Cable assembly design is not an easy job as it looks, though it may appear just connecting two similar or different connectors in one cable. Designing its assembly takes time, patience and experience. There are lot of things to be considered, calculated, simulated and tested. Failure in any of these areas will lead to problems in manufacturing, or even in the customer that are primarily credited by poor designing.
But over the years, through the use of computer-aided software, equipment, and tools, errors are minimized, if not removed. Here are the major cable assembly design problems:
- Open connection– or high resistance connections occurs when supposedly connected terminations are having no electrical connection or weak electrical connection or intermittent connection. This is caused by accumulation of oxides over time from mated contacts. This is called micro-fretting. It can be avoided from designing by considering good wiping condition, and adding plating (if applicable, especially gold plating.) Other possible causes are weak mating force (or spring force), or intermittent crimp conditions, or over crimping, or terminal buckling or sink down. Other open connection problems for cable assembly design that are used many times on daily basis like mobile chargers. This can be solved by adding stress relief like mold or spring types.
- Short connection– is the connection of undesired terminations in one or both ends of the cable. Primary cause is the design and choice of insulating material which supposedly keep wires isolated from one another. This happens primarily in extreme environment conditions where the cable assembly is subjected to heat melting the insulators giving way to conductors to connect to another.
- Not good impedance– occurs if the effective resistance of the whole cable assembly design does not conform to the impedance required in the system. It can be prevented by choosing the right cable, proper shielding and insulation and wire sizes which suits the needs of the system.
Mis-wiring, though can be trapped in the production by means of electrical checking, but will still pose problem in supplier. It is caused primarily by improper presentation of cable assembly design drawing.
Inclusion of keying or POKAYOKE in the design is also important to prevent errors of mating in different position or with undesired connectors.
Bad packaging can also be attributed to cable assembly design which can cause deformities and other problems that will affect the functionality of the product.
These are critical and functional design problems that needs to be taken cared of at design stage. With the proper implementation of standards such as FMEA (failure mode and effect analysis), and collaboration of every concerned personnel, these can be reduced, if not eliminated.