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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
Kits and Systems
201-2100
Professional Repair Kit
Kit to repair circuit board damage including pads, lands, conductors, base material and plated holes.
201-2400
Master Repair Kit
Kit to repair circuit board damage including pads, lands, conductors and base material.
201-1400
Land/Pad Repair Kit
Kit to repair circuit board damage including lands and pads.
201-7100
Precision Tool Set
Nine precision-crafted tools for detailed circuit board work.
Tools and Materials
115-2706
Bonding Film
Dry film adhesive used to bond lifted lands, pads and conductors.
115-3210
Bonding Iron, 120 VAC
Delivers the optimal heat for curing adhesive bonding film.
CircuitMedic Part
Bonding Iron Tips
Used with a Bonding Iron to heat, cure and bond adhesive backed Circuit Frames.
circuit-frames
Circuit Frames
Circuit Frames
235-2106-5
Cleaning Brushes
Disposable brushes for solvent cleaning and application of coatings.
Coatings
Color Agents
Use to tint the color of epoxy used for solder mask repair or circuit base board repair.
115-3302
Circuit Bond Epoxy
Clear, superior strength epoxy in two-compartment plastic packages.
235-3050
High Temp Tape Discs
High temperature polyimide tape discs, .50" diameter.
355-0614
Knife with #16 Blades
A must-have tool for precise cutting, scraping and trimming.
355-3102-5
Micro Probes
Sharp probes for dispensing adhesive and positioning small objects.
335-3197
Scraper, Curved Tip
Hardened stainless steel tip for scraping solder mask and removing defects.
Additional Items and Supplies
Cleaner
Cleaner
General purpose cleaner for removing contamination.
Microscope
Microscope
Precision microscope with stand and lighting for work and inspection.
Hot Plate
Tweezers
Multiple sizes and tip configurations of tweezers for various small parts handling needs.
Wipes
Wipes
Nonabrasive, low-linting wipes for cleanup.
Bonding Iron Tips
Bonding Iron Tips fit into the handheld Bonding Iron. The bottom surface of each Bonding Tip is used to apply heat and pressure to bond adhesive-backed replacement lands, pads, and edge contacts to a circuit board surface. The pressure/force listed is the recommended load in pounds to apply to the top surface of the replacement adhesive-backed pads, lands, and conductors. The load is based on the Bonding Tip surface area to meet the recommended load for Circuit Frames at 200 - 400 psi.
Part No. Size Pressure/Force
115-2801 115-2801 Bonding Tip, Tapered N/A
115-2802 115-2802 Bonding Tip, .080" (2.03 mm) Diameter 1.00 lbs
115-2803 115-2803 Bonding Tip, .120" (3.05 mm) Diameter 2.26 lbs
115-2804 115-2804 Bonding Tip, .040" x .060" 0.48 lbs
115-2805 115-2805 Bonding Tip, .080" x .120" (2.03 x 3.05 mm) 1.92 lbs
Circuit Bond Epoxy
Circuit Bond is a clear, low viscosity, superior strength epoxy precisely measured out into two-compartment plastic packages, so it's easy to use, and there's no measuring. For over a decade, this high-strength epoxy has been qualified and used by thousands of high-rel electronics manufacturers across the globe.
1. Circuit Bond has a working pot life of 30 minutes. It should not be mixed until ready to use.
2. To use Circuit Bond, remove the plastic clip separating the resin and hardener. Squeeze back and forth from one half of the package to the other to mix the contents.
3. Cut a corner off the package and squeeze all the contents into a Plastic Cup. Stir the contents to ensure it is thoroughly mixed.
4. Circuit Bond may contain bubbles from the mixing process. If needed, use a vacuum system to remove bubbles.
5. Color Agent can be mixed in with Circuit Bond to match surface colors if desired.
6. Apply using a Foam Swab, Micro Probe, or Mixing Stick as required.
7. Cure Circuit Bond for 24 hours at room temperature or 4 hours at 65°C (150°F).
Specifications
Packaging2 gram pre-measured packages
Mix ratio4 parts resin to 1 part hardener
Mix Ratio by Weight (R/H)100/25
ColorClear, transparent
Pot life30 minutes
Cure cycle24 hours at room temp (25 °C) or 4 hours @ 65°C
Thixotropic Index1
Specific Gravity1.20
Percent Solids100%
Viscosity (after mixing)2000 cps
Operating temperature range-55°C to 135°C
Hardness88 Shore D
Lap Shear, Alum to Alum1100 psi
Glass Transition Temperature, Ultimate92°C
Coefficient of Expansion, cm/cm/°C6 E-05
Dielectric strength400 volts/mil
Dielectric Constant, 1KHz@25°C4
Shelf Life6 months minimum
Circuit Frames
Circuit Frames have a dry-film adhesive backing that is heat-cured in 30 seconds. Use Circuit Frames to repair and replace damaged surface mount pads, lands and conductors without the mess of liquid epoxy, with a bond strength equal to the original, in just a few minutes. The dry-film adhesive backing makes this delicate repair procedure easy, fast, and highly reliable. Circuit Frames are available with a bright tin, tin/lead and nickel/gold plating finishes. This reliable IPC recommended procedure meets the highest conformance level for this type of repair. For over 30 years Circuit Frames have been used by thousands of commercial, medical and military manufacturers around the globe. Below are examples for some Circuit Frame patterns.
Color Agents
Color Agent is a one-part, air-drying, semi-paste ink commonly used to print hard surfaces, including circuit board base materials. Color Agent can be used to tint the color of epoxy used for solder mask repair or circuit baseboard repair. To use, mix a small amount of color agent with 2 part epoxy as the epoxy is initially mixed. Add more color agents to increase the color intensity if needed.
Part No. Description
115-9102 115-9102 Color Agent, Yellow
115-9185 115-9185 Color Agent, Red
115-9293 115-9293 Color Agent, Blue
115-9348 115-9348 Color Agent, Green
115-9358 115-9358 Color Agent, Light Green
115-9376 115-9376 Color Agent, Medium Green
115-9424 115-9424 Color Agent, Dark Gray
115-9457 115-9457 Color Agent, Light Brown
115-9560 115-9560 Color Agent, Dark Green
115-9561 115-9561 Color Agent, Green
115-9995 115-9995 Color Agent, Black
115-9996 115-9996 Color Agent - White
Images and Figures
4.1.2 Lifted Conductor Repair, Film Adhesive Method
Lifted Conductor
4.1.2 Lifted Conductor Repair, Film Adhesive Method
Figure 1: Cut out a piece of dry film epoxy and place it under the lifted conductor.
4.1.2 Lifted Conductor Repair, Film Adhesive Method
Figure 2: Place Kapton tape over the lifted conductor.

4.1.2 Lifted Conductor Repair, Film Adhesive Method
Figure 3: Bond the lifted conductor using a Bonding Iron.
4.1.2 Lifted Conductor Repair, Film Adhesive Method
Figure 4: Completed repair.
Procedure
  1. Clean the area.
  2. 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.
  3. Clean the area.
  4. 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. Place a piece of High-Temperature 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 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. Visual examination and tape test per IPC-TM-650 (ANCI/IPC-FC-250A) test method 2.4.1.
  2. Electrical tests as applicable.
Procedure for reference only.