IPC 7711A - 第250页
NOTES IPC-7721A Number: 4.2.5 Revision: A Date: 11/99 Subject: Conductor Repair , Through Board Wire Method P a g e4o f4 Copyright Association Connecting Electronics Industries Provided by IHS under license with IPC Not …
17. If desired bond the wire to the printed wiring board surface with adhesive, epoxy
or Tape Dots.
CAUTION
Some components may be sensitive to high temperature.
18. Cure the epoxy per Procedure 2.7 Epoxy Mixing and Handling.
19. After the epoxy has cured clean the area.
EVALUATION
1. Visual examination for alignment and overlap of wire.
2. Electrical tests as applicable.
IPC-7721A
Number: 4.2.5
Revision: A
Date: 11/99
Subject: Conductor Repair, Through Board Wire 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: 4.2.5
Revision: A
Date: 11/99
Subject: Conductor Repair, Through Board Wire 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 modification/repair conductive pattern is fabricated via a solder/copper com-
posite of screen printable polymer thick film (PTF). The interconnects are established
at conductor lands and through hole locations of the original conductor. Electrical
continuity is optimized between two or more points of interconnection by solder
fusion of the new conductor pattern to the original etched PCB pattern.
NOTE
This modification/repair method is UL recognized, Type 1 94-V-0. It is compatible
with both digital and analog printed wiring board applications and it has resistance
of less than 3.0 milliohms/sq. It consists of greater than 90% copper and solder. The
resin system employed is thermal setting and adhesion of approximately 1.5 kg on
a 6 mm x 0.6 mm wide strip. It is typically applied to either or both sides of printed
wiring boards on thru-hole or surface mount PCB’s prior to assembly, without any
final solder resist coating. (Line resist coating can be applied and it is considered
optional.)
CAUTION
This modification/repair method can be employed on a single-sided, double-sided or
a multilayer printed wiring board. Its primary application is for signal carrying conduc-
tors. New or additional power distribution should be designed into the new conduc-
tor pattern on the basis of 0.25 mm of line width 2.6 amps of current required, up to
a maximum of 3.4 amps. When applying this method to the wave solder side or a
thru-hole printed wiring board, it should be covered with a solder (line) resist.
REFERENCES
2.1 Handling Electronic Assemblies
2.2 Cleaning
2.5 Baking and Preheating
TOOLS AND MATERIALS
Screen printer/screens with matalizer and IR belt ovens
Modification/repair master artwork
Conductive Ink, directly solderable
SMT compatible solder paste
IR solder reflow (fuse) belt oven
Flux cleaner, deionized water
Electronic multi-point tester
PROCEDURE
1. Convert conductor design revision via CAD to additive layer conductor pattern
including vias to be exposed and etch deletes to be performed.
Figure 1 Isolation layer.
Figure 2 Copper ink is applied.
Figure 3 Solder ink fused to copper
ink.
7721A
Repair and
Modification of
Printed Boards and
Electronic Assemblies
Revision:
Date: 2/98
Conductor Repair/
Modification, Conductive
Ink Method
Number: 4.2.6
Product Class: R, F, C
Skill Level: Expert
Level of Conformance: Medium
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.
Page1of2
Copyright Association Connecting Electronics Industries
Provided by IHS under license with IPC
Not for Resale
No reproduction or networking permitted without license from IHS
--``,``,-`-`,,`,,`,`,,`---