Hello John, Your second statement is a little vague about the 16th card shutting down the line with the 2x240 QFPs misplaced... i'll try to interpret, assuming the cards are actual product, which I think they are, your 16th card failed because 2 out of 240 QFPs were misplaced. Is this a one time occurance or can you repeat this? You are assuming your machines are in spec based on the calibrations done by the manufacturer. Based on experience, these calibrations are not always correct! There are a number of possibilities that could cause errors like this. First and most likely, a bent nozzle could easily create a deviation that incorrectly places the QFP. Second, a placement head could be sporadically failing in a specific motion sequence. Thirdly, axis table motion could possibly be out of spec, or something that's not tested with the calibration. Honestly John, there are too many possibilities without knowing more about the equipment and what the calibrations have fixed or verified. To answer your question, what to measure to predict this occurring: You can only determine complete machine placement accuracy (and capability) with a test, even multiple tests, designed to exercise all axes, heads and nozzles during the placement routine. Tests like this need to use glass plates and glass components so that variability in materials is removed from the placement process. Only then can the machine tell us what's wrong. And, only with multiple components and multiple plates exercising the machine, can you begin to statistically determine its performance and placement capability. Let me know if you require additional assistance. Thanks!
This message was posted the OnBoard Forums
reply »