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1. Maintenance Strategies for Electrical Equipment at Onesteel Newcastle Wiremill.
2. Our facilities in Newcastle Onesteel Market Mills in Newcastle consists of
Dual line Rod Mill
Single line Bar Mill
Pipe and Tube Mills
Wire Rope Mill
3. What do we do at Wire Products? We process over 200,000 tonnes per annum of Rod, Bar and Y Bar to produce, manufacturers wire, rural fencing products, galvanised wire, pre stressed strand and wire, wire rope, plastic coated wire, bail ties and precision drawn bars.
4. Electrical equipment at Newcastle Wiremill
5. What is Maintenance Strategy? Maintenance strategy is concerned with deciding how to maintain a plant, setting up an appropriate maintenance organisation, establishing usable maintenance systems and directing the maintenance effort.
Maintenance strategies are often referred as maintenance plans or life plans. At Onesteel each unique type of equipment has a number of maintenance activities applied, which will assist in ensuring that equipment can reliably meet its production requirements.
6. Maintenance strategies at NWM broadly fit into 4 categories 1. Fixed time inspections/ replacement.
7. Maintenance strategies at NWM broadly fit into 4 categories 2. Condition monitoring.
8. Maintenance strategies at NWM broadly fit into 4 categories 3. Fixed time maintenance.
9. Maintenance strategies at NWM broadly fit into 4 categories 4. Run to failure
10. Why do we develop and review Maintenance strategies?
11. Effects of strategy review on DC motors
12. At NWM we are reviewing many of our Maintenance Strategies .
13. Strategy Development can be time consuming and not cost effective.
14. Example 1. The current strategy is not documented at all. The Low Relaxation Wire Machine puts indented wire under tension while being induction heated to approx 420 deg C.
The machine runs up to 20 shifts a week.
The Tension on the Wire is critical.
15. Low relaxation Wire Load cell calibration The calibration is completed annually by a tradesman who has been on site for 30 years, but has never been formally documented.
Ultimately it was unacceptable to have no documented control over this critical inspection.
Approximately 8 hours was spent on documenting the procedure and entering it into SAP.
16. Low relaxation Wire Load cell calibration 10.0 JOB PROCEDURE
10.1 Cut wire in the middle of the induction heaters
- Disconnect the air & water from the 4 northern induction heaters and remove heaters
- at Master Capstan apply wooden clamp to brake disc
(found in main switch cubicle) to prevent any movement.
- position large RAM spear into the side of the payoff
to prevent rotation of payoff, tag RAM out to prevent
it being used.
10.2 Calibrate the LRW as per attached procedure "Calibrating the LR Wire Load Cell Weight Indicator"
10.3 Complete zero and span calibration of the portable load cell.
- Dog clamps and load cells to be fitted as per photo.
- The portable load cell (Strainstall) must be zerod before it is connected to the shackles.
- Obtain PCS calibration report from QA manager (calibration completed annually).
- From report obtain range factor for range 1 (0 to 30 KN
- Apply 240 power to load cell indicator and connect
portable load cell to the rear transducer socket.
- Turn on and allow warm up time for 15 minutes.
17. Example 2. The operating strategy of the plant has changed or needs to be improved. A number of areas of plant were nominated for six sigma projects. Each project was to contribute $250k to the bottom line.
Maintenance strategy reviews were included in the Wire Business plan to line up with these projects.
18. WIRE’S RELIABILITY VISION – 07/09 ASSET (MAINTENANCE) STRATEGY
19. Example 3. The operating cycle of the plant has changed or needs to be improved. No 2 Galvanising line had excellent and comprehensive maintenance strategies in place.
Over a number of years overcapacity due to changes in the market and business restructuring has reduced the plant to operate 1 week in 4.
The Frequency of inspections has been extended significantly.
20. Example 4. There are specific failures that are not being addressed by the current strategy.
21. DC motor failures at NWM in 2004 and 2005
22. DC motor failures at NWM in 2004 and 2005
23. What could have caused the failures? Inadequate maintenance practices.
The wrong tools
Inadequate brush tension
Neutral axis and compounding.
25. WHAT WAS CHANGED? Education
All tradesmen attended a session on correct methods of DC motor servicing. A commutator assessment sheet is supplied at each inspection.
26. WHAT WAS CHANGED? Repair standards.
A repair standard has been developed. Price is not the major reason for using a repairer.
Filter cleaning schedules.
The frequency of filter cleaning was increased in some cases from 4 to 2 weekly.
Inadequate Brush Tension.
A brush tension measuring device has been purchased and some initial experimentation completed.
Overloads and Fuses were reset to correct levels or replaced
It was acknowledged that DC Motor bearings have to be greased.
Has been recently introduced to all DC motors in the last 12 months.
29. Top down assessment RCA and FMEA
30. Bottom up assessment RCM If you have no failure data or you cant afford a failure you start at component level and for each component ask the following.
1. What are the maintainable items? E.g. Motor bearing
2. If the item fails what effect does it have on the process?
3. What can cause the item to fail.
4. If it fails is it apparent. If not can it be detected?
5. What can be done to prevent it from failing?
6. How often should this be done?
31. Output from an RCM process.
33. The most common shortfalls in the electrical maintenance strategies Inspections were short on detail with no measures included. E.g. Brush length, brake pad wear
A number of more complicated calibration tasks had not been documented.
Inspections needed to flag when equipment is close to requiring overhaul. (So the work can be planned)
Thermography was not valued therefore never formalised. Thermography saves time and over servicing.
Lube was not valued for rotating electrical equipment.
Once a strategy was in place we would never review it.
34. Strategy development needs to be resourced adequately if it is to be done effectively Our experience is strategies will not be developed or reviewed effectively if the process is rushed and not resourced adequately.
The process needs to be driven and will require input from many plant staff.
35. Resourcing strategy and reliability work at NWM.
36. In Conclusion. To improve Maintenance you have to have a strategy.
To set cost efficient strategies you need to ensure the actions in the strategies address the failure modes.
Improvement of maintenance strategies should be embedded into the companies business plan.
There are gains to be made if applied correctly.
If you want strategies put in place that are based on more than gut feel, it is time consuming and needs to be resourced effectively. One the most significant issues we have found is that the customer feels the process takes too long and therefore they do not see the gains.
37. Questions? Thanks for listening