Electronics Forum | Wed Dec 08 18:40:39 EST 1999 | shane.M
We encounter a similar problem, whereby stringing becomes a real problem when board temperatures are raised. We tried slightly larger dots, but this did nothing more than block the nozzles of the pick & place machine. You basically have only two opt
Electronics Forum | Mon Dec 13 21:05:34 EST 1999 | Curtis T.
Ken, we always build the bottom side of the board first. That also insures that there isn't any problems with the actives being reflowed and falling off in the glues curing process. By the way we do both paste and glue on the bottom of the boards t
Electronics Forum | Tue Dec 07 14:23:34 EST 1999 | JAX
Vahid, What type of error are you talking about? If you mean accuracy I would stick to round fiducials. As far as machines, the only question is about active component placement. For passive components Fuji(CP-series) is the way to go. O
Electronics Forum | Tue Dec 07 15:27:55 EST 1999 | John Thorup
Hello Vahid The most accurate fiducial for you depends somewhat on your board characteristics like contrast, spacing, inner layer features and obstructions. The more important consideration is what does the particular machine like best? The manufac
Electronics Forum | Tue Dec 07 21:38:54 EST 1999 | Sosina outry
Correct me if i am mistaken, I always hear the circle is better fid mark than any. Due to shape and dimension, one value of diameter is needed while square you need width and lenght. beside whichever fid mark, the accuracy will base on cad and techn
Electronics Forum | Mon Dec 06 10:26:56 EST 1999 | Dave F
Yins: We all use "Mnemonic" words or phrases to help in remembering facts. As part of our on-going training, we're trying to use a mnemonic to help people remember the resistor color code. Certainly, we "sailors" learned one that doesn't fit wit
Electronics Forum | Fri Dec 10 08:58:15 EST 1999 | Boca
Allow me a disagreeable moment here. 'Bad boys..' is memorable (learned it in high school), and that is the point of using a memory device is it not? Its purpose is not cultural training, moral instruction, or a life plan it is just a memory devic
Electronics Forum | Fri Dec 10 09:12:16 EST 1999 | Dave F
Boca: I appreciate your point, but that's surely not what the 60+% percent of our female assemblers think!!! Why make someone feel bad when there's no point, aside from learning a new way of doing something? I'm not sure that it makes any less of
Electronics Forum | Fri Dec 10 08:58:19 EST 1999 | Dave F
Glen: Thanks for the clarification. I agree with Wolfgang that fluxer setup could be the source of the problem. Bottom-side wave solder shorting has a fairly wide range of potental causes. For instance slow conveyor speed can produce the same con
Electronics Forum | Mon Dec 06 13:54:01 EST 1999 | Andy Yates
Mathematically, measure the component offsets from nominal then calculate the average and the SD of the offsets in x and y. You can then use the following equation to calculate the CpK: CpK = (Process Width - Abs(Average offset)) / (3 * SD offset)
