Ed-
This sounds to me like a solid-solder-deposit technology, where the assembler purchases the bared PCB
with the solder already deposited and reflowed. The parts are then placed, with the help of tacky flux,
and reflowed again. The idea is to eliminate the pasted deposit process which is inherently difficult to
accurately reproduce 100% of the time because it is so susceptible to so many variables. They claim they
can reduce paste solder defects by up to 70-80%. MaskTek and Sipad are two companies with proprietary
applications of this technology. I'm sure I'll read about it if I am wrong : )
Ryan Jennens
Phoenix Engineering
Ed Holton wrote:
> Fellow professionals:
> Yesterday, while doing some research on soldering and a new soldering
> method, I discovered that there is a number of U.S. patents for soldering
> and soldering techniques. I remember several months ago, there was some
> discussion about another company having a general SMT assembly process
> patent, but I never found out what the resolution of the issue was. For
> example, below is a copy of the abstract of U.S. Patent # 4,605,153 I found
> during my research. To me, this sounds like the reflow pads used for MELF
> components. I have used this pad numerous times over the years, getting
> the idea, and seeing it discussed in SMT magazines, at NEPCON seminars, and
> in the IPC design standards. There were numerous other patents listed as
> reference with this patent, all pertaining to soldering.
>
> I am not a patent lawyer, and my knowledge of law is limited to one
> Business Law class in college and the reading of John Grishm novels. I
> consulted our company lawyer, and he has a basic knowlege of patent law,
> but was unable to answer the question. He could research it futher. I
> thought I would ask my fellow professionals first.
>
> The question: If there is a U.S. Patent for a soldering process, can the
> method be used by other companies for assembly? If it is a new process, is
> permission needed, etc.? If the process is already in use, learned as
> described above, what are the legal ramifications? All of my assembly
> knowledge is based on practical experience, reading of journals, training
> classes and discussions with you, my fellow professionals. Never has
> anyone ever stated that an assembly process is patented, and you must
> obtain permission to use this process, or pay royalties, etc. To find that
> a SMT pad design is patented really amazed me, if this idea is patented, I
> am sure that with futher research that there are numerous other patents for
> all aspects of assembly and soldering. At what point, or how is it
> determined if the patent is proprietary or is it public domain?
>
> Thanks
>
> Ed Holton
> Manufacturing Engineer
> Hella Electronics
>
> THE PATENT:
>
> United States Patent
>
> 4,605,153
> Van Den Brekel, et. al.
>
> Aug. 12, 1986
>
> Shaped solder pad for reflow soldering of surface mounting cylindrical
> devices on a circuit board
>
> Abstract
>
> A solder pad is provided at each end of a mounting position for a
> cylindrical electronic device on a circuit board. Each solder
> pad has two humps of solder spaced apart in a direction normal to the axis
> of the device, the humps defining a channel in which
> the end of a device can rest prior to being reflow soldered. The humps have
> a convex arcuate outer surface in plan view and
> when viewed in a direction parallel to the axis of the device has a profile
> which is of convex arcuate form. The humps are
> formed by depositing a thick patch of solder paste at each hump position
> and heating the circuit board and solder paste to melt
> the paste. After positioning of devices, the solder is reflowed to attach
> the devices.
>
> Inventors:
> Van Den Brekel; Jacques (Nepean, CA); Ho; Thomas K. Y. (Ottawa,
> CA).
> Assignee:
> Northern Telecom Limited (Montreal, CA).
>
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