2.6.1 Legend/Marking, Stamping Method

Since 1983 the experienced technicians at Circuit Technology Center have used this simple method to repair and update circuit boards for customers around the world.

For more information visit: Coating and Marking Rework.

Outline
This method can be used to add, change or replace legend and markings on printed boards or printed board assemblies. This method uses epoxy ink and an ink stamp to place the legends on the printed board surface in much the same manner as taking a "fingerprint".

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 8.0	Marking
Procedure References
1.0	Foreword
2.1	Handling Electronic Assemblies
2.2	Cleaning
2.5	Baking And Preheating
2.7	Epoxy Mixing and Handling
IPC7721 2.6.1	Legend/Marking, Stamping Method

Tools and Materials

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.

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

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

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

Oven
General purpose oven for drying, baking and curing epoxies.

Peg Stamps
Peg stamps for application of inks to replace text and markings.

Wipes
Nonabrasive, low-linting wipes for cleanup.

Images and Figures

Damaged Legend

Figure 1: Apply legend using a peg stamp.

Figure 2: Completed legend repair.

Procedure

Clean the area.
Scrape off any remaining character or legend with a knife and clean the area.
Caution: Abrasion operations can generate electrostatic charges.
Select the appropriate characters from the peg stamp set or have a special stamp made up.
Mix the epoxy ink. White is the most common color. Spread a thin, even coating of the epoxy ink on the ink plate or on a smooth surface.
Gently press the peg stamp into the epoxy coating to coat the character surface.
Gently press the peg stamp onto the desired location on the circuit board surface. (See Figure 1)
Cure the epoxy ink per the manufacturer's instructions.

Evaluation

Visual examination for proper characters, positioning and legibility.

Procedure for reference only.