Abstract:
Product quality control is the back bone for an
efficient process control system. By monitoring the
size of the board cut in a sawmill, performance of the
production system can be controlled. Feedback from the
quality control system is used to evaluate the status of
the production system and also used for preventive
maintenance of the system. The software technique
developed in this thesis involves three parts: image
acquisition and analysis, quality control analysis, and
power consumption analysis. An image of the boards is acquired, and board
edges are identified and analyzed to compute the board
widths. The effects of defects present on the board
surface on the computation of board width are studied.
The effect of camera distance from the surface of the
object is also analyzed. Computed widths were compared
with values measured with a caliper.
The quality control program reads the computed
board widths and then checks the measurements against
control limits. The program also computes board
averages and standard deviations and checks the averages
against control limits. Between board deviations
within cants and between saw pockets are also computed.
The n board averages are displayed to check the process
status.
A power meter is used to monitor the power
consumption of the production system. A program was
developed to read the power meter and to display the
data in a control chart or in tabular form as a means of
checking the power consumption of the system.
