Outline
This method can be used to add, change, or replace legends and markings on printed boards or printed board assemblies. It 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.| Procedure References | |
| 1-0 | 1.0 Foreword |
| 2-1 | 2.1 Handling Electronic Assemblies |
| 2-2 | 2.2 Cleaning Procedures |
| 2-5 | 2.5 Baking and Preheating |
| 2-7 | 2.7 Epoxy Mixing and Handling |
Tools and Materials
Clear, superior strength epoxy in two-compartment plastic packages. |
General purpose cleaner for removing contamination. |
Disposable brushes for solvent cleaning and application of coatings. |
One part, semi-paste ink used to tint the color of epoxy and for direct printing on circuit board surfaces. |
Sturdy rack for PCBs used for rework and positioning. |
A must-have tool for precise cutting, scraping and trimming. |
Precision microscope with stand and lighting for work and inspection. |
General purpose oven for drying, baking and curing epoxies. |
Peg stamps for application of inks to replace text and markings. |
Nine precision-crafted tools for detailed circuit board work. |
Nonabrasive, low-linting wipes for cleanup. |
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 a smooth surface.
- Press the peg stamp into the epoxy coating to coat the character surface.
- Press the peg stamp onto the desired location on the circuit board surface. (See Figure 2)
- Cure the epoxy ink per the manufacturer's instructions.
Evaluation
- Visual examination for proper characters, positioning, and legibility.
Images
Legend/Marking Repair, Stamping Method
Scrape off any remaining character or legend with a knife and clean the area.
Apply legend using a peg stamp.
Cure the legend ink per the manufacturer's instructions.
