One of the primary goals of manufacturing is to build a quality product, but there is more to quality than what you see on the production floor. Quality also means planning to avoid those problems and defects that can derail the delivery of a dependable final product. Consider for a moment the sinking of the Titanic. We know now that the quality of the steel and riveting used in shipbuilding processes of the time was not adequate for a vessel of that size to survive a collision with an iceberg, but that wasn’t the only problem the ship faced. The bulkhead design was compromised, binoculars weren’t available to lookouts, the crew made mistakes, and radio warnings of ice were ignored, and as everyone knows, there weren’t enough lifeboats for all aboard.
The lesson here is that quality control is a continual and all-encompassing process. If quality control, crew training, and risk management for the Titanic had been more thorough, the catastrophe might have been averted. In electronics, the quality of a circuit board is the sum of the entire manufacturing process as well, and not just the final inspection before it is shipped. Let’s take a closer look at the overall process of quality control in electronics manufacturing, and how to assure your circuit board is unsinkable.
Quality Control in Electronics Manufacturing Begins with Incoming Parts and Materials
To ensure quality from the start, PCB contract manufacturers will use their in-house engineering staff to review the design and evaluate its component requirements. In most cases, the parts that are specified on the bill of materials will be acceptable, but there are some concerns that the review will be looking for:
- Performance: There may be better options for some circuits where a replacement component or a design change will yield better results in the performance of the PCB.
- Price and availability: The components may be of good quality, but if they aren’t affordable or are unavailable, the circuit board won’t be completed.
- Component life cycle: Parts that are going to be discontinued by their manufacturer before the projected end of the project will impact circuit board production. It’s better to replace end-of-life or obsolete parts before production starts then to go through a redesign later.
Meticulous engineering review is an important part of the overall quality control process to ensure the successful manufacturing of a circuit board. The design will simultaneously be examined for its manufacturability in a DFM review, and any required changes will be recommended to the customer. Once all reviews are completed and any necessary changes are made, the next step in the quality control process will begin with the procurement of parts and materials.
To obtain good quality parts and avoid those that are counterfeits, the PCB CM must use the services of experienced procurement staff. This team will have developed a vast network of pre-qualified component manufacturers, distributors, and part brokers to work with. An established CM will have a network of PCB fabricators to choose from so that they can select the best vendor for the type of circuit board technology that needs to be built.
Lastly, all of the PCB fabs, parts, and materials that have been ordered will be inspected for quality. Once they are certified as fit, the board will be ready for manufacturing.
Maintaining the Quality While the Work is in Progress
Quality control in PCB manufacturing can be broken down into four main areas:
Quality can’t be maintained unless the manufacturing areas are clean, organized, and prepared for work. In the same way, the manufacturing equipment must be in good order to deliver the level of precision needed for PCB assembly.
2. Training & Certification
The contract manufacturer should hold the certifications required for building your specific type of electronics. Likewise, the manufacturing technicians should be IPC certified for soldering, rework, and other assembly operations.
3. Process Monitoring
The PCB CM should also have documented process controls in place. Procedures for assembly and system processes are crucial to maintaining consistency and quality in manufacturing.
4. Inspection Points
During PCB manufacturing there must be multiple inspection points to examine the previous assembly operation instead of trying to catch everything at the end. Inspections like these should be performed manually with automated optical inspection equipment to detect incorrectly placed components and bad solder joints.
Once manufacturing is completed, pass the circuit board to the final test phase to ensure the quality of the build.
Test and Final Quality Assurance
For the final phase of quality control in the circuit board assembly, the PCB contract manufacturer will run the board through an automated test. The most common of these tests are the In-Circuit Test (ICT) and Flying Probe. Their purpose is to validate the assembly process. By using probes to contact designated test points, the test system will send signals throughout the board to all of the parts. Signals will verify whether or not the pins have a good solder joint connecting them to the board. The automated test systems can also be used for detailed functional tests to determine if the components and their circuits are performing to their specifications.
When testing is complete, the fully assembled circuit board delivered to the customer will have passed rigorous quality control checks. At VSE, we’ve made strict quality control one of our highest priorities. We know that you need your printed circuit boards to operate without fail, and that requires the highest levels of quality in every step of the manufacturing process.