IPC 7711A.pdf - 第298页
NOTES IPC-7721A Number: 4.7.2 Revision: Date: 2/98 Subject: Surface Mount Pad Repair , Film Adhesive Method P a g e4o f4 Copyright Association Connecting Electronics Industries Provided by IHS under license with IPC Not …
14. After the timed bonding cycle lift the bonding iron and remove the tape used for
alignment. The pad is fully cured. Carefully clean the area and inspect the new
pad for proper alignment.
15. If the new pad has a connecting circuit apply a small amount of liquid flux to the
lap solder joint connection area and solder the circuit from the new pad to the
circuit 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 pad
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. Mix epoxy and coat the lap solder joint connection. Cure the epoxy per the
manufacturers recommended instructions.
NOTE
Additional epoxy can be applied around the perimeter of the new pad to pro-
vide additional bond strength.
CAUTION
Some components may be sensitive to high temperature.
17. Apply surface coating to match prior coating as required.
EVALUATION
1. Visual examination
2. Measurement of new pad width and spacing.
3. Electrical continuity measurement.
IPC-7721A
Number: 4.7.2
Revision:
Date: 2/98
Subject: Surface Mount Pad 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: 4.7.2
Revision:
Date: 2/98
Subject: Surface Mount Pad 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 procedure covers the repair of a damaged hole that has no inner layer connec-
tion. An eyelet is used to repair the damage to the hole and the eyelet flanges replace
the pads on the printed wiring board surface.
CAUTION
This procedure is used only to restore the integrity of a through connection in a
double sided board or a multilayer board where there is no inner layer connection. If
there is an inner layer connection see appropriate procedure.
REFERENCES
2.1 Handling Electronic Assemblies
2.2 Cleaning
TOOLS & MATERIALS
Ball Mills, Carbide
Caliper
Cleaner
Eyelets
Eyelet Press System
Eyelet Repair Kit
Eyelet Setting Tools
Hand Held Drill
Liquid Flux
Knife
Microscope
Pin Gauges
Solder
Solder Iron
Wipes
EYELET SELECTION CRITERIA
ID Inside Diameter
The eyelet inside diameter should be a 0.075 - 0.500 mm greater than the compo-
nent lead diameter.
LUF Length Under Flange
The length of the eyelet barrel under the flange should be 0.630 - 0.890 mm greater
than the thickness of the printed wiring board. This added length allows for proper
protrusion when setting the eyelet.
Figure 1 Drill out the hole using a
hand held drill and ball mill.
Figure 2
The eyelet flange can be used
to secure a new conductor in place.
Figure 3 Set the eyelet using an
eyelet press.
Figure 4 Completed repair.
7721A
Repair and
Modification of
Printed Boards and
Electronic Assemblies
Revision:
Date: 2/98
Plated Hole Repair,
No Inner Layer
Connection
Number: 5.1
Product Class: R, F, W
Skill Level: Intermediate
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.
Page1of4
Copyright Association Connecting Electronics Industries
Provided by IHS under license with IPC
Not for Resale
No reproduction or networking permitted without license from IHS
--``,``,-`-`,,`,,`,`,,`---