Which method is NOT part of the inspection for bare circuit boards according to IPC-A-610?

Tactile examination is not considered a formal method of inspection for bare circuit boards according to the IPC-A-610 guidelines. The IPC-A-610 focuses primarily on visual inspection methods and defined criteria for evaluating the quality of printed circuit boards (PCBs).

The other methods listed are crucial for ensuring the integrity and functionality of the circuit boards. Inspection for surface defects involves examining the board for any physical imperfections that could affect performance, such as scratches, discolorations, or contamination. Inspection for conformance to design specifications ensures that the board has been manufactured according to the established standards and design documents. Dimensional accuracy checks assess whether the dimensions of the board align with the technical drawings or specifications, which is critical for component placement and overall assembly compatibility.

By focusing on visual and measurement-based inspection approaches, IPC-A-610 ensures that bare circuit boards meet the necessary quality standards without relying on tactile methods, which may not provide reliable or consistent results across different boards.