Figure 1: Mill out the damaged area using a milling machine
or Precision Drill System.
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| 1. |
Clean the area to be filled, including the edges.
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| |
| 2. |
Mill out the damaged area using a milling machine
or Precision Drill System and carbide end mill.
(See Figure 1).
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| 3. |
Clean the area.
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Figure 2: Cut a groove into both
sides of the key slot using a Micro
Drill System and carbide saw.
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| 4. |
Install 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 approx. 1/3 of the circuit board
thickness. The groove depth should be approx.
double the groove width. (See Figure 2).
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| 5. |
Cut a piece of replacement base board material
that is the same thickness and type as the circuit
board. The replacement piece should be longer
than the length of the slot to allow for ease
of handling.
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Figure 3: Machine a tongue onto
both sides of the replacement
base material.
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| 6. |
Install an end mill into the milling machine.
Machine a tongue onto both sides of the replacement
piece. The dimensions of the tongue should match
the size of the milled groove. (See Figure 3).
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| 7. |
Where required apply Kapton tape to protect
exposed parts of circuit board bordering the
prepared area.
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| 8. |
Carefully check the fit of the replacement piece
and then clean both the replacement piece and
the slot. The replacement base material should
fit firmly into the slot so that it will not
move or fall out when epoxied in place.
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| 9. |
Apply Kapton tape to the surface of the circuit
board adjacent to the slot. The Kapton tape
should protect any adjacent contacts or components.
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| 10. |
Mix the epoxy.
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| |
| 11. |
Apply a small amount of epoxy to the edges of
the replacement piece and to the inside edges
of the slot.
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Figure 4: Insert the replacement
piece into the slot.
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| 12. |
Insert the replacement piece into the slot.
Check alignment. Remove excess epoxy. (See Figure
4).
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| 13. |
If needed, apply additional epoxy to the edges
of the slot. A mixing stick sharpened at the
end may be used to apply the epoxy.
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| 14. |
Cure the epoxy per Procedure 2.7 Epoxy Mixing
and Handling.
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Caution
Some components may be sensitive to high
temperature.
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| 15. |
After the epoxy has cured remove the Kapton
tape.
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| 16. |
If needed use a knife or scraper
and scrape off any excess epoxy. |
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| |
Note
If needed, apply additional thin coating
to seal any scraped areas.
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Figure 5: Cut off excess material
and file to match edge.
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| 17. |
Cut off excess length of replacement material
and file to match contour of existing edge.
(See Figure 5).
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| |
| 18. |
If a new slot is needed, machine using milling
machine and appropriate milling cutter. Use
great care to correctly relocate the slot.
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| 19. |
Clean the area. |
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Figure 6: Micro-Drill System. |
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Evaluation |
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| 1. |
Visual examination and measurement
of key slot location and dimension. |
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