Design Validation Test (DVT) is where a custom fiber optic design is stress-tested under real-world conditions, and where many programs discover that what worked in EVT prototypes does not reliably survive the transition to repeatable manufacturing. Based on Coastal Connections, a subsidiary of Impact ES' experience supporting programs from prototype through mass production, here are five things engineering teams must get right in DVT before moving to production.
EVT prototypes are often built by experienced technicians under ideal conditions. DVT builds must demonstrate that the same optical performance—insertion loss, return loss, PER—can be achieved across the natural variation of a manufacturing process: different assemblers, slightly varying material batches, and realistic production conditions.
If performance data shows high scatter at DVT, the design or process is not ready for production. The sources of variation must be identified and controlled.
DVT is where assemblies are tested under operating conditions, not just room temperature. Thermal cycling, vibration, shock, humidity exposure, or vacuum testing (depending on the application) must be completed at conditions representative of actual use.
The acceptance criteria for environmental testing must be defined before testing begins, not calibrated after seeing results. Coastal Connections performs in-house thermal cycling from -65°C to 150°C EVT, and partners with Experior Labs for more extreme environmental requirements.
A 100% interferometric inspection protocol may be appropriate for high-value assemblies, but it must be compatible with the production volume and cost targets. DVT is the time to develop and validate inspection methods that will be applied in production, not prototype-stage techniques that are too slow or expensive to use at scale.
Every critical measurement must have a defined pass/fail criterion and a defined measurement procedure that produces consistent results across operators.
DVT should use materials from qualified production suppliers, not whatever was available for EVT prototypes. If production will use a different fiber spool, a different batch of connector bodies, or a different adhesive lot, that is a design change that should be evaluated in DVT, not discovered in production.
Supply chain qualification includes confirming that your key suppliers can support your production volume requirements and lead times.
By the end of DVT, every step of the assembly process must be documented in work instructions that any trained technician can follow to produce a conforming assembly. If producing a good cable still depends on individual expert judgment, the process is not ready for production.
Coastal Connections develops detailed process documentation during DVT that forms the foundation of our production quality system. This documentation is refined through PVT and becomes the controlled manufacturing procedure for mass production.
DVT is the last checkpoint before production investment. Moving to PVT with unresolved DVT issues is a predictable path to production problems.
Not sure if your DVT is truly complete? We've helped engineering teams catch the gaps before they become production problems. Request a technical conversation with our team at sales@coastalcon.com — no pitch, just an honest look at where your program stands.
