
CMI has been FDA-registered since 1985, and its quality system aligns with the FDA’s Quality Management System Regulation (QMSR), effective February 2, 2026. For medical OEMs sourcing composite components—including surgical table accessories and imaging-adjacent structural parts—this means pre-production documentation can be structured to support the full design history file from the start of the program, not assembled retroactively.
Why In-House Tooling Strengthens Sample Validity
One of the most common sources of dimensional error in composite fabrication is the gap between the team that designs the tooling and the team that runs the process. When tooling is outsourced, interpretations of drawing intent can differ, and corrections require coordination across organizational boundaries. At CMI, the engineers who designed the molds are available throughout fabrication. That continuity reduces the risk that a dimensional discrepancy in the sample reflects a tooling interpretation issue rather than a process problem, and it speeds root cause analysis when something needs to be addressed.
In-house tooling also means that modifications during the pre-production stage can be made without going back to an outside vendor and restarting a lead time. For programs with compressed development schedules, that flexibility directly affects whether the pre-production stage fits within the program timeline. Learn more about CMI’s co-molding capabilities and how integrated tooling supports complex part geometries.
Process Validation Evidence for Production Approval
The purpose of a pre-production sample is to generate documented evidence of process capability before full production resources are committed. That evidence — dimensional records, material certifications, cure cycle data, inspection results — is what allows a production approval to be made on the basis of data rather than assumption. Programs that compress or skip the pre-production stage typically surface their process problems at first article inspection, when tooling is already committed and modifications require significantly more time and cost than they would have at the pre-production stage.
For programs operating under CMI’s production quality system, the pre-production documentation package becomes part of the ongoing production record, providing a traceable baseline for any future process deviations, engineering changes, or customer audits.For OEMs in regulated industries, such as medical devices, defense, and aerospace, these baseline requirements can play an important role in supplier qualification, depending on the applicable regulations and program-specific requirements. Pre-production is the stage where process risk is either managed or deferred, and deferring it means paying for it later at a point in the program when time and tooling commitments leave far less room to correct it. Explore CMI’s full range of composite solutions to understand how pre-production fits within the broader program lifecycle.
Start the conversation before tooling is committed.
CMI’s engineering team can walk through your program requirements, documentation needs, and pre-production timeline.