Electronics Forum | Wed Jun 26 08:53:32 EDT 2002 | davef
We have not done a DOE on board warping. Consider: * How close the board gets to its Tg during the reflow cycle * Amount of copper on each side and the balance between the two * Thickness of the board * Overall length x width * Time at temperature
Electronics Forum | Wed Jun 26 21:05:15 EDT 2002 | ianchan
Hi Dave F, customer calls it "warp", we can call it "twist/bow"..etc. the "warp" occurs on individual PCB cells of 28per each panel. the overall dimension of the panel is 139mm x 168mm, and each individual PCB cell is 2.4mm x 1.2mm. Thickness is 0.
Electronics Forum | Thu Jun 27 17:24:17 EDT 2002 | Daan Terstegge
Never did a DOE on that, but I think it would be quite difficult to warp a board inside the oven if it was flat when it entered the machine. If there's no center-board support then it's another story, then the board will bend due to it's own weight.
Electronics Forum | Tue Jun 25 13:30:42 EDT 2002 | Jeff Park
Folks, I am interested in learning more about solder robbing pads to help and avoid bridging for wave solder applications. I have heard of a few companys that use this process in their design but have not seen any documents for design rules etc.
Electronics Forum | Tue Jun 25 15:42:39 EDT 2002 | Daan Terstegge
Hi Steve, To my opinion your peak temperature is a little low. If you are sure that the BGA (especially the balls under it) reaches this 205 degrees then it should be OK, but if you measured somewhere else on the board then it's probably better to r
Electronics Forum | Wed Jun 26 10:36:24 EDT 2002 | Steve L
Thanks for all of your valuable inputs. The paste we are useing is PWS0111Ae36 (Alpha MEtal), peak temp from 210 to 225 C. The paste was on the floor about 3 weeks. ianchan, when you mentioned "no more than 6 hrs in the stencil", you mean no more t
Electronics Forum | Fri Jun 28 03:04:21 EDT 2002 | Dreamsniper
Forgot to include the following: Dwell time is from 55 secs to 68 secs. Indium specs for the paste is maximum peak @ 228'C and 30 to 90 secs dwell time above 183'C. PCB is a 6 layer board with Dimension of 205 x 166 mm but is slightly dense with 11
Electronics Forum | Tue Oct 01 08:01:23 EDT 2002 | mjz289
WE USE A HELLER 1500 EXL OVEN (5 ZONE OVEN) AND HAVE BEEN DOING PBGAs FROM 292 TO 780 BALLS WITH .O32" PITCH (.8 mm) AND METAL STIFFENERS ON TOP WITH NO PROBLEMS. I AM GETTING 210 - 215 DEGREES C AT THE BGA BALLS WITH 50 - 65 SECONDS ABOVE LIQUIDUS
Electronics Forum | Wed Jun 26 11:13:09 EDT 2002 | robbied
Can anyone help? Our Solder bar suppier is discontinuing the Sn63 Pb37 solder that they currently supply us. Another company has offered us a 'direct replacement' which is their own Sn63 Pb37 solder bar. The only problem I have with this is that the
Electronics Forum | Mon Jul 01 15:37:56 EDT 2002 | pjc
Possible cause can be design related- if the solder land is too small. Check w/ IPC SM-782 Solder Land Design Guide Another is board finish. I have seen problems like this with Gold finished PWBs- which creates a more brittle solder joint.Another pos
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