Ioan, We use a kind of Universal reflow profile, where I can pass mixed boards with same overal results. The trick is based on long pre heating time ( 145 oC to 155 oC ) where all components temperatures achieve same level prior peak reflowing, reducing in this way the peak difference on last zone.This profile takes about 6 minutes inside oven ( seven zone Conceptronics ) and you can use for a 150 components board or a 500 components board without changes. Sometimes is impossible follow solder paste recomendations for reflow profile due to different heat transfer across components, the results are big differences in peak temperature ( > 10 Celcius degree ) and some colder joints can happen or component overheating , this occur at reflow profiles of about 3 minutes. For high mix production the better is reduce the number of profiles used to optimize line changeover and reduce mistakes from erroneous profile load. If you have different solder paste, different boards this could be a nigthmare. Thanks Jorge Dourado de Santana Maintenance / Process Engr Microtec - Brazil ################################################################ 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 ################################################################