|
|
|
|
 |
| A sound strategy begins and ends with a strong planned preventative maintenance program... |
|
| Preventative maintenance entails stopping a machine to measure and examining its moving parts to determine if they are still satisfactory for continued use or ready for regular replacement. |
|
| Planned preventative maintenance includes both operational maintenance and planned maintenance. |
|
|
Operational Maintenance
|
| Operational maintenance refers to activities performed while equipment is in service. Typical activities include: |
|
|
• |
Lubrication |
|
• |
Changing duplex filters or strainers |
|
• |
Testing alarms and other safety features |
|
• |
Tightening loose bolts and joints |
|
• |
Continuous vibration monitoring |
|
• |
Watching and listening for signs of trouble |
|
|
| For most equipment, it will include maintaining logs of: |
|
|
• |
Important parameters |
|
• |
Maintenance and preservation activities |
|
• |
Any changes and significant observations |
|
|
| An effective log program should include: |
|
|
• |
Regular gathering of information |
|
• |
Collection of enough information for intelligent interpretation |
|
• |
Periodic review of data |
|
|
| The logs and records should be subject to review by the maintenance department and verified by audit. |
|
|
|
|
|
|
Planned Maintenance
|
| Planned maintenance systems (PMS) are those in which maintenance is scheduled based on elapsed time or on a specific number of operating cycles. Selecting correct intervals between performances of maintenance tasks is critical to the success of the program. If the intervals are too large, breakdown maintenance is the result. If too small, the shutdown of equipment to replace good parts quickly results in the perception that the program is nothing more than “going through the motions.” Sooner or later, the persons responsible for the tasks will do nothing but “go through the motions,” or worse, feel free to document work not actually performed. Breakdown maintenance will again result. |
|
| When intervals in a PMS have been selected, extensions should not be allowed without compelling reasons. Valid support for such an extension might include documenting a careful review of operating parameters to detect any subtle deterioration, an analysis by an outside consultant, or an “on the fly” borescope or other examination of critical areas. Requests for extensions should be documented and require the approval of top management. Production convenience must not be permitted to dictate. |
|
| Inspection frequencies should be assigned based upon: |
|
|
• |
The importance of equipment and the consequences of its failure |
|
• |
Previous inspection results and failure history |
|
• |
Service conditions |
|
• |
Time in service |
|
• |
Jurisdictional requirements |
|
• |
Insurance company recommendations |
|
|
| There are disadvantages to this approach also. |
|
| First, periodic disassembly and inspection of every critical piece of machinery is costly and time consuming. The second problem is how to establish the maintenance intervals. Thirdly, a machine that is actually operating properly can be degraded by frequent disassembly. |
|
|
|
|
|
