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FTI's patented GromEx system is a cost-effective method
for reinforcing fastener holes  in
composite materials using a thin interference fit metal
sleeve or grommet. GromEx is based on FTI's proven cold
expansion technology and is designed specifically for
use in composites.
The amount of radial expansion of the grommet in the hole
is carefully tailored to ensure adequate grommet retention
and at the same time prevent localized damage to the composite.
The GromEx system is easier to install, more reliable,
and has improved performance over adhesive bonded or swaged
grommets.
Initial clearance fit of grommet:
• Ease of installation
• Prevents installation damage
Installation without adhesives
or sealants:
• Significant installation labor savings
• Reliable, better process control
• No messy compounds or cure procedures
• Assured grommet concentricity in hole
Quality installation:
• Consistent fit
• Can be used in a wide range of composites
Improved damage tolerance:
• No fastener installation and removal damage
• Better galvanic compatibility
• Enhanced resistance to lightning strike damage
• Protects the hole geometry under compressive loads
GromEx is versatile, allowing
for use in a broad range of materials and with various
standard NAS or other fastener types. FTI's GromEx System
can be used in a wide variety of composite materials and
applications.
Applicable Composites:
• Carbon/epoxy, carbon/BMI, Carbon/polyamide
• Aramid/epoxy
• Glass/epoxy
• 2D cross-laminated tape and fabric laminates, short fiber,
composites, and 3D products
Grommet Materials:
• Commercially pure titanium
• Passivated austenitic stainless steel
• Countersunk (100° reduced head, 130°) and "T"
shaped, .008 inch nominal wall thickness. Standard fastener
clearance (.000 to .004 inches).
Thicker walled grommets available.
Fastener Sizes:
• Standard system:
From 3/16 to 3/8 inch in 1/16 inch increments
Custom applications:
• Contact FTI for details
The FTI GromEx system is a total
package of integrated technology and tooling backed by
FTI's specialized engineering and comprehensive technical
support and training programs.
GromEx is available as a complete system of tools tailored
to meet the user's needs. The most cost-effective way
to purchase the GromEx system is the GromEx Tooling Set
(GRTS),including all durable hand tools for a specific
installation packed in a kit box. Grommets are purchased
in the configuration required.
Example; GromEx system for
use with a nominal 100° flush reduced head (3/16 inch
nominal) fastener (such as NAS1581V5R5) comprises the
following tooling:
Starting Drill GRD-30-1
Chuck Assembly LB-PC-8
Combination Gage GRCG-30
Mandrel Gage GRMG-30
GromEx Mandrel GRM-30-25-V1
Grommet Trimming Tool GRCT-30
Nosecap Assembly GRC-30-1
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