Browse Prior Art Database

Assembly Process for Double-Sided Circuit Boards

IP.com Disclosure Number: IPCOM000113911D
Original Publication Date: 1994-Oct-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Best, DP: AUTHOR [+3]

Abstract

An enhanced process flow for manufacturing Double-Sided, Double-Pass (DSDP) hybrid printed circuit boards is disclosed. The circuit boards may have surface mount (SMT) components attached after Pin-In-Hole (PIH) components are attached and this process flow also allows for minimal spacing between SMT and PIH parts.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 82% of the total text.

Assembly Process for Double-Sided Circuit Boards

      An enhanced process flow for manufacturing Double-Sided,
Double-Pass (DSDP) hybrid printed circuit boards is disclosed.  The
circuit boards may have surface mount (SMT) components attached after
Pin-In-Hole (PIH) components are attached and this process flow also
allows for minimal spacing between SMT and PIH parts.

The enhanced DSDP process flow can follow either one of two
sequences:

1.  SMT/PIH/SMT Flow
       a.  Assemble and solder bottom side SMT components.
       b.  Assemble and solder PIH components.
       c.  Assemble and solder top side SMT components.

2.  PIH/SMT/SMT Flow
       a.  Assemble and solder PIH components.
       b.  Assemble and solder bottom side SMT components.
       c.  Assemble and solder top side SMT components.

      The enhanced process flow is accomplished by altering tooling
at the screen printing process.  The squeegee that is used to push
the solder paste across the stencil must be shortened and/or slotted
depending on the specific application.  This allows the squeegee to
clear the appropriate PIH components already attached to the circuit
board.

      The solder stencil must also be altered for the enhanced
process flow.  Openings must be cut in the stencil to allow the leads
of the appropriate PIH components to protrude through such that the
stencil lies flat against the circuit board during the screen
printing proces...