We recently announced that all our operatives will be trained to become Certified IPC Specialists.
Virtually all electrical and electronic assemblies and sub assemblies are connected to each other or the outside world by means of a cable or wire harness of some sort. A wire harness generally consists of a number of wires formed into a specific shape by means of cable restraints and terminated in crimps, connectors or solder joints. Each crimp, connector or solder joint is a potential weak link in the chain of connectivity, the early failure of any part of which can cause the failure of the entire unit.
A poorly made cable or harness may pass all the initial tests and yet fail when subjected to real world conditions especially as many are used in adverse environments such as aerospace.
Faulty cables and harnesses can be amongst the hardest items to diagnose.
The only way to guard against such failure is to ensure that all cable terminations are made correctly, using quality tools (calibrated where appropriate) and to internationally accepted standards.
The full title of the applicable IPC standard is IPC/WHMA-A-620B, Requirements and Acceptance for Cable and Wire Harness Assemblies.
The standard consists of a collection of acceptability criteria for cable, wire and harness assemblies. The acceptance criteria are based on visual inspection of the assemblies, measured criteria such as pull force are not addressed (but not excluded).
For each type of wire termination it sets out the target conditions, acceptable deviations and unacceptable conditions. Each of these is shown by means of a photograph and described by means of text, in case of a discrepancy, the written criteria always takes precedence over the illustrations.
The standard recognises that not every Electrical or Electronic Assembly needs to be built to the same standard, you would not expect a car radio to be built to the same standard as an aircraft autopilot! Hence the standard has criteria for three separate classes of product:
Class 1 – General Electronic Products
"Includes products suitable for applications where the major requirement is the function of the completed assembly." – Basically so long as it worked when tested that’s good enough!
Class 2 – Dedicated Service Electronic Products
"Includes products where continued performance and extended life is required, and for which uninterrupted service is desired but not critical. Typically, the end-use environment would not cause failures." – The computer on your desk for example.
Class 3 – High Performance Electronic Products
"Includes products where continued performance or performance-on-demand is critical, equipment downtime cannot be tolerated, end-use environment may be uncommonly harsh, and the equipment must function when required" – e.g. aerospace products.
The class should be specified by the customer. Tenkay most frequently manufacture to Class 3.
Because the standard sets out acceptability criteria it does not mean that this is the only criteria nor indeed that deviations are always not permitted. The customers requirements always trump the standard. The standard recognises the following order of precedence:
- The purchase order or contract between customer and vendor.
- Master drawing or master assembly drawing reflecting the customer’s detailed requirements.
- IPC/WHMA-A-620B.- when specified, and to the class specified, by the customer.
- Other documents as specified by the customer.
We believe that by training our staff to become Certified IPC Specialists they will become much better at identifying and solving problems since they will be working to well-defined criteria of what is acceptable and unacceptable. This is a key component of our Right First Time Quality Initiative.
Note – Text in parenthesis is quoted from the standard, copyright 2012 IPC www.ipc.org
Have you decided to subcontract your manufacturing, or perhaps your current supplier is the wrong fit for you? We’d be more than happy to chat through your requirements, so please give us a call today on 01903 855 464.
We are pleased to welcome Richard Purseglove into his new role as Engineering Manager. Richard has been a valued member of the Tenkay team since he joined us in January 2010. His quick progression has transpired through his hard work and dedication to the company.
Richard is most looking forward to helping drive the company forward through initiating ongoing improvements to the service we provide.
"I take pleasure in adopting the 'kaizan' approach (continuous improvement) to ensure we get the best out of what we have."
"I am also looking forward to adopting a managerial style that suits myself, my team and Tenkay as a whole."
To contact Richard please click here.