Dipl.-Ing. Wolfgang Krahl

Use of a digital microscope for quality testing of structural clay products

Photos/Fotos: Krahl/KI Meißen

»1 Digital microscope VHX 5000

Photos/Fotos: Krahl/KI Meißen

»2 Surface of a facade panel, recorded with HDR (right) and without HDR (normal image, left)

»3 Surface of a roof tile with a fault, shown without depth sharpening correction

»4 Surface of a roof tile with a fault, shown after depth sharpening correction

»5 2D roof tile surface with efflorescences from a soluble salt and a bulge

»6 3D roof tile surface with efflorescences of a soluble salt and a bulge (now seen from the visible side)

»7 Digital microscope with a 30° angle axis

»8 Detail of a roof tile surface with efflorescences, shown without a depth sharpening correction at a tilt angle
of 15° from the z-axis

»9 Detail of a roof tile surface with efflorescences, shown after depth
sharpening correction at a tilt angle of 15° from the z-axis

»10 Panoramic (stiched) image of a roof tile surface with efflorescences (composed of nine individual 3D images)

»11 Detail of a roof-tile surface with efflorescences, shown after depth sharpening correction

»12 Digital zoom in Figure 12 (magnification up to 700x)

»13 Measurement functions for 2D images [1]

»14 3D image (top left) and 3D depth profile (below) of a fault on the surface of a roof tile

»15 Conventionally produced spray granules

»16 As-determined granule size distribution

For many different forms of industrial testing, a digital microscope offers advantages over conventional stereoscopic or light-optical microscopes. This applies in particular to the inspection of surfaces and fracture faces, the analysis of inclined or vertical surfaces and the on-site inspection of large components. This article illustrates the technology‘s potential by way of case examples.

1 Introduction

Since October 2016, Keramik-Institut GmbH has been using a VHX 5000 digital microscope (»1) to examine sample specimens made of sundry ceramic materials. The microscope is equipped with:

a control unit and graphics system

a standard VHX camera

a 20–200 x zoom lens

a tripod with free-angle viewing

an XY stage

a motorized Z axis for automatic height adjustment