4.1.2 Lifted Conductor Repair, Film Adhesive Method

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.

Minimum Skill Level - Intermediate
Recommended for technicians with skills in basic soldering and component rework, but may be inexperienced in general repair/rework procedures.

Conformance Level - High
This procedure most closely duplicates the physical characteristics of the original, and most probably complies with all the functional, environmental and serviceability factors.

Acceptability References
IPC-A-600 2.0	Externally Observable Characteristics
IPC-A-610 10.0	Laminate Conditions


Procedure References
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

Tools, Materials and Supplies

Bonding Film
Dry film adhesive used to bond lifted lands, pads and conductors.

Bonding Iron, 120 VAC
Delivers the optimal heat for curing adhesive bonding film.

Bonding Tips
Bonding Tips used to bond adehesive backed Circuit Frames.

Circuit Bond Epoxy
Clear, superior strength epoxy in two-compartment plastic packages.

Circuit Bonding System
System to repair damaged conductors, BGA pads, and SMT pads.

Flex-Rack PCB Holder
Sturdy rack for PCBs used for rework and positioning.

Circuit Frames
Circuit Frames for surface mount pad, BGA pad and conductor repair.

Cleaning Brushes
Disposable brushes for solvent cleaning and application of coatings.

Color Agents
One part, semi-paste ink used to tint the color of epoxy and for direct printing on circuit board surfaces.

Cleaner
General purpose cleaner for removing contamination.

High Temp Tape Discs
High temperature polyimide tape discs, .50" diameter.

Knife with #16 Blades
A must-have tool for precise cutting, scraping and trimming.

Micro Probes
Sharp probes for dispensing adhesive and positioning small objects.

Microscope
Precision microscope with stand and lighting for work and inspection.

Precision Tool Set
Nine precision-crafted tools for detailed circuit board work.

Scraper, Curved Tip
Hardened stainless steel tip for scraping solder mask and removing defects.

Tweezers
Multiple sizes and tip configurations of tweezers for various small parts handling needs.

Wipes
Nonabrasive, low-linting wipes for cleanup.

Procedure

Procedure

Clean the area.
Remove any obstructions that prevent the lifted conductor from making contact with the baseboard surface.
Caution: Be careful while cleaning and removing all obstructions not to stretch or damage the lifted conductor.
Clean the area.
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.
Place the dry film epoxy under the lifted conductor. (See Figure 1)
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.
Place a piece of high-temperature tape over the lifted conductor. (See Figure 2)
Position the circuit board so that it is flat and stable. Gently place the hot bonding tip onto the 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.
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.
Replace surface coating to match prior coating as required.

Evaluation

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

Images and Figures

Lifted Conductor Repair, Film Adhesive Method

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

Figure 2. Place high-temperature tape over the lifted conductor.

Figure 3. Completed repair.

4.1.2 Lifted Conductor Repair, Film Adhesive Method

Procedure to repair lifted conductors and circuits using a dry film epoxy method. Minimum Skill Level: Intermediate Conformance Level: High

Procedure to repair lifted conductors and circuits using a dry film epoxy method.

Minimum Skill Level: Intermediate
Conformance Level: High