Cables and wires play a crucial role in the manufacturing of various cable assemblies. Given their vital importance, it is essential that the cable used meets the required standards. The wires must adhere to the necessary specifications outlined in IPC-A-620, which is an industry-consensus standard document detailing the requirements and acceptance criteria for cable and wire harness assemblies. The IPC and Cable Harness Manufacturers Association collaboratively developed IPC/WHMA-A-620. This standard establishes the necessary criteria for wire preparation, crimping of formed and stamped contacts, soldering of terminals, machined contacts, splicing, and molding. It also covers wrapping or lacing, marking, connectors, shielding, ultrasonic welding, wire-wrap terminations, and insulation displacement connectors.
IPC/WHMA-A-620 describes the materials, techniques, testing criteria, and acceptance methods used in the production of crimped, soldered, and mechanically secured interconnections, as well as the intertwined assembly practices associated with cable and wire assemblies. While IPC/WHMA-A-620 can be used as a reference document for product procurement, it does not specify the end product or the frequency of in-process inspections.
Terms and Definitions
IPC-T50 provides specific terms along with their corresponding definitions. These terms are utilized in the IPC-A-620 document, each with distinct definitions to delineate particular requirements.
- Shall or Must – This indicates that the requirement outlined in the document is mandatory for all product classes.
- Should – This represents recommendations and can be utilized to reflect general industrial procedures and practices, serving as guidance.
- Wire Diameter – Denoted as “D,” this refers to the overall diameter of the conductor, including its insulation.
Classes of Products
Clients are expected to identify the class under which the cable and wire assembly is to be inspected. The decision to accept or reject the assembly should be based on applicable documentation, including specifications, contracts, standards, drawings, and reference documents. IPC-A-620 provides a procedure that defines this standard, encompassing three product classes:
- Class 1 (General Electronic Products) – This class comprises products that are significant for their applications, with the primary requirement being the functionality of the completed assembly.
- Class 2 (Dedicated Service Electronic Products) – This category includes products that require consistent performance and extended life, as well as products that need seamless services but are not necessarily critical. Failures in this class are typically not caused by the end-user environment.
- Class 3 (High-Performance Electronic Products) – This class involves products that require on-demand or continuous performance, where downtime is not permitted or where the equipment must operate whenever needed, such as in life support systems and other critical systems. Additionally, products in this class may be exposed to harsh end-use environments.
Specialized Designs
IPC-A-620, as an industry consensus standard document, provides criteria for commonly used technologies. However, it does not address the necessary combination of product design. When specialized or uncommon technologies are used, it may be necessary to establish specific acceptance criteria. In developing these criteria, customer consent and involvement are crucial, ensuring that the criteria include an agreed-upon definition for acceptance of all product characteristics. Whenever possible, new or existing criteria for specialized products should be submitted using the Standard Improvement Form included in the standard.
