IPC 7711A - 第284页
NOTES IPC-7721A Number: 4.6.2 Revision: Date: 2/98 Subject: Edge Contact Repair , Film Adhesive Method P a g e4o f4 Copyright Association Connecting Electronics Industries Provided by IHS under license with IPC Not for R…
14. After the bonding cycle remove the tape used for alignment. The new edge
contact is fully cured. Carefully clean the area and inspect the new edge con-
tact for proper alignment.
15. If the new edge contact has a connecting conductor apply a small amount of
liquid flux to the lap solder joint connection area and solder the conductor from
the new edge contact to the conductor on the printed wiring board surface. Use
minimal flux and solder to ensure a reliable connection. Tape may be placed
over the top of the new edge contact to prevent excess solder overflow.
NOTE
If the configuration permits, the overlap solder joint connection should be a
minimum of 3.00 mm from the related termination. This gap will minimize the
possibility of simultaneous reflow during soldering operations.
16. Remove tape and clean the area.
17. Trim the extending edge of the new edge contact with a file. File parallel to the
beveled edge until the excess material has been removed. (See Figure 7.)
18. If sealing the lap solder joint connection is required, mix epoxy and coat the lap
solder joint connections. Cure the epoxy per the manufacturer’s instructions.
CAUTION
Some components may be sensitive to high temperature.
NOTE
Additional epoxy can be applied around the perimeter of the new edge contact
to provide additional bond strength.
19. Apply surface coating to match prior coating as required.
EVALUATION
1. Visual examination, measurement of new pad width and spacing.
2. Electrical continuity measurement.
IPC-7721A
Number: 4.6.2
Revision:
Date: 2/98
Subject: Edge Contact Repair, Film Adhesive Method
Page3of4
Copyright Association Connecting Electronics Industries
Provided by IHS under license with IPC
Not for Resale
No reproduction or networking permitted without license from IHS
--``,``,-`-`,,`,,`,`,,`---
NOTES
IPC-7721A
Number: 4.6.2
Revision:
Date: 2/98
Subject: Edge Contact Repair, Film Adhesive Method
Page4of4
Copyright Association Connecting Electronics Industries
Provided by IHS under license with IPC
Not for Resale
No reproduction or networking permitted without license from IHS
--``,``,-`-`,,`,,`,`,,`---
OUTLINE
This method is used to replate edge contacts by selective swab plating. Edge con-
tacts may require replating if they become contaminated with solder or are scratched
during handling. Other applications may arise when the plating on the edge contacts
does not meet the minimum thickness specification or if the specification changes.
This electroplating process uses a DC power supply. One lead is connected to the
connector edge contacts that need plating. A second lead is connected to the plat-
ing probe. The plating probe has an anode fastened to the tip. The anode has
absorbent wrapping. The anode is dipped into high-speed proprietary plating solu-
tions. When the saturated anode is swabbed across the printed wiring board con-
nector edge contacts, the metal contained in the solution is plated wherever electri-
cal contact is made. Prior to replating any solder contamination must be removed.
CAUTION
This method can be used to replate any metal surface including connector edge
contacts, but it is essential that the surface to be plated is free of deep scratches,
nicks, pin holes or other defects. If the edge contacts need to be replaced see
appropriate procedure.
SAFETY
A thorough review of this method should be made before repairs are attempted.
Technicians should become familiar with the tools included and should practice on
scrap printed wiring boards
To expect the best results a clean work environment is essential. A smooth work
surface and good lighting are recommended. Safety glasses and safety gloves
should always be worn when handling hazardous chemicals.
The work area should be adequately ventilated. It is particularly important to have
adequate ventilation when using gold solution, since gold solution contains a very
small percentage of free cyanide. If ventilation is not adequate, use a fan to move
fumes away from the operator.
CAUTION
It is essential to follow the manufacturer’s instructions supplied with the plating
equipment.
REFERENCES
2.1 Handling Electronic Assemblies
2.2 Cleaning
Figure 1 Apply tape.
Figure 2 Flow solder.
Figure 3 Solder stripping solution.
Figure 4 Rinse.
7721A
Repair and
Modification of
Printed Boards and
Electronic Assemblies
Revision:
Date: 2/98
Edge Contact Repair,
Plating Method
Number: 4.6.3
Product Class: R, F, W, C
Skill Level: Advanced
Level of Conformance: High
Material in this manual was voluntarily established by Technical Committees of IPC. This material is advisory only and its use
or adaptation is entirely voluntary. IPC disclaims all liability of any kind as to the use, application, or adaptation of this material.
Users are also wholly responsible for protecting themselves against all claims or liabilities for patent infringement. Equipment
referenced is for the convenience of the user and does not imply endorsement by IPC.
Page1of6
Copyright Association Connecting Electronics Industries
Provided by IHS under license with IPC
Not for Resale
No reproduction or networking permitted without license from IHS
--``,``,-`-`,,`,,`,`,,`---