The Process for Box Build Assemblies

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Custom Interface Team

Typically, a box build will contain printed circuit board assemblies (PCBAs), wire harnesses, point-to-point wiring, and the mechanical structure of the box. Building all of this together is similar to making a cake, with multiple layers. The order and structure of the pieces is critical to the success of the project.

  • Build and test all printed circuit board assemblies used in the device.
  • Build and test all device cables and wire harnesses.
  • Cut, strip, and label the ends of individual wires in preparation for assembly.
  • Start the assembly of the box build from the bottom. Work up through each level. This includes bolting parts together, seating and interconnecting circuit boards, and connecting wire harnesses and point to point wiring.
  • Incorporate customer manufacturing specifications into each level. Inspect each level for:
    • Required labels
    • Wire routing
    • Screws with critical torque specifications
    • Continuity test points.
  • Conduct a final inspection prior to installing the covers of the assembly.
  • Test the device
  • Record the results.

Here are some basic considerations to ensure success of your box build assembly.


The electronic manufacturing services company must know the dimensions of your finished product, and its appearance. Supply design drawings with tolerance and clearances clearly labeled. Provide the size and weight of the finished unit in advanced. This is helpful to production, storage, and shipping.

Bill of Materials (BOM)

Provide your electronic manufacturing services company a detailed Bill of Materials (BOM) listing all components and materials needed. Details are important and helpful. Clearly state where the source of the materials, what you will provide, and what electronic manufacturing services company will provide.


Electronic manufacturing services with an in-house prototyping can provide key information for design and function testing. This can be done prior to production to identify changes needed before assembly begins.


Provide your electronic manufacturing services company of specific tests required during assembly and on the final product. Many times, a visual inspection is satisfactory, but functional thresholds may need to be met (and tested). Be sure to communicate with your assembler so they are aware of any required electrical and functional testing.

To avoid a long list of questions and multiple meetings to understand your needs, provide as much information as possible.

Simple box builds final test results may be a PASS/FAIL.  A contract manufacturer focused on quality will collect more information and develop a more comprehensive test procedure.

Learn more about Box Build Assemblies here >


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