Customer Overview

A leading defense prime contractor was engaged in the development of a sophisticated RF electronics device. The project had stringent requirements, including minor exposure to jet fuel and the necessity for precise placement of components on a conductive-coated machined aluminum housing. The production demand was set at a steady rate of 100-200 units per month over a three-year period.

Customer Problem

The customer was designing an RF electronic device that required a gasket to shield internal components and protect against external environmental factors, including minor jet fuel exposure. The gasket needed to be precisely positioned on a conductive-coated machined aluminum housing. The design faced challenges due to the gasket’s irregular shape, small pass-thru holes, and the need for thin-walled raised ribs in the lightweight housing. Despite exploring various solutions like adhesive-backed extrusions and conductive sheet gaskets, achieving consistent installation remained difficult.

  • Irregular Gasket Shape: The gasket’s long unconnected features and small pass-thru holes complicated design and installation.

 

  • Exhausted Gasketing Options: The customer considered adhesive-backed extrusions and conductive sheet gaskets.

 

  • Dimensional Constraints: Solutions needed to be wider than the thin-walled raised ribs.
  • Thin Inner Walls: The aluminum housing had thin inner walls (0.060 wide) to reduce weight.

 

  • Installation Difficulties: Consistent placement of the gasket was challenging with the proposed solutions.

Customer Requirements

• EMI Shielding
• Precisely placed gasket
• Fuel exposure resistance

Radome Sealing and Venting Solutions for Enhanced Electronic Enclosure Protection

Solution Partner

How Did Sealing Devices Get Involved?

The customer was working on other projects with Sealing Devices and reached out to request design assistance. Applications Engineering was able to review the application requirements and work directly with the customer to offer the Form-In-Place robotically dispesed solution.

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Sealing Devices’ Solution:

Sealing Devices offered a special Form-In-Place (FIP) gasket solution using Parker Chomerics Cho-Form 5575 Silver-Aluminum filled dispensable silicone. The gaskets were applied robotically, ensuring precise and continuous paths based on the customer’s geometry. The conductive filled elastomers bonded directly to the housings, leveraging the housing for strength and effectively handling the 0.060 wide walls. The gasket material could be formed in relatively small areas, and the housings were designed with compression stops to compress the gasket to the proper amount, typically 25%, maximizing both environmental and EMI sealing performance. Along the perimeter of the part, a raised outer edge provided additional EMI grounding, set the compressed height, and offered mechanical protection from direct contact.

• Precise Gasket Placement: The FIP gaskets were formed in small areas, leveraging the housing’s strength.

• Controlled Compression: Housings designed with compression stops ensured the gasket was compressed to the proper height (typically 25%), optimizing environmental and EMI sealing performance.

• Metal-to-Metal Contact: A raised outer edge around the gasket provided additional EMI grounding, set the compressed height, and protected the gasket from direct contact.

To meet the requirement for jet fuel exposure, Sealing Devices offered a Fluorosilicone dispensed gasket. A second bead of Fluorosilicone was applied outside the conductive bead, providing resistance to jet fuel. The outer walls of the housing were designed to be wider for strength, accommodating this second bead.

Results:

Sealing Devices provided a tailored Form-In-Place gasket solution for the customer’s RF electronics device, ensuring precise installation and robust environmental and EMI sealing. This approach reduced installation costs and offered product variants, enhancing both performance and profitability for the customer.