Laminating by Vapor Phase Reflow
Publication Date: 2003-Sep-24
The IP.com Prior Art Database
Paul J. DePietro: INVENTOR [+2]
AbstractThe purpose of this disclosure/invention is to respond to the need to produce Insert wire that is lead free. The Electrical/Electronic industires across the globe have recognized the need to reduce/eliminate the lead (Pb) content of ALL soldered connections made in electrical apparatus. This process will allow for the use of available lead free solders to be used in the laminating of our existing SS tapes and insert HST wire.
Laminating by Vapor Phase Reflow
A. Introduction: General Purpose of Invention
The purpose of this disclosure/invention is to respond to the need to produce Insert wire that is lead free. The Electrical/ Electronic industries across the globe have recognized the need to reduce/ eliminate the lead (Pb) content of ALLsoldered connections made in electrical apparatus. This process will allow for the use of available lead free solders to be used in the laminating of our existing SS tapes and insert HST wire.
B. Prior Art:
Currently in manufacturing we are using solder specifications similar to Sn 62 - 63% Sn, 37% Pb. Laminating is processed in a specifically designed machine the heart of which is a flow solder fountain. Two machines are now in operation at the Westborough facility
C. Disadvantages of Prior Art:
The cost per meter of the existing process should be examined for cost reductions. I believe there are obtainable cost savings in raw materials, such as fluxes, solder and solvents also there are savings in hazardous waste removals to be gained. A significant disadvantage is that, to use a " flow solder machine, retrofitted to a lead free solder alloy would mean the operating temperature would have to raised to accommodate the higher melting point of lead free solders. This increase in operating temperatures would be detrimental to the insert HTS wire and would likely add to the operating cost of the existing equipment. In part this information was gathered from current publications. (See pages 62 & 63, ASSEMBLY / February 2002)
D. Components, and operation of Invention:
Components: In place of the flow-soldering machine I would introduce a "Vapor Phase Reflow machine (See attachment). Excerpts from the article for descriptive use are, " Vapor phase reflow is fast and efficient. Condensation transfers heat 10 times faster that hot air and eight times faster than infrared radiation." Furthermore it is a clean process. And I quote again. " Perfluorinated fluids are inert, noncorrosive, nontoxic, nonpolluting and nonflammable. They evaporate completely without leaving any residue behind." Tape dispensers and transports exist both in design and practice. They should be used where possible. The exception is the transport that will be in the VPR. This mechanism will consist of rolls; spools and guides designed to withstand a stable temperature of 245C. I envision the VPR transport to be mounted on a vertical tooling plate that is attached to an elevating device so situated to allow for the component tapes to be loaded at room temperature.
Tape Components: Stainless steel tapes as supplied would be plated with a lead free solder alloy. I have two specifications from the reference article. Tin Silver (Sn Ag) melt at 221 to 245C.Tin Antimony (Sn Sb) melts at 232 to 240 C.
In operation the set up would be as in prior art. The VPR would have to be brought up to temperature. During the warm up the tapes would be positioned in...