Moreover, profilers provide a wealth of historical profiles and process data. That data can be extr

Editor's note: This column originally appeared in the November 2012 issue of Revista SM T. In this day and age, technology and expertise into PCB assembly are dramatically increasing buffet trays and for some assemblers, is hard to keep up with advances. Take, for example, the thermal profile, one of the most important yet constantly changing in the process of assembling elements PCB.Por Unfortunately, there is still a belief in our industry that one size fits all when it comes to the thermal image. Recall, for the sake of our OEMs and products, all thermal profiles are not equal.
However, the importance of a good thermal profile goes far beyond that fact. Many critical aspects of the thermal profile must be accepted by OEMs as a way to effectively track the reliability of its products. To begin, let's define a thermal profile. The effective thermal profile is created for welds perfect connections they need to be and to ensure they comply with the manufacturer's specifications pulp associated welding, types of components on the PCB, the type of PCB, and the mass Like wearing a special badge.
For each new assembly, thermocouples are attached to each PCB and then runs through the reflow oven to determine buffet trays the hot and cold spots on the board. The temperature was measured to ensure that the board does not overheat, which can damage components or too cold, to create perfect solder joints.
At least a half-dozen key and critical aspects are related to the creation of an effective thermal profile. These include: Reflow oven calibration; The number of zones in the reflow oven; The design of the oven itself; The thermal analyzer; Whether or not a card panelized or individual; Blend component material; Thermocouple and accessory components.
Top notch calibration reflow oven means meet manufacturer specifications reflow oven. Compliance also includes performing regular preventive maintenance on the reflow oven and bring a disciplined record keeping.
The number of heating zones in the reflow oven differs. In a reflow oven small table, can not be just four to six zones. In a full-size furnace may be 12 to 16. As shown in Figure 1, generally, the more the best areas to allow incremental increases in temperature or increased temperatura.Por is therefore always better to have 12 zones versus six to eight, because the goal is to find the best place on the board in front of the hottest and ensure that all components are installed properly.
Meanwhile, the furnace design plays a significant role in thermal profiles. Above the liquidus temperature (TAL) should be maintained at certain levels. Extra caution should be applied to avoid ramping up the temperature too high, too fast. A shock absorber temperature must be observed to avoid damage to the components and the board itself. On the other hand, if the oven is not actually keeping TAL, there will be enough moisture soaking and it can lead to incorrect assembly joints, buffet trays creating open joints and intermittent connections. buffet trays
As shown in Figure 2, the thermal profile generator, a rectangular size device TV remote control, having thermocouple buffet trays wires attached to a plate, the temperature of thermocouple monitors and records the temperature profile of the PCB. Ensure that the device is properly calibrated buffet trays is importancia.Perfiladores sum today offer a range of advanced features, including accurate data acquisition, it is important to collect details as crucial as oven temperatures and the area, as areas being measured, and the degree of precision the zones are.
Moreover, profilers provide a wealth of historical profiles and process data. That data can be extracted from the past in order to be studied carefully before making a new profile. Basically, profilers offer a library of different sets of tables with many considerations as a basis for the right to create a brand new recipe or profile thermal process.
Process Window Index (PWI), associated with the profiler, is another key element in creating a thermal profile. Whatever the process window is the profile