Electronics Forum | Sat Dec 11 12:15:21 EST 1999 | Steve Thomas
We have a pretty challenging board (2-up panel, 15"x20", 48 20mil pitch QFP 100's and 2 25mil QFP128) that gives us LOTS of lead bridging on the 20 mil parts. There is typically very poor wetting on these parts also, and some joints just flat aren't
Electronics Forum | Mon Dec 13 05:43:27 EST 1999 | Wolfgang Busko
Hi Steve, 20 mil pitch shouldn�t be that problem nowadays. In your case bridging and poor wetting seem to go hand in hand. For the poor wetting try to eliminate it by using different paste (higher activated) and work on your profile. Coplanarity also
Electronics Forum | Mon Dec 13 09:43:28 EST 1999 | Chris May
As Wolfang says about slightly bent legs, handling is of the essence. Are these devices decanted into another tray for your machine. It may be worthwhile doing a "movement" chart for these components. Do not explain why or when you are doing it beca
Electronics Forum | Fri Dec 10 17:08:51 EST 1999 | John Thorup
Tell those leads not to be drinking so much. Anyway... too bent to work in a sequencer or auto insertion machine is a lot less bent than if you're trying to manually stick it into a hole. As far as where the lead exit/enters the body of the compone
Electronics Forum | Thu Dec 09 13:37:35 EST 1999 | Mike F
Does anyone have a suggestion for soldering boards with 1 inch long leads sticking out the bottom? Our vendor is using a drag solder machine, but I'm not happy with the preheat and controls on it. We assemble boards with numerous LED's( 200 to 700 pe
Electronics Forum | Thu Dec 09 17:29:15 EST 1999 | Russ
Mike, It sounds like you have a serious problem, I don't know much about drag soldering or what your specific soldering problem is with your present supplier. I do know that with a conventional solder machine these leads won't even make it through
Electronics Forum | Thu Dec 09 18:21:20 EST 1999 | Boca
Mike, Russ is right, no 'normal' wave machine will solder PCB's with 1" long lead length. I have seen waves modified to clear up to 5/8" leads, but the deeper the wave the uglier things get. They get uglier in that a lot more dross is produced, con
Electronics Forum | Fri Dec 10 10:49:24 EST 1999 | Mike F
Some of our boards have over 700 LED's, so looking for the long leads is the most accurate way to check polarity. Also, not all LED's have a flat side and tinted domes can make it difficult to see the internal structure. Auto insertion didn't work, f
Electronics Forum | Fri Dec 10 12:40:44 EST 1999 | Brian W.
It sounds like the process is very labor intensive, and all the verification is done after the parts are soldered. Assuming you are hand placing the components: 1 - Contact Systems semi-automatic placement machine. It show polarity when placing, so
Electronics Forum | Fri Dec 10 14:49:57 EST 1999 | John Thorup
Hi Mike consider buying your LEDs from a value added distributor or sending the to a service house for trimming. It's no trick to cut so that one lead is longer than the other although you may have to pay a tooling charge. These people are equipped
