Archive | April, 2008

1032

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April 1, 2008
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The Fundamentals: How To Reduce Storeroom Inventory Painlessly

This article is the fourth in a series dealing with some of the basic “hows” of the Maintenance profession.

Ouch! Holding on to Excess, often unwanted and obsolete parts really eats into your bottom line.

A storeroom is, by definition, a waste of capital. It is a bucket of money set aside for contingencies associated with the unpredictable nature of the manufacturing process.

In a perfect world, storerooms would not even be necessary. Your world-class preventive maintenance efforts would ensure that machinery seldom wore out. Parts would arrive from suppliers 10 minutes before they were scheduled for replacement based on recommendations from the predictive maintenance side of the house. Since there would be no emergencies, the need for a selection of replacement components to be kept on site would be eliminated.

In the real world, production facilities don’t operate in ideal settings; some level of spare parts availability must be maintained. Each maintenance organization must determine the minimum number of extra components necessary to sustain production and then strive to reduce excess supply with a minimum of waste.

Changing the scenario
Sometimes, storerooms seem to be stocked with the philosophy that the plant should be completely rebuildable from parts on hand. That philosophy might have merit if holding costs associated with the yearly maintenance of parts inventories did not range from 18 to 30% of the inventory’s value. On a million-dollar storeroom inventory, this translates into between $180,000 and $300,000 per year. As a result, the cost of your parts supply doubles every three to five years.

Pretty shocking, isn’t it. This is real money, too—not just an on-paper figure that the accounting department has circulated. The components of this expense include the opportunity cost of not spending the money on something else, interest, the cost of the storage facility, handling, spoilage, taxes, employees and loss.

If this picture describes your maintenance stores reality and you wish to change the scenario, you must first determine the scope of the problem. Your CMMS will be one of your most useful tools as you undertake this task, because it will allow you to identify slow-moving and non-moving inventory, overstocks and components that have become obsolete due to a change in your process. Once these superfluous parts have been identified, a systematic program of reduction and elimination must be undertaken.

Each maintenance manager must look at the available personnel in the department and assign a single person to spearhead the campaign to reduce surplus stores. The planner or storeroom coordinator would be excellent candidates for this role if some of their current duties could be shifted to free up the hour or two per day—every day—that this project will require. The designated individual should then be assigned the task of reducing inventory via the following methodology:

  • Analyze suggested spare parts and stocking levels for any new equipment that is being purchased. There is a reason that this action is first. The use of suggested stocking levels provided by the manufacturers of the equipment in your plant is one of the reasons that your storeroom inventory is at unacceptable levels.

    From the machine manufacturer’s point of view, promoting a healthy spare parts list has the benefit of increasing their bottom line, as well as the secondary benefit of keeping breakdown times shorter. If they can convince you to purchase what amounts to most of a spare machine, they have, in effect, sold you two, and the one out on the plant floor can be repaired more quickly if it breaks down.

  • Work with your machine suppliers during the design stage of new equipment so that you can take advantage of existing stocks of spare parts. This is called standardization—and it is one of the most important and cost-effective steps you can take to control storeroom inventory.

    If you have 17 machine centers on your manufacturing line and each is powered by a small- to medium-horsepower motor just slightly different in some manner from each of the others, you will have to stock 17 replacement motors in the storeroom. But, if some care and thought is put into standardization during the design stages, you may be able to stock only a few—and might even be able to lower the inventory to one.

  • Most CMMS programs allow for automatic reordering of parts after a stores issue has occurred. This function is based on minimum and maximum inventory parameters that have been pre-programmed into the system. These reorder points and stocking levels are generally based on the manufacturer’s suggestions and should be analyzed for validity. Since the best time to reduce inventory levels is before you purchase the new part, these reorders must be scrutinized by an individual with the authority to override the system.

As an example, if you have a bearing come up for reorder because one was issued the previous day, several factors must be considered before the requisition is transmitted to your supplier. How many identical bearings are still in stock? Has a cross-reference been run to determine if any other in-stock bearings will work in the application? When was the last time one of these bearings failed? Why did this one fail? Was the issued part actually used? What is the delivery time on a new bearing? What is the criticality of the affected machine? If you normally stock two of these bearings, but you have only used one in the last three years, and the re-order time is two days, then most likely you do not need to re-order this component at present. If it turns out that temporary loss of the machine’s functionality will not cause an interruption in production, then you do not need to reorder next time, either.

It is very important to remember that reorder points and stocking levels must be formally changed in your CMMS or stores program if you decide that you can operate your process with lower levels of spares. Otherwise, the orders will just keep on coming.

  • Depending on the nature of your business and geographic proximity to your suppliers, it may be possible to negotiate the staging of larger, more expensive replacements such as motors, gearboxes and pumps at the supplier’s regional sourcing areas for quick dispatch to the plant site. As an example, assume that your process includes several of a certain model speed reducer, and that it takes three hours to replace one if it fails. If your supplier is only an hour away and will agree to keep one of the gearboxes on hand, then there is no need for you to duplicate the action.
  • Another method to reduce inventory costs is to share between plants on big-ticket items when such an option is geographically practical. These spares can be centrally housed and their expense shared among the locations.
  • If you have a situation in which you are using a predictable quantity of a certain component in your process, this is a good candidate for consignment from your supplier. A consignment arrangement is merely an agreement to pay for an item when it is issued from the storeroom rather that when it is placed into the storeroom. Most vendors are agreeable to these types of arrangements on components that tend to move quickly. Typically, the plant must buy the parts from the supplier if they have not been used within a year.
  • The actions discussed so far have dealt with delaying the procurement of spares or reducing the size of the purchase. But what should you do about the excess inventory you already own? Very simply, you must get rid of it as quickly as possible.

    The most preferable way to do this is to sell the parts back to the supplier you bought them from in the first place. Most vendors are agreeable to this idea provided that the part is in its original wrapping or package and not obsolete. Sometimes there may be a restocking fee assessed, but rarely will it be higher than the 18 to 30% “holding cost fee” you already are paying.

    To your supplier, your surplus part is an item of commerce, and if you don’t need it, one of their other customers might. Additionally, if you have held the item in inventory for several years and sell it back for its original purchase price, it often is a bargain for the supplier—who may be paying a good deal more to the manufacturers due to the impact of inflation over time.

  • If your supplier does not want to repurchase, there are other avenues you can try. If your company has multiple plants, chances are that one of them may need the part you don’t need. Another option might be to offer the excess to other manufacturers and competitors in your area. Depending on your company’s policies, sales to the public or to employees also might be considered. In light of liability concerns, however, you MUST be certain to check with your legal department regarding all outside sales or disposals of excess inventory.
  • The Internet can be a great resource in reducing storeroom inventories, particularly for electronic or electrical components that are easily shipped. Internet auction sites such as eBay are a possibility, as are surplus and salvage dealers who specialize in the reduction of storeroom inventories. Charitable donations to trade schools and technical colleges are yet another option to explore. Again, due to liability concerns, check with your legal department before proceeding.
  • Once you have sold as much excess inventory as you can—and adjusted all of your stocking levels and reordering intervals to reflect your actual needs—you still will be left with merchandise that nobody seems to want. At this point, your choices have become limited. On the one hand, there is that very real holding cost if you keep the inventory—and it is a penalty that re-assesses every year. On the other hand, if you write off the inventory and dispose of it, the company, in effect, has spent money but received no value.

    A better approach might be to use these excess—unwanted—parts as tools in your maintenance training program. If you are stuck with obsolete bearings, you have an opportunity for all of your millwrights to practice bearing installation. If you have an obsolete motor, all of your multicrafts can practice wiring the motor to a switch or a breaker.

Getting it done
Keep in mind that your storeroom inventory level did not get where it is overnight. It climbed slowly but steadily over time. Consequently, its reduction also must proceed at a measured pace—if you want to avoid unnecessary waste while eliminating undesirable surplus materials.

One of the key elements in painless storeroom inventory reduction is to have one person responsible for the process, and to have that individual work at the project on a daily basis. Even if he/she can spare only an hour per day for the task of inventory reduction, the time will be well spent. TF


Ray Atkins, CPMM, CMRP, is a veteran maintenance professional with 14 years experience in the lumber industry. He is based in Rome, GA, where he spent the last five years as maintenance superintendent at Temple-Inland’s Rome Lumber facility. He can be reached at raymondlatkins@aol.com

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182

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April 1, 2008
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The Fundamentals: The Great Misunderstanding

What’s your definition of maintenance?

One of the most frequent remarks we hear from students taking maintenance crafts classes is: “Managers don’t want it done right. They just want to get it running again.” Such comments indicate that the students and their managers don’t truly understand the definitions of maintenance. Even in our current enlightened age of machine reliability, this misunderstanding is prevalent throughout industry. Unfortunately, before we really can progress in achieving the reliability required of our machinery, this dilemma must be solved.

A case in point
Suppose a craftsperson attends a class on drive-belt installation. In the class, the craftsperson is taught that the proper way to install belts is to reduce the shafts’ center-to-center distances and then place the belts on the pulleys. He/she is instructed to never roll the belts onto the pulleys.

Upon returning to the plant, the craftsperson receives a call from operations stating that a set of belts is smoking and must be replaced. There are only two hours left in the shift, after which, the plant will be down for eight hours. Remembering what was taught in the belt installation class, the craftsperson decides to follow the standard learned in class. Arriving at the machine he/she notices that the motor mounting bolts are rusted and cannot be easily loosened. In fact, they may have to be replaced, too.

To follow the class standard would add over an hour to replacing the belts, as opposed to cutting off the old ones and rolling on the new ones. The production manager is hovering over the craftsperson, urging that he/she get the drive up and running again. What is this individual to do? What is the proper thing to do?

In order to please the operations manager, the craftsperson decides to cut off the old belts and roll on the new. The machine is soon up and running again and the production manager pats the craftsperson on the back—congratulations for a job well done. But, the craftsperson doesn’t feel good about what has just happened, and even worries that the belts may fail because cords could have been broken in the process of rolling them onto the pulleys.

Implications
Let’s consider all the implications of performing the belt installation in the previously described manner.

  • The craftsperson performed substandard work.
  • The new belts probably were damaged and could fail again, leading to more downtime.
  • The job probably will have to be performed again.
  • The operating crew saw the craftsperson performing substandard work.
  • The premature failure of the new belts could place the craftsperson in jeopardy for not performing the job to the standard for which he/she was trained.
  • The sign hanging in the work area encourages personnel to “Do it right the first time,” something that was not done here. The craftsperson’s morale falls another notch.

Solutions
People are constantly faced with such dilemmas because of a basic misunderstanding that permeates industry. In order to arrive at the proper solution, let’s revisit the belt replacement and consider some additional information.

The craftsperson arrives at the machine and surveys the situation. There is much to be said for the slogan, “Do it right the first time,” and this individual considers doing maintenance on the machine by installing the belts according to the standard learned in the training class. He/she notes that there are only two hours left in the shift after which the mill will be down for eight hours. The belt failure has the production line down and the cost of lost production is $5000/hr. The cost of new belts is $400. Labor costs also will be incurred.

The craftsperson is knowledgeable of all costs and considers them. It is likely that the belts would be damaged in the process of rolling them onto the pulleys, resulting in rework. That would mean another set of belts at a cost of $400 plus labor. Not doing the job right the first time would likely double the cost of replacing the drive belts, making the total costs approximately $1000. There also is the risk of premature failure due to possible belt damage during the installation.

Having this information and knowing that the primary goal is to make profit for the company, the craftsperson weighs the costs and the risks. He/she decides NOT to perform maintenance work. Maintenance work is always performed to a standard of precision—and it requires time. The craftsperson makes this good faith decision based on the information at hand and decides to perform stopgap measures in order to resume production. He/she announces to the operating crew that maintenance will not be performed on the drive at this time, but that the belts will be rolled onto the pulley so production can start up again. Reasons for this decision are discussed with the production manager and agreement is sought.

After the production line is up and running, the craftsperson notes in the work order why the decision was made to do substandard work. He/she also initiates a follow-up work order detailing the work required to bring the machine up to plant standards.

Understanding
There clearly is confusion in industry over the true definition of “maintenance.” When we see a craftsperson using the tools of his/her trade to perform tasks on machinery, we automatically assume that maintenance work is being performed. Frequently this is not the case. He/she simply may be attempting to resume production.

Craftspeople and managers both need to know the difference between performing maintenance work and performing tasks directed at resuming operations. Only by having adequate information and knowledge can we make informed decisions that will result in the company goal of making profit. Training, coupled with improved communications, will help to erase The Great Misunderstanding.

Bill Hillman brings 30 years of experience in the steel industry and 6 years in the wood products industry to his current position as a managing partner of Asset Management Specialists Co. His entire career has been spent in working in the field of equipment asset management, including over 20 years in the area of predictive maintenance. Chairman of the Board of the International Council for Machinery Lubrication, Hillman is a Certified Maintenance and Reliability Professional, certified by the Society of Tribologist and Lubrication Engineers and a Certified Infrared Thermographer, among other things. Telephone: (903) 407-9488; e-mail: billcmrp@yahoo.com

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177

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April 1, 2008
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The Fundamentals: Fundamental Solutions

FRP Metal-Parts Wash-Boxes

0408_fund_boxes1Molded Fiber Glass Tray Company high-strength fiber-reinforced polymer (FRP) composite metalparts wash-boxes cost approximately 1/3 the price of traditional stainless steel models. Designed to handle heavy payloads (150 lb. capacity), they are engineered to withstand small-part washing system chemicals and provide continuous operation at temperatures to 350 F. By minimizing the “dumps” from high-speed conveyor-to-container, use of these lighter-weight units requires less labor and reduces part damage/scrap.

Molded Fiber Glass Tray Company
Linesville, PA

0408_fund_bearings1Steel Bearing Alternatives

SKF’s MRC® hybrid ceramic ball bearings combine traditional steel rings with nonconductive silicon nitride balls. This combination facilitates insulating properties to prevent electrical arcing and associated surface damage. Bearings provide ideal “drop-in” replacement solutions within existing design envelopes. According to the company, these ceramic components are lighter, harder and more durable than all-steel bearings, and can run at higher speeds and lower operating temperatures.

SKF
Kulpsville, PA

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207

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April 1, 2008
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Boosting Your Bottom Line: Plug Into Programs

Improving your facility’s energy efficiency is one of the most cost-effective options to address high energy costs, and it’s an option that is itself a growing industry with financial and technical resources to highlight energy savings in your facility. As the Consortium for Energy Efficiency (CEE) reports, $3.7 billion was dedicated to energy efficiency programs in 2007 in the U.S. and Canada, 47% of which was dedicated to the commercial and industrial sectors (http://www. cee1.org/ee-pe/2007/2007EEPReport.pdf).

In the United States, motors consume approximately 75% of the electricity in the industrial sector. As such, zeroing in on motors and motor systems at your plant or facility is a great first step toward reducing your energy costs. A range of efficiency programs dedicated to motor-related efficiency are available throughout the U.S. and Canada. The types of programs can range from prescriptive programs, which provide rebates or other financial incentives for the purchase of NEMA Premium motors, to technical assistance programs, which provide technical expertise or funding to hire outside technical expertise. Often, program types overlap, with several types incorporated into one framework that best suits the goal of the specific efficiency program.

In much the same way as the efficiency industry budget is growing, so too is the number of programs that focus on NEMA Premiumefficiency motors and adjustable speed drives (ASD). In 2007, more than 170 motor and ASD programs were available in the U. S. and Canada. These programs fall into a number of categories, including specifically:

  • Prescriptive
  • Upstream
  • Custom Retrofit
  • New Construction
  • Standard Performance Contract (SPC)
  • Financial Assistance
  • Technical Assistance
  • Education/Awareness
  • Motor Management or MDM Materials
  • Other

For more information about programs in your area, download the CEE 2007 Program Summary: Energy efficiency Incentive Programs for Premium Efficiency Motors & Adjustable Speed Drives in the U.S. and Canada (http:// www.motorsmatter.org/). If getting started in the direction of energy efficiency seems like a daunting task, fear not! There are resources available to help you, and they’re free! The Motor Decisions Matter (MDM) Campaign and its sponsoring organizations have developed several tools and resources that you can use to develop a motor management plan that meets your company’s needs. This information can also lead to partnerships with your local sales and service center, vendor, electric utility or other energy-efficiency representatives who are wellpositioned to offer added support. MT


The Motor Decisions Matter campaign is managed by the Consortium for Energy Efficiency, a North American nonprofit organization that promotes energy-saving products, equipment and technologies. For further information about MDM, contact Ted Jones at tjones@cee1.org or (617) 589-3949, ext. 230.

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April 1, 2008
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Don’t Look At Your Feet

0408_foot_11If you’re aligning equipment using foot value tolerances, you may need all the luck you can get and then some. “Modern” as that approach is, this author says it doesn’t stand up in the real world.

My company specializes in laser shaft alignment equipment. Recently, a prospective customer commented that he liked our equipment, but wondered when we were going to get “modern” about alignment tolerances. Generally accepted shaft alignment tolerances in industry use two criteria: Radial shaft centerline offsets at or near the coupling and angular shaft relationships. My customer’s opinion, based on an article he had read, is that shaft alignment tolerances should be based on offset values at the motor feet. If that’s the approach you’re taking, I would have to ask, “Do you feel lucky?”

0408_foot_fig11

Based on 28 years of experience in the alignment field, I have great concerns about using the foot value tolerance scheme. They include the following: 1. Companies will spend an enormous amount of time and labor going the “extra mile’ to achieve this standard. 2. Use of the foot value tolerance vs. angle and offset tolerances will NOT improve machinery reliability. 3. The foot value tolerance method will not improve bearing or seal life. 4. This foot value tolerance method will frustrate and discourage aligners who are motivated to perform precision maintenance, as very small measurement errors will result in large foot value fluctuations. 5. The foot value tolerance method breaks a basic measurement principle by amplifying measurement errors.

0408_foot_fig21Basic shaft alignment
Every shaft rotates about an axis. In shaft alignment (see Fig. 1), the driven machine is usually considered as a stationary machine element. The rotational axis of the driven machine serves as the measurement datum (reference line). The driver is usually considered to be movable. The movable rotational axis is compared to that of the stationary. Shafts are considered misaligned when the two rotational axes are not colinear.

As shown in Fig. 2, misalignment can be represented by expressing the horizontal (x) or vertical (y) position of the movable rotational axis in relation to stationary shaft at various axial positions (z).

  • Offset Misalignment is the actual radial position of the movable rotational center relative to the stationary center. If the shafts are not parallel, the offset misalignment is different at every axial position.
  • Angular Misalignment is the slope relationship of the two shafts. The slope has a positive value if the offset values are more positive at the rear feet than at the coupling.

For example, using the graph in Fig. 2, we can see that:

Offset Misalignment = -20 at the coupling center,
0 at the front motor feet and +30 at the rear motor feet
Angular Misalignment = 20 mils/10” = 2.0/1”.

0408_foot_fig31Measuring and correcting misalignment
Misalignment is measured with dial indicators or laser sensors as the shafts are rotated (see Fig. 3). The measurement planes are defined by the axial locations of the sensors. Correction planes are where shims can be added or removed.

Misalignment forces…
Misalignment, as illustrated in Fig. 4, creates forces at the coupling that are exerted on the shafts and, subsequently, on bearings.

The force effects of misalignment can be simplified by considering the misalignment as a simple lever. Misalignment at the coupling creates a moment of force acting on an effort arm. This will create a first class or second class lever with either the inboard or outboard bearing acting as a fulcrum. The length of the motor shaft between its bearings is the resistance arm.

0408_foot_fig41Alignment tolerances…
It is very unlikely that perfect alignment is achievable— or is really that important. The objective of shaft alignment is to minimize radial forces by minimizing the offset at the coupling where power is transmitted. Further, we minimize axial forces by minimizing the slope relationship of the two shafts. The tolerances we recommend (see Fig. 5) are based on angle and offset values. You can choose to be more or less permissive.

Zone of good alignment using angular and offset tolerances…

The graph in Fig. 6 shows a zone of acceptance for a 3600 RPM machine using angular and offset tolerances. When the movable shaft axis falls completely within the shaded “bowtie,” acceptable alignment is achieved. There are a range of foot values that are acceptable.

0408_foot_fig51The plotted line represents a shaft with offset misalignment of 1 mil (0.001”) at the coupling center. The slope is 0.1 mil/1”. This is a very good alignment!

Zone of good alignment using foot value tolerances…
The graph in Fig. 7 shows a zone of acceptance for a 3600 RPM machine using the foot value tolerances (inset box) referenced by the author of the article my customer had read—which is what compelled me to write this article. When the movable shaft axis falls completely within the shaded area, acceptable alignment is achieved. There is a very small range of acceptable alignments. Small measurement errors will make these tolerances hard to satisfy!

0408_foot_fig61Measuring errors
It is impossible to produce error-free shaft alignment measurements, even with very resolute laser systems. Bearings must have clearances to assure free shaft rotation at varying temperatures. Machine shafts shift slightly within those clearances as the shafts are rotated in the measurement process. Therefore, the machine shafts are not perfectly repeatable. The effects of measurement errors are always minimized when the planes of interest are between the measurement planes. The effects of errors are amplified when the planes of interest are external to the measurement planes.

The effect of a 0.5 mil measurement error in one measurement plane is shown in Fig. 8. This creates an angular error of 0.5 mil in 6”, or 0.08 mil/1”. When the offset tolerance is applied at the center of the coupling, the error is small because that plane of interest is between measurement planes. When the tolerance is applied at the feet, however, the error is amplified because those planes are external to the measurement planes.

0408_foot_fig71Conclusion
This article is intended to offer insight on shaft alignment tolerances for close coupled machines with flexible couplings. Precision alignment is important, but perfect alignment is not achievable—nor is it needed to reduce destructive coupling forces. Tolerances should be based on solid measurement principles and with the understanding that alignment measurements are only as repeatable as the machine shafts can repeat themselves during manual rotation.

0408_foot_fig81Final thoughts…

  • Understanding the rotational axes assists in making alignment corrections.
  • Shafts will only “seek” co-linearity if they are coupled.
  • Therefore, the objective of shaft alignment is to reduce coupling forces.
  • The angle and offset tolerance method meets this objective.
  • The actual angular and offset values that are acceptable are negotiable, but tolerances should not be made smaller than the machine shafts are capable of reproducing within bearing clearances.
  • Small measurement errors are amplified when misalignment is calculated at the feet.
  • Foot values should be used only to make alignment corrections.
  • The required bearing clearances are larger as shaft diameters are larger.
  • It is not that hard to achieve small foot values in a classroom with small demonstrators. In that environment, the bearing clearances are usually small and the amplified errors are also small because the feet are not that distant from the coupling.
  • In real-world situations, small measurement errors produce foot value fluctuations that are greater than the stated foot value tolerance.
  • Small measurement errors have little adverse effect when applying angular and offset tolerances.
  • Consequently, when applying foot value tolerances in real world situations, the aligner must be either lucky or a liar to achieve his goal.

Perhaps this article can launch a discussion on industrywide shaft alignment standards. If others want to weigh in on this perspective, we would welcome your thoughts. MT


David Zdrojewski is founder and CEO of VibrAlign, Inc., headquartered in Richmond, VA. Telephone: (804) 379-2250; e-mail: david.z@vibralign.com

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April 1, 2008
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What Keeps Customers Rolling? “Five Factors of Excellence”

Sometimes, it’s best to view things from the perspective of an expert. That said, you also should expect your suppliers to be experts in their fields.

Providing unfailing operation from ball bearing failure requires looking at the subject the way experts do—with a cold eye on the factors leading to success and failure. Ignore them and the result could be production interruptions that cost your company time, money and reputation. Embrace them and you can look forward to a number of benefits, including fast product delivery and fatter profit margins.

When Goodrich Aerospace (GA) of Vermont opened the door to The Five Factors formula, good things rushed in. According to senior buyer Ross Lowery, long lead times for product delivery vanished, even “troublesome” parts were always in stock and the mind-bending exercise of price comparisons for various quantities of parts came to an end. GA thus expanded its contract with the formula originator, Intercontinental Bearing Supply Company (IBSCO). This Houstonbased supplier of ball bearings and services defines and utilizes The Five Factors for its clients as follows:

Factor One: Traceability…
Goodrich Aerospace is a Prime Contractor and OEM for the Federal government. Accurate and complete traceability is requisite, especially for bearings. Thus, if there’s a failure in the field, IBSCO’s ball bearing experts will be able to isolate those failures to a given stock number and then take necessary precautions. If it is shown to be a factory defect, IBSCO can do a recall of the specific bearing and minimize the impact. For example, a ball bearing in a piece of handheld equipment used in brain surgery heated up so much that doctors couldn’t handle the device. Diagnosis: a lubrication overfill from bearings acquired through a distributor. Traceability made it possible to pinpoint each of the bearing lots that went into the surgical tool for that particular customer.

On the other hand, ruling out a bearing malfunction can help lead to the real cause of a problem. For example, a client reported that a ball bearing was corroding fast. When a review of the suspect bearing lots showed no prior history of problems, the client shifted focus and discovered the culprit to be its own process that allowed etching fluid into the bearing housing assembly.

As industry relies more on high technology, these days, such situations are not isolated incidents. A problem in a manufacturer’s process creates a domino effect that can cause long-lasting harm to business relationships. Every part received and delivered by your bearing supplier should be accompanied with a Manufacturer’s Certification and lot number or traceability identifier. By providing the Manufacturer’s Certification, it makes the distributor 100% accountable for each bearing—from the point of entry to point of delivery. You ought to know what you are getting, whether you’re buying a $2 bearing or a $10 bearing.

Factor Two: Delivery…
Suppliers that “out-think” the customer are a step ahead. By being prepared, they can significantly reduce lead-times for delivery. This is critical given the fact that in today’s economic climate, delivery time can stretch from 30 to 55 weeks. With IBSCO’s help, Goodrich Aerospace has reduced its delivery time to days—or a few weeks at most—by obeying one rule: Managing inventory well is the key to managing delivery time.

IBSCO manages Goodrich Aerospace’s inventory. In doing so, GA’s needs are evaluated on a weekly basis with the help of a complex computer matrix and extensive data about sales cycles. As a result, short-term trend changes can be accommodated, such as those occasions when product is required sooner or later than anticipated.

That type of flexibility helped Goodrich Aerospace pause in its delivery of a braking system. Components needed to move forward on the project were delayed, forcing GA to hold back its own production. The change was accommodated without harm to the outcome. There have been other instances where replacement parts for military aircraft, for example, came in sooner than expected. Again, communication about what’s in the pipeline and safety stock for unique situations provided the solution.

Also, remember delivery is not just related to time. Procurement and Quality Control requirements are a significant issue. The U.S. government enforces the Defense Federal Acquisition Register Schedule (DFARS). This means all government-contract parts must be manufactured, purchased and built with raw materials from the United States market or a North Atlantic Treaty Organization (NATO) country. If DFARS compliance is required, all raw material and product components must be made from U.S. steel that can be traced back to the milling process. This has grown more difficult as the domestic steel industry has eroded, even as demand and manufacturing costs have increased.

Factor Three: Re-lubrication…
The ability to re-lubricate bearings serves a dual purpose. First, it restores the shelf life for product with expired use dates. The ability to re-lubricate expired bearings is essential to the aircraft and aerospace industry.

But the primary purpose is producing a custom lubricated bearing. This means while product specific to client needs is stocked, the commonly used sizes are onhand and available for lubing as needed.

Also, buying basic ball bearing stock at bargain prices allowed a medical firm to improve gross sales, even as the value of the U.S. dollar dropped. How? The currency imbalance meant overseas customers would eventually want to buy more American-made products because when the dollar value dropped so did the price. By stocking up on basic parts, the medical firm was well prepared when overseas demand for its equipment increased.

Factor Four: Custom Lubrication…
Goodrich Aerospace benefits when its provider buys large quantities of “vanilla” stock on its behalf—stock that later can be custom-lubed to GA specs. When incorporated in this type of purchase, OEMs like Goodrich Aerospace may get a better price than they would get from the factory they normally buy from.

Also, as technologies change, adjustments to lube specs may be required. Sometimes re-lubes are needed because the design specs change due to improvements in technology. Dental tools, for example, pose a particular challenge. They require lubricants that can withstand hot-steam cleansings after each use, yet are not so heavy that they promote heat build-up during operation.

Goodrich Aerospace chose IBSCO because of its expertise in custom lubrication blends, fill amounts and understanding the specific needs of the customer.

Factor Five: Certification…
A factory certification is essential because it includes lot numbers that allow the material to be traced all the way back to the smelting factory. Certification ensures that you’re getting the legitimate part you ordered. You need paperwork to make sure there’s a pedigree.

Lubricants, as well as ball bearings, must be documented. The original factory certification papers must include a lot number and where it was made. Substantial time can be saved if your supplier is factory authorized to do re-lubes. Without this authorization, manufacturers can expect to wait 30 weeks for delivery of a full-warranty product. You need certification detailing what work was done before it was shipped to you. Also, it is essential that the factory scrutinize the processes of the distributor that has been authorized to do full-warranty work—twice a year.

When it comes to ball bearings, those who pay attention to these Five Factors of Excellence should have no trouble rolling along. MT


Jack O’Donnell has spent 37 years in the bearing business. He has served as president of IBSCO since 1998. IBSCO is a distributor of NHBB, NMB, IJK, Barden and Timken products. Telephone: (800) 231-6480; e-mail: jack.odonnell@ibsco.com

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April 1, 2008
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Get Where You Want To Go: Operator-Driven Reliability

0408_odr_11ODR is not an overnight trip. Success requires all parties to be using the same road map.

For decades, maintenance professionals have advocated and used information management systems, planned maintenance activities, emphasized preventive maintenance and assessed equipment utilization to eliminate non-essential assets (reducing numbers of equipment). These professionals also have been aware of the need for operator and mechanic training and, to some extent, decentralizing asset responsibility. Accordingly, they have been striving to build operator-ownership of equipment through basic care.

That said, specialists in asset management and reliability have spent years in various relevant pursuits. Over the past decade, these pursuits have been joined by an approach called Operator-Driven Reliability, or ODR. Yet, while commendable in its aims, ODR is not capable of standing alone. It must be supported by related endeavors that involve management philosophies and “buy-in” from all levels—including those within maintenance. In and of itself, ODR is not an off-the-shelf approach that can be implemented on short notice.

Cooperative efforts needed
Any write-up or technical presentation would be incomplete if we neglected to recognize our limitations. Thus, we know that in the “real world” even the most competent reliability professional is rarely in a position to implement best practices without the cooperation of others. There always will be a management component involved. Regrettably, others (including managers) sometimes pursue only short-term interests. Short-term interests are destined to be repair-focused, whereas long-term interests are (generally) reliability-focused.

Consistently achieving good performance and high profitability requires long-term pursuits. It calls for industrial enterprises to totally abandon their repair focus and unequivocally embrace the reliability-focused approach. To what extent this focus has been transferred or carried over into your equipment repairs can be determined by carefully reading the following point-by-point summary based on the philosophy of W. Edwards Deming.

0408_odr_21It is especially important that modern, reliability-focused plants be consistent in adhering to a well-formulated or even formalized management philosophy. Continually adhering to such a philosophy is an indispensable requirement if tangible and lasting equipment reliability improvement results are expected from ODR.

Acknowledging Deming’s work
Adapting the thinking of W. Edwards Deming, the noted American statistician whose teachings on quality and profitability were often neglected at home, but venerated in post-WW II Japan, we give the following experience-based advice to the manager whose facility would profit from equipment uptime extension and failure risk reduction. It is a guide that not only will strengthen your traditional reliability efforts, but also help lead you to where you want to go in your journey to Operator-Driven Reliability. While these points, in various iterations and combinations, may have appeared previously in this publication, their importance can’t be overstated. Suffice it to say, for reliabilityfocused professionals, it’s impossible to consult this type of “road map” too often.

  • Create constancy of purpose for improvement of product, equipment and service. Implement whatever organizational setup is needed to move from being a repair-focused facility to a reliabilityfocused facility. Do this by teaching your reliability workforce to view every maintenance event as an opportunity to upgrade and letting the most competent equipment repair shop assist in defining these opportunities.
  • Take time to determine if the OEM or the competent non-OEM repair shop is in a better position to assist you in achieving plant uptime and profitability goals. Realize that this determination may well be outside the normal limits of a purchasing group. In fact, a Purchasing Department may have made it a practice to award contracts only on the basis of tangible first-cost and schedule commitments.
It follows that your reliability professionals may need to be tasked with the development of rigorous specifications that are driven only by safety and the ultimate life cycle cost. These professionals may have to be given a written role statement so as not to leave any doubt as to the nature of their involvement. Also, this role statement needs to be disseminated to other job functions. It is well known that the expectations of “others” as to the duties and achievements of reliability professionals may have to be corrected.
  • Never allow costly experimentation by anyone in your workforce. Do not let them “re-invent the wheel,” when there is proof that a good technical text or an experienced mentor or shop could point the way to a proven solution.
  • Unless your problem pump or other machine is indeed the only one in the world delivering a particular product from point “X” to point “Y,” insist on determining the operating and failure experience of satisfactory (!) machines, pumps or mechanical seals elsewhere. Never accept an “alliance” partner’s claim that disclosing such experience violates ethics or the law, or that this information is in any way confidential and proprietary.
  • Upgrading must result in downtime avoidance and/or maintenance cost reductions. Insist on being apprised of both feasibility and cost justification of suitable equipment upgrade measures.
  • Adopt a new philosophy that makes mistakes and negativism unacceptable. Ask some serious questions when a critical process machinery repair is done incorrectly three times in a row.
  • Ask the responsible worker to certify that his or her work meets the quality and accuracy requirements stipulated in your work procedures and checklists.
  • Again, end the practice of awarding business to outside shops and service providers on price alone. Ask your reliability staff to use, acquire or develop, technical specifications for critical or high-reliability components. These specifications must be used by your Purchasing Department. Accept less costly (or “cheaper”) substitutes only if it can be proven that their life-cycle costs are lower than those of the high-reliability and lower failure risk components specified by a competent reliability professional.
  • Constantly and forever improve the system of maintenance quality—and improve the responsiveness of your outsourced services providers. You must groom in-house reliability specialists competent to gage the adequacy of all maintenance quality and of the various outsourcing services.

Insist on daily interaction of process/operating, mechanical/ maintenance, and reliability/technical workforces (the “PMT” concept). Institutionalize root cause failure analysis and make joint RCFA (root cause failure analysis) sessions mandatory for these three job functions. Do not accept this interaction to exist via e-mail alone!

  • Institute a vigorous program of training and education. As an example, for decades, the industrial mechanic/machinist has been allowed to find and replace a defective pump component. Unfortunately, he or she has thus become a skilled parts-changer and many machinists, mechanics and technicians have become entirely repair-focused. Train your engineers, technicians, maintenance workforce—and operators—to become reliability- focused! Let a competent repair shop assist you in achieving these training goals and do accept the premise that repair-focused plants will go out of existence.
  • Require your reliability professionals to develop their own training plans. Insist on stewardship and on reaching the training goals. Subsidize this training!
  • Institute leadership. Give guidance and direction. Impart resourcefulness to your reliability professionals. Become that leader or appoint that leader. The leader must be in a position to delineate the approach to be followed by the reliability professional in, say, achieving extended pump run lengths or general equipment uptime extension—the subject of thousands of articles and hundreds of books!
  • Drive out fear. Initiate guidance and action steps that show personal ethics and evenhandedness that will be valued and respected by your workforce.
  • Break down barriers between staff areas. Never tolerate the ill-advised competition among staff groups that causes them to withhold pertinent information from each other.
  • Eliminate numerical quotas. No reasonable person will be able to solve 20 elusive equipment problems in a 40-hour week. If a problem is worth solving, it’s worth spending time to solve the problem. Until you have groomed a competent and well-trained failure analysis team, consider engaging an outside expert on an incentive-pay basis.
  • Regardless of who’s involved— your shop or an outside shop— remove barriers to pride of workmanship. Don’t convey the message that jobs must be done quickly. Instead, instill the drive to do it right the first time and every time. To that end, work with companies and individuals that will utilize the physical tools, written procedures, work process definitions and checklists found at Best-of-Class companies. To the extent that these tools and procedures would benefit your company, take steps to make them available to your staff.
  • Institute both fairness and accountability at all levels. As a manager, take the lead. Eliminate roadblocks and impediments to progress. Realize that what you are trying to do—increasing plant-wide equipment MTBF— has long since been accomplished elsewhere. You, too, can achieve this goal.

In summary, then, accept the fact that the quality and dependability of any business entity or shop is only as good as the knowledge base its personnel will allow. The various aspects of people based quality and dependability pertain to contractors and inhouse staff—that means everybody, including engineering, maintenance and operations. They pertain to your shop, just as they do to the OEM and non-OEM shop. This knowledge base changes over time; therefore it needs to be periodically re-assessed.

In a recent series of articles, we used the term “Competent Pump Repair Shop” (CPRS) to indicate that your diligent efforts to find and work only with the competent ones will be rewarded. Once you have taken steps to work with diligent and capable outsiders, all of your reliability initiatives—including those related to Operator-Driven Reliability— will bear more fruit. MT


Contributing editor Heinz Bloch is the author of 17 comprehensive textbooks and over 340 other publications on machinery reliability and lubrication. He can be contacted at: hpbloch@mchsi.com.

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April 1, 2008
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Addressing The Impact Of "Process Creep"

0408_process_11

It’s insidious. Over time, equipment can move out of its original design conditions, greatly eroding performance and reliability.

To geologists, the term “creep” defines the slow displacement of earth materials along a down slope. Because the activity is so gradual, it typically can be detected only over a period of several years. For energy industry operators of highly engineered-toorder equipment, “process creep” defines the gradual transition of machinery out of its original design conditions. Over time, this trend erodes performance and reliability that can affect maintenance, productivity and safe operation.

In an industry where many critical rotating machines have been in service for 20 to 30 years or longer, considerable equipment is performing outside of its design parameters for various reasons. Processes may have changed as a result of catalyst improvements, changes in feedstock, government mandates or simply as responses to increased market demand. Whatever the reason, these changes directly affect the performance and reliability of the equipment.

The warning signs of “process creep” are gradual. The product, service, operating philosophy and maintenance history all have an impact on the severity of problems encountered. However, there are similarities among equipment problems that experienced engineers can identify quickly.

  • In steam turbine equipment, corrosion and fouling will lead to decreased power.
  • Turbocompressors may demand increased power while demonstrating decreased mass flow, loss of ratio pressure, increased vibration or speed fluctuations.
  • Reciprocating compressors may experience excessive wear of rings, packings, riders or valves.
  • Most noticeably, there simply may be shorter cycle times between shutdowns to replace parts.

While operators may be aware of the root causes, they may not be aware of the impact on the unit’s operation or the long-term impact on unit reliability. Most equipment operators are aware when a unit is not operating within the unit design, however, few are aware when they are operating beyond specification. When referring to this condition, OEMs are suggesting that a unit may be beyond design load and safe operating limits. Typically, there are warning and shutdown instruments to prevent this from occurring. Operating off original design point is not unique and it costs the client money in terms of lost efficiency and increased operating costs.

Proactive revamp solutions
During the past 10 years, there have been significant technological developments for turbo, steam and reciprocating products. Advanced computer design techniques, improved manufacturing processes and superior materials all have played roles in providing greater efficiencies and performance improvements for rotating equipment.

One solution to addressing the negative effects of process creep is a proactive revamp program designed to identify equipment issues before they become a problem. By revamping older units, a client can meet new or changing process requirements within the parameters of the existing equipment, providing a cost-effective and time-saving alternative to purchasing new equipment. Steps can be implemented to improve the safety, efficiency and reliability of the equipment, achieve lower cost of ownership and extend equipment life.

A proactive revamp program is intended to make the client aware of the benefits of upgrading the equipment in terms of increased production and improved reliability. Developing a value proposition can demonstrate a signifi- cant improvement in unit performance. This translates into increased production—which directly impacts an operation’s bottom line. Often, revamps pay for the initial investment in less than a year as a result of increased production. This is especially true in critical processes where installed equipment has been in service for many years.

While equipment operators may have considered revamping, or even replacing older units with new equipment, the step change in performance offered by improved technology is a fairly recent development—just in the past 10 years. Previously, the primary incentive to revamp a machine was to address significant changes in process conditions. More recently, technological developments in our product designs offer the opportunity to substantially improve efficiency in older installations. In the past, economics did not favor major changes to the equipment for process creep alone. It was easier and often cheaper to run off-design in inefficient ways.

In many cases, the installation benefits alone of a thoroughly evaluated proactive revamp can be large, bordering on the benefits of new hardware itself. This is largely because the unit is already in position and the necessary piping and support structure is installed. Installation of a new unit would more than likely result in major re-work of the piping and possibly the foundation and locations of surrounding auxiliary equipment. These benefits can be manifested in actual work scope costs, as well as a reduction in unit downtime.

Revamps based on knowledge
In Dresser-Rand’s case, we prepare proactive revamp programs for rotating equipment across the spectrum of upstream, midstream and downstream applications—for our own and other manufacturers’ equipment. The same benefits we propose for our legacy brand products are equally applied to all brands of similar products.

The first step in any planned revamp program is to gather information. We meet with the client on site, ask questions to get a better understanding of what the client needs and define any problems that may already exist. We then obtain data that specify performance requirements, and review the data and model performance.

0408_process_21To determine if equipment is being pushed beyond its normal operating conditions, we conduct a comparison with the appropriate operating conditions (current or planned) as plotted on the existing hardware’s performance curve. In addition to a review of historical documents, mechanical and rotordynamic reviews are performed to investigate issues that would indicate operation outside the design map.

In the case of turbo units, we employ our SmartPerf model analysis. This performance selection program for centrifugal compressors is a useful tool (because it eliminates the time and labor of a full-scale design review) to determine whether a revamp is appropriate in a particular situation. The revamp specialist can quickly investigate different options and determine which one best suits the client’s needs. With the information on the laptop, the revamp specialist can give the client a visual perception of the proposed revamp in a colorful, cross-section diagram of a compressor, complete with curves and data.

We then select operating conditions (or use client-provided data) that may maximize the flow through the compressor. Or, we may use the available driver power and develop an alternate aero solution (for a complete flow path or a mix-andmatch solution) to allow the unit to perform at those conditions. Budgetary pricing and a scope of recommendations are developed for the appropriate scenarios, and the information is provided to the client in a written proposal, teleconference, or face-to-face presentation.

The proactive revamp review process, which typically takes between one and three weeks, takes into consideration the entire process and all supporting equipment and systems such as gears, electric motors and control systems. The entire system is taken into consideration when evaluating a critical piece of equipment.

Proven success
This proactive approach to revamp solutions has already demonstrated success. On a recent syn gas train revamp, we developed the model and made some operating condition assumptions to optimize the unit’s performance. We then made an educational presentation based on our technology and findings. The client provided us with actual operating conditions with which to further refine our solution. As a result, the client ultimately revamped five casings at three facilities, thereby reducing power consumption, improving rotordynamics and increasing the uptime of the critical units.

In another client application, the SmartPerf revamp tool was used to determine the feasibility of increasing capacity at an ethylene production facility in Latin America. After intensely analyzing the design, reviewing hardware options and formulating revamp solutions, the Dresser-Rand team reviewed and selected the best revamping options for the facility’s charge gas, ethylene and propylene compressors. We then proposed the best options for maximizing production capacity by gaining a thorough understanding of the process and how the equipment could be revamped to best meet the client’s requirements.

While new equipment is always an option, in some cases the negative effects of process creep can be eliminated by a thorough, strategic revamp program. Depending on the scope, a revamp may average anywhere from 50 to 75% of the cost of new equipment, based on hardware alone. In addition, a revamp usually can be delivered more quickly than a new unit—and installation costs are reduced compared to new equipment.

The short-term benefits of a successful revamp are usually realized through the correction of minor, recurring reliability issues that may or may not have been directly related to off-design operation. The long-term benefits, however, typically translate into increased production, improved equipment availability, and increased profitability of the operation. MT


Doug Craig is director of Worldwide Revamps for Dresser- Rand, one of the largest suppliers of rotating equipment solutions to companies that operate in the worldwide oil, gas, petrochemical and process industries. Dresser-Rand operates manufacturing facilities in the United States, France, Germany, Norway and India and maintains a network of 27 service and support centers around the globe.

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