Geometrical instruments – Gauge – Having a movable contact probe
Reexamination Certificate
1999-07-09
2002-10-29
Fulton, Christopher W (Department: 2859)
Geometrical instruments
Gauge
Having a movable contact probe
C033S549000
Reexamination Certificate
active
06470587
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates generally to the field of quality assurance and, more specifically, to a method and system for part measurement and verification.
BACKGROUND OF THE INVENTION
Parts manufacturers must inspect individual parts to ensure that they meet the appropriate design criteria. Moreover, the growing complexity of modem manufacturing technology places increasingly higher demands on industrial measurement and verification systems. Known methods of measurement and verification, however, have not been completely satisfactory with respect to accuracy, speed, and ease of use.
Known methods of inspecting manufactured parts include using single dimension measurement systems, coordinate measurement machines, and laser tracking systems. Known single dimension measurement systems involve two separate stages: data acquisition and data analysis. In the data acquisition stage, a measurement probe is placed in a gage block to measure a part feature. The result of the data acquisition stage is a list of features and their measurements. In the data analysis stage, the measurement data is taken to a separate computer where it is analyzed. The computer must first transform the measured data to a format and reference frame compatible with the data describing the design criteria. Next, a comparison of the measurement of each feature with the design criteria is made to verify that the feature meets the design criteria. One of the problems associated with this approach is that it requires two or more separate systems, at least one for data acquisition and another one for data analysis. A third system may be required to perform the data transformation. Another problem is that there is a time delay between when the data is acquired to when it is analyzed to verify the part. A third problem is that the known single measurement systems are not sufficiently accurate for applications requiring very high degrees of precision, such as is called for in the manufacture of aircraft. When analyzing the data, the measurement is assumed to have been taken from a particular location marked by the gage block. If the gage block is not at that location or has been moved, the measurement will not be accurate.
Coordinate measurement machines (CMMs) measure manufactured parts using contact probes. Typical CMMs comprise one or more probes that are coupled to a horizontal surface on which the part to be measured is placed. CMMs often use control panels to move the probe across the part and computer terminals to provide the measurement results. One problem with using CMMs is that the part to be inspected must be carried to the CMM itself. Large or bulky parts may be difficult to carry to the CMM, and carrying parts from different parts of the manufacturing facility to the CMM may be time consuming and inefficient.
A laser tracker is a portable device that uses lasers to take measurements of a manufactured part. Laser trackers offer an advantage over CMMs in that they can be taken to the part to be measured. In addition, laser trackers can be used to measure parts that are too large to be placed on a CMM. A problem with a laser tracker, however, is that it requires a direct line of sight in order to be able to measure a part. Many parts may be placed in fixtures, causing an area of a part to be hidden such that there is no direct line of sight that the laser tracker can use to measure the area. Moreover, with some oddly shaped parts, the laser tracker may need to be maneuvered in an inconvenient manner in order to take measurements.
While these devices and methods have provided a significant improvement over prior approaches, the challenges in the field of quality assurance have continued to increase, with demands for more and better techniques having greater flexibility and adaptability. Therefore, a need has arisen for a new method and system for part measurement and verification.
SUMMARY OF THE INVENTION
In accordance with the present invention, a method and system for part measurement and verification are provided that substantially eliminate or reduce the disadvantages and problems associated with previously developed systems and methods.
A system for part measurement and verification is disclosed. The system comprises a set of design criteria specifying a part and a fixture with gage blocks for positioning the part, where each of the gage blocks represents a known position. At least one probe is operable to measure the scalar values of the part and the gage blocks. A handheld information processor or computer is coupled to the probe for receiving the measurements and is operable to transform the measurements and compare those measurements to the design criteria in order to verify the part.
A method for part measurement and verification is disclosed. The method comprises eight steps. Step one calls for specifying the part with a set of design criteria. Step two requires storing the design criteria in a handheld information processor. Step three provides placing the part in a fixture with gage blocks at known locations. In step four, the method provides for configuring the handheld information processor to receive part measurements. The next step calls for measuring the part with a handheld probe to generate part measurements. Step six calls for receiving the generated part measurements in the handheld information processor. Step seven requires transforming the generated part measurements to a different reference frame. The last step calls for comparing the transformed part measurements to the design criteria in order to generate a part verification report.
In another method for part measurement verification, there are six steps. The first step calls for storing a digital representation of a part in a memory. The second step calls for configuring the logic unit to read data from the probe representative of part measurement. Step three requires receiving the probe data. Step four provides for generating part measurements from the probe. Step five calls for transforming the part measurement from the first reference frame to a second reference frame. The final step calls for comparing the transformed part measurement to the digital representation to verify the part.
Another system for part measurement and verification is disclosed. The system comprises a belt operable to be worn by a user. There are one or more pouches fixed to the belt and adapted to receive a probe. A wiring harness contained within the belt has couplers to connect the probe to an information processor.
A technical advantage of the present invention is that a system and method for part measurement and verification is provided that is capable of real time data measurement, acquisition, analysis, verification and reporting of inspection results. Another technical advantage of the present invention is that it is a self-contained, highly portable tool-based inspection system. Another technical advantage is that the present invention provides more flexible and adaptable part measurement and verification. Another technical advantage of the present invention is that it can be performed in software on a single information processor. Another technical advantage is that the present invention provides a single system that is entirely contained on a belt to be worn by an individual user.
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Cunningham Clifton Dale
Fitch James McKinnon
Howard James Jeffery
Koesters James Paul
Leenhouts Michael Alan
Baker & Botts L.L.P.
Fulton Christopher W
Vought Aircraft Industries, Inc.
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