Electronics Forum | Fri Oct 16 14:11:16 EDT 2009 | davef
thermal and pad
Electronics Forum | Thu Oct 15 11:04:28 EDT 2009 | spitkis2
Thanks Jim. Pressing the QFN into paste was what I thought of, just wasn't sure if it would cause solder paste to be pressed outside the pad area and possibly bridge with an adjacent pad. Do you recall the ratio of paste coverage to the pad area?
Electronics Forum | Fri Oct 16 14:45:58 EDT 2009 | cyber_wolf
Many pick and place platforms rely on nozzle spring pressure to determine how hard a part is getting pushed into the paste.
Electronics Forum | Fri Jan 29 07:41:24 EST 2010 | davef
Señor Tech: Consumer walkie-talkies are cheap toys. Look at commercial W-T for light industrial use by Motorola or Kenwood.
Electronics Forum | Fri Oct 09 00:57:05 EDT 2009 | jjmag921612000
SteveO, I had personal experience with this using a Panasonic MPAV2B. It took a while, but I believe the end result was to have some additional "Z" travel to press the QFN into the paste. Also, the design of the paste on the ground was key to keep t
Electronics Forum | Wed Oct 21 08:06:06 EDT 2009 | scottp
I agree with Dave. If the device has a lot of power we'll put thermal vias between the solder deposits with annular rings of soldermask to keep solder out of the holes. We've never had to mess with placement pressure. We've been using QFNs for yea
Electronics Forum | Wed Oct 20 04:42:02 EDT 1999 | park kyung sam
we did this for pad design of pcb and can also use it off- line programming for mounter. we had checked out all the component we used in our factory. we sorted 600 kinds parts using part size(L,W,T) ,number of lead ,shape with over 6,000 parts. a
Electronics Forum | Wed Sep 30 13:10:49 EDT 2009 | spitkis2
Hi guys, Can someone please clarify whether adjustment of Z axis travel is a critical parameter during placement of QFN devices. If so, to within what tolerance? In other words, should a pick and place machine position a QFN down on the board so t
Electronics Forum | Tue Sep 21 13:12:56 EDT 1999 | Dave F
| My stencil thickness is 6 mil and we got qfp's with fine pitch. | how many percent should i reduce my stencil aperture using a 6 mil stencil for 0.5 mm pitch and 0.4 mm pitch ? | | thanks | Greg: I was going to link you to the IPC land pattern c
Electronics Forum | Tue Mar 21 02:15:26 EST 2006 | pavel_murtishev
Good morning Dave, Here are some of my assumptions. Please correct me if I am wrong. 1. Mask opening. Due to mask to PCB misregistration mask is not always centered relative to pad center how is should be. Sometimes edge of the mask matches with ed
