Electronics Forum | Wed Jun 26 11:29:53 EDT 2002 | slthomas
Go to the top of the page and enter your topic in the "Search SMTnet" window. It can take some tweaking to get it dialed in to the exact topic you want. Do you mean the paste was on site for 3 weeks, or was it actually out of the fridge for 3 week
Electronics Forum | Wed Jun 26 21:41:46 EDT 2002 | ianchan
Hi mate, "no more than 6hrs in the stencil" for us means: 1) we finish setup of reflow oven, P&P m/c, and lastly the printing machine(includes loading of stencil into printer machine). 2) once printer machine is setup, we rip-open the paste Can pr
Electronics Forum | Tue Jul 30 08:37:39 EDT 2002 | davef
When you talk about 'poor wetting', 'dewett', 'no wets', etc.; are you seeing solder pulling back or away from the pad? Please describe the condition. Dewetting. The condition in the solder joint in which the liquid solder has not adhered intimate
Electronics Forum | Wed Aug 14 16:44:54 EDT 2002 | dragonslayr
What is the surface finish? HASL, Entek? what? If HASL, ask your fab supplier for recommendations, maybe even rerun the boards through the HASL process. The fab house would have to strip off the old coating and reapply. Just a thought, depends on y
Electronics Forum | Wed Sep 18 10:06:30 EDT 2002 | Bob M
I place 15-20 mil a lot. You need to look at your pad to apature reduction. Your stencil thickness. The type of paste your using. We use 2-5 mil reduction on each side as a general rule on fine pitch. This varies depending on pad width. We also use 5
Electronics Forum | Wed Sep 18 12:35:56 EDT 2002 | stepheno
Fourth - > back to design of PCB. Are there solder dams of > mask between the pads? If yes, that helps. If > not, pay close attention to stencil aperture > width and be sure that the aperture deposits less > paste by 1-2 mils per pad, centered o
Electronics Forum | Mon Oct 07 13:15:41 EDT 2002 | razorsek
Russ, this post doesn't specificly address your original post but I thought it is relevant to your situation and future production. I have been having problems with voids using Kester's R596L paste. I contacted them for a solution to my problem. T
Electronics Forum | Thu Nov 07 09:23:05 EST 2002 | russ
What would the considerations be in utilizing a type 4 paste as opposed to type 3? We have an assembly that has a large amount of uBGAs (12 mil diam pad)along with 50 mil pitch BGAs assorted fine pitch etc... We are experiencing difficulty in paste
Electronics Forum | Thu Nov 14 11:08:29 EST 2002 | bcceng
Kevin, I have done the following process to a similar problem: 1. Plug holes (even to both sides of the board) 2. Clean any flux left on the surface, especially on bottom side. 3. Apply Kapton tape to the bottom side, you mite want to apply 3 layers
Electronics Forum | Mon Dec 02 09:47:54 EST 2002 | davef
Most modern spec do not distinguish between process methods. So, there is no allowance "if you are using bla bla bla method, you should see ... . But if you are using bla bla de bla method, ignore that and look for ... ." Most specifications requi
