Metal stencil coin repair method
First Claim
1. A method for repairing a defective surface protrusion on a metal stencil used in applying solder paste to a circuit board, the method comprising:
- mounting the metal stencil so that the defective surface protrusion is facing downward;
enhancing the detectibility of the defective surface protrusion by relatively positioning the metal stencil, a light source, and a visual apparatus, so that light from the light source reflects off of the metal stencil in the immediate vicinity of the defective surface protrusion toward the visual apparatus;
gently pressing a polymerized or polymer-coated tool tip up and against the surface protrusion on the metal stencil;
observing the location and degree of distortions in the reflected light while pressing the polymerized or polymer-coated tool tip up and against the surface protrusion; and
conditioning both the location and the amount of applied pressure upon the observed location and observed degree of distortions in the reflected light.
0 Assignments
0 Petitions
Accused Products
Abstract
During the manufacture of printed circuit boards, metal stencils are used as a mask over which a blade is used to squeegee solder through stencil holes onto conducting pads of the circuit board. A typical stencil is both expensive and delicate. Even minor dents, creases, or impressions (commonly referred to as “coins”) in the stencil can result in circuit board defects. Manufacturers frequently suffer significant losses scrapping their coined stencils and idling manufacturing lines while waiting for replacement stencils to be fabricated, shipped, and installed. An apparatus and method is provided for repairing metal stencil coins.
26 Citations
20 Claims
-
1. A method for repairing a defective surface protrusion on a metal stencil used in applying solder paste to a circuit board, the method comprising:
-
mounting the metal stencil so that the defective surface protrusion is facing downward; enhancing the detectibility of the defective surface protrusion by relatively positioning the metal stencil, a light source, and a visual apparatus, so that light from the light source reflects off of the metal stencil in the immediate vicinity of the defective surface protrusion toward the visual apparatus; gently pressing a polymerized or polymer-coated tool tip up and against the surface protrusion on the metal stencil; observing the location and degree of distortions in the reflected light while pressing the polymerized or polymer-coated tool tip up and against the surface protrusion; and conditioning both the location and the amount of applied pressure upon the observed location and observed degree of distortions in the reflected light. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. A method for repairing a defective surface protrusion on a metal stencil used in applying solder paste to a circuit board, the method comprising:
-
enhancing the detectibility of the defective surface protrusion by relatively positioning the metal stencil, a straight-line light source, and a visual apparatus, so that light from the straight-line light source reflects off of the metal stencil in the immediate vicinity of the defective surface protrusion toward the visual apparatus, and so that distortions in the linearity of the reflected light pattern reveal the defective surface protrusion; gently pressing a polymerized or polymer-coated tool tip up and against the surface protrusion on the metal stencil; observing the location and degree of distortions in the reflected light while pressing the polymerized or polymer-coated tool tip up and against the surface protrusion; and conditioning both the location and the amount of applied pressure upon the observed location and observed degree of distortions in the reflected light.
-
-
14. A method for repairing a damaged framed metal stencil used in applying solder paste to a printed circuit board, the method comprising:
-
mounting the frame of the framed metal stencil to a repair stand; selectively directing light from a light source positioned at a selected location and at a selected angle to the stencil; inspecting the stencil for coins by observing distortions in reflections of the selectively directed light; selecting a repair tip for a handle tool having interchangeable tips, the repair tip having a shape, sharpness, bluntness, and depth appropriate for repairing a detected coin; repairing the selected coin by pressing the handle tool at a selected location of the stencil and at a selected angle to the stencil to substantially eliminate the detected coin; and viewing the stencil on both sides to evaluate whether the repair was adequate and the surface in the area of the previously-detected coin is substantially flat and free of blemishes. - View Dependent Claims (15, 16, 17, 18, 19, 20)
-
Specification