Green pcb 01

Design Validation Tests

The DVT build occurs when one configuration of your production-worthy design is made of components from production processes (and hard tools) on an assembly line following production procedures.

EVT DVT PVT download800x600 04
Download the Guide to Engineering Builds

14 pages of definitions, workflows, best practices, and common causes for delay at each phase.

The design validation test build is supposed to be one configuration of your production-worthy design, made of components from production processes (and hard tools) and on a line following production procedures. Design validation testing is a critical build between engineering validation testing and production validation testing where engineering teams typically unearth critical issues that will be magnified as volumes increase during subsequent builds and ramp.

Very few companies actually stick to the requirement of one configuration during the design validation test stage – because even if miraculously there are no outstanding issues, there may be parallel efforts to cut cost or increase yields that create additional configurations to build.

If you do have functional, performance, or reliability issues that are driving Plan B and Plan C configurations at this stage, it can be costly because each of those alternates needs to be built in “full quantity” to ensure that design can be fully mass-production qualified by the end of the build. That’s the real test for whether you are at DVT or not: if you are running side configurations of 20 units, you are fooling yourself, and should call it EVT2.

What is the purpose of Design Validation?

Design validation testing has two core goals. First, the aim is to verify mass production yields with one production-worthy design (one configuration for each shipping SKU). At this phase, mass production processes are introduced and the team begins to understand the critical issues that will impact production.

The second goal is to qualify the first hard tool for every part in the assembly. It is important to ensure that the transition to hard tools doesn't introduce unexpected issues.

What is the typical quantity produced during DVT?

Design validation testing runs typically involve between 300 and 2,000 units.

All parts in these units should be from hard tools or mass production capable processes. In addition to this requirement, all functional test stations must be present with limits in place to understand true yields. Understanding yields is critical to moving on to the next phase of development.

What types of things might go wrong during DVT?

Design validation is where engineering teams first unearth the critical issues that could impact production. The introduction of mass production processes may reveal unexpected issues that take dedicated failure analysis work to resolve.

The common issues that might cause delays during DVT include:

  • High functional fallout rates — requiring the need for fast failure analysis and corrective actions.
  • Cosmetic yields are 0% — there may be an effort to try to track down and fix cosmetic aggressors, but it is usually fruitless because your cosmetic part suppliers are likely still shipping scratched parts (and you are having to waive them).
  • At least one key process, such as gluing, is still not under control. In order to fix this key process issue you team might conduct:
    • DOEs (Design of Experiments or just “experiments”) that run with alternate glues or curing parameters.
    • Nightly calls with vendors demanding additional support or giving updates to hardware company executives.

When is DVT complete?

Design validation is complete when there is high confidence in all corrective actions for any issue that causes unacceptable yields on units using mass production parts made from mass production tools.

Additional resources for engineering validation testing:

Accelerate development builds remotely.

Instrumental captures images on the assembly line and leverages AI to detect defects and enable manufacturing optimization from anywhere.