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Plated-Through Hole Clearing Tool

IP.com Disclosure Number: IPCOM000062133D
Original Publication Date: 1986-Oct-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Lubert, KJ: AUTHOR [+3]

Abstract

Plated-through holes (PTHs) on printed circuit boards (PCBs) are occasionally plugged with debris during the various manufacturing processes, e.g., vapor blast slurry, copper nodules, etc. These plugged PTHs can be cleared by utilizing a magnetic breakaway mechanism which limits the amount of force that can be applied, thereby minimizing the risk of damage. The tool is used in the following manner. As seen in Fig. 1, the tool 1 consists of a base plate 2 secured to assembly body 3 by means of a countersunk flat head screw (not shown). Mounted on body 3 is a guide bushing 5 for a plunger 6 Fig. 2, which is a cross-section of tool 1 that is recessed in plunger housing 7. The tool 1 works when placed on the surface of a PCB (not shown) over the PTH (not shown) to be cleared.

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Plated-Through Hole Clearing Tool

Plated-through holes (PTHs) on printed circuit boards (PCBs) are occasionally plugged with debris during the various manufacturing processes, e.g., vapor blast slurry, copper nodules, etc. These plugged PTHs can be cleared by utilizing a magnetic breakaway mechanism which limits the amount of force that can be applied, thereby minimizing the risk of damage. The tool is used in the following manner. As seen in Fig. 1, the tool 1 consists of a base plate 2 secured to assembly body 3 by means of a countersunk flat head screw (not shown). Mounted on body 3 is a guide bushing 5 for a plunger 6 Fig. 2, which is a cross- section of tool 1 that is recessed in plunger housing 7. The tool 1 works when placed on the surface of a PCB (not shown) over the PTH (not shown) to be cleared. A PTH clearing pin 8, secured by chuck 9, is aligned over the PTH. A magnifying lens 10, attached to a lens-mounting bracket 11 by means of a binding screw 12, provides visual assistance with the alignment. When pin 8 is aligned with PTH, finger pressure is applied to the top 13 of magnet housing 7. The housing 7 actuates on a Z axis to drive pin 8 into PTH to clear PTH. If the force applied is sufficient to clear PTH, the pin will push out debris. If the force applied exceeds the pre-set breakaway force of plunger magnet 14 (Fig. 2) to actuator bushing 15, the plunger magnet 14 will separate from the actuator bushing 15. The plunger housing 7 will bottom on th...