Outline
This procedure covers repairing a damaged hole with no inner layer connection. An eyelet is used to repair the damage to the hole, and the eyelet flange replaces the lands on the circuit board surface.Caution: This procedure is used only to restore the integrity of a through connection in a double-sided board or a multilayer board where there is no inner layer connection. If there is an inner layer connection, see the appropriate procedure.
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Images and Figures![]()
Damaged Plated Hole
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Figure 1: Drill out the hole using a Micro-Drill System or Tool Grip and ball mill.
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Figure 2: The eyelet flange can be used to secure a new circuit in place.
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Figure 3: Set the eyelet using an Eyelet Press or using a Tool Grip and Setting Tools.
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Figure 4: The small cone tip end of the lower Setting Tool faces up. The large cone end of the upper setting tool faces down.
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Figure 5: Flare the eyelet barrel using the flare end of the setting tool.
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Figure 6: Flatten the eyelet barrel using the flat end of the setting tool.
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Figure 7: Completed repair.
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Figure 8: Flat flange eyelet.
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Figure 9: Funnel flange eyelet.
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Procedure
Eyelet Selection Criteria
ID - Inside Diameter The eyelet inside diameter should be .075 - .500 mm (.003"-.020") greater than the component lead diameter. OD - Outside Diameter The clearance hole drilled through the circuit board should allow the eyelet to be inserted without force but should not exceed .125 mm (.005") greater than the eyelet's outside diameter. LUF - Length Under Flange The length of the eyelet barrel under the flange should be .630 - .890 mm (.025" - 035"), greater than the thickness of the circuit board. This added length allows for proper protrusion when setting the eyelet. FD - Flange Diameter The eyelet flange diameter should be small enough to prevent interference with adjacent lands or circuits. Note Be sure to select an eyelet meeting the proper criteria. An eyelet with an oversize flange may interfere with adjacent circuits. An eyelet that is too short will not protrude through the circuit board for proper setting. Procedure
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