Extensive logs of equipment operation information help technicians learn the normal operating characteristics and spot long-term trends. These monitoring functions are now typically handled by computers that are linked to automatic control centers within the facility or at other locations. As equipment operation conditions change, the computer analyzes the information and warns technicians of possible problems. However, it is still the responsibility of the technicians to be knowledgeable in the correct operation of all equipment.
Computerized monitoring systems can and do fail. Technicians must always be able apply their knowledge of the system or equipment in the field and make judgements as to what actions are needed. Maintenance personnel monitor the startup of equipment to ensure that the equipment is correctly calibrated.
Periodically, the technician makes adjustments and corrections to the equipment while it is operating.
A common task is adjusting the timing of a machine operations. For example, a packaging machine must be in the correct position at the correct time for wrapping product. Timing failures can damage the product and cause severe damage to equipment. Maintenance technicians are an important part of the changeover of equipment to different product lines because most problems occur at this time.
For example, if the same wrapping equipment is used for different products, maintenance personnel make adjustments to the equipment operation to suit the different product. Resources and programs are available to help guide the process.
In general, the process involves a few basic steps. Maintenance technicians monitor the startup of new or repaired equipment to ensure that it is operating properly. Automated control systems can activate alarms, such as sounds, indicator lights, or error codes, if problems arise.
Experienced operators and maintenance technicians use alarms as a guide when solving operational problems, but they also know to look for unusual causes as well. Equipment operators often work with maintenance technicians who operate or make repairs to the equipment while the operator monitors system operation from a control room or at the equipment location.
PM Systems Modern maintenance operations require more than just basic PM activities designed to prevent major problems. A preventive maintenance PM system is a system used to record and organize maintenance information, which is then used to make the decisions required to maintain the facility and equipment.
This information includes items such as equipment data, maintenance costs, consumables, time on task, and breakdown resolutions. With a consistent flow of accurate operation information, PM systems can help increase efficiency, reduce costs, and minimize health and safety problems.
PM systems can also be used to document compliance with environmental and health and safety regulations. The PM system may include the entire facility or only the departments that are expected to see the greatest benefit from improved maintenance practices. Establishing a PM system requires a significant amount of work and organization. Establishing a new PM system involves integrating information from many different sources. The PM system is then continually improved with new information from maintenance operations.
Plant Surveys. A plant survey is the first step in implementing a PM system. A plant survey is a complete inventory and condition assessment of the equipment and structure of a facility. Data from the plant survey is entered into the PM system to create a master file for each piece of equipment. This file lists the manufacturer, vendor, serial and model numbers, other identifying codes, parts suppliers, equipment location, and complete service history.
The plant survey is completed by in-house personnel or outside contractors. As part of the plant survey, the equipment is carefully inspected and analyzed. Its condition is noted along with any repairs needed to return the equipment to peak performance.
These repairs become the first corrective work orders in the new PM system. Equipment Documentation. All equipment documentation is gathered while assembling the master equipment files for a plant survey. This includes construction prints, wiring diagrams and schematics, replacement parts data, and installation, operating, maintenance, and troubleshooting manuals.
Obtaining copies of applicable codes and standards may also be necessary. System documentation may be a mixture of hardcopy documents or electronic files.
Maintenance personnel must be able to locate information quickly in either format. Hardcopy documents require two copies. A reference copy, often the original document, is stored in a secure and permanent location. The working copy is used for daily tasks.
The reference copy is used to make a new working copy if the working copy is lost or damaged. Any changes must be noted on both sets of documents. Electronic files are commonly used for storing maintenance information because they are easy to store, organize, and access. Electronic files of large, complicated drawings are sometimes easier to use than traditional hardcopy documents because specific sections can be enlarged on screen to display details.
The files are stored on shared computers or networked storage so that they are available to all maintenance personnel. Although electronic files are considered to be the reference copy, some organizations print paper copies to record changes and to use as backups in the event of computer problems.
The plant survey may use paper forms to collect information that is later entered into a computer. This forms the beginning of a master equipment file.
Information can also be entered directly into a laptop computer or mobile device and, if needed, transferred to a main computer later. Furnace 1 FUR Comment: Manufact. Document all hours worked and parts used.
Report Totals: Assets: 1. Information from the plant survey and other documentation is used to create a master equipment file on each piece of equipment. Do not restart them until the windings have been tested and the motor starter circuits have been examined to determine the reason for tripping. The results will indicate any need for a special service or maintenance activity. Replace it if it fails to function properly. Recommended maintenance procedures can be found in equipment documentation from the manufacturer.
System Implementation. Once all documentation is gathered, the list of PM tasks and their frequency is determined. The first place to look for specific PM task recommendations is in the operation and maintenance manuals for each piece of equipment.
For example, motor manufacturer PM requirements may include a three-month lubrication interval using a specific lubricant. Additional PM information can be found in service bulletins, online discussion boards, national codes and standards, and trade magazines.
It is important to review contractual requirements for PM. A manufacturer that provides a warranty with new equipment may specify the maintenance requirements that must be completed to maintain the warranty. Also, some insurance companies specify the minimum maintenance that must be completed on equipment that they insure.
Once the recommended PM tasks for a piece of equipment are known, they can be modified to meet plant conditions. For example, if the motor is running in an extremely hot location or is stopped and started frequently, the manufacturer may recommend a different lubricant or more frequent lubrication. The appropriate amount of PM is assigned to each piece of equipment, then the work is scheduled and assigned.
Routine lubrication and inspections might be assigned to equipment operators, while work requiring more skill is assigned to qualified maintenance personnel. Efficient scheduling generates an even workload throughout the year and ensures that equipment is ready when needed.
As maintenance tasks are performed for each piece of equipment, related information is added to the record for that unit. At extended intervals they require lubrication. The periods between greasings of the motor bearings can vary, primarily with the severity of the service conditions under which the motor operates. Lubrication Procedure. Ensure dirt and contaminants are not introduced when adding grease.
Run motor for about ten minutes before replacing outlet plug. Certain TEFC motors have a spring relief outlet fitting on the fan end. If the outlet plug is not accessible at surface of hood, it is the spring relief type and need not be removed when greasing.
A major cause of motor bearing failure is overgreasing. The quantity of grease added should be carefully controlled. Small motors must be greased with a lesser amount of grease than large motors. When greasing, stop motor and remove inlet and outlet plugs. Inlet grease gun fittings and springloaded outlets are arranged at each end on the motor housing. Use a hand lever grease gun.
Determine the quantity of grease delivered with each stroke of the lever. Add grease in the following quantity: Motor Frame Size. Texaco Unirex N2. Exxon Dolium R. Shell Rykon Premium. American Oil. What does PM aim to minimize? What are three examples of periodic maintenance tasks? When is the need for corrective work typically discovered?
What is project work? Which parts of equipment operation are maintenance technicians often involved in?
Why is a PM system valuable? What kind of information is collected in a plant survey? Where can recommendations for PM tasks and their frequency be found? Predictive maintenance PdM is the monitoring of equipment operation characteristics to determine the degree of wear in a system, compare them to normal tolerances, and predict potential malfunctions or failures. PdM is a system of looking for symptoms of a problem that has not caused a failure yet but probably will in the future.
Certain equipment operating characteristics are periodically measured and analyzed for clues that the equipment is approaching a breakdown. The simplest type of PdM uses manufacturer statistics on the average life span of the equipment. Life span is commonly provided in operating hours under certain operating conditions. Equipment operating time can be documented and components replaced before they reach their expected life span. This usually prevents the complication of replacing the equipment after a failure and when the work must be rushed.
Instead, the replacement can be scheduled for the best time within a window of time shortly before the expected end of life. More sophisticated PdM programs compare other operating characteristics to acceptable ranges. If the measurement exceeds the acceptable tolerance, even if the equipment continues to operate adequately, then corrective work is scheduled to address the problem. The equipment is then closely monitored after the maintenance.
If the problem reoccurs, the equipment application and design are analyzed and changes are made as required. Alternatively, the measurements may still be within tolerance, but they may be gradually trending toward the limit. This may trigger either the scheduling of corrective maintenance or further monitoring. For example, temperature is a commonly measured equipment characteristic, particularly for motors. Higher temperatures indicate either excessive resistance in the electrical wiring or excessive friction in the moving parts, such as bearings.
Motor temperatures higher than ambient are acceptable to some degree, as specified in manufacturer documentation. However, when temperatures approach or exceed the allowable tolerance, further testing is done to determine the cause of the problem and the next course of action. PdM uses tests and procedures to anticipate an equipment failure so that it can be prevented. Since it is a significant investment, PdM is most commonly used on expensive or critical equipment.
PdM relies on long-term trends in equipment operating characteristics to anticipate and prevent failures. In addition to temperature analysis, other common types of PdM programs include vibration analysis, ultrasonic analysis, oil analysis, and electrical analysis. Also, sometimes simple visual and auditory inspection by an experienced technician can be used as a PdM tool.
Unusual appearance or sounds of operating equipment may be obvious to trained maintenance personnel and are signs of a problem that is hard to detect by other means.
For example, dust collecting in certain spots may indicate air leaking from a duct or moving parts being gradually worn away. PdM Program Implementation Implementing a PdM program typically requires a substantial investment in training, equipment, time, and organization. Training involves learning to take measurements or conduct inspections that may be outside of the typical maintenance task skills.
Sometimes special equipment is needed, which adds to the expense and increases the training requirement. Fortunately, monitoring equipment, such as thermal imagers and vibration testers, are becoming increasingly user-friendly. It is also necessary to learn how to interpret or analyze the information and determine the most efficient response.
Perhaps the largest PdM investment is the time needed for maintenance technicians to periodically check the equipment. This is time not spent performing other maintenance work elsewhere.
Equipment must be monitored repeatedly, though it may be done on a random, scheduled, or continuous basis. Random monitoring is unscheduled equipment monitoring as required. This may be done whenever all time-sensitive work is completed and technicians are available for PdM work. It may also be done while a technician is already working on a machine, and it is convenient to add a task.
Scheduled monitoring is equipment monitoring at specific time intervals. These PdM tasks may be entered into a PM work order system like other scheduled work. Continuous monitoring is equipment monitoring at all times. This requires sensing devices that are permanently attached to the equipment being monitored. These devices may need to be periodically checked to download or record data, or the devices may automatically transmit data to a central PdM database for analysis.
PdM programs may generate large amounts of data quickly, which must be carefully recorded and organized so that it can be analyzed for problems or long-term trends. Computer software is well-suited to record, organize, and analyze PdM data. Even simple visual and auditory inspection by an experienced technician can identify subtle equipment changes that may lead to a problem. Since a PdM program typically requires substantial investment, it is most commonly used for expensive or critical equipment.
A PM program typically covers a large number of machines and equipment, but a PdM program may apply to only a small subset of the equipment. This typically includes equipment that cannot tolerate performance issues or failures and must be maintained to maximize its service life. Another disadvantage of PdM is that it is not a perfect prediction tool. PdM analysis may indicate that failure is approaching, but it is likely impossible to know the exact timing of the potential breakdown.
PdM is a tool used to inform decision making, but a person must balance the risks and costs involved and decide whether to take action.
For example, production demands might require risking a breakdown to continue critical operations. Once that critical period is over, and hopefully no failure has occurred, then the equipment can be removed from service and repaired.
Alternatively, a PdM program can be overly conservative, and useful service life of the equipment is wasted when it is repaired or replaced too early. The risk of wasting resources to ensure critical equipment is kept operating is part of the indirect costs of a PdM program.
What type of information does the simplest type of PdM use? What are three characteristics that may be measured as part of a PdM program? What types of equipment monitoring are used to collect data? Why is PdM typically limited to only certain equipment? What is the risk of having an overly conservative PdM program?
This includes systems for documenting work intended and completed, organizing equipment data, managing parts inventory, and analyzing costs.
Technicians should utilize the tools that are available to them in order to not only help themselves but to help other technicians who may work on the same equipment.
For unscheduled maintenance, urgency may dictate some tasks, such as documenting the troubleshooting process, be postponed.
However, these tasks should be completed as soon as possible to maintain complete maintenance records. Work Orders Work orders are used to organize, plan, and monitor scheduled maintenance tasks. A work order is a document that details specific maintenance tasks to be completed. Work orders commonly include time, date, name and location of the equipment, work description, approximate time to complete the work, and safety requirements.
Some work orders also list the steps for completing the task. Work order forms may be handwritten, but many facilities use computer systems that can also automatically generate work orders based on maintenance intervals and other information stored in the system database.
Work orders are often printed out so that they can be easily brought to the work site for reference. All work orders have a scheduled completion date. Work that cannot be completed by this date is listed in a delinquent work order report until the work is completed. Work Priority Work priority is the order in which work should be done based on importance.
The most important work is done first, followed by less important work. Work priority is indicated on a work order. Though work priority methods vary from plant to plant, a three-level priority method is commonly used. The highest priority is for work relating to safety, downtime, and production efficiency. Emergency or other high-priority work requests are handled as they occur during a shift.
The medium priority is for scheduled periodic maintenance. The lowest priority is for long-term projects. For example, some plants list PM tasks as the highest priority with only designated workers responding to emergency calls. Additionally, many maintenance technicians are on call during their lunch and breaks. This allows quick response to high-priority maintenance calls.
A work order documents all the information needed to identify a particular maintenance task. A delinquent work order report lists scheduled work orders that have not been completed. Logbooks A logbook is a notebook or electronic file that documents maintenance tasks and additional information, if needed. There may be different types of logbooks. Some are assigned according to units of equipment, like those that document operational maintenance monitoring. For example, a particular logbook contains all of the monitoring and maintenance documentation on Oven 3.
Logbooks are also used by individual technicians to document the various tasks they complete during a shift. This typically includes several tasks spanning different systems or equipment. Handwritten notes may be used during a shift, but this information is often entered into computer databases later.
Some facilities, however, may utilize mobile devices connected to a networked maintenance database for technicians to enter information and look up equipment histories directly. As a technician performs work on a particular piece of equipment, entries may be generated for both.
A single entry can be assigned to both a technician and a piece of equipment and easily appear in both electronic logbooks. This is one reason that computerized systems are particularly useful. Some maintenance organizations keep additional, specialized logs. For example, a maintenance department complaint log records all complaints regarding conditions in the facility and how each condition was addressed.
Logbooks can be extremely useful in troubleshooting. Well-organized and up-to-date maintenance records can provide hints indicating difficult problems. For example, a large air-conditioning chiller requires frequent monitoring and logbook entries.
If, during the course of taking readings, a technician notes a sudden rise in bearing temperature, the lubrication system is inspected immediately. If oil flow to the bearings is disrupted, the bearings may fail quickly due to overheating. Such a failure is extremely dangerous and expensive to repair. Logbooks are used by maintenance technicians to record tasks completed during a shift.
Received parts orders and checked them into inventory. Cleaned and organized parts inventory room. Troubleshot control board and heating element. Replaced faulty heating element. Checked temperatures of Oven 2 to ensure problem has been resolved. Return Oven 2 to regularly scheduled inspections. Lubricated chain drive on Conveyor 1. Inspected belt and rollers of Conveyor 1.
Checked temperatures and operation of Oven 1. Investigated report of unusual noise from motor of Mixer 2. Arranged with Joe Fisher to put Mixer 2 off-line at end of shift for further troubleshooting.
Maintenance personnel typically begin each shift by reviewing the logbook entries from previous shifts. Based on information in the log and the quantity and type of work orders issued, the maintenance personnel make a list of all work to be completed.
The work is then prioritized. In large facilities, a supervisor schedules daily activities. In smaller shops, maintenance technicians do their own scheduling. Computerized Maintenance Management Systems Maintenance tasks can be organized with hardcopy systems, but many facilities use computerized maintenance management systems. A computerized maintenance management system CMMS is a software package or web-based system that organizes PM information and automatically generates reports, work orders, and other data for implementing and improving future maintenance activities.
CMMS software was the norm until relatively recently, when web-based systems became common. Web-based systems have many advantages. They can be accessed by any Internet-capable device, even when off-site, and do not require local data backup. However, they require reliable Internet access at all times, which may not be feasible in some facilities.
Many different CMMSs are available, but they generally provide similar features, including providing quick access to maintenance information, issuing and tracking work orders, determining the costs of maintenance activities, scheduling maintenance work, managing maintenance inventories, and assisting in troubleshooting. CMMSs are used to collect a variety of information from many sources, organize and store this information, and provide data analysis as needed.
A CMMS provides many integrated features that organize, schedule, and record maintenance activities for improved maintenance efficiency. A CMMS organizes and stores information from a variety of sources and provides reports and analysis of maintenance activities.
CMMSs also help technicians analyze the frequency and type of PM work and make adjustments in order to keep equipment in peak operating condition with minimal cost. Excessive PM work increases maintenance costs, but inadequate PM work also results in high costs due to an increase in breakdowns. Determining the optimal frequency is an ideal task for a computerized system. Data compiled from the PM system is also used for assessing plant performance, equipment service life, energy costs, equipment purchasing needs, insurance costs, and personnel and plant budget decisions.
Some equipment or test instruments are capable of transmitting data directly to mobile devices. As more CMMSs become web-based, their information can be accessed, modified, or added directly from mobile devices. Such easy access helps keep the CMMS database of maintenance data upto-date and supplied with richer information, such as photos, detailed notes, and measurements.
Mobile Device Integration Increasingly, information is accessed through mobile devices such as smart phones or tablets. Technicians must be proficient in the use of such devices in the modern workplace. Mobile devices provide communication for maintenance technicians, but with many additional features. They are powerful tools for service and troubleshooting tasks.
Except for in high-security locations and other possible restricted situations, mobile devices have become necessary tools for maintenance technicians to have available at all times. The most common mobile device used for service and troubleshooting in the field is a smart phone. A tablet has many of the same functions as a smart phone, but it can display larger images.
This is especially useful when accessing or downloading blueprints and technical documents. Phone Communication. A smart phone offers many safety and convenience features for a maintenance technician.
For example, a personal phone can be used to contact emergency personnel during a plant fire. The phone is also used to communicate non-emergency information with other facility personnel or with outside suppliers, contractors, or technical help resources.
Technicians often form informal networks of trusted individuals to provide mutual help and support. With compatible devices on both ends, video calls are also possible. Data Networking. The data networking capabilities of mobile devices can be used for many other types of communication, such as email, text messaging, web browsing, and in-app communications.
Site-specific documentation can be downloaded, saved to a mobile device, and accessed as needed. Equipment manuals, prints, reference tables, charts, and troubleshooting procedures are examples of documentation that could be useful to have on a mobile device. Certain test instruments can communicate directly with mobile devices, making information gathering, analysis, and documenting faster and safer.
Audio Recorders. The audio recorder function of mobile devices can capture voice recordings or equipment noises in a facility. For example, audio notes can be recorded on location for reference later. With the use of a dictation function, information can be transcribed quickly for incorporation into a work order or saving as a text file for follow-up with the customer.
Recording specific equipment noise can also be useful when diagnosing a problem. For example, when starting an AC compressor, a recording of the clicking or humming noise emitted can be used when explaining a problem to another technician or the customer. The camera on a mobile device can be used in many ways. It can be used to document conditions when first arriving at a piece of equipment or location in the plant.
For example, photos of burnt insulation on wires, water on a floor, or corrosion on a valve can. These recorded images are also invaluable for showing how the problem looked before and after the remedy. A photo of equipment is also extremely useful for reducing downtime when replacing components. The photo of an installation before service begins can be a helpful reference when replacement and reinstallation procedures begin. For example, a picture of a terminal block and wiring connections taken before disassembly indicates where the connections must be when reinstalled.
The camera is also useful for inspecting items in obstructed or tight spaces that cannot be viewed directly. Warning: Always use caution when positioning a mobile device around hazardous moving parts and equipment or exposed energized circuits. Video is useful for visually documenting a problem, particularly ones that are hard to witness in person.
For example, if a malfunction is intermittent or can only be initiated from a distant switch, the mobile device can be set up to record video of the problem for later viewing. Third-Party Apps. In addition to the default software, mobile device capabilities can be extended with thirdparty apps. A large and ever-growing selection of apps that could be useful to a maintenance technician, such as a spirit level simulator, a decibel meter, or a personal protective equipment PPE selection assistant, are available.
Photos also help technicians order replacement parts quickly and efficiently. For example, sending a photo of a motor nameplate to a parts supplier reduces the possibility of error in the description of the replacement motor or parts needed. In addition, showing the installation configuration of a particular component is helpful when specifying parts.
A mobile device display can save troubleshooting and repair time as well. For example, enlarging the view of a photo can offer a magnified view of a component. This is especially useful for reading. Third-party apps extend the capability of mobile devices by providing industry-specific features. Some equipment manufacturers provide apps with helpful reference information.
Specialized apps may be available that provide maintenance and troubleshooting help for specific types of equipment.
The technician inputs the variables and the app completes the calculations. Some equipment may. Common mobile device accessories include a durable case for physical protection and additional batteries to extend the length of time between charging.
Special add-on accessories may be available to add new functionality. For example, a thermal imager attachment can be used with a smart phone to allow thermal-imaging capabilities. Another example is a remote body camera that documents tasks and is operated by and communicates through the mobile device. Mobile device accessories may provide a new hardware-based feature while using the mobile device for power and interface capabilities.
Inventory Management Commonly used consumables and replacement parts must be readily available to maintenance personnel. As parts are used, replacements must be ordered to maintain the inventory.
If an essential replacement part is not available, the machine remains inoperative until the part is available. In a perfect inventory control system, there would always be just enough parts to repair the equipment with no unused supplies.
Excessive inventory should be avoided because it costs money to purchase, store, and track each part. Also, stocking too many unused parts makes finding necessary parts difficult.
Like PM tasks, inventory management involves finding just the right balance between too much and too little. Small organizations can organize and reorder their parts manually, but inventory management becomes increasingly complex for larger facilities. Inventory management includes the organization and management of commonly used parts, vendor and supplier information, warranty information, and purchasing records.
Inventory management is a common part of a CMMS. For example, as parts are noted as replaced in a troubleshooting report, the replacements are automatically removed from the inventory count. Part Numbers. All spare parts should be numbered so their location and quantity can be tracked. Part numbers also associate the part with data such as supplier, equipment use, purchase date, and cost. A part number can be any number that clearly identifies the individual part, such as a manufacturer number, a supplier number, or a unique number specific to the plant.
A complete description should be included with the number in the inventory system. Using unique identifying numbers helps prevent confusion when selecting parts. Two 3 A fuses may look alike and be the same size, yet they may have different operating characteristics.
For example, a non-time-delay fuse is a fast-acting fuse that provides overcurrent protection. A time-delay fuse is used with equipment like motors that are subject to temporary startup or surge currents. A time-delay fuse may damage equipment requiring a non-time-delay fuse. Likewise, a non-time-delay fuse used in place of a time-delay fuse would cause needless disruption when it blows while a motor starts normally.
To expedite data entry and tracking, a part number label is often printed in a computer code that can be read automatically. Barcodes have been used for this purpose for decades because they are inexpensive and reliable. Scanning barcodes as parts are entered and removed from inventory allows the computer to keep up-to-date records of available parts. Inventory Control. When a part is removed from inventory, it should be noted in the inventory record on either a computerized or hardcopy filing system.
When the inventory of a certain part reaches a predetermined minimum number, more are ordered. Some computerized systems automatically generate orders that can be faxed or emailed to the supplier.
The inventory of each part is typically kept within a minimum and maximum number. Computerized inventory systems can analyze how frequently parts are used so that their minimum and maximum inventories can be adjusted. Barcodes are often used for inventory control, which requires the organization and management of parts commonly used for maintenance tasks. Some parts are located together in a central storage area and others are kept close to their associated equipment. Each type of part should be stored in separate and clearly labeled boxes.
It is the responsibility of maintenance personnel to ensure that the inventory is organized and accurately recorded. When searching for parts, the maintenance personnel should have the old part nearby or have a written copy of the part number to help ensure that the correct part is selected. A well-organized parts storage area is important for an efficient maintenance organization.
Ordering Parts. The cost of ordering parts includes both the cost of the parts and the time required for placing the order and sorting the parts when they arrive. Parts are most often ordered over the phone or online. Comparing prices helps locate the best price, and careful ordering saves time and money, which can be critical when a part is needed to repair malfunctioning equipment. When ordering, it is important to note the complete part number.
Manufacturer, distributor, and facility part numbers may differ, so it is important to use the correct one. If possible, it may be helpful to have a sample of the part to refer to. Online catalogs may provide detailed specifications and list supplier inventory and shipping, delivery, or pick-up information.
The order is logged in a parts order book. When the parts arrive, the order should be checked to ensure that they are as ordered and that the price and quantity are correct. Then, the order is logged as received. If a partial order is received, the items still expected and when they should arrive are noted. A picture of the part needed can be used for reference, if required. Knowledgeable parts suppliers can be of great assistance when encountering problems with locating parts for discontinued or specialized equipment.
Balancing Costs Maintenance personnel must often balance the costs and benefits of maintenance and repairs to equipment. As maintenance and repair information is collected for each piece of equipment, the costs can be analyzed and compared. It usually takes about a year of data to be able to see maintenance trends.
Decisions are made based on this information, which is why it is important to keep accurate and thorough records. As time passes and more information is added to the equipment files, costs are continually reviewed and decisions may change.
The two common ways in which costs are analyzed to determine the best value for a facility are maintenance versus failure costs and repair versus replacement costs. Maintenance versus Failure Costs.
If frequent PM for a certain piece of equipment costs more than the costs of its failure, then it makes sense to reduce PM tasks. Performing excessive PM work drives up the cost of maintenance operations. However, performing too little PM work can result in high failure costs due to downtime, poor productivity, and equipment replacement.
A comparison of maintenance costs to failure costs may identify ways to optimize the level of PM. Determining the optimal amount of PM for each piece of equipment requires a lot of data over a long time. When maintenance personnel have enough data available to review maintenance routines and their actual costs, they may adjust the level of PM.
For example, a particular maintenance task interval might be lengthened from quarterly to semiannually. Alternatively, frequent equipment breakdowns drive up failure costs, signaling that the equipment requires more PM. For example, if a recurring problem is found to be caused by lubrication issues, the related components are inspected more frequently. The relatively small increase in maintenance costs is more than offset by significantly reduced production disruptions.
Maintenance costs are relatively simple to calculate, though they can include a wide variety of costs. Costs include the maintenance personnel labor and the purchasing of parts and expected consumables, such as fluids, filters, and worn-out components.
Consideration should also be given to personnel, facilities, and equipment that support these activities. For example, a large inventory control system improves maintenance efficiency, but it costs money to operate. Similarly, tools and repair equipment are needed by the maintenance personnel to help them do their jobs.
These costs and other maintenance support costs are added as overhead, and a small percentage is allocated to each labor hour to estimate the contribution to equipment maintenance costs.
As for failure costs, the most direct types are the costs to repair or replace failed equipment. Depending on the type of equipment and its importance to facility operations, multiple indirect costs may also be applicable, and they can be significant. Indirect failure costs. Only some of these costs can be measured accurately, but estimates of others are still important. Accountants typically assist with these calculations. A variety of factors, both direct and indirect, should be accounted for when calculating maintenance and failure costs.
Sometimes both maintenance and failure costs are high and may be unavoidable for certain critical systems, including those related to health or safety issues. However, the maintenance department should always look for ways to reduce these costs, such as through upgrading system controls, installing more modern equipment, or rearranging components to improve access and efficiency.
Repair versus Replacement Costs. When equipment fails, the maintenance department may need to choose between repair or replacement. In some cases, the failure is so catastrophic, or the choice to replace is otherwise so obvious, that no further analysis is needed. However, often the decision requires some work to compare the two options. The cost of repair parts or replacement equipment is just one portion of the total repair cost.
Multiple other factors must be considered. Extra labor and parts acquisition costs could be significant. Depending on the circumstances, either repair or replacement may take longer. For example, physically bringing a large piece of new equipment into the facility could disrupt nearby piping, ductwork, wall openings, or electrical services.
Was it maintained as required by the manufacturer, and what does the warranty cover? The manufacturer may require certain conditions for making repairs to maintain a warranty or as part of the purchase contract.
These situations typically involve authorized technicians at either the manufacturer or certified repair agency. If the warranty applies, the repair versus replacement decision is then heavily influenced by the manufacturer. In some cases, it is simply less expensive to have work done by outside specialists. For example, in a plant with only a few refrigeration systems, the in-house personnel perform most maintenance.
But if a serious problem requires that refrigerant be removed from the system, an outside contractor is called. The cost of refrigerant recovery equipment is too large for this plant given the frequency that the equipment is needed.
Insurance companies or regulations may require that certain equipment, such as elevators, boiler safety valves, and gas and electric meters, be serviced by outside personnel with special training.
Perhaps a newer model is more energy efficient, increases production, offers more features, is smaller, requires less maintenance, or otherwise affects future costs. Even if the immediate replacement costs are greater than repair costs, replacement may still be a better long-term decision.
Out-of-Plant Services Outside help is often necessary for advice or work that requires expertise not available from the regular maintenance crew. For example, installing new equipment or making major renovations may require companies with specialized tools and expertise. Also, special projects may require extra personnel on a short-term basis. Outside companies can help perform this work while the regular maintenance crew maintains other plant operations.
In addition, outside companies typically provide warranties for their work in case problems occur during the equipment break-in period. If a maintenance project requires special equipment, the best option may be to hire an outside organization with the necessary skills and equipment to complete the work. What information is typically included on a work order? What is an example hierarchy of work priority? How can logbook information be useful for troubleshooting? What are some advantages of web-based CMMSs?
What are some ways that mobile device cameras are particularly useful for maintenance and troubleshooting? How might some equipment communicate with mobile devices directly?
What are disadvantages of maintaining a large on-site inventory of replacement parts? Why are part numbers important for managing inventory? What are common considerations when calculating all maintenance costs? How can manufacturer warranties affect repair versus replacement considerations? Why are out-of-plant services sometimes needed? Troubleshooting is the systematic investigation of the causes of system problems to determine the best solution.
The ability to troubleshoot effectively is a skill that combines technical expertise, logical and creative thought processes, and interpersonal skills. Check out the new look and enjoy easier access to your favorite features.
Try it now. No thanks. Try the new Google Books Get print book. No eBook available Industrial Mechanics. Albert W. American Technical Publishers, - Mechanics - pages. Industrial Mechanics, 4th Edition, presents a comprehensive introduction to the concepts, principles, and equipment used in industrial mechanical systems as required by industrial mechanics, technicians, and maintenance Edition: 4th Industrial Mechanics by Albert W.
The free mechanical engineering books in this category are designed to help you prepare for their exams. Topics such as materials science and mechanical systems are explained. Using a direct and straightforward style of writing that has won praise from readers, it focuses on the needs of industrial mechanics, technicians and engineers working with industrial mechanical and power transmission products, and integrates safety and troubleshooting components within each chapter to encourage diagnostic : Pearson Education.
Description Industrial Mechanics, 4th Edition, presents a comprehensive introduction to the concepts, principles, and equipment used in industrial mechanical systems as required by industrial mechanics, technicians, and maintenance personnel.
This new edition includes the latest information on workplace safety, tools and tool safety, fastening methods, printreading, precision measurement.
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Craig, and this book stands as one of the most popular university textbooks on robotics. Description Industrial Mechanics presents an introduction to the concepts of industrial mechanical systems, principles, and equipment. All aspects of the systems, principles and equipment, including rigging, lifting, ladders and scaffolds, hydraulics, pneumatics, lubrication, bearings, belts and pulleys, mechanical drives, vibration, alignment, and electricity are discussed throughout the text.
Code Library. Automobile Engineering. Aerospace Engineering. Engineering Books. Computer Engineering. Chemical Engineering. It is important to note that the number of questions can change at any time. When you are ready to write your exam you may contact your regional office to. Industrial Mechanics presents an overview of the principles of industrial mechanical systems and the equipment in these systems. This edition presents the latest information on all aspects of mechanical systems, including rigging, lifting, ladders and scaffolds, hydraulic systems, pneumatic systems, lubrication, bearings, belts and pulleys, mechanical drives, vibration, alignment, and electricity.
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Industrial mechanics November 1, 2.
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