DRC Check
The Design Rules Check (DRC) is the first also most important step in PCB quality control. If this step can’t be well controlled then the following steps will be hard to move on. When we receive a new order from a customer, we will use an automated tool to verify that the layout does not have any specific placement, routing or other addressable layout errors.
This DRC check will check the netlist and layout against the PCB design constraints and rules. It checks the board’s component placement and trace routing integrity for overlapping components, untraced pins, incorrect layer placement and constraints that are set for trace width routing and clearances. We also do the manufacturing rule check to make sure the PCB design is manufacturable. If we find any errors we will get in contact with the customer, or if we find the PCB design is not manufacturable we’ll provide some suggestions to customer, to do some changes on their design thus to match with our production capacity.
Electrical Testing
Electrical Testing is the second step for PCB quality control, also a key step. For prototype orders and production orders we have different methods.
Prototype Orders:
We offer Flying-Probe E-Test which means your circuit board (PCB) is checked through a device called a Flying-Probe E-Tester. The Flying probe testers we use have few restrictions on access, require no test fixtures, and can test boards with virtually unlimited number of nets. The Tester will check for short circuits, open circuits and make sure the nets of the PCB we made is the same as the nets in your design. After testing is complete, the fail rate of your boards will be less than 1%.
Flying-Probe E-Test can save e-test fixture cost for you, while its testing time takes long so we only employ it in prototype orders.
Bulk Orders
We use Testing fixtures to test PCB quality for bulk orders. The fixture contains an array of small, spring-loaded pogo pins; each pogo pin makes contact with one node in the circuitry of the DUT (device under test). By pressing the DUT down against the bed of nails, reliable contact can be quickly and simultaneously made with numerous of individual test points within the circuitry of the DUT.
The Tester will check for short circuits, open circuits, and make sure the nets of the PCB we made is the same as the nets in your design. After testing is complete, the fail rate of PCBs will be less than 0.1%. It is effective and more accurate, and in bulk order we’ll do 100% fixture e-test for you.
AOI ( Automated optical inspection )
We use an AOI to check the inner layers of multi-layers PCB. AOI visually scans the surface of the PCB. The board is lit by several light sources and observed by a scanner or by a number of high definition cameras. This enables the monitoring of all areas of the board.
This inspection is much more reliable and repeatable than manual visual inspection.
The last step for PCB quality check of each order is a 100% visual inspection. Each part is checked for workmanship, quality, cleanliness and a number of other attributes before the boards are packaged for shipping. We’ll always try to provide our “ABP” service and quality for you!