Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Is the demand for in-circuit testing still high for PCBA?

Views: 1599

#55893

Is the demand for in-circuit testing still high for PCBA? | 7 August, 2008

As the pcb design is getting smaller and smaller, do you think that in-circuit testing is still applicable considering its limitations?

reply »

#55904

Is the demand for in-circuit testing still high for PCBA? | 8 August, 2008

Yes, sure. In fact in some applications ICT is coming back. Mainly due to the fact that more and more SMT discrete components have no markings, so AOI cannot tell you if you have the correct value on the PCB. Fixed pin or flying probe ICT is a valuable tool for MDA functions. Companies such as Teradyne/GenRAD, Seica and Agilient can take your PCB CAD data and give you a test coverage report. Also, design tools for fixtures are available from most fixture vendors. Obviously, flying probe ICT does not require fixtures. These systems have AOI cameras too. I think FPT delivers the best total coverage considering that Vectorless testing will confirm that bumped package devices are connected and not shorted, tests for opens and shorts in the circuits, plus AOI camera can check components with markings and ICT function measures discrete comps to ensure they are the correct value. Both modern fixed pin and flying probe ICT machines are very easy to program these days- some say they don't require a EE to program. Powerful software auto generates and auto debugs test programs for you, however full CAD data is needed for this.

reply »

#56048

Is the demand for in-circuit testing still high for PCBA? | 19 August, 2008

But the problem with flying probe is the cycle time. I'm not sure if there is a flying probe out in the market today that can match the cycle time of the conventional bed-of-nails ICT.

reply »

#56066

Is the demand for in-circuit testing still high for PCBA? | 20 August, 2008

They are faster today, but still not up to fixed-pin machine speeds. They tend to be 7x to 10x slower. Any of the machine suppliers can run a test evaluation and give you a report on test coverage and test times. There are techniques to make them faster. Try these guys:

www. seica.com

www.spea.com

www.texmac.com/takaya_index.html

reply »

#56089

Is the demand for in-circuit testing still high for PCBA? | 21 August, 2008

I would say yes. I don't believe that ICT will every be replaced by boundary scan. Now on some assemblies, boundary scan is viable and certainly a better choice considering test access constraints. But ICT still will play a vital roll in the future. Also, most systems today are boundary scan compatible, which is nice since you still have the ability for general in-circuit testing.

Flying probe is getting faster, but will never be at the speed of your ICT. The thing with flying probe is it doesn't provide as much test coverage as ICT. They are mainly for passive testing.

reply »

Used SMT

SMT in-printer dispensing