IPC-7721(S).pdf - 第57页

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 a brush or roller technique. A stencil is used to outline the ch…

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NOTES
IPC-7721
Number: 2.7.2
Revision:
Date: 2/98
Subject: Legend/Marking, Hand Lettering Method
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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 a brush or
roller technique. A stencil is used to outline the characters.
REFERENCES
2.1 Handling Electronic Assemblies
2.2 Cleaning
2.5 Baking and Preheating
2.6 Epoxy Mixing and Handling
TOOLS & MATERIALS
Cleaner
Cleaning Wipes
Epoxy Ink
Ink Plate
Ink Roller
Knife
Microscope
Oven
Stencil
PROCEDURE
1. Clean the area.
2. Scrape off any remaining character or legend with a knife and clean the area.
CAUTION
Abrasion operations can generate electrostatic charges.
3. Select the appropriate stencil or have a special stencil made up. (See Figure 1.)
4. 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.
5. Position the stencil on the printed wiring board surface and hold in place firmly.
6 Roll or brush the ink onto the stencil. Do not smudge characters or apply excess
ink.
7. Cure the epoxy ink per the manufacturer’s instructions.
EVALUATION
1. Visual examination for proper characters, positioning, and legibility.
Figure 1 Replace legend using a
stencil.
Figure 2 Completed legend repair.
7721
Repair and
Modification of
Printed Boards and
Electronic Assemblies
Revision:
Date: 2/98
Legend/Marking,
Stencil Method
Number: 2.7.3
Product Class: R, F, W, C
Skill Level: Intermediate
Level of Conformance: High
Material in this manual was voluntarily established by Technical Committees of the IPC. This material is advisory only and its
use or adaptation is entirely voluntary. IPC disclaims all liability of any kind as to the use, application, or adaptation of this
material. Users are also wholly responsible for protecting themselves against all claims or liabilities for patent infringement.
Equipment referenced is for the convenience of the user and does not imply endorsement by the ipc.
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NOTES
IPC-7721
Number: 2.7.3
Revision:
Date: 2/98
Subject: Legend/Marking, Stencil Method
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