Soldermask

When soldering a printed circuit board (PCB), areas that are not meant to be soldered are protected by a layer of solder resist, typically a polymer material that prevents short circuits and contamination. This layer, often green or red in color, is called the soldermask and can be applied to either or both sides of the board. The soldermask protects the conductive traces from shorting due to debris but must be selectively applied to leave component pads uncovered to allow electrical contact. Exposed areas of the board, such as pads and edge connectors, may be "tinned" or plated with solder, while gold plating is sometimes used for edge connectors due to its resistance to tarnish and good conductivity. Solder paste, used to assist in the soldering of surface mount components, is applied to the exposed copper regions, promoting better solder flow during bonding. When designing PCBs with surface mount components, solder paste files are required for both top and bottom layers where these Read More

The manufacturing process for a two-layer printed circuit board (PCB) involves several precise steps to ensure quality and functionality. It begins with cutting the board material according to customer specifications, followed by drilling holes as per engineering data. Next, electroplating is used to deposit a thin copper layer on the hole walls, and the circuit pattern is transferred onto the board. Graphics electroplating adds layers of copper, gold, nickel, or tin where needed, and etching removes unwanted copper. A soldermask is applied to protect the circuit, and a silkscreen is added for identification purposes. The board then undergoes 100% fly probe testing to detect any defects. Finally, a thorough inspection ensures all boards meet quality standards, with minor defects being repaired as necessary. Read More

The text outlines various types of positioning holes used in the PCB production process, such as pressing positioning holes, mechanical drilling position holes, and copper plating inspecting holes. These holes serve different functions, including aligning layers, positioning for drilling and soldermask application, and ensuring the integrity of copper plating. The document highlights that these positioning holes are used in the production panel by the PCB supplier and do not appear in individual PCBs, with exceptions for special processing boards like HDI and laser drilling PCBs. Read More

This document outlines the quality control procedures for PCB (Printed Circuit Board) testing. It includes tests such as solderability, soldermask and silkscreen adhesion, plug-in component insertion, and hole section analysis. The solderability test ensures that each pad on the PCB surface is fully wetted and smooth. Adhesion tests use 3M adhesive tape to check for any peeling of soldermask or silkscreen layers. The plug-in test involves inserting components into the PCB to check compatibility. Hole section tests are compared against Gerber file requirements, and any issues are addressed promptly, with escalation to customers if needed. The Acceptable Quality Level (AQL) for these tests is set to zero defects. Read More