Thermal modeling of an epoxy encapsulation process

Conference · Tue Jan 01 00:00:00 EST 1991

OSTI ID:5327762

Baca, R G; Schutt, J A

The encapsulation of components is a widely used process at Sandia National Laboratories for packaging components to withstand structural loads. Epoxy encapsulants are also used for their outstanding dielectric strength characteristics. The production of high voltage assemblies requires the encapsulation of ceramic and electrical components (such as transformers). Separation of the encapsulant from internal contact surfaces or voids within the encapsulant itself in regions near the mold base have caused high voltage breakdown failures during production testing. In order to understand the failure mechanisms, a methodology was developed to predict both the thermal response and gel front progression of the epoxy the encapsulation process. A thermal model constructed with PATRAN Plus (1) and solved with the P/THERMAL (2) analysis system was used to predict the thermal response of the encapsulant. This paper discusses the incorporation of an Arrhenius kinetics model into Q/TRAN (2) to model the complex volumetric heat generation of the epoxy during the encapsulation process. As the epoxy begins to cure, it generates heat and shrinks. The total cure time of the encapsulant (transformation from a viscous liquid to solid) is dependent on both the initial temperature and the entire temperature history. Because the rate of cure is temperature dependent, the cure rate accelerates with a temperature increase and, likewise, the cure rate is quenched if the temperature is reduced. The temperature and conversion predictions compared well against experimental data. The thermal simulation results were used to modify the temperature cure process of the encapsulant and improve production yields.

• Research Organization: Sandia National Labs., Albuquerque, NM (United States)
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5327762
• Report Number(s): SAND-90-3048C; CONF-9110196-2; ON: DE91017845
• Resource Relation: Conference: PATRAN users conference, Newport Beach, CA (United States), 1-3 Oct 1991
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
42 ENGINEERING
ENCAPSULATION
Q CODES
EPOXIDES
DIELECTRIC PROPERTIES
THERMODYNAMIC PROPERTIES
TRANSFORMERS
COMPUTER PROGRAM DOCUMENTATION
ELECTRICAL INSULATION
FAILURES
GELS
MATHEMATICAL MODELS
COLLOIDS
COMPUTER CODES
DISPERSIONS
ELECTRICAL EQUIPMENT
ELECTRICAL PROPERTIES
EQUIPMENT
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
360603* - Materials- Properties
990200 - Mathematics & Computers
426000 - Engineering- Components
Electron Devices & Circuits- (1990-)