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Nové metody a postupy v oblasti přístrojové techniky, automatického řízení a informatikyÚstav přístrojové a řídicí techniky ČVUT v <strong>Praze</strong>odborný seminář Jindřichův Hradec, 28. až 29. května 2009Fig. 1 Lead free reflow profile3. Automated soldering device with resistence heaterThe major parts of this oven are the Soldering Tank, Main frame, Electric Heater,Temperature Sensor, Temperature Indicator, Cooling Device, and Controller. This projectconcentrated to design and to manufacture the device consisting of these parts above exceptthe cooling device.Fig 2 Real device picture4. Test results with resistive heatingThe cooling was done by adding some specific amount of cool liquid to the tank. Firstwe added 100ml liquid and then 150ml of the liquid. The results with this type of cooling areshown in figure 4.Fig. 3 Temperature graphs. A is the first time cooling, B is the second time cooling5
Nové metody a postupy v oblasti přístrojové techniky, automatického řízení a informatikyÚstav přístrojové a řídicí techniky ČVUT v <strong>Praze</strong>odborný seminář Jindřichův Hradec, 28. až 29. května 2009Soldering device with resistance heater increases quickly the temperature of the liquidto the peak temperature. It is easy to built device. But for this device it is difficult to controlthe increase of temperature as there is a large amount of accumulated energy even when thehearer is switched off. The increase of temperature caused by this thermal inertia is clearlyseen in the measured temperature profile. The biggest problem however of this type ofconstruction is the necessity to have a separate device for cooling. For this reasons, weabandoned resistive heating and designed the device with Peltier elements.5. Soldering device with peltier heaterPeltier element is a thermoelectric element consisting of semiconductor materialspaired to accomplish heating or cooling processes as a result of peltier effect. If a voltage isplaced on a Peltier element, one side is cooled and the opposite side simultaneously heats up.Simply by reversing the polarity of the supply voltage, the hot and cold sites of the Peltierelement can be swapped [4].Peltier element can be used in single or cascade combination. The elements arearranged to fit the needs. In this project, the elements are interconnected in series and parallelconstructing a cascading layer of peltier element. Each element and combination in any layerneed to be controlled precisely regarding the temperature curve.6. Structure of soldering device with Peltier heaterThis soldering device uses HB TEC1-12710. This device uses 5 layers peltier. As wekeep the temperature on the bottom layer equal environment so the average delta T on 1 layeris:(220-20)/5= 40 o CThe current for each layer is controlled independently.Table: 2 Peltier HB TEC1-12710PerformanceSpecificationsHot Side25ºC 50ºCTemperature (ºC)Qmax (Watts) 85 96Delta Tmax (ºC) 66 75Imax (Amps) 10.5 10.5Vmax (Volts) 15.2 17.4Module Resistance(Ohms)1.08 1.246
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