Authors*: Olli Tuovinen1
Tomas Björkqvist2
Pedro Fardim3
Reference: O PAPEL vol. 74, num. 4, pp. 51 – 58 APR 2013
Groundwood processes (GW, PGW) are among the major processes
for mechanical pulping. Its major advantage over Thermomechanical
pulping process (TMP) is lower requirement of electrical energy.
Pulp stone (grinding wheel) plays a central role in groundwood
process. The pulp stone consists of vitrified ceramic surface made
of aluminium oxide grits. Condition of these grits on the pulp stone
surface defines largely the pulp quality and energy consumption of
groundwood process. Therefore, it is important to be able to quantify
this kind of surfaces. This paper gives an introduction to the principle
of automatic 3D reconstruction of surfaces from stereoscopic
images and evaluates its applicability in reconstruction of surfaces
of grinding wheels as well as of single grits. The paper also gives
an example of the interrelation between topographic changes in
grinding surface and groundwood wood pulp properties. Based on
the results, reconstruction of the topography by the application of
stereo photogrammetry is considered a suitable method for detailed
3D visualisation and quantification of a pulp stone surface or single
grits in them. Topographic changes obtained in a grinding wheel
and grit, for instance by dressing or by grinding, can be visualised
and quantified in detail by using stereo photogrammetry and high
resolution SEM images. Stereo photogrammetry is applicable in the
basic research of grinding surfaces and grinding grits. The fact that
the preparation of specimens and the production of SEM micrographs
require specific instruments and skills appears as a limitation of the
applications. The authors intend to apply digital photogrammetry
in future basic research of the groundwood processes. The main
objective of these studies is to resolve interactions between the
grinding grits and wood, including the impact on mechanical pulp
quality and energy consumption.
Authors’ references:
1. M.Sc., Metso Paper Oy, PO Box 427, FIN-33101 Tampere, Finland
2. Dr.Sc., Tampere University of Technology, PO Box 692, FIN-33101 Tampere, Finland
3. Professor, Åbo Akademi University, FIN-20500 Åbo, Finland
Corresponding author: Professor Pedro Fardim, Åbo Akademi University, FIN-20500 Åbo, Finland. E-mail: [email protected]
Tomas Björkqvist2
Pedro Fardim3
Reference: O PAPEL vol. 74, num. 4, pp. 51 – 58 APR 2013
Groundwood processes (GW, PGW) are among the major processes
for mechanical pulping. Its major advantage over Thermomechanical
pulping process (TMP) is lower requirement of electrical energy.
Pulp stone (grinding wheel) plays a central role in groundwood
process. The pulp stone consists of vitrified ceramic surface made
of aluminium oxide grits. Condition of these grits on the pulp stone
surface defines largely the pulp quality and energy consumption of
groundwood process. Therefore, it is important to be able to quantify
this kind of surfaces. This paper gives an introduction to the principle
of automatic 3D reconstruction of surfaces from stereoscopic
images and evaluates its applicability in reconstruction of surfaces
of grinding wheels as well as of single grits. The paper also gives
an example of the interrelation between topographic changes in
grinding surface and groundwood wood pulp properties. Based on
the results, reconstruction of the topography by the application of
stereo photogrammetry is considered a suitable method for detailed
3D visualisation and quantification of a pulp stone surface or single
grits in them. Topographic changes obtained in a grinding wheel
and grit, for instance by dressing or by grinding, can be visualised
and quantified in detail by using stereo photogrammetry and high
resolution SEM images. Stereo photogrammetry is applicable in the
basic research of grinding surfaces and grinding grits. The fact that
the preparation of specimens and the production of SEM micrographs
require specific instruments and skills appears as a limitation of the
applications. The authors intend to apply digital photogrammetry
in future basic research of the groundwood processes. The main
objective of these studies is to resolve interactions between the
grinding grits and wood, including the impact on mechanical pulp
quality and energy consumption.
Authors’ references:
1. M.Sc., Metso Paper Oy, PO Box 427, FIN-33101 Tampere, Finland
2. Dr.Sc., Tampere University of Technology, PO Box 692, FIN-33101 Tampere, Finland
3. Professor, Åbo Akademi University, FIN-20500 Åbo, Finland
Corresponding author: Professor Pedro Fardim, Åbo Akademi University, FIN-20500 Åbo, Finland. E-mail: [email protected]
