X-ray or gamma ray systems or devices – Specific application – Tomography
Patent
1991-08-05
1994-03-01
Porta, David P.
X-ray or gamma ray systems or devices
Specific application
Tomography
378207, 378 62, G01N 2304
Patent
active
052915352
ABSTRACT:
A method and apparatus for the detection of excess or insufficient solder conditions at electrical connections on printed circuit boards are disclosed. The invention analyzes a cross-sectional image of an electrical connection to obtain the average solder thickness of the connection. This average solder thickness is then compared to an upper threshold value to determine if the connection is an excess solder defect, and a lower threshold value to determine if the connection is an insufficient solder defect. In one embodiment, the present invention compensates for variations in image intensity due to the background by employing a first and second correction factor in the calibration technique. The first correction factor is the measured background gray scale value local to the connection, while the second correction factor is determined to have a substantially linear relationship to the background image intensity local to each solder connection. The present invention further includes a process control feedback system which detects and compensates for trends in the solder application process. This helps to insure that defective solder joints are avoided before they are produced. In one embodiment, the process control feedback system is fully automated.
REFERENCES:
patent: 4481664 (1984-11-01), Linger et al.
patent: 4561104 (1985-12-01), Martin
patent: 4575751 (1986-03-01), Duschl
patent: 4628531 (1986-12-01), Okamoto et al.
patent: 4677473 (1987-06-01), Okamoto et al.
patent: 4688939 (1987-08-01), Ray
patent: 4731855 (1988-03-01), Suda et al.
patent: 4803639 (1989-02-01), Steele et al.
patent: 4809308 (1989-02-01), Adams et al.
patent: 4852131 (1989-07-01), Armistead
patent: 4926452 (1990-05-01), Baker et al.
patent: 5097492 (1992-03-01), Baker et al.
Hasenkamp, "Radiographic Laminography", Materials Evaluation, Aug. 1974, pp. 169-180.
Moler, "Development of a Continuous Scanning Laminograph", Final Report No. IITRI V6034-24, Oct. 1968.
Blanche, "Nondestructive Testing Techniques for Multilayer Printed Wiring Boards", Nondestructive Testing: Trends and Technique, NASA SP-5082, Oct. 1986, pp. 1-13.
Hamre, "Nondestructive Testing Techniques for Multilayer Printed Wiring Boards", Report No. IITRI-E6024-15, Sep. 1965.
Soron, IRT Corp., "X-Ray Inspection Meets Increased PWB Throughput", Density Challenge--Part 1, Electronics, Oct. 1987, pp. 36-37.
Pound, "Image Processing Boosts the Power of Non-destructive Testing", Electronic Packaging and Production, Jun. 1985.
Casey, "X-Ray Inspection", Manufacturing Systems, Jul. 1987, p. 18ff.
Phelps, Christi, "Four Pi Captures Contract, Capital; Unveils Product", San Diego Business Journal, Week of Oct. 10-16, 1988.
Stanley et al., "A New NDE Capability for Thin-Shelled Structures", AFWAL-TR-84-4120, Materials Lab, Wright Patterson AFB, Sep., 1984.
Deane et al., IRT Corp., "Using X-Ray Vision to Verify SMD-Board Quality," Electronics Test, Feb., 1987, pp. 32-35.
Corey, IRT Corp., "Artificial Perception Gives Super Vision", Research and Development, Oct., 1984.
LaClair, "Nondestructive Measurement and Inspection Process", IBM Technical Disclosure Bulletin, vol. 18, No. 12, May, 1976.
Hufault et al., "Lead-Indium Solder Joint Analysis", IBM Technical Disclosure Bulletin, vol. 19, No. 11, Apr., 1977.
Wittenberg, "IRT Improves SMT X-Ray Inspection System", Electronic Engineering Times, Oct. 5, 1987, p.53.
Four Pi Systems product brochure for "3DX Series 2000" Automated Inspection System, Copyright 1988.
Adams John A.
Baker Bruce D.
Corey Robert L.
Ross Edward W.
Epperson Dennis H.
Four PI Systems Corporation
Porta David P.
Wong Don
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