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Browse Prior Art Database

Nondestructive Evaluation of Arm/ E-block Laser Weld Integrity

IP.com Disclosure Number: IPCOM000109135D
Original Publication Date: 1992-Jul-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 1 page(s) / 36K

Publishing Venue

IBM

Related People

Madison, MR: AUTHOR [+2]

Abstract

The invention disclosed is a nondestructive method for testing the quality of laser welds used to affix arms to E-blocks in a direct access storage device (DASD) file, thus improving overall DASD reliability.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Nondestructive Evaluation of Arm/ E-block Laser Weld Integrity

      The invention disclosed is a nondestructive method for testing
the quality of laser welds used to affix arms to E-blocks in a direct
access storage device (DASD) file, thus improving overall DASD
reliability.

      In the past, such laser welds were evaluated by collecting a
random sample of parts and subjecting these to destructive testing.
But the inventors discovered a correlation between the arm's
vibrational spectrum and the quality of the laser weld.

      The following test is thus proposed.  After the arms have been
laser welded to the E-block, the assembly is excited by either a
small-amplitude shaker, a Piezo electric transducer (PZT) exciter, or
a modal impulse hammer.  The ring-down is then monitored by a
noncontacting sensor (e.g., a photonic, inductive, or capacitive
probe; or a laser-Doppler vibrometer or interferometer).

      The response is then Fourier transformed to isolate the
dominant resonant frequencies which comprise its spectrum.  By noting
the location of the first bending resonance, the quality of the weld
can be determined.  If this peak is shifted to a higher frequency
than its normal position, the weld is rejected.

      Disclosed anonymously.