Encapsulated

The solutions of encapsulation electronics by polymers

Choice of polymers / Conception / Technique of surmoulage

The encapsulation of the electric or electronic components :

Protection against the outside environment:

• Humidity (to insure the waterproofness)
• Dust
• Mold
• Chemicals
• Man: hacking and against way

Improvement of the mechanical holding of components:

• Under an important pressure (ex: at the bottom of the oceans)
• In front of vibrations
• In front of possible shocks

To insure:

• A good electric insulation (decrease of the risks of electric shock to the application)
• The robustness of the assembly in a severe environment
• The immunity of the card (or the access only to wished functions) in its protection
• A better flammability (the capacity of a material to ignite more or less easily in the contact of a flame, a spark either a high temperature)
• So necessary bio-compatibility (compatible with an alive body: pacemakers for example)
• A good thermal conductivity

To decrease the cost of the set:

• A single action: encapsulation
• A little expensive resin compared with the materials which it would be necessary to use for the electric components to reach all the objectives
• Possibility of integrating functions as fixations, supports
• Possibility of realizing complex geometries with the use of an equipment of replication, very useful for the average series

The constraints:

The coated components undergo various constraints:

• Thermal constraints due to the molding (exothermic Peak or T ° of transformation)
• Mechanical constraints due to the retreat of réticulation or of the retreat during the solidification of the resin
• Constraints due to the differential dilations in functioning between the materials of the card and the material of surmoulage (attention not linear behavior!)

To anticipate these constraints requires:

• A knowledge of the not linear behavior of resins during the stake opens it
• Know the evolution of the mechanical properties of resins during the functioning of the system
• To know how to couple the thermo-mechanics of the various elements of the system, then anticipate the potential risks the electronics during its functioning