4.4.1 Lifted Land Repair, Epoxy Seal Method

This method is used to re-bond a lifted land. Liquid epoxy is inserted under and around the land to bond it back down to the circuit board surface.

Acceptability References
IPC-A-600 2.0 Externally Observable Characteristics
IPC-A-610 10.0 Laminate Conditions
  Lifted Land.
Lifted Land
Procedure References
CTC 1.0 Foreword
CTC 2.1 Handling Electronic Assemblies
CTC 2.2.1 Cleaning, Local
CTC 2.2.2 Cleaning, Aqueous Batch Process
CTC 2.5 Baking and Preheating
CTC 2.7 Epoxy Mixing and Handling
IPC7721 4.4.1 Lifted Land Repair, Epoxy Method see procedure below

Tools and Materials
Cleaner
Epoxy
Knife
Land Repair Kit
Oven
Scraper
Tape, Kapton
Wipes  

Procedure 4.4.1 Lifted Land Repair, Epoxy Method

Apply epoxy under lifted land.

Figure 1: Carefully apply a small
amount of epoxy under the entire
length of the lifted land.
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 damage 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 the knife or scraper may be used to apply the epoxy. (See Figure 1).
Place Kapton tape over lifted land.

Figure 2: Place Kapton tape over the lifted land.
5.       Place a piece of Kapton 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 Procedure 2.7 Epoxy Mixing and Handling
   
  Caution
Some components may be sensitive to high temperatures.
   
  Note
Double sided and multilayer circuit 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.
   
9. Install the proper component and solder in place.
   
 
Note
This method is used to repair lifted lands, but the repaired lands may not have an inter-metallic 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.
   
Completed repair.

Figure 3: Completed repair.
Evaluation
   
1.      
Visual examination and tape test per IPC-TM-650 test method 2.4.1 (ANSI/IPC-FC-250A).
   
2. Electrical tests as applicable.


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4.4.1 Lifted Land Repair, Epoxy Seal Method