The client and challenge
The customer, a faucet and fixture designer and manufacturer, was developing its next-generation kitchen faucet, which includes an E-Box, IR and handle sensor to control the hot and cold-water flow automatically. The functionality is controlled by software running on a microcontroller-based circuit board in the head of the faucet.
To ensure the manufacturability of the design produced by its research and development (R&D) group, the customer needed to validate the hardware design, schematic layout and PCB design and layout. Once the hardware design was validated, the customer needed to develop a production test fixture that would be used to test several PCB boards separately prior to final assembly. This test fixture needed to be completely designed and integrated into the production process used by a third-party contract manufacturer.
The EASi solution
EASi conducted a design review, which consisted of a schematic/layout review, Design Failure Mode Effects Analysis (DFMEA), power consumption evaluation with Q-currents, and component Failure Mode Effects Analysis
(FMEA). We analyzed the design of the overall systems and each of the three PCBs (valve board, handle sensor and IR proximity sensor), identifying design limitations and potential manufacturing and/or performance issues, and recommended design changes for an optimal product.
The customer accepted all design proposals, and based on our understanding of the product, the customer requested that we design and develop the necessary test equipment and software.
Commissioning: Shipping, assembly, acceptance testing, installation and commissioning at the contract manufacturer’s site was completed by our program manager. It was delivered first-time right at the manufacturing facility.
Design, development, assembly at the manufacturing facility, system commissioning and training was completed in 30 days. Final deliverables for the production test fixtures include:
- Test fixture requirement specification document
- System design document
- Bill of materials (BOM) and estimated cost from suppliers
- Test procedure document with instructions to the run the test sequence
- LabVIEW executable and source code files
- Mechanical and electrical drawings, as well as 3D models and 2D drawings
- Test executive
- Completed test station
EASi’s design review provided the necessary subject matter expertise to validate the hardware design, identify the necessary changes and move to production.
The test fixture designed by EASi can be used to check four types of PCBs and acts as a go/no-go gauge to segregate bad PCBs from the manufacturing line. It reduced test time for one unit of PCB from 30 minutes to 5 seconds, 75 percent less than the customer’s target of 20 seconds. Most of the components in the fixture are standard. The test executive is displayed on a touchscreen monitor that is mounted on the fixture and connected to the PCBs through an interface box.
The Unit Under Test (UUT) selection is based on operator selection. Operators on the production line can start the test with no action and the interface monitors the elapsed time, with options to edit the limits and the selection of the UUT (E-Box, Latching Sensor and Handle Sensor). Each PCB is compared against the tolerance band (upper and lower limits) given in the test executive. The fixture logs actual test case data captured on the monitor through a barcode scanner.
In total, our delivery model enabled the customer to outsource nearly 700 hours of work.