3/10/2024 0 Comments Solder paste reflow profileDeveloped in combination with T4 and finer mesh leaded and lead-free. An evolution of the highly successful NC258 platform, M8 brings no clean solder paste to the next level. M8 no clean solder paste is designed for the most demanding high density electronic assemblies. The oven has two floating temperature sensors (top and bottom) and a provision for one sensor to clamp/attach onto the PCB (the external sensor). Boards with ENIG surface treatment will initially generate IMC of Ni3Sn4, but only a very small amount of Cu6Sn5 compounds will be generated. Features: - For use with demanding, high density electronic assemblies. The Eurocircuits eC-reflow-mate is a batch oven with quartz infra-red heaters on the top and bottom plus convection (controlled air flow). If the time is too long, bad IMC of Cu3Sn will continue to be generated. The peak temperature of the product is also reached at this stage (the assembly reaches the highest temperature in the furnace). TAL must remain within the parameters specified by the solder paste manufacturer. It is generally recommended to control it at 1-3μm as the best. Observation test of heating conditions R&D, quality control, etc. Easily achieved by the temperature profile of lead-free solder mounting. Can observe the melting state of solder paste. The thickness of IMC is acceptable between 1-5μm, but it is not good if IMC is too thick. HOME > PRODUCTS > REFLOW SIMULATORSRS-1C FEATURES. Metal Compound (IMC), is a critical stage within the reflow oven because the temperature gradient across the assembly must be minimized. The initial structure of the Sn-Cu alloy is a good Cu6Sn5 medium. Taking the surface treatment of OSP (organic protective film) as an example, when the solder paste melts, it will quickly wet the copper layer, and tin atoms and copper atoms will penetrate each other at their interfaces. At this time, the tin in the solder will react with the copper or nickel on the pad to form an intermetallic compound Cu5sn6 or Ni3Sn4. The reflow zone is the area with the highest reflow temperature in the entire reflow section, usually also called "liquid holding time (TAL, time above liquids)". Another purpose of uniform heating in the preheating zone is to allow the solvent in the solder paste to evaporate moderately slowly and activate the flux, because the activation temperature of most fluxes falls around 150☌. In order to avoid uneven temperature inside and outside the parts or between different parts, which may lead to deformation of the parts, Therefore, the temperature rise rate in the preheating zone is usually controlled between 1.5☌ and 3☌/sec. However, the parts on the surface of the PCB are of different sizes, and the area of the soldering pad/pad connecting copper foil is also different, and its heat absorption degree is also different. In this area, the temperature rises slowly (also called a primary temperature rise) so that some solvents and water vapor in the solder paste can evaporate in time, and electronic components (Especially BGA, IO connector parts) slowly heat up to prepare for the high temperature later. So, our reflow profile does match the solder paste specification.The preheating zone usually refers to the area where the temperature rises from normal temperature to about 150☌. The cooling ramp rate, from Figure 2, is (250-90)☌/(5.7-3.8) min = 160☌/(114 sec) = 1. 40☌/sec, which is within the acceptable rate of the solder paste spec. The peak temperature is 250☌, again within the specification recommended range as seen in Figure 1. There is no “soak” in this profile, so we can ignore this part of the solder paste spec.įrom Figure 2, the time above liquidus is 4.4 – 3.1 minutes (78 Seconds), right within the recommended range of the solder paste spec. This result is just over the recommended spec, but within the acceptable spec as seen in Figure 1. Ramp Profile: From Figure 2, the oven goes from room temperature to liquidus in 3.1 minutes (186 seconds) this gives a slope of (219 – 25)☌/(186 - 0 ) sec = 194/186 = 1.04 ☌/sec. Now, let’s take each reflow profile requirement individually: The solder paste reflow specification is shown in Figure 1 below.įurthermore, let’s assume that we have a reflow profile that we have used in the past, as seen in Figure 2. Assume we want to start using Indium Corporation’s Indium8.9HF Pb-Free Solder paste. Matching a reflow profile to a solder paste spec is a required skill for an SMT process engineer.
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