IPC 7711A.pdf - 第266页
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…
OUTLINE
This method is used to rebond a lifted land. Liquid epoxy is inserted under and
around the land to bond it back down to the printed wiring board surface.
REFERENCES
2.1 Handling Electronic Assemblies
2.2 Cleaning
2.5 Baking and Preheating
2.6 Epoxy Mixing and Handling
TOOLS AND MATERIALS
Cleaner
Epoxy
Heat Lamp
Polyimide Tape
Knife
Oven
Wipes
PROCEDURE
1. Clean the area.
2. Remove any obstructions that prevent the lifted land from making contact with
the base board surface.
CAUTION
Be careful while cleaning and removing all obstructions, not to stretch or dam-
age the lifted land.
3. Mix the epoxy.
4. Carefully apply a small amount of epoxy under the entire length of the lifted land.
The tip of a knife or scraper may be used to apply the epoxy. (See Figure 1.)
5. Place a piece of Polyimide tape over the lifted land and press the land down into
the epoxy and into contact with the base board material. (See Figure 2.)
6. Apply additional epoxy to the surface of the lifted land and to all sides as
needed.
7. Cure the epoxy per the manufacturer’s instructions.
CAUTION
Some components may be sensitive to high temperatures.
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.
8. Carefully remove any excess epoxy 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.
Figure 1 Apply epoxy under the entire
length of the lifted land.
Figure 2 Place tape over the lifted
land.
Figure 3 Completed repair.
7721A
Repair and
Modification of
Printed Boards and
Electronic Assemblies
Revision:
Date: 2/98
Lifted Land Repair,
Epoxy Method
Number: 4.4.1
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
--``,``,-`-`,,`,,`,`,,`---
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
--``,``,-`-`,,`,,`,`,,`---