Poh, If the boards are HASL ( Hot Air Soldering Level ) the difference is probably in the quality of HASL process, some vendors gives irregular surface finish and when stencil contacts with that irregular surface gives more height from board level, so you are measuring HASL irregularity with solder paste deposition, thats explain the difference in height. You can examine the surface finish with microscope or using the solder paste height toll to check the differences between the 3 suppliers. You will be able to note also that is difference in height between vertical and horizontal pads Thanks Jorge Santana Process / Maintenance Engr Microtec - Brazil > -----Original Message----- > From: Poh Kong Hui [SMTP:[log in to unmask]] > Sent: 26 de Junho de 1999 16:57 > To: [log in to unmask] > Subject: [TN] Different Paste Height > > Hi, > > Have anyone encountered that PCB from different suppliers give > different > paste height. > > We are using 3 PCB suppliers for one of our product, and the average > paste > height we are getting (on 2 suppliers), using 6 mil stencil with > rubber > squeegee (70 durometer) gives an average paste height of 6.5 mil. > However, > there is one supplier's PCB that gives the average paste of 8 mil. > > We need to double the squeegee pressure to achieve the paste height of > near > 7.0 mil > > Could anyone advise me the cause to such issue. > > Thanks > > Poh > > ################################################################ > 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 ################################################################