Form-In-Place EMI Gasket Technologies

Introduction

Form-In-Place (FIP) is an automated system for dispensing conductive elastomer EMI shielding and environmental gaskets onto metal or plastic substrates. FIP is particularly well suited for compartmentalized cast, machined metal or plastic enclosures used for packaged electronic assemblies.

Utilizing programmable 3-axis CNC dispensing equipment, the compound is laid accurately onto the substrate and creates a secure bond during the curing process. The computer controlled dispensing equipment ensures consistency between parts during the production process and if necessary rapid part program changes during the course of the production cycle. In addition it supports all levels of volume -- from prototyping to high volume production -- via the use of one or multiple dispensing heads. The system can apply custom gasket configurations onto parts on multiple levels of the part and on slopes up to approximately 70 degrees. 

The compounds are Room Temperature Vulcanizing elastomers or High Temperature Vulcanizing elastomers filled with proprietary conductive particles. The gaskets formed with room temperature compounds may be handled after 3 hours and are cured in 24 hours. The gaskets formed with high temperature compounds require oven curing. 

The compounds have a working compression range from 10% to 50% of the gasket height, with a recommended design compression of 30% against a mechanical compression stop. FIP is designed to support low closure forces and is compatible with plastic, metal and plated or chromate finished substrates.

Gaskets are dispensed on substrates within a placement tolerance of +/- 0.001"and gasket cross-sectional tolerances from +/- 0.003" to 0.007" dependant on the gasket design. As a normal course of equipment operations, starting points and termination points of the gasket will have profiles that are approximately 25% larger than the running gaskets. Trimming operations can be performed on the start and end points to ensure no gasket is on a pressure stop and to minimize the extra size of the gasket at these points.

Form-In-Place Gasketing Features and Benefits

• FIP gasketing offers a total cost savings in the areas of reduced raw materials, labour and assembly time
• Room temperature cure gasketing compounds eliminate the need for costly heat curing systems, allowing the use of inexpensive plastic or metal substrates
• Single component compounds eliminate the need for mixing ingredients, thereby shortening production cycles, improving the consistency of the gasket compound and eliminating related waste
• Easy to program operating system allows for quick prototyping, part to part change over and minimal tooling investment
• High shielding effectiveness of 85-100 dB up to 10 GHz
• The compact FIP gaskets provide more critical space for board level components and smaller assembled package dimensions
• Excellent adhesion on a wide variety of metal and plastic substrates including:
1. Aluminum and other castable alloys
2. Stainless Steel
3. Plastics (including plated plastics)
4. Copper, silver and nickel filled paint on plastics
• Low compression force for use where mating surfaces lack mechanical stiffness

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