4.1.2 Lifted Conductor Repair, Film Adhesive Method

Printed Board Type: R/F
Skill Level: Intermediate
Conformance Level: High
Revision: E
Revision Date: Mar 28, 2001

OUTLINE
This method is used to repair damaged and lifted conductors. Dry film epoxy is used to rebond the lifted conductor.

CAUTION
This method should not be used to rebond a conductor that has been stretched or damaged.

ACCEPTABILITY REFERENCES
IPC-A-610 2.0	Externally Observable Characteristics
IPC-A-600 10.0	Laminate Conditions
PROCEDURE REFERENCE
1.0	Foreword
2.1	Handling Electronic Assemblies
2.2	Cleaning
2.5	Baking and Preheating
IPC7721 4.1.2	Lifted Conductor Repair, Film Adhesive Method

Lifted Conductor

TOOLS & MATERIALS
Bonding Film
Bonding Iron
Bonding System
Bonding Tips
Cleaner
Epoxy
Knife
Microscope
Scraper
Tape, Kapton
Tweezers
Wipes

Figure 1: Cut out a piece of dry film epoxy and place it under the lifted conductor.

PROCEDURE

1. Clean the area.
   
   
2. Remove any obstructions that prevent the lifted conductor from making contact with the base board surface.
   
   CAUTION
   Be careful while cleaning and removing all obstructions, not to stretch or damage the lifted conductor.
   
   
3. Clean the area.
   
   

4. Figure 2: Place Kapton tape over the lifted conductor.

   Cut out a piece of dry film epoxy that closely matches the size of the lifted conductor. Be careful not to contaminate the dry film epoxy with materials that could reduce the bond strength. (See Figure 1).
   
   NOTE
   Dry film epoxy thickness should be selected to meet the requirements of the circuit Board.
   
   
5. Place the dry film epoxy under the lifted conductor. (See Figure 1).
   
   
6. Select a bonding tip with a shape to match the shape of the lifted conductor.
   
   NOTE
   The bonding tip should be as small as possible but should completely cover the entire surface of the conductor.
   
   

7. Figure 3: Bond the lifted conductor using a Bonding System.

   Place a piece of Kapton tape over the lifted conductor. (See Figure 2).
   
   
8. Position the circuit board so that it is flat and stable. Gently place the hot bonding tip onto the Kapton tape covering the new conductor. Apply pressure as recommended in the manual of the repair system or repair kit for 5 seconds to tack the conductor in place. Carefully peel off the tape.
   
   
9. Gently place the bonding tip directly onto the new conductor. Apply pressure as recommended in the manual of the repair system or repair kit for an additional 30 seconds to fully bond the conductor. The conductor is fully cured. Carefully clean the area and inspect the new conductor.
   
   
10. Replace surface coating to match prior coating as required.

EVALUATION

1. Figure 4: Completed repair.

   Visual examination and tape test per IPC-TM-650 (ANCI/IPC-FC-250A) test method 2.4.1.
   
   
2. Electrical tests as applicable.