|
|
 |
During the rolling of strip, various kinds of defects may arise, many of which occur within the same time or strip intervals. A central task when diagnosing the causes of these periodic defects is to identify the plant and equipment components, process signals, and incoming periodic strip defects, which can be characterised by "defect frequencies" proportional to the strip speed.
Conception of the developed diagnostics system:
Quality-related signals, such as strip thickness profiles and additional acceleration signals, are analysed for any dominating defect frequencies and automatically compared with defect frequency matrices. Then made available as results for the mill operator are a weighted 'or-der of rank', also in graphical form, of the possible defect causes and, additionally for the maintenance expert, the edited spectra. Included in the cause analysis are:
- periodic changes in the production system
- the plant and equipment's own dynamics
- unstable vibrational states: self-excited "chattering vibrations"
Offline analysis of defect causes:
Defect intervals can also be input manually in the system in an offline function and thereby compared automatically with every speed-proportional defect possibility.
System use:
The system was first installed in 2003 at a two-stand skin-pass mill.
|
|
