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Browse Prior Art Database

Step Hold Soldering Method

IP.com Disclosure Number: IPCOM000103021D
Original Publication Date: 1990-May-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 42K

Publishing Venue

IBM

Related People

Dibble, EP: AUTHOR [+4]

Abstract

Disclosed is a method for achieving high quality, reliable solder joints in step holes of a printed circuit card using wave soldering.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Step Hold Soldering Method

      Disclosed is a method for achieving high quality, reliable
solder joints in step holes of a printed circuit card using wave
soldering.

      In the figure, the step hole is a plated through hole 1 in a
printed circuit card 2 in which the pin 3 portion of the hole is
larger than the remaining portion.  This allows maximum printed
circuit wireability.  The disclosed assembly method uses a wave
soldering process to achieve solder joints 4.  Previous method using
solder paste gave poor results.

      Modules 5 are placed and fixtured so the pins are located in
the step portion 6 of the plated through holes 1. The assembly of
modules and card are them immersed in a hot glycerine EDTA bath 7.
This pre-heats the assembly thermal mass near the reflow temperature
of the solder.  It also cleans the surfaces to be subsequently
soldered.  The card and module assembly is then passed over a Tin
Bismuth solder wave 8.  Solder is compressed against the bottom of
the card and proceeds up the barrel of the plated through hole and to
the pin 3 tips.  The assembly is then allowed to "cool" in the bath.
The solidified solder system forms a high quality solder joint.

      Other materials for the bath and solder could be selected.

      Disclosed anonymously.