PCB变形的建模与仿真----讲诉.doc

印刷电路板在回焊过程中变形的建模与仿真 摘要 在SMT中，回焊是非常重要的工站。在回焊过程中受到热冲击已成为印刷电路板(简称为PCB)组件生产过程中产生缺陷的主要原因之一。PCB组件组成材料不同，热膨胀系数热参数较PCB之间电连败导个PCB组传统,经试验调来进电预测对;对PCB热组从 本文利用有限元法对PCB组进态温场应场ANSYS软对PCB组应进拟PCB组组热经过温区热拟时个PCB组温场个贴装3个PLCC4层PCB简拟约条该组应热变选PCB上3个点约对两点约;底面4顶点约;底面两对边约过PCB组较匀温场调对PCB约变关键词:;热应;建模;温场;; , Modelling and simulating for PCB Deformed in refolw soldering Abstract of thesis Reflow soldering is very important technics in SMT. Thermal impact to PCBA during reflow soldering is considered one of the main drivers for manufacturing defects. The materials making up a PCBA is various, and the thermal property of the materials is also different ,this may cause some defects for example wargpage. Excessive warpage in the PCB may result in gaps forming between the module leads and the molten solder on the solder pads, then the failure of electronically and physical connection lead to PCBAs defect. The traditional approach of experimentally analysing production defects would be costly and virtually impossible, and cant reach the demand of the producer for the fast renovation and the acute competition. An alternative to this approach is to derive computational and numerical models that encapsulate representations of the key process physics, so that effect analysis of the pertinent process variables may be examined. The application of the modelling and simulation to a sample PCBA has been carried out to explore how undue variations in the reflow temperature can be minimized by a number of different strategies. It has been shown that simple movements of components can have quite beneficial effects on the overall process thermal history of the PCB. The paper use finite element analysis method analysis the thermal impact of PCBA during the reflow soldering ,and building the temperature and stress distribution model. The paper model and simulate the thermal warpage of PCBA during reflow soldering , get the temperature and stress distribu