I work for a manufacturer of solder paste, flux etc.  We have developed a
number of tests we perform in house to evaluate ours and our competitors
products.  Most of the tests involve printing and them measuring the print
deposited with a CyberOptics laser scanner to derive volume statistics.
The things we look at are the pad to pad volume on a board for common
aperture openings, print to print volume, resolution, tack life (practical
life on a stencil until the printing suffers), and then plot trend data.
The trend data is collected for average volume, standard deviation, height,
width, the print axis vs the aperture axis, changes over time, etc.   This
type of data collection is easy to do with the correct equipment and
software.  The solder paste is printed on ceramic substrates to give a good
look at the paste character without the influence of solder mask and HAL.
Some elements of this technique may be suited to testing screen printers.
Contact me offline if you wish and we can discuss specifics.

Denis Meloche
Heraeus Cermalloy
610-825-6050




At 05:55 PM 8/5/97 -0400, you wrote:
>Hello TechNetters,
>
>Has anyone out there designed a test board specifically for evaluation of
>screenprinters and/or screenprint process DOE.
>If so, what types of land patterns did you include? BGA, mBGA, other CSP,
>Fine Pitch (15,20?).  Would you be willing to share the design?  I realize
>Topline has a board to do this but I feel that it does not include some of
>the newer packaging technologies and would like to cover all the options.
>I am also familiar with a board which was designed for stencil evaluation
>for AMTX and which was given out at NEPCON west.  I am currently looking to
>evaluate my screenprint process based on volume of solder deposited and
>height of the bricks.  Are there any other measurable results I may want to
>consider?  Also, I would be interested to know what others are doing for
>process control and SPC at their screen print operations.
>
>Greg Parke
>(617) 422-3192
>
>