Three Things to Know About IPC 620 Standard Revision B

Three Things to Know About IPC 620 Standard Revision B

IPC 620 standard applies to the cable assembly and wire harness industry. It is an important process, materials, and inspections standard. IPC 620 standard describes the materials, methods, tests, and acceptability criteria associated with the production of solder interconnections and related assembly activities in the cable and wire harness assemblies. IPC/WHMA-A-620 standard was originally released in the year 2002, and now it has become the industry standard for quality parameters. It determines the expectations between WHMA members and respective customers about the necessary guidelines that identify the acceptable quality workmanship for cables and wire harnesses.

Cable and wire harnesses are used in an expansive range of electronic products. It includes aerospace products, automobiles, medical equipment, telecommunications, IT technology, construction, and robotics, and automation. Wiring harnesses decrease cost compared to multiple individual assemblies, reduces installation times, protect conductors from external conditions, and enhances safety. The technicians need to bear in mind the relevant IPC 620 industry standards and specifications to develop customized harnesses or assembly for the concerned project.

IPC 620 standard Revision B remains the only industry-consensus standard for requirements and acceptance of cable and wire harness assemblies. The A-620 was released in the year 2002 without a “Test” section. The standard was revised for the first time in the year 2006. The test section (section 19) was the major change in the A-620 standard in the revision. The Test Section uses three product classes for assemblies as per their intended use. General electronic products come under class one. It includes products suitable for applications in which the most important requirement pertains to the function of the completed assembly. Class two is concerned with dedicated service electronic products and includes products that require continued performance and extended life. Class three consists of high-performance electronic products which require continued performance or performance-on-demand. The product cannot suffer any downtime and the operational environment may be unconditionally harsh.

Here are a few things you should know about IPC/WHMA-A-620 Standard Revision B.

When Was Revision B Issued?

IPC/WHMA-A-620 gained certain significant updates in its Revision B module in the year 2012. The updates cover lead-free acceptance criteria, electrical and mechanical testing, and enhanced criteria and illustrations for molding and potting. It has 682 full-color pictures and illustrations. In the B revision of IPC/WHMA-A-620 engineers will find many technical updates, greater ease-of-use, and compatibility with other key assembly standards. Revision B defines the classes of products and includes criteria for Target, Acceptable, Process Indicator, and Defect conditions. It supports the collection of visual quality acceptability requirements for each class.

Revision B represents a consensus among industry leaders. After revision A in the year 2006, revision B was developed during a six-year process by members from user and supplier companies. IPC 620 Standard Revision B was prepared by the IPC Wire Harness Acceptability Task Group of the Product Assurance Committee and the Wire Harness Manufacturers’ Association Industry Technical Guidelines Committee.

What Changes Were Made Between A-620 Rev A And A-620 Rev B?

Revision B of the IPC 620 standard implements the following changes.

  • Table 19, which constitutes the Continuity Test Minimum Requirements under Class 3 adds the following words,

Rev A: “2 ohms or 1 ohm plus the resistance of wire whichever is greater”

Rev B: “2 ohms or 1 ohm plus the maximum specified resistance of wire whichever is greater”

  • Under section 19 of Electrical Test Methods that specifies the Dielectric Withstanding Voltage (DWV), the following paragraph was included:

“On points to be tested, harnesses shall […]be tested for DWV for all isolated continuity paths as defined in continuity tests. Conductive connector shells and unused contact positions shall [N1D2D3] be included where a risk of a short exists.”

  • Under table 19 of the Dielectric Withstanding Voltage Test (DWV) which details the minimum requirements, there is an addition of the following note:

Note 2: Voltage Level is applicable when clearance distance tested is ≥0.58 mm [0.019 in] an agreement between the User and Manufacturer to de-rate these test levels would be expected.

  • Under section 19 of Electrical Test Methods that details Insulation Resistance (IR), there is an addition of the following paragraph:

“On points to be tested, harnesses shall be tested for DWV for all isolated continuity paths as defined in continuity tests. Conductive connector shells and unused contact positions shall be included where a risk of a short exists.”

What Are the Current Revisions of the IPC 620 Standard?

Revision C of IPC 620 includes new sections that cover safety wiring, safety cable, wire seals, grommets, and raceways, and it improves upon the jack posts section. It was ensued five years after revision B for cable and wire harness assembly. It includes technical updates and makes it easier to use. There is another newly released D revision of IPC/WHMA-A-620, Requirements and Acceptance for Cable and Wire Harness Assemblies. It addresses more than 375 documented comments, and the major change was to remove the “target condition” from the entire standard. There is also the revision of Section 18 solderless wrap criteria and a new section for over-molding of flexible flat ribbon. The revision D is 420 pages long.

To Conclude:

A redline document that outlines all changes in the desired revision of the IPC 620 standard is available. Technicians can get training, certification, and instructional materials based on the IPC/WHMA-A-620B to define workmanship and quality in the production of cable and wire harnesses, and related assemblies.

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