The NPI engineer will attach thermocouples to multiple locations across the sample board. If one isn't provided, then the NPI engineer may request one for use during the set-up process. Ideally, the OEM will have provided their assembly partner with a populated printed circuit assembly. Using their skill, judgement and experience, the NPI engineer will select the profile and temperature settings that they believe are best suited to the new assembly. One dedicated to assemblies that contain sensitive parts and require lower temperatures.One dedicated to densely populated assemblies with elevated temperatures.The time taken to perfect the baseline profile will pay dividends as most assemblies will then fall within one of them. Over time, some EMS providers may develop a range of 'baseline' profiles, which can then be selected depending on the PCBA they are working on. The New Product Introduction ( NPI) engineer will usually start the process by selecting an oven profile they have used before and that is stored on their system. So what should your EMS partner be doing to perfect their reflow oven profile? Let's find out. If you fail to profile the oven correctly, then all of the hard work and effort that has gone into loading feeders, programming the machines, optimising the build and then running the production line will be wasted. The reflow oven is used primarily for the reflow soldering of surface mount electronic components to printed circuit boards (PCB). There is however one specific step that can make all of the difference when it comes to quality and consistency - creating the surface mount (SMT) reflow oven profile. But, broadly speaking, the process steps that they go through to produce PCBAs are the same. But consistently producing them in volume can take time to perfect.Įlectronics manufacturing services (EMS) providers may well have their own preferences when it comes to their choice of machine type and brand.

Nitrogen capable reflow ovens and SMT ovens are typically equipped with an automatic gas sampling system and an Oxygen Analyzer.Printed Circuit Board Assemblies ( PCBAs) are often viewed as commodity items. The Oxygen levels in a Nitrogen reflow process can be as low as less than 10ppm but may be higher than 500ppm for some less critical processes. The use of Nitrogen or Forming Gas is meant to reduce or eliminate oxidation of the assembly during the heating process. A number of specifications are employed including a maximum and minimum peak temperature inside the reflow soldering oven, such as Flux Activation Time (FAT), Time Above Liquidus (TAL), heating and cooling ramp rates, etc.Ī reflow furnace can process circuit boards in air atmosphere or in a controlled Nitrogen or Forming Gas environment. The recipe is optimized to achieve the profile that the solder reflow machine manufacturer has specified for the solder paste that is used on the board. The temperature that the board “sees” as it is processed through the oven is called “ the profile”. The program with the temperatures for all of the zones, as well as the belt This set point corresponds to the temperature the circuit board should be exposed to as it passes through that zone. During the reflow soldering process, the zones are programmed with a thermal set point. Depending on the length and throughput of the oven there may be few zones, 8 or less, or many zones, 12 or more. Inline reflow ovens are configured with a number of heating zones followed by cooling section(s). The most modern reflow ovens use closed-loop convection. Convection reflow ovens had many advantages including vast improvements in heating uniformity. Later on, the industry, led by companies like BTU International, switched to convection heat transfer. In the early days of electronics manufacturing, infrared (IR) heating technology was employed. For larger manufacturers, an inline or conveyor belt reflow oven is the best choice. An led reflow furnace can be a small batch (box) style oven for very small lab scale operations. Thermal processing of solder for electronics manufacturing takes place in a reflow oven.

Reflow oven