At 03:09 PM 12/12/96 -0500, you wrote:
Jim,
The difference between flying probe systems and grid systems goes as follows;
Grid Systems
1. Fixturing technology consistant to 20 mil pitch. When testing 15 mil
pitch you need an alignment mechanism (if poor registration on 20 mil pitch
false opens and shorts will occur).
2. Test times < 10 sec. per pcb not including placing and removing.
3. Fixtures take 1 to XX hours to build depending on complexity. Hand
loading of pins will get you .5K to 2K /hr. If there is a rev change and
parts are moved a new fixture must built.
4. When puchasing a grid, you purchase many grid points that are not
allways used. Typically $6 /pt
5. Continuity testing good to around 5 ohms depending on tester and fixture.
6. Resistor testing on some machines accuracy depends on system and fixture.
Flying Probe Systems
1. Test times are NET and POINT count dependant. Also test times will
climb if prober can not do "Adjancey." Adjancey is software driven from the
gerber data, the user will imput an "air gap" value and all nets within this
value are tested against each other. Some software out there will allow you
to do combinational testing between a grid and prober to reduce test times.
2. There is no fixture, generally your talking 5<= mil pitch. Also
registration is corrected on each PCB. Some use cameras others are manual.
3. Cotinuity is good to at least 1 ohm. Isolation typically is 250V,
most systems option to 1000V.
4. Cost from $250-400K US depending on size, software, and Voltages.
5. Some systems will allow for innerlayer testing, others lay horizontal
and bow, some will tension the PCB.
6. Resistor testing is not a problem on flying probes, accuarcy usually
to .1 ohms.
To sum it up, flying probes are for tight pitch, poor registration and low
volume (<50 panels). Grids do very well to 20 mil pitch and higher volume.
If you are in a quick turn enviroment with re-revs flying probe is the only
way to go, no fixture that has to be rebuilt or reworked.
If you have any more questions please feel free to contact me.
Regards,
Jeff Garland
Sales Engineer
Lavenir Technology Inc.
603-431-6279
FAX 603-431-6578
email [log in to unmask]
>Helloooo, again....
>
>Could anyone explain the difference between flying probe PWB testing and a
hard
>tooled bed-of-nails test? Pros and Cons?
>
>Thanks,
>
>Jim Marsico
>(516) 595-5879
>[log in to unmask]
>
> ********************************
> * ______ _ _ _____ *
> * / ___ | | | | | _____ *
> * / /___| | | | | | _____ *
> * __/ ____ | | | | |______ *
> * |____/ |_| |_| |________| *
> * *
> * SYSTEMS, INC. *
> ********************************
>
>***************************************************************************
>* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
>***************************************************************************
>* To unsubscribe from this list at any time, send a message to: *
>* [log in to unmask] with <subject: unsubscribe> and no text. *
>***************************************************************************
>* If you are having a problem with the IPC TechNet forum please contact *
>* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] *
>***************************************************************************
>
>
>
Jeff Garland
Lavenir Technology, Inc.
[log in to unmask]
603-431-6279
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To unsubscribe from this list at any time, send a message to: *
* [log in to unmask] with <subject: unsubscribe> and no text. *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] *
***************************************************************************
|
