One of our customers recently asked:
The budgets of our customers are being continually slashed, yet they still want and need the same level of spare parts support. Is there a way of using Spares Calculator to help them spend their money more wisely so that they get the best spare parts ranging and scaling package within their budget?
This is a great question and it raises a really important point: What is the purpose of Spare Parts Optimization?
What is the Goal of Spare Parts Optimization?
The goal of Spare Parts Optimization is to maximize Operational Availability whilst minimizing Life Cycle Costs.
We achieve this by modelling the logistic performance of systems and equipment in an operational scenario and selection the optimum level of spare parts so that the goals are achieved.
Spare Parts Logistic Parameters
Here is a list of the key spare parts logistic parameters:
- Total Units in Service
- Daily Operating Hours
- MTBF (Mean Time Between Failure)
- NFF Ratio (No Fault Found Ratio)
- Repair Turn Around Time
- Unit Cost
Now let us consider how we can optimize each of these parameters to maximise our Operational Availability and minimize our Life Cycle Costs.
Total Units in Service
The Units in Service are controlled by operational needs and we have no control over this parameter.
Daily Operating Hours
The Daily Operating Hours are also controlled by operational needs and we have no control over this parameter.
MTBF (Mean Time Between Failure)
MTBFs can have a massive impact on the operational and logistic performance of a system. Therefore, it is imperative that high quality LRUs and components are selected. Spares Calculator can be used to produce an A:B cost comparison between different LRUs and suppliers.
NFF Ratio (No Fault Found Ratio)
Logistically, the NFF ratio is of equal importance to the MTBF. NFF ratios can be reduced by introducing local filtering equipment, improved diagnostics and by providing high quality maintenance training. Spares Calculator can be used to compare the cost of additional training and test equipment to the cost of additional spare parts.
The Repair Turn-Around-Time has a massive impact on the quantity of spare parts and it might be possible to achieve some kind of expedited repair policy in extreme circumstances. This is sometimes called a crisis resupply policy. Spares Calculator can be used to model the normal and crisis situations so that you can define optimum stock levels.
The Unit Cost is a no brainer and it would be an insult to your intelligence to state that reducing the unit cost would reduce the overall Life Cycle Cost.
In summary, Spare Parts Optimization is the process of maximizing Operational Availability whilst minimizing Life Cycle Costs. The operational parameters are fixed but we can influence the MTBF, NFF ratio, the Repair Turn-Around-Time and the Unit Price. It’s just a matter of trading-off the cost of various logistic scenarios.