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
Electronics Forum | Tue Dec 17 18:44:13 EST 2002 | davef
Two suppliers of singulation machines are: * Wand 847.459.2400fax2421 * Circuit Technology 847.705.2140fax2141 Search the fine SMTnet Archives for additional discussion. Also, look here: http://www.assemblymag.com/execute-vSection-Articles-vSu
Electronics Forum | Tue Dec 17 09:48:44 EST 2002 | russ
Temps are related to the components/PCBs being soldered. I am not aware of any Industry standard. If you are soldering flex circuits, .020" boards etc.. We use 500 deg tips a little thicker PCB/lead we go to 600, and so on. We never exceed 800 in a
Electronics Forum | Wed Dec 18 11:32:22 EST 2002 | johnw
The other thing to look at is the component spec, most will state a max, e..g SMT ceramic Caps are actually rated to be hand soldered at 500F!... fine if it's a light PCB but if it's a big thing with lot's of grounding.... Teh component suppliers re
