EMI/RFI Band Application System for M85049/128 Bands
The termination of EMI/RFI shielding materials is a specialized science in today’s aerospace wiring systems. Application tooling is a critical factor in the overall performance of the wiring system components. DMC® has worked closely with the world’s leading connector accessory manufacturers and standards organizations to develop the necessary tooling and accessories to meet the stringent demands of aerospace and defense system contractors. The resulting products afford the user a repeatable and reliable means of terminating shielding on aerospace wiring systems. Tooling is available for all bands qualified to AS85049/128.
M85049/128 BAND CONFIGURATIONS
M85049/128 Shield Termination Bands are available in two distinct configurations, Stamped and Welded Buckles, and two different widths, .250 in. (6.350 mm) and .125 in. (3.175 mm). The bands come flat or pre-coiled and ready for use.
The buckle for the M85049/128-3, M85049/128-4, M85049/128-7, and M85049/128-8 bands is a STAMPED buckle. This configuration is low-profile style with a slot for the other end of the band to pass through.
The buckle for the M85049/128-1, M85049/128-2, M8549/128-5, and M85049/128-6 bands is a WELDED buckle. This configuration is folded style with a loop for the other end of the band to pass through
One-Step Tool Application
"Stamped Buckle" Band Applied
Two-Step Tool Application
"Welded Buckle" Band Applied
PROCEDURES FOR BANDING
Careful measurement should be made prior to installing the backshell. The outer jacket is then uniformly removed at a distance which would allow the braid to make a comfortable transition onto the backshell termination area. This dimension will vary depending upon the differences between cable and backshell diameters or other application dependent factors.
The braid is then trimmed to a length which will allow it to extend 1 inch past the backshell termination platform. Then the braid is carefully folded rearward to expose the wires which will be inside the backshell.
A sufficient number of wraps of self-vulcanizing tape (normally red in color) are applied over the wires to buildup a diameter slightly less than the inside diameter of the backshell. Care should be taken not to apply tension to the contacts located in the outer perimeter of the connector.
These layers of tape are followed by a minimum of one layer of Teflon tape which will prevent adhesion with the backshell and other components.
The backshell is then installed onto the connector, using a nonabrasive tool such as a strap wrench. The braid is then carefully moved from under the backshell. It is important to retain the woven characteristics of the braid during this step.
Use self vulcanizing tape or a preformed component to build up the area behind the backshell. It is important that the braid is supported in the transition from the backshell rear diameter to the natural diameter of the wire bundle. Leave approximately 1/8 inch spacing between the tape wrap and the backshell.
The braid is pushed into position over the backshell termination platform. Care must be taken to make sure the weave is uniform and no large “windows” are present.
A shield termination band is then loaded into the tool. The band is then slid over the connector/backshell assembly into a position of alignment with the termination platform. Apply an adequate amount of pressure in line with the cable as it enters the backshell to allow the 1/8 inch space to be reduced to zero. The tool is then activated to the preset tension. The band is then bent sharply at the buckle approximately 90° then cut-off using the cut-off lever on the tool (applies to two-step only). If the band is uncurled for any reason, it must be double looped through the buckle before termination.
The 90° tab is then curled and folded back over the buckle using the rollover tool (applies to two-step only).
For braiding a non-jacket cable use fine point shears to trim the excess braid as close to the connector side of the bands as possible. Do not leave any unsecured braid wires longer than 1/8 inch. Do not allow the trimmed wires to fall in any areas where they may present a foreign object damage hazard.
Procedure for Splicing
The jacket is present, and shield are cut and separated to expose the wires requiring service. Care must be taken to avoid damaging the insulation on internal wires. The required service is then completed.
The wire bundle is then protected by a few wraps of self-vulcanizing tape followed by 2–3 layers of teflon tape. An appropriate size split ring set is then selected and installed. One layer of teflon tape is applied over the split ring set to hold the halves in position while the next steps are being performed
The braid is then overlapped across the split ring set. Be sure the braid ends protrude completely under the band in both directions.
Heat shrinkable tape is then applied over the splice. Where a jacketed cable is used, be sure the tape extends onto the jacket in both directions.