The high-precision grinding process is a critical step in the manufacturing of rigid boards, including rigid PCBs and ceramic substrates, ensuring tight dimensional tolerances, flatness, and smooth surface finishes required for subsequent assembly processes. This process involves using abrasive tools to remove material from the board’s surface, typically to achieve thickness uniformity within ±0.01 mm, which is essential for ensuring proper layer alignment in multi-layer PCBs and reliable component mounting.

The process begins with securing the rigid board to a vacuum chuck or fixture to prevent movement during grinding, ensuring stability and accuracy. Diamond abrasive wheels are commonly used due to their hardness and ability to maintain sharpness when grinding hard materials like glass-reinforced epoxy (FR-4), ceramics, or metal-clad substrates. The wheel’s grit size is carefully selected based on the desired surface finish: coarse grits (120-240 mesh) are used for rapid material removal, while fine grits (800-2000 mesh) produce smoother surfaces with Ra values as low as 0.05 μm, reducing the risk of signal loss or dielectric breakdown in high-frequency PCBs.

Coolant is continuously applied during grinding to dissipate heat, which prevents thermal damage to the board’s substrate and reduces abrasive wear. The coolant also flushes away grinding debris, avoiding scratches on the surface. The grinding parameters, including wheel speed (typically 3000-6000 RPM), feed rate (0.1-1 mm/min), and depth of cut (0.005-0.05 mm per pass), are precisely controlled using CNC systems to ensure consistency across large production runs.

For multi-layer rigid boards, grinding is often performed after lamination to ensure each layer has uniform thickness, facilitating proper alignment during drilling and plating. In ceramic substrates used in power electronics, high-precision grinding ensures flatness, which is critical for achieving good thermal contact with heat sinks. Post-grinding inspection using laser profilometers or coordinate measuring machines (CMMs) verifies that the board meets the required specifications, ensuring that subsequent processes such as etching, drilling, and component mounting can be performed accurately, ultimately enhancing the performance and reliability of the final product.