Circuit Board Repair Guide > Base Board Repair > 3.5.3 Repairing Damaged Base Board Corners and Edges

Repairing Damaged Base Board Corners and Edges

Repair Circuit Boards | Repair SMT Pads | Repair BGA Pads | Repair Lands | Repair Edge Contacts
Repair a Conductor | Plated Hole Repair | Base Board Repair | Replace Solder Mask or Coatings

This method is used to repair mechanical or thermal damage to circuit board base material. This procedure is used when extended areas of base material must be completely replaced. This method may be used on single sided, double sided or multilayer printed circuit boards or printed circuit board assemblies.

Caution
Surface circuits may need to be replaced in the damaged area. Be sure that the appropriate circuit diagrams, or photographs reflecting the original circuits are available so that they may be replaced after repairing the base board material. Damage to internal circuits or planes may have to be restored using surface wires.
 
Damaged base board corner needs repair
Damaged Base Material

IPC Acceptability References
IPC-A-600 2.0 Externally Observable Characteristics
IPC-A-610 10.0 Laminate Conditions
 
Related Procedure Reference
CTC 2.1 Handling Electronic Assemblies
CTC 2.2.1 How to Clean a Circuit Board
CTC 2.2.2 Cleaning Circuit Boards, Aqueous Batch Process
CTC 2.3.1 Coating Removal, Identification of Coatings
CTC 2.4.1 Replace Solder Mask or Coatings on Printed Circuit Boards
CTC 2.4.2 Coating Replacement, Conformal Coatings/Encapsulants
IPC 7721 3.5.3 Base Material Repair, Edge Transplant Method

Tools and Materials
Alcohol Swabs - Self-saturating Isopropyl alcohol swabs. Squeeze handle to release alcohol.
Circuit Bond Pack - Clear, superior strength epoxy in two-compartment plastic package.
Cleaner - General purpose cleaner for removing contamination.
Cleaning Brushes - Disposable brushes for use with solvents for cleaning and application of coatings.
Color Agents - Use to tint the color of epoxy used for solder mask repair or circuit base board repair.
End Mills - Designed for end cutting and hole boring.
Foam Swabs - Ideal for absorbing cleaning solvents, and applying color agents and epoxies.
High Temperature Tape Discs - High temperature polyimide tape discs, .50" diameter.
Knife with #16 Blades - A must-have tool for precise cutting, scraping and trimming.
Microscope - It is a challenge to undertake precision repair without a good microscope.
Micro Drill System - Versatile power tool for milling, drilling, grinding, cutting and sanding circuit boards.
Ball Mills, Abrasives, Cutting Tools - Ball mills, abrasives and cutting tools for working on circuit boards.
Milling Machine - Use for precision milling of circuit board materials.
Oven - General purpose oven for drying, baking and curing epoxies.
Precision Drill - Precision drill press for accuracy and controlled depth drilling.
Scraper - Hardened stainless steel tip for scraping solder mask and removing defects.
Wipes - Nonabrasive, low-linting wipes for cleanup.

3.5.3 Base Material Repair, Edge Transplant Method

Printed Board Type: R/W  |  Skill Level: Expert  |  Conformance Level: High  |  Rev.: D  |  Rev. Date: Jul 7, 2000

Cut away damaged base material with saw

Figure 1: Cut away damaged base material with the Saw or milling cutter.


1.  Clean the area.
 
2.  Cut away the damaged board material using the Saw or milling cutter. Remove all evidence of the damaged material. No fibers of laminate material should be exposed. File the edge to ensure that the edge is flat. (See Figure 1).

Caution
Exercise care to avoid damage to any internal conductors. If any internal conductors are damaged, surface wires may be required to restore electrical connection.
   
Cut groove into edge of circuit board

Figure 2: Cut a groove into the
edge of the circuit board.


3.  Clean the area.
 
4.  Install a carbide saw into the Micro Drill System. Set the speed to maximum and machine a groove in the edge of the circuit board where the new base material will be installed. The groove must be centered in the edge to ensure that the new piece will fit properly. The groove width should be approximately 1/3 of the PC board thickness. The groove depth should be approximately double the groove width. (See Figure 2).
Mill tongue onto edge of replacement base material

Figure 3: Mill a tongue onto the
edge of the replacement base material.


5.  Cut a piece of replacement base board material that is the same thickness and type as the piece removed. The replacement piece may be oversized, the excess material will be removed after the replacement piece has been epoxied in place.
 
6.  Install an end mill into the chuck of a milling machine. Machine a tongue onto the entire mating edge of the replacement base material. The dimensions of the tongue should match the size of the milled groove. (See Figure 3).
 
7.  Where required apply High Temperature Tape to protect exposed parts of circuit board bordering the prepared area.
Check fit of new base material in circuit board

Figure 4: Check fit of new base
material. The tongue must mate
with the groove in circuit board.


8.  Check the fit to be sure the new base material properly mates with the groove in the circuit board. (See Figure 4).
 
9.  Mix the epoxy.
 
10. Coat both the tongue and groove surfaces with liquid circuit board epoxy and fit together. Remove excess epoxy.
 
11. Cure the epoxy per Procedure 2.7 Epoxy Mixing and Handling.
 
12. After the epoxy has cured remove the High Temperature Tape.
Micro Drill System used for milling, drilling, grinding, cutting and sanding circuit boards

Figure 5: Micro Drill System.
13. If needed, scrape off any excess epoxy using the knife or scraper.

Note
If needed, apply additional thin coating to seal any scrapped areas.
 
14. Saw or mill off excess base material and file flush with existing edge.
 
15. Clean the area.
 
16. Complete by drilling holes, slots, etc. or adding circuitry as required.
 
17. If needed, replace solder mask or conformal coating.
 
Evaluation
 
1.  Dimensions of area replaced should be checked to conform to specifications required.




Special Order. Usually ships within 3 business days. Ships From: Haverhill, MA, USA.

How to purchase. For customer service call 1-519-651-3060.
View cart

Minimum order $50 + shipping
Image Description Part No., Price and Quantity
Alcohol Swab Alcohol Swabs (package of 50), 235-1000-50

Self-saturating foam swabs filled with 99% Isopropyl alcohol. Ideal for removing flux residue and cleaning surfaces prior to soldering, coating and application of epoxy. Overall Length: 4.125". Squeeze handle until it "pops" releasing alcohol into the tip.

Enlarge
235-1000-50

$39.00 pkg/50

 
Liquid circuit board epoxy Circuit Bond Pack  MSDS, 115-3302

Clear, low viscosity, superior strength epoxy, precisely measured out into a two-compartment plastic package so it's easy to use and there's no measuring (2 gram). Shelf life: 6 months minimum.

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115-3302

$12.95 each

 
Cleaning Brush Cleaning Brushes (package of 100), 235-2106-100

Disposable brushes for use with solvents for cleaning and application of coatings.



Enlarge
235-2106-100

$29.95 pkg/100

 
Color Agents for Circuit Boards Color Agent, Green, 115-9348

Use to tint epoxy for solder mask and base board repair. Color agent may also be applied directly to the circuit board surface for color matching. Supplied in 1 oz. (29 ml) collapsible metal tubes. MSDS

115-9348

$19.95 each

 
Color Agents for Circuit Boards Color Agent, Light Green, 115-9358

Use to tint epoxy for solder mask and base board repair. Color agent may also be applied directly to the circuit board surface for color matching. Supplied in 1 oz. (29 ml) collapsible metal tubes. MSDS

115-9358

$19.95 each

 
Foam Swab Foam Swabs, 3/16" Tip (pkg. of 100), 235-2102-100

Foam Swabs have 3/16" tip. Ideal for absorbing cleaning solvents, and applying color agents and epoxies.


Enlarge
235-2102-100

$49.50 pkg/100

 
High Temperature Tape Discs 235-3050 High Temp. Tape Discs, .50" Diameter, 235-3050

High temperature tape discs are made of polyimide film with 1.5 mil of silicone adhesive that will not leave any residue. They can withstand temperatures of up to 500°F (260°C).
235-3050

US $5.95 pkg/60

 
Knife 355-0614 Knife with #16 Blades, 355-0614

A must-have tool for precise cutting, scraping and trimming. Includes five #16 blades.


Enlarge
355-0614

$9.95 each

 
Scraper 335-3197 Scraper, 335-3197

Hardened stainless steel tip for scraping solder mask and removing defects.



Enlarge
335-3197

$9.95 each

 

Products above ship direct from manufacturer and are special order/non-returnable. Will ship within 3 business days.



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Links to Related Products


Base Board Repair Kit used to repair damage to base board material   Base Board Repair Kit 201-3110
Most types of damage to base board material can be repaired with this versatile base board repair kit. The kit is industry approved and meets IPC guidelines. The kit includes epoxies and color agents. The high strength, high temperature epoxy withstands demanding physical environments.


Micro Drill System used for drilling, grinding, cutting circuit boards   Micro Drill System 110-4105
The Micro Drill System is a repair technician's dream and is ideal for milling, drilling, grinding, cutting and sanding circuit boards. It removes coating, cuts circuits, cuts leads, drills holes, cuts slots, shapes FR4 and performs many other procedures using various interchangeable bits. Unlike most hand-held tools, the Micro Drill has a tiny, high speed DC motor in the hand piece, eliminating cumbersome drive cables and giving you better control. A separate power supply keeps the hand piece lightweight and reduces operator fatigue. Base unit has controls for forward/reverse and speed up to 45,000 RPM.



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