Electronics Forum | Sat Dec 14 18:40:29 EST 2002 | arzu
we are using aegis circuitca for manufacturing preparation. It works fine. we are a prototype center with small series of different cutomers.Our problem: keeping control over all components... Some are standard in house (used by other depertments as
Electronics Forum | Mon Dec 16 09:36:54 EST 2002 | russ
I have never had this problem. It sounds like you are right in imagining that there must have been a bad supplier of PCBS or an inadequate design rule being followed, or a very bad wave process to have this cracking over wave solder. Some books requ
Electronics Forum | Mon Dec 16 10:54:48 EST 2002 | davef
Knee of barrel and pad crack: Caused by thermal stress during soldering, because epoxy expands in the "z" 3X more than "x" or "y" which are restricted by the fiber. Related to: * Design of pads too large relative to hole diameter * Temperature at o
Electronics Forum | Tue Dec 17 18:16:18 EST 2002 | davef
Square apertures can have a larger area within the same space than a round aperture. You can buy IPC 7525 from IPC. The theory you are missing has to do with: * Aspect ratio * Area ratio Search the fine SMTnet Archives for background on these rati
Electronics Forum | Wed Dec 18 12:04:53 EST 2002 | slthomas
That issue (gasketing is what I usually see it called) was the driving force behind us getting new printers. Our old semi-auto clamshells just weren't repeatable enough, particularly over changes in squeegee travel direction. If the paste in the
Electronics Forum | Thu Dec 19 13:10:49 EST 2002 | gramsey
Really? Where does it say that? I have had the opposite experience and 3.2.2 from the IPC-7525 states for square or rectangular apertures - "Having a radiused corner for all apertures can promote stencil cleaning". It actually recommends circular ape
Electronics Forum | Thu Dec 19 14:29:03 EST 2002 | mark
It sounds like the stencil wasn't polished. Most stencil sources that only offer laser cut stencils do not have the electro polishing chemistry because they don't want to deal with the waste treatment issues. I suggest you verify that the stencil is
Electronics Forum | Thu Dec 19 14:29:06 EST 2002 | mark
It sounds like the stencil wasn't polished. Most stencil sources that only offer laser cut stencils do not have the electro polishing chemistry because they don't want to deal with the waste treatment issues. I suggest you verify that the stencil is
Electronics Forum | Fri Dec 20 11:32:51 EST 2002 | D. Adams
Check your stencil apertures making sure they are trapazoidal and smooth. I have hadjobs where the laser stencil was improperly cut (poor laser settings leaving a rough hole even after electropolish. Be sure to specify a .0005 trapazoid in your ste
Electronics Forum | Mon Dec 16 15:10:56 EST 2002 | Randy Villeneuve
We do not bake any of our boards prior to wave solder. If we did we would have one heck of a large oven. I would assume you are concerned about moisture sensitive components. In most cases your top side parts should only get to 80 degrees centigarde
