>Dear all, > >I am a student currently doing research in SMT. One question concerning >the trend of reflow oven came into my mind: Which type of oven is most >popular used in industries nowadays? Force Air Convection? Yes. These machines are dominant in the market today; have been for several years. >Does anyone still keep and use the pure IR oven for daily production? >Why? Or does this type of oven has already obsoleted for a long time that I >cannot even find one as scrap? Yes, but probably 5-7 years ago, most of the furnace manufacturers adopted the forced convection design. Prior to that you would see "convection/IR" designs, and claims that the various IR designs heated convectively. Keep in mind, the older panel emitter IR designs do heat "convectively" in that the heat transfer is partially direct, and partially a result of the IR heating the internal parts of the oven which heat air, which heats the work. You would have no difficulty finding an older IR oven in use. We have two, you see used equipment brokers listing them all the time. The reason we do is that our older equipment can still do the job, and it would be difficult to justify replacement of the machines. Most people agree that the forced air convection heating is more efficient, i.e. heats the work more quickly and more evenly than the direct radiation heaters. The 5 zone forced convection ovens can give as nice a profile as a much longer IR furnace. There are, however; disadvantages. The forced convection units require fans to move extremely hot air. This becomes a design challenge to develop reliable blowers capable of continuous operation in a very hot environment. The passive IR units had many fewer moving parts, and therefore were pretty reliable. The convection machines use more energy. It also becomes more difficult to design a furnace with forced "air" for an inert environment as compared to the conventional IR design - simply a problem of preventing infiltration of outside air. regards, Jerry Cupples Interphase Corporation Dallas, TX USA http://www.iphase.com/ *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ***************************************************************************