Browse Prior Art Database

SELF ADJUSTING REFLOW ALIGNMENT AND RETENTION CLIP

IP.com Disclosure Number: IPCOM000007973D
Original Publication Date: 1997-Mar-01
Included in the Prior Art Database: 2002-May-09
Document File: 1 page(s) / 60K

Publishing Venue

Motorola

Related People

John Dascanio: AUTHOR [+2]

Abstract

Proper alignment and retention of hand placed reflowable components or structures can be difficult if precise placement is needed but built in retention features are not practical. The concept of this device type is a pallet mounted retention clip or feature that aligns and holds items secure in solder paste with moderate accuracy before reflow processing and that release retention pressure to allow for more precise alignment due to component self centering on the solder pads during heating. These self adjust- ing reflow alignment and retention clips are made of bi-metal materials that "actuate" with gross phys- ical motion during heating due to the difference in the thermal coefficients of expansion of the two laminated metals.

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MO7VROLA Technical Developments

SELF ADJUSTING REFLOW ALIGNMENT AND RETENTION CLIP

by John Dascanio and Craig Lee

  Proper alignment and retention of hand placed reflowable components or structures can be difficult if precise placement is needed but built in retention features are not practical. The concept of this device type is a pallet mounted retention clip or feature that aligns and holds items secure in solder paste with moderate accuracy before reflow processing and that release retention pressure to allow for more precise alignment due to component self centering on the solder pads during heating. These self adjust- ing reflow alignment and retention clips are made of bi-metal materials that "actuate" with gross phys- ical motion during heating due to the difference in the thermal coefficients of expansion of the two laminated metals.

  The clips can be shaped into any suitable form that provides for component lead-in, alignment, and snap-to-position function. The clips are designed to have a static retention force at room temperature and no retention force at elevated temperatures. During the heating of the reflow process, these spe- cial clips release their holding pressure to allow for the natural alignment process that occurs between a

component and the PCB pads once the solder is in the molten state allowing the component to float into a relaxed position, i.e., self centering by the solder's surface tension affect.

  The process of manually placing compone...