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Six Tips to Improve Your MRO Spare Parts Management Phillip Slater Materials Management Specialist www.PhillipSlater.com Australia Spare parts are the lifeblood of reliability. No plant can operate at a high level of reliability without a reliable supply of functional spare parts. Spare parts form the bedrock on which reliability is built. Yet, spare parts are also the most overlooked contributor to maintenance and reliability outcomes. Our research has shown that many companies routinely operate without properly implementing even the most fundamental aspects of spare parts management at their sites. Often these companies have storerooms with neat shelves and clear labels but this is not enough for high performing MRO spare parts management. To help you make a difference in your reliability outcomes here are six tips to improve your MRO spare parts management. Tip #1: Develop Clear Spare Parts Stocking Criteria To stock or not to stock, that is the question. One of the major flaws in most spare parts management systems is the absence of clear criteria on when to stock an item and when not to stock an item. The absence of any guidelines forces your team into a process of ad hoc and inconsistent decision making. The result of this is that you stock items that don’t require stocking and don’t stock items (sometimes critical items) that should be stocked. To avoid this you simply need to develop and implement specific guidelines to aid decision making on when to stock an item and when to not stock an item. Tip #2: Provide Clear Guidelines on How Many Parts to Stock Once you have established clear spare parts stocking criteria the next step is to establish clear guidelines on how many of an item to stock. By developing and implementing clear stocking guidelines you provide the logic for decision making on stock levels and calculating reorder quantities. The advantage of this is that it provides guidance to your team, continuity for decision making, and provides the basis for future audits of inventory holdings. Tip #3: Accept that Some Stock Outs are OK One of the main fears of most reliability and maintenance engineers is that, at the time of actual need, the required spare part will not be available. This is commonly referred to as a stock out. But how do you eliminate all stock outs? The short answer is that you can’t, not without tying up massive amounts of money that would be better used elsewhere. Even then, I am not sure that you could guarantee eliminating all stock outs. This would possibly require holding multiple units of every part in your plant. That’s not viable. That’s the truth. What you can do is accept stock outs in areas where they have little or no impact or where a viable supply alternative exists. Then work to eliminate stock outs for the items that really matter. Tip #4: Review the Holdings of Critical Spare Parts Maintenance and reliability engineers will happily (well, not happily) undertake a review of spare parts that are not classified as critical, yet they will shy away from reviewing items that are classified as critical. The argument is: ‘the item is critical and so we must stock it’. Thus the classification drives the review action rather than a cost benefit or stocking analysis. But what if the classification was wrong, or the item was significantly overstocked, or the supply arrangements had changed? Surely these are factors that can be reviewed and have nothing to do with the part’s criticality? It doesn’t make sense to limit your reviews based on the idea of criticality. This will drive you to review parts that are critical but not defined as such and not review parts that are defined as critical but which may no longer be critical. Critical parts may be just as overstocked as any other item, or there just might be a viable alternative to holding the item at all. Tip #5: Identify the Causes of Excess Spare Parts Inventory The impact of not holding a required spare part can be massive. Downtime costs often far outweigh the purchase and holding costs of spares and this can lead to holding far more of some spares than is really required. As a result accountants will often target this as an area of easy cost savings. If you want to keep the accountants off your back and maintain control of your spares holdings it is important to regularly review your inventory and eliminate excess spare parts holdings. To do this most effectively inventory reviews need to focus on much more than just data analytics. The real drivers of excess inventory lay in the processes and decision making that influences your inventory levels, with the most common culprit being the returns process. Tip #6: Review Your Storeroom Security Many companies are fully aware of the importance of maintaining security around their spare parts inventories. They secure their spares in lock-up areas, ensure staff are on hand to manage the level of spares requests during periods of high maintenance activity, and provide a rock solid approach for identifying storeroom entrants during Vol 24 No 1
<strong>AMMJ</strong> the afternoon and night shifts. Then they leave the back door open! To ‘make life easier’ there is often a gate left open through which anyone can enter. While the efficiency in terms of supplying spares and minimizing downtime is obvious, this practice actually puts your reliability at risk. Removing items from the storeroom without proper record, no matter how honest the intent, will not trigger reordering when required and next time you need that item it will not be in stock. Spare parts management is like every other aspect of operations management: success requires clear guidelines, differentiation of outcomes, critical evaluation, and discipline in execution. Follow these six MRO spares management tips and you will go a long way to achieving the reliability results that you deserve. Phillip Slater is a leading authority on materials/parts management is the author of four operations management books, including Smart Inventory Solutions. For access to more information on MRO spare parts management visit The Warehouse, a new knowledge base at Phillip’s website www.PhillipSlater.com V-Belt Maintenance V-Belt Maintenance is a requirement if you want to insure optimum belt drive performance. This process requires proper maintenance and discipline in order to insure effective belt operation and a long service life. When coupled with a regularly scheduled maintenance program, belt drives will run relatively trouble-free for a long time. General Rules: (if you want to stop V-Belt failures) 1. Insure proper alignment of sheaves both parallel and angular using a sheave laser alignment tool. Do not use a straight edge or string if one expects optimal life from your V-Belts. 2. Use a span sonic tension meter to measure deflection and tension of a V-Belt. To determine defection and tension required go to the following link: www.gates.com/drivedesign WARNING: Over-tension of belts is the number one cause of V-Belt Failure. 10% over-tension of V-Belts result in a reduction of bearing life by 10%. 3. Use Infrared for identifying over tension. Use vibration analysis for loose or damaged belts and strobe-lights for operator or maintenance craft inspections. 4. Upon installation, new belts should be checked for proper tension after 24 hours of operation using a strobe light or tachometer. Failure to execute this process on critical assets could result in V-Belts not meeting expectations of the end user. 5. Tighten all bolts using a torque wrench and proper torque specifications. Failure Modes experienced on V-Belt Drives: • Tension Loss, Caused by: o Weak support structure o Lubricant on belts o Excessive sheave wear o Excessive load • Tensile Break, Caused by: o Excessive shock load o Sub-minimal diameter (see chart below) o Extreme sheave run-out o Improper belt handling and storage prior to installation (crimping) • Belts should be stored in a cool and dry environment with no direct sunlight. Ideally, less than 85˚ F and 70% relative humidity. • V-belts may be stored by hanging on a wall rack if they are hung on a saddle or diameter at least as large as the minimum diameter sheave recommended for the belt cross sec-tion. • When the belts are stored, they must not be bent to diameters smaller than the minimum recommended sheave diameter for that cross section. (see chart above) • If the storage temperature is higher than 85˚ F, the storage limit for normal service performance is reduced by one half for each 15˚F increase in temperature. Belts should never be stored above 115˚F. • Belts may be stored up to six years if properly stored at temperatures less than 85˚F and relative humidity less than 70%. • Belt Cracking, Caused by: o Sub-minimal diameter (see chart opposite) o Extreme low temperature at start-up o Extended exposure to chemicals or lubricants “TOOL BOX TRAINING” rsmith@gpallied.com Copyright 2010 GPAllied www.gpallied.com Spare Parts Management “TOOL BOX TRAINING” Courtesy of Ricky Smith Reference: Belt Drive Preventive Maintenance Manual by Gates Corporation. 55 Vol 24 No 1
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