Ensuring High Quality Products through Exacting PCB Assembly Testing & Inspection

May 9, 2016

Printed circuit assembly is a complicated process that involves a number of individual stages. The various stages include adding solder paste to the circuit board, placing different components, soldering, testing, and inspection. All these processes are necessary to produce PCB assemblies that offer exceptional performance. Also, it is important to monitor every step to ensure that the highest quality products are produced. In this way, any problem can be detected quickly, and the PCB assembly process can be adjusted accordingly.

PCB Assembly Testing and Inspection Procedures

Testing and inspection help mitigate future faults and risks. Today, a number of procedures are employed by PCB manufacturers and assemblers all over the world. Mentioned below are some of the prominent PCB assembly testing and inspection procedures:
  • Visual Inspections: Visual inspection is an extremely crucial aspect to ensure that all circuit board issues are detected and rectified as early as possible. This aids in reducing the time and cost of the PCB assembly process. It will also reduce rework and time wastage. This process is conducted manually using high power microscopes.
  • Automated Optical Inspection (AOI): Automated Optical Inspection is a useful process, both for continuous process monitoring, and post-reflow inspection. AOI helps to:
    • Find incorrect orientation and polarities
    • Detect missing and incorrectly placed components
    • Identify short and open circuits, and thinning of solder
    • Detect faults and defects such as scratches, nodules, and stains on the board
  • In-circuit Test (ICT): This test is employed to detect open circuits, defective and wrong value components, current leakages, and incorrect polarities in the board. In-circuit testing also helps in examining the performance of various components like capacitors, diodes, resistors, and transistors, among many others.
  • Flying Probe Test: Generally, flying probe testing is employed to check PCB assembly prototypes and small volume builds. Convenience and cost-effectiveness are the most important factors for wide use of this method for detecting irregularities in the PCBs.
  • X-ray Inspections (3D and 2D): X-ray inspection provides vital visual verification against component misalignment, voids, open and short circuits, insufficient fill, etc. This method is generally used for QFN, BGA, and through-hole components.
  • Functional Tests: Every PCB product performs a different function, and thus demands a different testing approach. Functional testing equipment allows the testing and inspection of every product according to its exact function. This test is done to detect any functional defects in a PCB assembly.
  • Burn-in Tests: Burn-in testing is conducted to ensure that the PCB can perform perfectly in aggressive industrial applications, and environmental conditions.Exceptional PCB performance can only be achieved through stringent testing and inspection. So, when contacting manufacturers for PCB assembly services, don’t forget to inquire about the testing and inspection procedures employed by them.

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I approached Sierra after being referred to them from another PCB designer. What impressed me was that they were more than willing to take a complex PCB requirement. The PCB assembly they provided was small, lightweight, but provided the amount of power needed for our computer product. Great experience.

- Susan R – Business Computer Industry

I liked Sierra’s quick turn PCB assembly services. They provided a prototype within a few days, and it worked without a hitch. I was extremely satisfied with the quality of the PCB. Their prices are great too.

- Jason G. – Telecom Industry

Sierra Assembly Technology has a great group of people to work with. They are open to almost any request and always get the job done quickly. I’ve been in some tight spots before and needed certain products within a small time window, and Sierra has always been reliable.”

- Richard S. – LED Lighting Manufacturer

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Sierra Assembly Technology Inc.

10880 Mulberry Ave

Fontana, CA 92337

Phone: 909.355.5400

Email: sales@sierraassembly.com