Hi Matthew, which company does suply LPISM and DFPISM ? Regards Wolfgang Nuechter > ---------- > Von: Matthew Park[SMTP:[log in to unmask]] > Antwort an: TechNet E-Mail Forum.;Matthew Park > Gesendet: Donnerstag, 24. September 1998 17:13 > An: [log in to unmask] > Betreff: Re: [TN] Help! Plugging vias > > Chiman!, > > What is the customer's purpose of plugging vias completely with > solder mask? I don't think it is possible. Maybe some fab guru's > can elaborate on it. > > We tent all via holes from the bottom side to prevent solder > pluggings during wavesoldering process. It does a wonderful > job with LPISM, even though holes are not plugged with > soldermask. Our via size is from 0.4 - 0.6mm. If via is bigger > than 0.7mm, it does plug the hole with solder sometimes. > > Try DFPISM (dry film), it does excellent job of tenting small and > large vias with soldermask. > > regards > Matthew S. Park > NII Norsat International Inc. > > > >>> Chi-man Chan <[log in to unmask]> September 24, > 1998 2:59 am >>> > Currently we have a big problem on plugging vias with solder > resist. Our > customer requires that vias must be completely filled with solder > resist. (i.e. light cannot go through). The via size is 0.3-0.5 mm. > We > use liquid imageable solder resist. I have tried to print with 43T > then > 32T open screen wet on wet on both side of the board. It does > not work. > The vias seems to be blocked with resist after screen-printing. > However, > some vias open again after track dry and developing. I have > reduced the > thinner from 5% to 2%. It does not work and causes a lot of > bubbles > among tracks. In order to completely plug these vias, we now > print these > boards with dot pattern before solder resist printing and after hot > air > solder leveling. Some vias are very close to SMD. It is a very hard > and > time-consuming job. I think there should be an easier way to do > this > job. > > Any feedback is appreciated. > > > Regards, > > Chan Chi Man > [log in to unmask] > > ################################################################ > TechNet E-Mail Forum provided as a free service by IPC using > LISTSERV 1.8c > ################################################################ > To subscribe/unsubscribe, send a message to > [log in to unmask] with following text in the body: > To subscribe: SUBSCRIBE TechNet <your full name> > To unsubscribe: SIGNOFF TechNet > ################################################################ > Please visit IPC's web site (http://www.ipc.org) "On-Line > Services" section for additional information. > For technical support contact Hugo Scaramuzza at > [log in to unmask] or 847-509-9700 ext.312 > ################################################################ > > ################################################################ > TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c > ################################################################ > To subscribe/unsubscribe, send a message to [log in to unmask] with > following text in the body: > To subscribe: SUBSCRIBE TechNet <your full name> > To unsubscribe: SIGNOFF TechNet > ################################################################ > Please visit IPC's web site (http://www.ipc.org) "On-Line Services" > section for additional information. > For technical support contact Hugo Scaramuzza at [log in to unmask] or > 847-509-9700 ext.312 > ################################################################ > ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################