Electronics Forum | Sat Mar 20 06:18:58 EST 2004 | agp
I haven't heard of anybody yet who have done smt and reflow after thruhole and solder wave. Thru hole components usually have low resistence to heat and could easily burn when subjected to the 210deg-245deg.C reflow temperature. For pc boards with co
Electronics Forum | Tue Jul 06 00:23:11 EDT 2010 | cksam
I am doing the case study of the component chip 0201 tombstoning problem. The significant causes was the reflow profiling preheat slope or ramp up rate. I really can't differential between preheat slope and ramp up rate. Could anyone here show me the
Electronics Forum | Tue Jun 06 12:27:11 EDT 2006 | flipit
Are you using 08MPF nozzles with front lighting? If so, these nozzles wear quickly if you place a lot of chip caps and resistors. I was using the 3500 vision system and found the vision recognized the nozzle once it was worn and became shiny. You
Electronics Forum | Fri Aug 10 04:19:05 EDT 2001 | wister
There are lots of voids at solder joint of chips,the thickness of multilayer pcb is 3.2mm,top side have lots of chip component and bottom side has several BGA and QFPs.For top side profile,the preheat time is about 100s,soak time is about 75s,time ov
Electronics Forum | Thu Mar 11 03:03:26 EST 2010 | grahamcooper22
Hi , Looking at your photo....can I also see a hole in the middle of the joint on the chip component ? Maybe its not just a problem with th ejoint son diodes ? Did you also get mid chip solder balls on chips? If so, I'd almost guarantee the pcb has t
Electronics Forum | Fri Jun 21 12:49:58 EDT 2002 | surinder
Hi Russ, Thanks for your input.My board has SMT Chip components, SOT23,SOIC's & 2QFP (25MIL PITCH). Also,taking consideration that the board is well design for Wave.This board has been designed end of last year. We have latest model of Electrovert ma
Electronics Forum | Sat Feb 22 11:27:16 EST 2003 | stefwitt
In the early days of SMT we were using vibratory bulk feeders for chip components. It was quite obvious that some of the components had to try several times getting through the gravity trap or with the right side up through the light sensor. As a res
Electronics Forum | Wed Feb 16 07:55:19 EST 2000 | Dave F
CK: I hear you about pads. Most secondary side SMT pads are primary side SMT pads that are on the secondary side. This only matters when boards are wave soldered. Rather than changing to larger components, consider a bigger fight than that ... ge
Electronics Forum | Mon Jan 17 08:09:05 EST 2000 | Mark Anderson
As stated previous, the following elements all have a effect on solder beading. Solder Paste, stencil apertures(reduction of home plate), stencil thickness, printing parameters, placement height, reflow preheat and soaking slope and dwell, manufactur
Electronics Forum | Mon Dec 13 18:17:44 EST 1999 | Calvin Wong
We have this solder ball & beads around chip components since day one of manufacturing using non-clean process. We managed to eliminate the solder beads around ceramic type chip componenets when we have a slow ramp up of pre heat at solder reflow. Ho
