ICT vs. flying probe testing - which is better? 2

[tfr]

How do you decide which is the best test? Any comments would help.

 

[gscotland]

ICT testing is better assuming that you have been given good access and the product has been designed for testability. As most PWB assembly plants are aware the highest area or opportunities for defcets are likely to be due to the manufacturing processes themselves and indeed this figure is likely to be around 90%.
So 90% of test faults are going to be due to manufacturing defects and in the interest of economics, detection and repair must be done at the earliest opportunity.
By using ICT and incorporating simple techniques like vectorless testing early and economic detection can be done.
The problems associated with ICT is the NRE cost to produce a fixture and the designers commitment to providing good test access.
The NRE is a simple return on investment calculation and will be related to product volume,however the testability of the product (test access) is also a simple ROI issue and requires a strong manufacturing engineering community to resist over the wall designs.

Flying probe appears as the panacea to all ICT problems ,no fixtures, fast time to market etc, however like all situations in the physical world you have to compromise, this compromise is test time, Test access due to a double pass philosophy and worst of all repeatability.
Many companies claim to have an effective flying probe philosophy my experience is that it is a poor substitute for bed of nails testing!