(2000)
Publication Type: Thesis
Publication year: 2000
Publisher: Meisenbach
Edited Volumes: Fertigungstechnik - Erlangen 99
City/Town: Bamberg
Within this Dr.-thesis a new measurement principle for the detection of Gull-Wing-Lead parameters has been introduced. The aim was to detect and compute a complete set of geometrical lead-parameters by evaluation of a single high-resolution image. Thus a quality assurance tool for joining methods requiring high coplanarity tolerances has been developed. The measurement principle is basing on the so-called non-frontal camera position where the normal-direction of the SMD is tilted twice against the camera axis. The SMD is mounted on a linear DC-servo module that moves the component in front of the CCD-line. The so generated line-scan is evaluated within two steps. First, the periodicity of the lead-row is computed by employing a wavelet-algorithm. Because of the non-frontal view, every bad positioned lead causes an error in periodicity. Second, the so detected badly positioned leads are examined in a more accurate way. After an edge-detection and the computation of the related regression straight lines, position and geometrical parameters of the lead can be extracted.