Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
1998-12-21
2001-03-27
Young, Lee (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S605000, C029S843000, C029S840000, C336S192000
Reexamination Certificate
active
06205646
ABSTRACT:
FIELD OF THE INVENTION
The invention is related to electronic air-wound coil components and handling these components in circuit board manufacture, and more specifically to methods and apparatus for handling these components in a pick-and-place machine and adjusting the coils subsequent to attachment to a circuit board, for tuning the coils and/or circuits in which they are interconnected.
BACKGROUND
Coils are commonly used as inductor elements in electronic circuits. The coils consist of wire bent to form a series of spaced loops. In high frequency applications, such as radio frequency broadcasting, cable television, cellular phones and other communications technology, air-wound coils are often surface mounted on circuit boards.
Circuit boards are commonly produced by forming wiring that extends on the surface and through holes in a sheet of fiberglass. The wiring includes pads for attaching components to the board. Solder paste is deposited on the pads and then terminals of the components are positioned on the solder paste. Then the assembly is heated sufficient to melt particles of metal in the solder paste to form solder alloy connections between the pads and the component terminals.
A pick-and-place machine is used to place the components onto the wiring substrate. Wiring substrates and components are fed into the machine and a head picks-up the components and places them at component sites on the board. Typically the solder paste is deposited on pads at the component site before the board is fed into the machine. The head includes either a vacuum probe or a mechanical gripper to pick-up, position, and release the components at the sites.
Generally, the position of a coil is not nearly as critical as the positioning of other common components on the circuit board substrate and grippers can place such coil components onto circuit boards without the need for a vision system. Since the surface of uncoated air-wound coils has openings, common vacuum probes can not be used to pick-up the coil components. Thus, mechanical grippers are typically used for placing air-wound coils. However, it is well known to coat the coils of an air-wound coil with a layer of epoxy to allow the coils to be handled using a vacuum probe. In some applications the coils can not be covered with epoxy because the spacing between the loops must be adjusted for tuning the coil and/or circuit of the circuit board. In such a case, uncoated coils are placed on the circuit board using a gripping head.
SUMMARY OF THE INVENTION
It is an object of the invention to provide methods and apparatus for utilizing vacuum probes for pick-up and placement of air-wound coils that may require post attachment tuning.
As the speed at which pick-an-place machines operate increases, and the price of vision systems is reduced, vacuum probe pick-up has generally displaced gripping as a method of picking-up components. Typically, the only components on a circuit board that requires a gripper head is an air-wound coil that requires post attachment tuning. For this one component, the head must be changed from a vacuum probe head to a gripper head, the component placed, and then the gripper head is replaced with a vacuum head for placing other components.
In the invention, a surface of material is provided on the top surface of the coil, and the surface or material thereof is adapted so that it will not interfere with bending the coil to adjust the spacing between loops after the coil is attached to the circuit board. In one particularly preferable embodiment, the surface is inherently removed during heating for reflow soldering the components to the circuit board or during washing of the assembled circuit board with a solvent to remove flux residue after the reflow heating. In another particularly preferred embodiment, the surface is mechanically connected to the coil so that it can easily and reliably be disconnected. Alternately, the surface can be cut, broken, stretched between the loops without damaging the coil so that the loop spacing can be adjusted.
Other alternatives and advantages of applicant's inventions will be disclosed or become obvious to those skilled in the art by studying the detailed description below with reference to the following drawings which illustrate the elements of the appended claims of the inventions.
REFERENCES:
patent: 2722662 (1955-11-01), Tyminski
patent: 3648205 (1972-03-01), Bunch et al.
patent: 3824518 (1974-07-01), Slenker
patent: 3947934 (1976-04-01), Olson
patent: 4035695 (1977-07-01), Knutson et al.
patent: 4325040 (1982-04-01), Whitley
patent: 4759120 (1988-07-01), Bernstein
patent: 4866573 (1989-09-01), Bernstein
patent: 4980663 (1990-12-01), Moyer
patent: 5809633 (1998-09-01), Mundigl et al.
patent: 5867897 (1999-02-01), Mimura et al.
patent: 5894292 (1999-04-01), Everest, III et al.
patent: 652761 (1960-01-01), None
patent: 3-35509 (1991-02-01), None
patent: 6-36937 (1994-02-01), None
patent: 10-313155 (1998-11-01), None
Belk Michael E.
Philips Electronics North America Corp.
Trinh Minh
Young Lee
LandOfFree
Method for air-wound coil vacuum pick-up, surface mounting,... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for air-wound coil vacuum pick-up, surface mounting,..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for air-wound coil vacuum pick-up, surface mounting,... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2518806