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Multilayer Ceramic Via Hole Location Inspection Fixture and Technique

IP.com Disclosure Number: IPCOM000051379D
Original Publication Date: 1981-Jan-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Kutch, G: AUTHOR [+2]

Abstract

An arrangement is provided that will allow rapid inspection to determin the location of, for example, any of tens of thousands of punched via holes within engineering specification tolerances. This is achieved by using true (radial) dimensioning with respect to the theoretical center of the punched pattern, as established by four-corner locating holes. In this case, an unfired green ceramic sheet with punched via holes is being inspected.

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Multilayer Ceramic Via Hole Location Inspection Fixture and Technique

An arrangement is provided that will allow rapid inspection to determin the location of, for example, any of tens of thousands of punched via holes within engineering specification tolerances. This is achieved by using true (radial) dimensioning with respect to the theoretical center of the punched pattern, as established by four-corner locating holes. In this case, an unfired green ceramic sheet with punched via holes is being inspected.

The technique employs a software program that constructs a mathematical grid against which the measured data values are compared to determine their locational errors. A special fixture is utilized to facilitate set-up and reduce inspection time.

As shown in the figure, green sheet 1 is perforated using multiple-punch die- sets with a resultant pattern of via holes totaling upwards o 35 K in number. The sheet requires that the location of the via holes meet a tolerance using radial (true) dimensioning. Four locating holes 5 punched in greensheet 1 are then placed over four corresponding locating pins 2 on inspection fixture 3.

Inspection fixture 3 also contains two reference pickup points 4 located on a common centerline. The fixture is initially characterized by establishing the best fit center-point of the four pins 2 with respect to the two pick-up points 4 so that computer correction can be made for misalignment. With the best fit center-point referenced to...