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Locating and Holding Method for Pin Grid Surface-Mounted Substrates During Card Attach

IP.com Disclosure Number: IPCOM000040012D
Original Publication Date: 1987-Sep-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Emerick, AJ: AUTHOR [+2]

Abstract

Positioning and holding of pin pattern surface-mounted substrates on a printed circuit card during card attachment presents a problem. In through-hole substrate-to-board attachment, the holes align and hold the substrate during soldering. Because surface mounting has no positioning and holding method integral to the pins (Fig. 1), the pins are liable to shift during reflow. The following method describes how the pins are prevented from shifting during reflow. If two or more pins on a surface-mounted substrate are longer than the rest of the pins in the grid, they can be used to position and hold the substrate during solder reflow. These pins could be nonfunctional and preferably are placed on opposite corners of the substrate, as space permits. The pins are treated as regular pins, i.e.

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Locating and Holding Method for Pin Grid Surface-Mounted Substrates During Card Attach

Positioning and holding of pin pattern surface-mounted substrates on a printed circuit card during card attachment presents a problem. In through-hole substrate-to-board attachment, the holes align and hold the substrate during soldering. Because surface mounting has no positioning and holding method integral to the pins (Fig. 1), the pins are liable to shift during reflow. The following method describes how the pins are prevented from shifting during reflow. If two or more pins on a surface-mounted substrate are longer than the rest of the pins in the grid, they can be used to position and hold the substrate during solder reflow. These pins could be nonfunctional and preferably are placed on opposite corners of the substrate, as space permits. The pins are treated as regular pins,
i.e., reformed for compliance to holes or left as straight pins. The pins would have accurate location with respect to the pin grid. Holes for these pins would be placed in the card as nonfunctioning electrically, but in accurate relation to the functional pads. These holes would have no metallization and thus would not have solder joints. The functional pins would be sheared to the specified length, with the locating pin being longer. The substrate would then be positioned, as seen in Fig. 2. The substrate 1 (Fig. 2) is placed on the card or board 2 with the locating pins 3 inserted into the the loc...