Electronics Forum | Wed Aug 20 20:10:30 EDT 2008 | davef
Naw, accounting is boring. Standoff could be an issue. Coupla things: * Above 30 thou, just about any cleaning process, more sophisticated than a garden hose, will produce acceptable results * Below 10 thou, can be cleaned with best efforts, but not
Electronics Forum | Thu Aug 21 08:33:09 EDT 2008 | davef
There is no standard as such. It's easy to see why. It's too complicated and has such a small payoff. Standoff is comprised of: * Package height * Solder thickness between the pad and the component lead * Delta of pad thickness and solder mask For p
Electronics Forum | Tue Oct 03 11:35:51 EDT 2000 | aaronho
Screen printing has much lower profile than dispensing. So it is suitable for chips without body stand-off, (Even sot23 has stand-off). But is is much faster. Dispensers can not catch up with some chip shooters.
Electronics Forum | Sun Jun 12 08:37:20 EDT 2005 | davef
Paramjeet Singh Gill Flip chip with aqueous flux, that's interesting. * What is the stand-off from the board is your flip chip? * What machinery and materials do you use clean your boards? * How do determine the cleanliness of the board under the fl
Electronics Forum | Thu Jul 03 15:03:39 EDT 2003 | Jim Nunns
My design group wants to change our route keep out around all SMT parts to 5 mil even under the parts with zero standoff. Are others in the industry routing under parts that have no standoff? My fear is that we will get shorting if the mask is scaped
Electronics Forum | Tue Mar 15 13:24:44 EST 2005 | pjc
There is equipment available to clean NC residues off low standoff devices, well below 0.8mm (0.031"), from Speedline Technologies- Electrovert and Accel. See this paper under Accel: "High Reliability Underfill Performance through Proper Flip-Chip D
Electronics Forum | Mon May 29 02:15:06 EDT 2000 | Dreamsniper
Hi Buddy, We've tried shifting to this process before and from our point of view here are some of the advantage and disadvantages that we discovered. Advantage 1) Cheap Equipment cost as you just need to use your Solder Paste Printer rather than buy
Electronics Forum | Tue Mar 24 20:25:18 EDT 2009 | davef
It is very common to use low residue flux with low-standoff parts. On the other hand, sure you can clean under low-standoff parts. We've talked about this previously. Search the fine SMTnet Archives to find threads like: http://www.smtnet.com/Forums
Electronics Forum | Thu Apr 05 22:27:06 EDT 2001 | davef
As a band-aid, consider running your chip wave when soldering these boards [Similar to Cals "dance with me babe" suggestion.] If the problem is as broad based as you say and the radial components have a tight fit, consider increasing the holes by a
Electronics Forum | Mon Mar 30 16:02:44 EST 1998 | Michael Allen
| We have successfully put .016" vias in .030" pads. | There is no issue with .030" solder balls, since | the actual volume of the .002" via in pad is small | compared to the ball+solder paste volume. | We did notice random bubbles where, apparentl
