Browse Prior Art Database

Two-Stage Precision Fine Pitch Quad Flat Pack Component Alignment Tool

IP.com Disclosure Number: IPCOM000101596D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 66K

Publishing Venue

IBM

Related People

Yu, S: AUTHOR [+2]

Abstract

This article describes a tool for automated quad flat pack (QFP) placement in paste for vapor phase soldering.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 68% of the total text.

Two-Stage Precision Fine Pitch Quad Flat Pack Component Alignment Tool

       This article  describes a tool for automated quad flat
pack (QFP) placement in paste for vapor phase soldering.

      This tool (see the figure) allows the component to be aligned
in two stages.  When the QFP is picked up by a robot and placed in
the tool, the component's plastic body rests on seat A for initial
alignment.  There are four pieces of A for the four component sides.
The surface of A has a positive slope. Therefore, the opening is
wider for the component to enter to accommodate the total accumulated
tolerance.  The alignment tool is mounted on a vibrator.  The
combination of vibration and the slope of A adjusts the component to
a more accurate position.  Since the molded plastic body has less
tolerance than the lead frame, using the body as alignment reference
offers the best control.

      The fine tuning of position is performed by blades B. There are
two blades for each component side.  When the QFP is centered by A,
the air cylinder C activates to raise the blades on four sides.  The
cylinder C is stopped by stopper D which is adjusted according to the
component body and lead dimensions.  The blades are inserted between
leads.  The blades are tapered at tip and the width of blades are
made to provide optimum precision alignment.  The QFP is then picked
up by the robot and placed on footprint on printed circuit board
(PCB).

      Two sensors and recei...