Browse Prior Art Database

Wave Solder Timer

IP.com Disclosure Number: IPCOM000050495D
Original Publication Date: 1982-Nov-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Nalasco, M: AUTHOR

Abstract

When a semiconductor module is to be joined to a printed circuit card, the module pins are inserted through holes in the printed circuit card, and the assembly is slowly passed over a bath of molten tin-lead solder. The pins of the module, which project through the card to the back side of the card, come into contact with the molten solder, and as the card passes across the back, the soldering operation takes place. Since the contour of the surface of the solder bath is convex, the duration of exposure of the module pins to the solder is critical.

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Wave Solder Timer

When a semiconductor module is to be joined to a printed circuit card, the module pins are inserted through holes in the printed circuit card, and the assembly is slowly passed over a bath of molten tin-lead solder. The pins of the module, which project through the card to the back side of the card, come into contact with the molten solder, and as the card passes across the back, the soldering operation takes place. Since the contour of the surface of the solder bath is convex, the duration of exposure of the module pins to the solder is critical.

The feature described herein is a testing technique for timing the duration of the exposure of the module pins to the surface of the molten solder. The figure shows the principle of the invention. A test module 2 is shown with two of its pins 3 and 5 connected to the timing circuit. The timer 6 consists of a turn-on circuit 8 which sends an enabling pulse to the gate 9 when the circuit is completed between the pins 3 and 5 by the solder 4. The gate 9 then starts the digital counter 10. When the circuit between pins 3 and 5 is opened by removal from the solder 4, the turn-off circuit 7 sends a disabling signal to gate 9 which stops the digital counter 10. The accumulated value on counter 10 is proportional to the duration of immersion of pins 3 and 5.

The module pins 3 and 5 are inserted through the holes of a printed circuit card, and the assembly is passed over the solder bath 4 at a selected speed. W...