Electronics Forum | Mon Apr 01 23:16:44 EST 2002 | dwoon
Hi, Heard about flux encapsulant - a compression-flow flux and underfill product for flip chip assembly. It eliminates the need for a separate underfill operation. Does anyone has experience in actual production run? What is the possible effect for
Electronics Forum | Fri Apr 05 08:00:18 EST 2002 | Chris Lampron
Good Morning Everyone, It has recently come to my attention that components (PLCC's)are being placed in the sockets prior to wave soldering. Some of these components are MSD's. They have been overexposed to the atmospere, then are subjected to the w
Electronics Forum | Fri Apr 05 08:35:30 EST 2002 | jax
When the remedy is as easy as not inserting the part until after wave........, maybe say at test, you shouldn't need more than one problem. If you think there is a problem, change it. Since we won't know as much about your process as you,( paste/flux
Electronics Forum | Fri Apr 05 17:38:54 EST 2002 | davef
We socket no parts prior to the wave. This practice is an artifact of the days when we�d solder PTH socketed parts from the heat of the wave being conducted through the socket leads to the leads of the component. Sockets??? Thaint sockets no more.
Electronics Forum | Tue Apr 09 00:09:25 EDT 2002 | craigj
Question. When profiling and looking at the profiles cooling rate. Over what temperature range should the slope be monitored and what sort of cooling rates should be looked for. Paste supplier says no more than 6degC per sec, some components maybe lo
Electronics Forum | Tue Apr 09 08:44:43 EDT 2002 | davef
Read IPC-7530 "Guidelines for Temperature Profiling for Mass Soldering Processes (Reflow & Wave)". There is no advantage in dropping off much faster than 4�C/sec. In fact, you risk fracturing your newly formed solder connections due to board warping
Electronics Forum | Tue Apr 09 00:26:46 EDT 2002 | craigj
Are currently investigating a change of solder paste for various reasons and are considering a move from 63/37 to using 2% silver solder paste for increased long term reliabilty of solder joints with gold finish PCBs and to further reduce reflow temp
Electronics Forum | Wed Apr 10 22:46:04 EDT 2002 | davef
On SMTnet, we've discussed the the frailties of controlling paste height, when volume is a more telling measure. Sometimes if you seperate too quickly, the paste tries to stay attached to the aperture walls. This creates a 'U' shaped deposit with r
Electronics Forum | Wed Apr 10 11:46:28 EDT 2002 | mlovett
I would like to know the Stated Specification for PTH size tolerances. Or is there a generalised acceptable limit?. We have some PCB's with hole sizes that I consider to be way off what I would deem acceptable, ie Finished hole size should be 0.89mm
Electronics Forum | Wed Apr 10 22:25:29 EDT 2002 | davef
BAKING MSD AT 5% You can bake at any RH% you�d like. The further you get from 5%, the longer it takes. Those guys in production are just bustin� ya. For background, look at: * http://www.seikausa.com/mcdrysmt.pdf * http://www.aecouncil.com/Papers