IPC 7711A.pdf - 第267页
OUTLINE This method is used to repair damaged and lifted lands. The lifted lands are repaired with dry film epoxy. They are re-bonded to the printed wiring board surface using a bonding press or bonding iron. CAUTION It …
9. Install the proper component and solder in place.
NOTE
This method is used to repair a lifted lands, but the repaired land may not have
an intermetallic connection to the remaining plated hole. The solder joint of the
replaced component will restore the integrity of the electrical connection or an
eyelet or buss wire may be used. See Plated Hole Repair Procedures.
10. Replace surface coating to match prior coating as required.
EVALUATION
1. Visual examination and tape test per IPC-TM-650, Test Method 2.4.1.
2. Electrical tests as applicable.
NOTES
IPC-7721A
Number: 4.4.1
Revision:
Date: 2/98
Subject: Lifted Land Repair, Epoxy Method
Page2of2
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 repair damaged and lifted lands. The lifted lands are repaired
with dry film epoxy. They are re-bonded to the printed wiring board surface using a
bonding press or bonding iron.
CAUTION
It is essential that the board surface be extremely smooth and flat. If the base board
is damaged see appropriate procedure.
REFERENCES
2.1 Handling Electronic Assemblies
2.2 Cleaning
TOOLS & MATERIALS
Ball Mills
Bonding Iron
Bonding System
Bonding Tips
Cleaner
Dry Film Adhesive
Polyimide Tape
Knife
Microscope
Scraper
Tweezers
Wipes
PROCEDURE
1. Clean the area.
2. Remove any obstructions that prevent the lifted land from making contact with
the base board material.
3. Use the knife and scrape off any epoxy residue, contamination or burned mate-
rial from the board surface.
4. Clean the area.
5. Cut out a piece of bonding film that matches the area of the lifted land. Be
careful not to contaminate the dry film epoxy with materials that could reduce
the bond strength.
NOTE
Dry film adhesive thickness should be selected to meet the requirements of the
printed wiring board.
6. Place the dry film under the lifted land. (See Figure 1).
7. Place a piece of Polyimide tape over the lifted land and press the land down into
contact with the adhesive film. (See Figure 2).
Figure 1 Cut out dry film material to
match the area of the lifted land.
Figure 2 Place tape over the lifted
land.
Figure 3 Bond the land down using a
commercially available system.
Figure 4 Completed repair.
7721A
Repair and
Modification of
Printed Boards and
Electronic Assemblies
Revision:
Date: 2/98
Lifted Land Repair,
Film Adhesive Method
Number: 4.4.2
Product Class: R, F
Skill Level: Advanced
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
--``,``,-`-`,,`,,`,`,,`---
8. Select a bonding tip with a shape to match the shape of the lifted land.
NOTE
The bonding tip should be as small as possible but should completely cover the
entire surface of the new land.
9. Position the printed wiring board so that it is flat and stable. Gently place the hot
bonding tip onto the tape covering the new land. Apply pressure and heat as
recommended in the manual of the repair system or repair kit. (See Figure 3).
10. After the bonding cycle remove the tape used for alignment. The film is fully
cured. Carefully clean the area and inspect the land.
NOTE
Double sided and multilayer printed wiring boards, may require an eyelet to
restore the through connection. Refer to section 5.0 Plated Hole Procedures.
11. Carefully remove any excess bonding film inside the plated hole using a ball mill
or drill bit. Turn the ball mill or drill bit by hand to prevent damage to the wall of
the plated through hole.
12. Install the proper component and solder in place.
NOTE
This method is used to repair a lifted land, but the repaired land may not have
an intermetallic connection to the remaining plated hole. The solder joint of the
replaced component will restore the integrity of the electrical connection or an
eyelet or buss wire may be used. See Plated Hole Repair Procedures.
13. Replace surface coating to match prior coating as required.
EVALUATION
1. Visual examination and tape test per IPC-TM-650, Test Method 2.4.1.
2. Electrical tests as applicable.
NOTES
IPC-7721A
Number: 4.4.2
Revision:
Date: 2/98
Subject: Lifted Land Repair, Film Adhesive Method
Page2of2
Copyright Association Connecting Electronics Industries
Provided by IHS under license with IPC
Not for Resale
No reproduction or networking permitted without license from IHS
--``,``,-`-`,,`,,`,`,,`---