Electronics Forum | Mon Sep 23 22:31:48 EDT 2002 | davef
Comments are: * It�s interesting, but not surprising that your time above liquidous varies around the sides of this component. * You are correct in thinking that it is better to reduce than to increase the temperature differences around the component
Electronics Forum | Fri Nov 08 17:49:04 EST 2002 | davef
Questions are: * So, what is your thinking on this "insufficient contact causing intermitten failures"? * How do you print the paste? * Where do you place your therocouples when measuring reflow temperature? * What kind of solderability protection is
Electronics Forum | Tue Jun 28 13:04:08 EDT 2005 | slthomas
Are you saying that increasing the frequency of cleaning to every 3 boards *reduced* bridging, or that it's just something you tried? I don't understand why that would help(in my experience it has reduced "insufficient solder" conditions but not brid
Electronics Forum | Tue May 31 09:40:23 EDT 2005 | mattkehoe
We have some boards that exhibit poor solder wetting when reflowed. Nothing fancy, smallest pitch size .050. See photo's at http://www.sipad.net/SnPbwetting.htm Is this ; Contamination on the HASL finish? Insufficient solder,not enough to cover pad
Electronics Forum | Fri Apr 02 22:01:19 EST 1999 | Dean
| Anyone knows what is the optimum squeegee angle for screen printers. | | 45 Degrees. The forward velocity creates a downward pressure equal to the vector pressure (equalibrium). This is commonly known as paste "rolling action". Too obtuse an an
Electronics Forum | Tue Dec 08 15:19:42 EST 2015 | proceng1
Apply the correct amount of paste for the pad size should work ok, as long as the part starts out in the paste. If you have a reduced aperture and the leg doesn't quite touch any paste could result in non-wetting or insufficient solder issues. I gu
Electronics Forum | Wed Dec 08 11:26:04 EST 2010 | davef
3 Printer Area Conditions * As stated earlier, heat and humidity are damaging to solder paste. Ideally, the printing area should be maintained at 40% - 50% relative humidity and 72°- 80°F (22-26°C). In addition, no air (cool or warm) should blow dire
Electronics Forum | Tue Mar 03 03:02:17 EST 2009 | emmanueldavid
25% out of Lands in PCB, Insufficient/Inconsistent Alloy deposition which causes for poor Tackiness between Device Spheres & Paste deposited. Also note that Aperture Opening Designs in Your Stencil draws a huge role for these defects. 4. Placement: P
Electronics Forum | Wed Aug 15 13:40:55 EDT 2001 | rkevin
Just as there are a number of causes of solder balling there are also several factors which can lead to or encourage the formation of solder beads. - During the placement of the component solder paste may be squeezed out from underneath the compone
Electronics Forum | Fri Jul 13 19:08:55 EDT 2001 | mparker
Home plate apertures are designed to reduce or eliminate solder balls that occur when placing a chip and reflow of the solder. This aperture type is usually desired when processing with a "no-clean" solder paste. The design of the aperture is usually
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