Author Archive | Maintenance Technology

51

2:50 pm
August 10, 2016
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Workforce Optimization With a Button Click

randmThe editors of Maintenance Technology are pleased to introduce this new, monthly, Reliability and Maintenance Center column we’re calling SAP Tips and Tricks. In each issue, Kristina Gordon will open doors for SAP users to help you maximize benefits from one of the more powerful tools available to reliability and maintenance professionals.

Gordon has worked for more than 10 years in an array of pharma, chemicals, and polymers businesses that use SAP as their CMMS. She has conducted 13 full life-cycle implementations. Gordon’s specialty is working with plant maintenance, although she has also implemented the MM, FICO, PP-PI, and PS modules. As a functional lead, she has vast experience with configuration and development of functional specifications for the technical development of custom programs. In each issue she will explore timesaving keystrokes, reports, and basic use of the system that so many of you have implemented in your operations.

—Gary L. Parr, editorial director

With more than 183,000 companies in 130 countries using SAP, it’s hard to imagine how big business survived without this German-based software company. However, the world of S-A-P, (that’s right, never refer to it as “SAP” if you want to hang out with the cool crowd), is filled with many tips and tricks that can make your life and your business run more efficiently and make your workforce more effective.

To have a useful tool that will give you the results that you need, measuring yourself with different sets of key performance indicators (KPIs) is the most important step to understanding the data being entered into SAP. While KPIs can be measured in several ways, we are going to talk about some of the most critical and commonly used metrics in the plant-maintenance realm.

If a job is not estimated properly, or at all, you will never have an understanding of scope creep, discovery work, extra material cost, or other identifiers that could affect the final work cost.

If a job is not estimated properly, or at all, you will never have an understanding of scope creep, discovery work, extra material cost, or other identifiers that could affect the final work cost.

Measuring your maintenance costs against your total plant ERV (estimated replacement value) can give you one of the best indicators of your maintenance costs versus the best of the best. To do this, we take the total cost of maintenance per month and divide that by your ERV. Industry standards say that the maintenance spend should not exceed 2% of your ERV. Furthermore, your MRO (maintenance, repair, and operations) material inventory should never exceed 0.25% of your total ERV.

Other metrics that are important for an organization to track using SAP are daily work-scheduling efficiency and job-accuracy estimations. Scheduling efficiency is the product of the (total hours scheduled/available labor hours) multiplied by (scheduled hours worked/total hours scheduled).

Estimating accuracy will reveal how well your planning organization estimates and plans work. As shown in the accompanying screen shot, if a job is not estimated properly, or at all, you will never have an understanding of scope creep, discovery work, extra material cost, or other identifiers that could affect the final work cost. Once the work order is released, the estimated cost, in many cases, cannot be recalculated or added to, leaving the organization without a baseline for the initial estimate of the work.

Understanding your maintenance costs will give you the necessary information you need to properly forecast your budget.

By using these KPIs, you will begin your journey down the road to success by ensuring you have quality data in your SAP system, along with the knowledge to help you work smarter, not harder. MT

Kristina Gordon is SAP Program Consultant at the DuPont, Sabine River Works plant in West Orange, TX. If you have SAP questions, send them to editors@maintenancetechnology.com and we’ll forward them to Kristina.

155

2:43 pm
August 10, 2016
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Heed Drive-Belt Temperature Limits

randmBy Jim Seffrin, Infraspection Institute

Temperature is frequently used to gauge the condition of motors and power-transmission equipment. The following information applies to flexible drive belts and the temperature limits for them.

Drive belts are an integral component on many types of machines. Despite the critical role they play in machine operation, V-type drive belts tend to be out of sight and out of mind until they fail. In most installations, belt temperature largely influences the life of installed V belts.

As a rule of thumb, properly applied and maintained belts should not exceed 140 F (60 C), assuming an ambient temperature of less than 110 F (43 C). Belt life can be greatly reduced by higher operating temperatures. In fact, for every 18 F-deg. (10 C-deg.) increase in belt temperature, belt life is cut in half. Keeping this in mind, we can see that the life of a drive belt operating at 176 F would be reduced by 75%.

Thermogram shows overheating V-belts. Note castoff in the control photo. Images courtesy of Skip Handlin.

Many factors contribute to high belt-operating temperature, including, but not limited to, ambient air temperature, machine design, installation, alignment, and belt tension. Overheating belts that afford line-of-sight access can be readily detected and documented with an infrared imager.

Issues associated with overheating in drive belts may not be limited to the belts themselves, however. With regard to over-tensioned drive belts, excessive force applied to belts is often transferred to bearings in the driven system. In these situations, it’s not uncommon to see bearings overheat due to the excess force created by the over-tensioned belt(s).

Thermogram shows the effects of an improperly tensioned V-belt. In this example, over-tension causes both the belt and adjacent pillow block bearing to run hot.

It should be noted that the operating temperature of overheating drive belts is not necessarily linear. A worn belt that has reached critical temperature will begin to wear at an accelerated rate, which, in turn, will cause the belt to run hotter and wear even more quickly. This vicious cycle will continue until the belt either breaks or fails to perform its intended task.

Once detected, overheating belts should be investigated for cause and proper corrective measures undertaken as soon as possible. Doing so can help prevent unscheduled downtime and may prolong belt life.

Thermal imaging offers several distinct advantages over other types of inspections for belted systems. Thermal imaging is non-contact and nondestructive. Imaging is performed remotely and requires no shutdown of inspected systems. Because infrared imagers produce real-time data, results are instantaneous and allow rapid inspection. MT

Jim Seffrin, a practicing thermographer with 30+ years of experience in the field, was appointed to the position of Director of Infraspection Institute, Burlington, NJ, in 2000. This article is based on one of his “Tip of the Week” posts on IRINFO.org. For more information on infrared applications, as well details on various upcoming training and certification opportunities, email jim@infraspection.com or visit infraspection.com.

192

2:30 pm
August 10, 2016
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Who Cares About Compressed Air?

gun for compressed airBy Ron Marshall, For the Compressed Air Challenge

Compressed air is one of the most expensive sources of energy in an industrial facility. Consider the amount of energy that goes into air compressors, compared with the actual useful work returned at the compressed-air tool or machine.

Training courses on the fundamentals of compressed air include details on the high cost of producing this valuable resource for a point of use. Participants in such classes are usually amazed when they learn about the inefficiency of the energy transfer. The realization that compressed air isn’t free and, in fact, is quite pricey compared with other forms of energy, can mark a turning point in the attitudes of many users—and, for the health of their companies, they finally start to care.

randmHuman nature is a funny thing. If we don’t know the cost of something, it’s easy not to care about it—which results in waste. For example, people in my Canadian hometown are quite familiar with effective means for staying warm in cold weather. Yet, in the dead of winter, it’s not unusual for us to see wide-open windows in occupied apartment buildings around the community. To my eye, this is a sign of poor temperature control caused by faulty heating systems. In an attempt to keep their living spaces from becoming overheated, the residents resort to controlling the temperatures by the brute-force method of opening windows. After all, they don’t have to pay the heating bill; the building owner does. In short, it’s evidently easier for these apartment dwellers to continue wasting heat than to pick up the phone and call the building superintendent to fix a problematic thermostat.

A similar situation persists in industry when it comes to compressed air. Those of us who have spent much of our careers preaching about energy efficiency continue to see it time and again: a lack of caring from the plant floor on up. That can be changed, though. A good way to do it is to make people aware that what they are doing (or not doing) reduces their sites’ profitability, and could ultimately affect their job security.

Since compressed-air systems typically aren’t equipped with electricity meters, it’s easy for users to believe their compressed-air utility comes at no charge. This misconception leads to all types of inappropriate applications, i.e., using compressed air for cooling, mixing liquids, or cleaning dust. Proper training for all personnel is required to drive home the fact that what users are doing may be costing the plant a fortune in lost profits.

Installation of permanent power- and flow-measuring instruments on compressed-air systems is another way to make operators of this equipment aware of the actual costs. It also proves to them the positive effect of energy-efficiency measures that are implemented to save costs. Measuring, in turn, leads to effective management of a costly resource. These instruments can then be used to assist a company in setting up systems such as those described in the ISO 50001 Energy Management Standard. MT

For more information on compressed-air topics and related training through the Compressed Air Challenge (CAC), visit compressedairchallenge.org, or contact Ron Marshall directly at ronm@marshallcac.com.

40

2:24 pm
August 10, 2016
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These Steps Maximize Ethernet Networks

Jim Davis of Motion Industries (motionindustries.com) has some practical advice for personnel dealing with Ethernet issues on the plant floor. He knows what he’s talking about. Davis manages the company’s Automation Center in Countryside, IL. Among other things, he brings 38 years of real-world electrical experience to the table and holds four U.S. patents.

As a point of reference, Davis notes that Ethernet has become the de facto standard in control-system communications, and equipment vendors are increasingly including it and its variants in automation equipment. Since the protocol’s formalization as a communications standard (IEEE 802.3) in 1983, Ethernet data rates have increased from 2.94 megabits/sec. to 100 gigabits/sec. A 400-gigabit/sec. version is expected in late 2017.

For motion-control and time-critical applications, there’s a version of Ethernet called IEEE1588. This system uses a timing scheme to insure that data packets arrive in a timely and predictable manner.

Standard Ethernet is commonly referred to as TCP/IP. The four main industrial-control versions are:  EthernetIP, EtherCAT, ProfiNEt, and Modbus TCP. These protocols take the regular version of Ethernet and add layers of control to allow industrial controllers to efficiently talk to each other. Standard Ethernet is not deterministic, i.e., you don’t know exactly when a data packet is going to arrive. The industrial versions, however, have various means of insuring data determinism.

Davis offers these best-practice tips for working with Ethernet in plant-control systems. Following them should lead to trouble-free service.

randmChoose quality components.
Select high-quality, shielded CAT6 cables. When choosing an Ethernet switch, purchase from a quality supplier. As for Ethernet connectors, specify industrial-grade devices. Don’t try to save a few dollars by using office-type connectors. The extra money spent will pay dividends. A dead Ethernet switch or bad connector will take your system down.

Use full-duplex industrial-rated switches rather than hubs.
An Ethernet switch routes the packets only to the appropriate destination. A hub spits out the data to every node on the network. Thus, a switch is clearly more efficient.

Route cable properly.
Be sure to keep any Ethernet cables well away from higher voltage and/or noisy conductors. For example, it’s not a good idea to run those cables next to 460-VAC motor wiring. Always use dedicated conduits for Ethernet cables in a plant environment.

Troubleshoot the system.
When starting up a system, ping all of the IP connections first. Ping is a command on your PC to “find” the IP node. To ping a device, go to the “search programs and files” dialog on your PC, type in the word RUN, and press enter. The RUN dialog box will open. Type the word PING followed by the IP address you are testing. For example, if a PLC has an IP address of 192.168.45.1, type PING 192.168.45.1 and press enter. If you see a dialog box with “request timed out,” this means that your PC cannot find the node. You may have an incorrect setting in your device or a faulty connection. If your ping test is successful, you will see a series of messages similar to this: Reply from 192.168.45.1: bytes = 32 Time <1ms TTL = 128. This message denotes that the node 192.168.45.1 is on your network and can send/receive data. If you want to ping your own PC, use an address of 127.0.0.1.

Document your system.
Document every node on the network. Include the physical name (“PLC,” “PUMP DRIVE #1”), its IP address, subnet mask, and gateway address. Make sure to label the control panel with the IP, subnet, and gateway information for the Ethernet items within. This information will be critical if a component fails and needs to be reprogrammed. MT

For more information on industrial-control networks, visit motionindustries.com and the MiKnowledge Hub.

22

2:03 pm
August 10, 2016
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Design Influences Rotary-Gear Pump Maintenance

Smart-sensing technology contributes to the predictive maintenance of wastewater and other facility pumps.

Pumping infrastructure represents an enormous investment for large facilities. All images courtesy of Pulsafeeder, a unit of IDEX Corp.

Pumping infrastructure represents an enormous investment for large facilities. All images courtesy of Pulsafeeder, a unit of IDEX Corp.

By Bobbie Montagno, Pulsafeeder Engineered Products

Pumping infrastructure represents an enormous investment for large processing facilities. In any given plant, thousands of pumps are needed to move liquids from point A to point B.

Some of the primary applications for which rotary-gear pumps are used in refineries and chemical-processing plants involve treating wastewater to be reused for cooling towers, boiler feeds, or to dilute chemicals that are required for other processes. For these applications, harsh chemicals such as bleaching chemicals, cleaning agents, and corrosion inhibitors are dispersed on a high-volume, continuous basis. Over time, this can take a toll on the pumping equipment, establishing the need for proper maintenance programs.      

The cost of maintenance

In most plants, annual maintenance costs for pumping infrastructure can range from 2% to 5% of the replacement value of the infrastructure. At first glance, that range seems minimal. But the delta between 2% and 5% can equal millions of dollars (or in some cases, tens of millions) throughout the life of the plant. Total maintenance costs must also be measured beyond the physical expense of the parts, the tools, and the engineers who wield them. Maintaining pumps in a chemical plant, refinery, or wastewater facility directly affects uptime, which in turn affects the bottom line.

Pumps that run regularly, feature wear items, and handle hazardous and corrosive chemicals will inevitably require maintenance. This can be a blessing and a curse.

Plant managers who get it right, in a preventive and predictive fashion, can streamline operations and maximize uptime. Those who let maintenance slip into a reactionary or “run to fail” approach can hinder operations and create ripple effects that shorten the life expectancy of equipment.

Access to the inner workings of a pump is another important design feature that affects maintenance.

Access to the inner workings of a pump is another important design feature that affects maintenance.

Predictive maintenance

Predictive maintenance requires a long-term view. It involves planning, scheduling, condition monitoring, analysis, and spare-parts management. Predictive maintenance for pumps is aided by smart-sensing technology that can alert engineers to dry-run conditions, temperature changes, increases in vibration, or decreases in pressure.

Today, sensors are readily available and their value (and deployment) will continue to expand as wireless communications connect plant infrastructure to maintenance personnel using tablets and smart phones across the Industrial Internet of Things (IIoT).

Predictive maintenance can also be done without advanced communications technology. Readily available information and historical pump performance can be used to schedule the replacement of wear parts with minimal disruption to plant operations and minimal investment in sophisticated cloud-based controls. 

Short-term reactive maintenance

Although predictive maintenance is always the goal, sometimes reactionary maintenance becomes the reality. When budgets are cut, maintenance is often considered a quick fix to address short-term financial constraints.

Reactive maintenance provides short-term savings, until equipment fails. When a failure occurs, the response relies on the skills of the on-site team and the availability of spare parts. If either fails to meet expectations, substantial losses can result from downtime and lost production.

Design impact

Maintenance starts with a simple design. Some pumps are designed for a limited life, and purchasing decisions are purely based on cost. Other pump designs seek to provide reliability over a longer life, while balancing the anticipated cost of repairs. Rotary-gear pumps are often deployed to pump harsh and aggressive chemicals, so sealless designs are easier to maintain because there is no leak point for the harsh chemicals to damage the pump or surrounding equipment.

When it comes to rotary-gear pumps, the number of spare parts should always be considered. Maintaining a sufficient inventory of gears, shafts, O-rings, and liners is critical. Spare-parts kits should contain every part that a pump requires, and kits should be easy to procure (with just a single part number). If tied to a proper design, spare parts should be simple and easy to install. Some pumps feature symmetrical parts that only fit in one way, making parts replacement mistake proof, and keeping time to repair at a minimum.

Access to the inner workings of a pump is another important design feature that affects maintenance. If the pump’s gears are not readily accessible, then engineers need to decouple the motor, close the valves, and remove piping at the suction and discharge ports of the pump. Pumps that feature a front pull-out design can be repaired in place. This minimizes downtime by eliminating the need to lock-out/tag-out the pump, and move it to the repair shop.

Maintenance ROI

Maintenance costs for a single repair will always be insignificant, compared with the costs associated with lost production and process restarts. The true return on investment associated with maintenance should be connected to a plant’s uptime. The simpler the equipment is to maintain, the faster it can be done. This gives plant operators more flexibility to schedule maintenance between shifts or whenever it is most opportunistic (or least disruptive).

Although the demographics for engineering staffs continue to change, the loss of vast experience is gradually being offset by new technology that can sense issues and alert engineers to problems before they occur. This type of sensing technology, coupled with simple designs, intuitive access, and fewer parts to maintain, forms the cornerstone of preventive-maintenance programs that keep plants up and running, and also provides management with the data it needs to make better decisions for capital budgets and long-term infrastructure improvements. RP

Bobbie Montagno is the aftermarket business line leader at Pulsafeeder Engineered Products, Rochester, NY. For the past 30 years, she has held leadership roles in application engineering, product management, and aftermarket. She can be reached at bmontagno@idexcorp.com.

165

8:36 pm
August 9, 2016
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Put Efficiency In MRO Storerooms

Outdated designs, work processes, and technologies keep many of today’s storeroom operations from adequately meeting the needs of the maintenance efforts they’re expected to support.

While bar-code technology has been around for decades, only a few storerooms have fully implemented it to track and manage their MRO inventory.

While bar-code technology has been around for decades, only a few storerooms have fully implemented it to track and manage their MRO inventory.

By Wally Wilson, CMRP, CPIM, Life Cycle Engineering

Regardless of organization size, many storerooms are still operated as they  were when the plants first began operating—which could have been decades ago. They still have light-duty metal shelving that wastes substantial vertical-storage space and heavy-duty pallet racking with extra-wide aisles to accommodate large components. For many sites, changes that make MRO (maintenance, repair, and operations) storerooms more efficient are long overdue.

Why a storeroom deserves TLC

An MRO storeroom is a business within a business that’s expected to have available items to maintain a site’s operating equipment. While the maintenance department may be its primary customer, it serves many areas of an organization. Its main role is to manage the inventory investment and provide the needed parts and components for equipment repairs and support the overall objectives and goals of the business.

The culture of the maintenance organization directly affects how a storeroom functions. If the expectation is to provide repair parts quickly for equipment breakdowns, the storeroom will be forced to operate with a large inventory investment—and in a very reactive mode. If maintenance personnel are conducting reliability-centered maintenance (RCM) and planning and scheduling their work, the storeroom operates in a more efficient and proactive manner, and with less inventory.

Note that how inventory is managed affects the outcome of equipment reliability. Take, for example, the fact that a harsh storeroom environment can damage parts. Dust, dirt, heat, cold, vibration, and static electricity can affect the quality and performance of some parts when put in service.

Service life can also be affected by how items are physically handled and stored. Think about the impact of an electric motor that’s dropped or had its shaft struck by a lift truck. Mishandling of parts can cause concealed damage that does more than adversely affect the life of the components themselves. It also can cause collateral damage to other equipment with which those items are installed.

Here are some recommendations for bringing your storerooms up to date in terms of location, storage equipment, work processes, technology, layout, inventory-stocking decisions, and kitting approaches for planned work.

Changes that make their MRO storerooms more efficient are long overdue for many sites, starting with elimination of substantial space-wasting, light-weight vertical shelving.

Changes that make their MRO storerooms more efficient are long overdue for many sites, starting with elimination of substantial space-wasting, light-weight vertical shelving.

Update location

Past thinking was that the storeroom needed to be centrally located for easy access from anywhere on the site. This philosophy was driven by the role of the storeroom and the need of the employees to have access to everything from office supplies and consumables to repair parts for equipment maintenance.

Current thinking is that the storeroom should be located on the perimeter of a site for increased security. Placing a storeroom there also reduces delivery traffic that can cause a safety hazard for employees and delivery-vehicle operators. 

Locating the storeroom on the site’s perimeter increases the need to plan and schedule the preventive and routine maintenance work. To support the planning and scheduling of this work, parts need to be kitted and delivered to a staging area or specific job site. Ensuring that needed parts and services are available before a job is scheduled is critical—and directly supports proactive maintenance and MRO-storeroom operations.

If a storeroom isn’t staffed 24/7, grouping inventory by commodity helps off-shift personnel find parts they need without searching throughout the storeroom.

If a storeroom isn’t staffed 24/7, grouping inventory by commodity helps off-shift personnel find parts they need without searching throughout the storeroom.

Update storage equipment

Regardless of a storeroom’s location, how space is used determines whether it operates efficiently. Assessing the vertical space, along with the square footage, helps define which storage equipment will be best suited to effectively manage inventoried items. Most MRO storerooms contain about 70% small items, with larger components and sub-assemblies making up the balance.

The smaller items should be stored in high-density cabinets, that, compared with metal shelving, dramatically increase space utilization. Cabinets can reduce the footprint of metal shelving in a storeroom by two-thirds. These types of cabinets also provide protection from environmental hazards (dirt and contaminates) that can damage parts. 

If square footage is limited, but ample vertical space is available, vertical carousel units are a good option. These units combine the high-density cabinet capability with a small footprint for storing large numbers of parts. Keep in mind, however, that such units are not limited to small-item storage.

Most vertical-carousel units have a maximum weight capacity of 300 to 400 lb./tray. These units can be configured in varying heights from 16- to more than 30-ft. to maximize use of available vertical space. Implementing vertical carousels significantly increases the use of available square footage and reduces the required footprint even more than high-density cabinets. A limiting factor is usually the cost, which can range from $150,000 to $250,000 per unit.

Update work processes

Several basic work processes need to be in place to effectively manage the storeroom and the inventory. Some rely on areas of the business operation outside the storeroom to be successful. Processes internal to the storeroom include:

  • Receiving. Identifies tasks required for the storeroom clerk to document and verify receipt of a shipment.
  • Inventory-stocking. Activities required to locate and store items to ensure the parts are properly stored.
  • Inventory-issue. Tasks required to allocate items from the storeroom inventory.
  • Inventory-cycle counting. Activities required to verify and correct on-hand quantity discrepancies.
  • Inactive-inventory identification. Identifies non-critical, slow-moving items that are candidates for revised stocking levels.
  • Obsolete-inventory identification. Activities required to identify parts that are not attached to a current operating equipment asset.

Work processes that the storeroom supports include:

  • Incoming inspection. Inspections of incoming items that were fabricated or require certification before receipt.Return-to-inventory. Activities that credit returned items to a work order.
  • Return-to-supplier. Activities that address warranty, credit, or replacement of a defective part.
  • Planned-work kitting. Activities that ensure all parts are on-site before the job is scheduled for completion.
  • Repairable-component process. Activities that track and manage the rebuild of selected components from removal from service to return to the MRO storeroom inventory.

Update technology

Technological advancements can be valuable tools for dealing with MRO inventories. Many organizations, though, have invested hundreds of thousands of dollars to purchase and install a state-of-the-art inventory-management system, but failed to leverage all of its capabilities. The sad fact is that employees often don’t receive adequate training on how to use the software. Consequently, they continue to rely on spreadsheets and other workarounds to do their jobs.

The business software is one of the most critical aspects in effective management of today’s storerooms. While bar-code technology, which is supported by most of today’s available software applications, has been around for decades, only a few storerooms have fully implemented it to track and manage their MRO inventory. To maintain visibility of the storeroom inventory, its receipt, management, usage, and re-stocking of materials has to be streamlined and updated in real time.

If such software is managed properly, all authorized individuals have access to real-time inventory reporting. Accurate, real-time inventory visibility is essential to your maintenance planners. If they’re not confident the inventory is accurate, they will spend much of their time doing physical checks to confirm the parts are actually on site.

High-use items, such as personal protective equipment (PPE), tools, filters, and leak-prevention solutions, can be dispensed using various types of vending machines.

High-use items, such as personal protective equipment (PPE), tools, filters, and leak-prevention solutions, can be dispensed using various types of vending machines.

Update layout

A storeroom should be laid out with consideration for space utilization and material flow. Inventory analysis and classification, using the A-B-C identification system, lets the storeroom manager establish a cycle-count frequency and define what items are critical, what should be held in inventory as stock, what should be non-stock (order on demand), and what are commodities that should be vendor-managed in the shops.

Handling or moving inventory items multiple times is a waste of effort for the storeroom staff—and increases the chance of damaging parts and components. When determining the space needed for a specific commodity group, a cushion of 15% of the space should be reserved for expansion. This approach provides space for new parts stocked for equipment modifications or new equipment installations.

Generally, inventory is best located and managed by commodity grouping items. The main advantage for grouping by commodities is to reduce duplicate inventory. This minimizes dollars invested in inventory and frees up valuable space. If a storeroom isn’t staffed 24/7, having the inventory grouped by commodity helps off-shift maintenance personnel find parts they need without wasting time searching throughout the storeroom.

Update stocking decisions

Inventory should be tied to an operating-equipment asset. Not all parts—even those deemed critical—will be held in the storeroom inventory (nor should they be). The decision to stock a part in inventory should consider these factors:

  • Order lead time. The understanding of order lead time often varies within an organization. The order lead time typically starts when the order is received by the vendor and ends when the order leaves their shipping dock.
  • Expected usage. Many parts could have multiple applications across the site and if the MTBR (mean time between repair) is available, the stocking decision can be made more accurately.
  • Vendor reliability. When selecting vendors, consider past vendor performance and issues that could affect their ability to provide the needed parts.
  • Impact on safety, production, and/or environment. Gauge the potential blow to these areas if a needed part were not available for the equipment repair.

For consumable inventories, consider these options:

  • Vendor-managed inventories (VMI). Items in this category are high-use, low-dollar items that can be stocked at a point-of-use location.
  • Vending machines. Many consumables, such as personal protective equipment (PPE), tools, filters, leak-prevention solutions, and office supplies, can be dispensed using various types of vending machines.

Update kitting approaches

Ensuring that all correct parts are available for a job provides a strong platform for a proactive maintenance program.

A planned-work kitting program also helps the storeroom. The key benefit is the ability of the storeroom to reduce the level of parts stocked and total dollars of inventory investment. Reducing the inventory investment contributes to an organization’s ability to operate at a lower cost.

Adding to the storeroom’s efforts to reduce inventory, the purchasing group can secure parts as they are needed for repairs, thus reducing the need to expedite purchase orders for parts or stock large quantities of many items.

For example, it costs $150 to $300 to generate and administer the average purchase order from requisition to invoice payment. Using the auto-replenishment (material-resource-planning) capabilities of an inventory-management system cuts the purchase-order cost to $10 to $12 per transaction. If the kitting process is successful, much of the inventory can be ordered as needed, staged for the job, and the work executed as scheduled.

Kitting provides a number of other benefits for a plant, including better maintenance-technician utilization. In most organizations, that rate is about 25%. With a planned-work kitting program, the rate increases because jobs, by definition, are well planned, and technicians will not be wasting valuable time looking for the parts to complete them.

Start sooner than later

The common approach to revising storeroom operations is to turn to new technology to solve all problems. The first step, however, should be to determine where you are now and what barriers prevent you from having a functional storeroom that proactively supports your site’s reliability and maintenance efforts. You’ll most likely discover some problems that haven’t yet been addressed—perhaps because your site has never launched an initiative designed to capture the opportunities they represent.

If, in fact, you find that your MRO storeroom needs a makeover, start the process as soon as possible to reap the associated operational and financial benefits. Innovation is driven by a clear understanding of the problem, planning a strategy to facilitate the needed change, identifying key activities to achieve the goals of the strategy, and measuring the performance with lagging and leading indicators.

Having a strategy to execute an improvement plan puts a rudder on your storeroom ship. Monitoring the progress of the initiative with key performance metrics will validate your progress and drive the continuous-improvement effort forward. MT

Wally Wilson is a senior reliability consultant in materials management and work management, planning, and scheduling for Life Cycle Engineering (LCE.com), Charleston, SC. He can be contacted at wwilson@LCE.com.

Key Storeroom-Performance Metrics

Key performance indicators (KPIs) that report lagging storeroom performance can shape strategies and action plans to drive long-term continuous improvement. Leading indicators are the mid- and long-term performance goals and the strategy to trend the storeroom performance toward the target goals. The strategy should include key activities and process revisions to drive the expected performance. 

The following KPIs are used to measure storeroom performance:

  • Inventory-turns ratio. The best-practice MRO inventory turns ratio is three to four annually.
  • Inventory value. Best practice is 0.5% to 0.75% of the asset-replacement value.
  • Inventory issued. Indicates dollar value of inventory issued.
  • Inventory received. Indicates dollar value of inventory received.
  • Inventory transactions. Indicates the utilization of storeroom employees.
  • Incidence of inventory stock-outs. Best practice is less than 2% of total inventory requests for unplanned jobs.
  • Identified obsolete inventory. Expressed in dollars, the best practice is less than 5%.
  • Excess inventory. Stocking overage, expressed in dollars.
  • Inventory accuracy. Best practice is 98% overall inventory accuracy.
  • Inventory adjustments. From inventory cycle-count activities.

learnmore2“Mining Gold from 21st Century Storerooms”

“Consolidating Assets Maximizes Performance”

“How to Reduce Storeroom Inventory Painlessly”

“Uptime: PDCA Drives Parts Management”

169

8:23 pm
August 9, 2016
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Rethink Overall Vibration Monitoring

Clinging to a single approach that made economic sense for your plant ‘back in the day’ could be an expensive strategy.

By Trent Phillips, CMRP, CRL, Novelis

Overall values are the most common measurements and calculations used in vibration analysis. What’s more, some reliability and maintenance programs rely solely on them. The goal is to remove monitored equipment from service once the overall vibration level exceeds a certain threshold. Although this approach would appear to be quite cost effective, in reality it frequently isn’t. In fact, overall vibration monitoring can become extremely costly for a facility.

The dilemma

High vibration levels can be caused by internal and external sources. They include, among others, imbalance, misalignment, belt defects, mechanical looseness, bearing-related issues, gear defects, and cavitation. Once identified, they should all be corrected. Keep in mind, however, that equipment often experiences multiple defects at once. For example, it’s possible for the amplitudes of certain frequencies to increase while the amplitudes of other frequencies decrease. The fact that these situations indicate a variety of specific conditions poses a problem for those relying solely on the overall-vibration approach.

An overall vibration value is centered on the frequency range being acquired and calculated based on a formula selected by the manufacturer of the vibration-monitoring device. Expressed in a mathematical representation of the energy exhibited by all defects combined, plus the vibration currently experienced in the machine, the overall vibration value cannot accurately differentiate among defects caused by various machine conditions.

The solutions

What should you do once an overall vibration level exceeds your target amplitude and the equipment is removed from service?

First, stop with the assumptions. They’re often made about the causes of high overall values, and work is completed based on them. Relying solely on overall values and only making assumptions about their cause can easily lead to incomplete information about the health of your equipment. This, in turn, can lead to misguided equipment repairs or detection of problems only in the painfully late stages of failure. As a result, extra resources and efforts are invested in determining the true source of elevated vibration levels—which translates as misspent time, unnecessary equipment maintenance, increased costs, and unwanted downtime.

There are several actions you can take to ensure your vibration program is effective, i.e., that it correctly identifies conditional changes in the equipment and sources of vibration.

  • Make sure the most important equipment in the facility is monitored. Don’t arbitrarily assign monitoring intervals.
  • Confirm that monitoring intervals allow enough time to identify, plan, schedule, and correct the identified findings before unwanted equipment failures occur.
  • Verify that recommendations are implemented. Knowingly ignoring conditional changes in equipment health will result in downtime, extra cost, and lower capacity.

Be sure you understand the failure modes in each machine, based on principles of FMEA (failure-mode-effects analysis). Band alarms and analysis should be used to indicate changes in the condition of your equipment and, at the same time, identify their causes or sources. Specific bands can be easily created, measured, and trended around particular failure modes in equipment, including misalignment, imbalance, and bearings. This information leads to more accurate alerts of impending failure conditions than generic overall measurements—and, as an extra benefit, actually identifies the failing component.

Personnel considerations

Who should collect routine vibration data? This is an important issue given the fact that wasted time wastes dollars.

Operators and mechanics should be up to the task. Both can acquire comprehensive vibration measurements on equipment during the course of their normal work activities. They also can make sure machines are shut down if vibration levels exceed acceptable values and notify others regarding the need for corrective actions. This approach allows analysts to focus on collected data and determining root causes of defects.

Data considerations

What other valuable condition-monitoring data might be missing? Tracking process information such as temperatures, pressures, lubrication levels, and equipment speed is vital for achieving desired performance from plant equipment. It also represents one of the most overlooked opportunities within a reliability and maintenance program. 

Unfortunately, since most overall-vibration-measurement devices can’t log or process such information, many facilities are unable to apply proper analytics to it. A good vibration-data collector will be able to record and store these data, and routes can be created for personnel to guide them through its routine acquisition. The collected data can then be easily stored to meet the documentation requirements of your facility and trended to provide increased analysis capabilities that may otherwise go overlooked. Alarms can be automatically generated when certain measurements or observations are recorded.

Corrective action

How do you motivate others to take corrective actions? This is one of the biggest challenges in any condition-monitoring program.

The information that’s presented must be very concise and plainly show what action is required. It’s almost impossible to do this with overall vibration values. Although these values may hint that machinery conditions have changed, they won’t provide clear evidence of what has changed. As a result, precise conclusions can’t be formed.

In contrast, a comprehensive approach to vibration monitoring—with detailed collection and analysis of data—can provide a highly accurate indication of what’s wrong and what corrective action is required. Calling for more than simple overall data measurements, this type of approach is always the most effective method for identifying unwanted machinery conditions and determining specific component failures. MT

As global leader for reliability at Atlanta-based Novelis, Trent Phillips is responsible for training, coaching, auditing, and developing reliability programs. Contact: trent.phillips@novelis.adityabirla.com.


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