Browse Prior Art Database

TIMEOUT BOARDS FOR AUTOMATED SOLDER SCREEN PRINTING

IP.com Disclosure Number: IPCOM000005890D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2001-Nov-14
Document File: 2 page(s) / 73K

Publishing Venue

Motorola

Related People

Dave Tribbey: AUTHOR [+2]

Abstract

Solder paste printing, screening or stenciling, is the process of moving solder paste across a screen or stencil con- taining a series of apertures through which solder paste is deposited by the action of a squeegee, or pusher used to move the mass of paste. One of the important printing parameters to control is the viscosity of this page mass during the production process.

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MOlVROLA Technical Developments Volume 10 March 1990

TIMEOUT BOARDS FOR AUTOMATED SOLDER SCREEN PRINTING

by Dave Tribbey and Greg Watts

   Solder paste printing, screening or stenciling, is the process of moving solder paste across a screen or stencil con- taining a series of apertures through which solder paste is deposited by the action of a squeegee, or pusher used to move the mass of paste. One of the important printing parameters to control is the viscosity of this page mass during the production process.

   In the automated solder screen printing process there is a need to continue the printing process in the event of production line downtime usually resulting from material delays or equipment malfunction so that the paste contained on the stencil continues to move and maintain a constant dynamic viscosity. Failure to do this will result in the drying of the outer surface of the "roll" of solder paste in use, causing "dirty" or incomplete prints.

   One method of continuing this printing action is to provide a magazine (figure 1) of non-production printed wiring boards or substrates from which the robot can pick material after a preprogrammed interval of time has passed. This board is handled through the printing cycle and discarded for cleaning and subsequent reuse rather than being ad- vanced to the next station. The opposite side of double sided boards requires a magazine (figure 2) capable of contain- ing a multiplicity of non-production boards with the firs...