三防漆与灌封汇总.ppt

Electronic Module Conformal Coating and Potting MPC-T-1 Training Objectives Explain what coatings and pottings are and why they are used Describe coating and potting application methods and controls Provide examples of coating and potting within Delphi Provide resources for additional information Outline Definitions Coating Reasons for coating Material types Application methods and Delphi examples Quality issues Potting Reasons for potting Material types Application methods and Delphi examples Quality issues Additional sources of information What Is It? Conformal Coating A thin layer of a dielectric (electrically insulating) chemical compound that is applied to the surface and serves to protect the electronic circuitry. The material can be transparent or opaque. Potting (also referred to as encapsulation) A process of filling a complete electronic assembly with a solid compound for resistance to shock and vibration, and for exclusion of moisture and corrosive agents. Additional Definitions Ion: An atom or molecule where the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. Ionic contamination: Surface debris that contains ions Electrochemical migration (ECM): Also known as Dendritic Growth, is the growth of conductive metal filaments on or in a printed circuit board (PCB) under the influence of a DC voltage bias. The filament growth is facilitated by the movement of ions on the circuit board. Tin whiskers: A crystalline metallurgical phenomenon involving the spontaneous growth of tiny, filiform hairs from a metallic surface. The mechanism is encouraged by compressive mechanical stresses Silicone: Inert, man-made polymer compounds that include silicon, carbon, hydrogen and oxygen and some other chemical elements. Silicones can be used over a wide temperature range. Acrylic: Thermoplastic made by polymerizing acrylic acid or methacrylic acid . Acrylics are used for cast a