The PWI also assists you to find the single best profile that your process is capable of attaining. It tells you the exact range of your process window, and thus how robust your profile is. As a percentage of maximum deviation, this works out to be 12/20= 0.6 or 60%. For example, if the process ‘mean’ is set at 200 ☌ with the process window standardized at 180 ☌ and 220 ☌ respectively, then a measured value of 188 ☌ implies a process window index of −60%.Įxplanation of the mean being 200 ☌: Maximum deviation is 200-180=20 or 200-220=-20. Raw temperature values are normalized in terms of a percentage comparative to both the process mean as well as the window parameters. Any process window index (PWI) which is greater than or equal to 100% is as obvious out of the window. The center of the process window is usually declared as zero, and the extreme edges as ☙9%. A thermal profile is classified on the basis of how it fits in a process window. Process window is the essential temperature range. Factors that impact the cost of the PCB assembly, including:ĭownload Now Process window and its index of thermal profile.This control of temperature in an oven is called thermal profiling. It is necessary to control the temperature in the oven precisely to avoid thermal shocks to the components. Each zone has different characteristics based on temperature requirements. After mounting the parts, the entire board assembly is passed through a reflow oven.Ī typical reflow profile consists of four stages that include preheating, thermal soak, reflow, and cooling zone. This machine is highly reliable and accurately positions all components. At Sierra, a Juki pick-and-place assembly machine is used that can place 15000 parts per hour. Later, components are placed using a pick-and-place machine. Graph Showing Thermal Profiling Significance of thermal profiling in PCB assemblyĪt the beginning of the reflow process, it is necessary to apply solder paste (a combination of powdered metal solder and flux medium) on the board using a stencil (a thin sheet of material having apertures matching the footprint of a board). Component peak temperature and withstand capacity as mentioned in the datasheet.Solder paste type and manufacturer guidelines/datasheet.While setting the thermal profile we should consider the following points: Maintaining the precise temperature for a particular period has a significant effect on product quality. Whenever a fabrication entails heat-processing, it is important to use a specific method that can ensure the product is heated to a specified temperature and duration. This is a significant part of efficient design services that require advanced board manufacturing and assembly. Typically, a thermal profile is a complex set of time-temperature data for different processes like peak, soak or slope, and reflow. It involves controlling the temperature at numerous points on a given product as it passes through a thermal process. Thermal profiling or temperature profiling is very important for any manufacturing process with heat treatment. RLC Resonant Frequency and Impedance Calculator.Bandwidth Rise Time and Critical Length Calculator.Transmission Line Reflection Calculator.Trace Width and Current Capacity Calculator.
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