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The Power of Standardization
The Predictive Maintenance Process at Dell by Mark Burgett 

Today, maintenance at Dell combines low tech and high tech procedures to form a complete maintenance solution. By including the human senses, multiple predictive technologies and plenty of discipline, Dell has fostered a thriving culture based on finding issues before they become problems. Compared to other US companies, Dell, which was founded in 1984, is a relatively new manufacturing company.

In addition to manufacturing computers, we also operate product distribution centers across the US. Our portfolio of equipment is similar to what would be found in many light assembly or distribution operations, including:

• Incline / Decline Belt Conveyor

• Line Shaft Conveyors

• Diverters

• Sorters

• Vertical Lifts

• Robots

• Case Erector / Sealers

• Labelers

• Vacuum-Hoist

Our current equipment maintenance philosophy includes a strong component of both Predictive Maintenance (PdM) and Condition based Maintenance (CbM).

However, it has taken several iterations of our maintenance program to reach this point.

Maintenance Program Journey

Our original factories were full of new equipment and predominately required engineering design support.

Consequently, there was only a small organized equipment maintenance program.  When the equipment started to age and break, the maintenance program was transformed into strictly break/fix maintenance process. As the impact of equipment downtime became a major factor, Dell implemented a strong Preventative Maintenance (PM) program. The PM program was structured around establishing a time based maintenance schedule combined with break/fix response to immediate issues.

As the size of Dell manufacturing and distribution operations grew, so did the size of the PM program. PM’s, although necessary, had significant costs and staffing requirements. Dell began to look for new alternatives to our maintenance program. After years of a PM based program, Dell began to adopt the tools, procedures and philosophy of CbM. While CbM gave us positive localized results, it was not feasible to implement across entire facilities. That’s when we began to customize a Dell specific implementation of PdM.

Predictive Maintenance at Dell

Our current PdM program consists of scheduled, standardized inspection routes using a variety of tools and techniques. The routes are combined with the best of Reactive Maintenance, Preventative Maintenance and Condition Monitoring, with a strong Enterprise Asset Management System as a support. We strive to promote a proactive culture that finds and prevents issues rather that waits and fixes problems. A key component of our PdM program is the daily inspection route. We try to include everyone in our program and assign technicians to short but consistent PdM routes. We use a variety of tools. Examples are Visual Inspection, Ultrasound, Vibration, and Infrared.

We stress the importance of visual inspection and find it to be an under appreciated, inexpensive and valuable tool. In addition to our PdM routes, we also use automatic lubrication and oil analysis.

All PdM routes are rolled into standardized work packages, which are short duration, dedicated assignments.

This standard work approach facilitates scheduling, deploying, training and sustaining.

PdM Routes

Our PdM routes are primarily geared toward CbM, and are used as a proactive, systematic approach to ensure key production equipment performs reliably and efficiently. This systematic approach is a proven method that helps determine the stability or deterioration of critical equipment components. When applied to the distribution process it is taken to mean this; the use of advanced detection methods and tools to determine equipment condition, and to potentially predict failures.

CbM measures equipment health and usually is not an indicator of the present state of the equipment versus the as-designed state. Condition monitoring is used to compare the current state of equipment to its initial CbM baseline measurements. There are seldom sudden catastrophic equipment failures.

Most equipment provides some indications of functional deterioration before failure, and condition monitoring routes look for those early indicators. Condition monitoring at Dell includes, but is not limited to, technologies such as:

• Visual Aids

• Ultrasonics

• Vibration Measurement and Analysis

• Temperature Analysis

• Lubrication

• Oil Analysis

A Sound Implementation Process is Required

The first step in the process is to identify all critical equipment. Not all equipment is covered by Condition monitoring – if the consequences of their breakdown will minimally affect factory flow or reliability, it may be justifiable to run to failure and repair it as quickly as possible when the failure mode is easily identified. Well defined failure modes are essential to the success of the process.

The technician must be trained to know what signals to look for when completing a daily, or other frequency, scheduled route. They also require training on how to use their PdM tool set to detect the onset of equipment failure or partial failure. The success of the program is extremely dependent on dedicated technicians, dedicated not only to running the PdM routes, but also to learning and understanding how and when to use the various predictive tools. Technicians that know, embrace and create change play a vital and indispensable role in the roll out and implementation of CbM programs. Technicians who just follow the process because they are instructed to will not notice the subtle changes in equipment performance that we need for our PdM technicians to notice.

Defined Daily / Weekly Routes

After equipment and personnel are identified, the department must have the courage and discipline to allow the technician to complete the PdM route, above all other requirements. Consistency in completing the daily route is necessary to capture any sudden or increasing change during normal operating conditions.

Providing a one hour, undisturbed, window to look for problems, will pay tremendous dividends by detecting failures that a frequency PM would otherwise miss. The daily inspection of equipment and subsequent repair orders will reduce the number of events and significantly reduce the Mean Time To Repair and cost to maintain a piece of equipment.

Visual Inspection Routes

Human senses (look, listen, feel, smell) play an important part in the condition monitoring process. Using the human senses to check for and detect potential equipment failure is a low cost and effective method used to monitor the health of the equipment.

The chances of detecting equipment problems are greatly improved by having someone constantly monitoring equipment, looking and listening for potential problems.  Visual aids provide a quick reference that anyone can look at and instantly tell if equipment is operating within its predetermined specification, or if a piece of equipment is operating out of spec.  During visual routes the technician looks at:

Gauge Masks - These are translucent plastic masks placed over the gauge leaving only the gauge operating range exposed. Masks provide the standard operating range as well as a visual indication when, for some reason, the pressure has changed.

Temperature Labels - Non-reversing temperature labels placed on heat sensitive motors and other equipment. Temperature labels are a very inexpensive way to monitor component temperature continuously.

Training everyone in the area on how to detect and report a change in the temperature label is an excellent way to involve everyone working in the area.

Torque Seal -- Breaks in torque seal on critical nuts or bolts is a good indication that components are changed or are loosening.  Torque seal is another method that can be used by everyone working in the area and does not require technical expertise.

Open Guarding -- Lexan covered opening in drive guards that provide safe visibility to the machine’s drive and other critical components. Open guarding is also a method that employs not only the technician completing the daily route, but anyone that works in or passes through the area can notice a partially broken belt or wobbly drive component.

Floor Indicators -- Signs of belt or metal shavings underneath the conveyors, rust, oils spills and parts on the floor.

Physical Condition -- Condition of the equipment such as missing parts, old repair tags, guards properly installed, electrical wiring neatly secured and good product flow.

Although it requires a trained technician or engineer to determine the root cause and repair of most problems, the use of visual indicators involves everyone in the area and is not dependent solely on the technician.

Training personnel on what visual signs to look for is an excellent first step in Total Productive Maintenance (TPM).  You’ll probably find that most operations personnel are eager to help implement this plan.

Ultrasound 

Using ultrasound techniques as a component of the daily monitoring route provides the technician with an invaluable tool for detecting equipment problems that are impossible to identify during operating hours.  Ultrasound is a great problem locating and troubleshooting tool that helps in troubleshooting most pneumatic, hydraulic and vacuum problems. Technicians can easily learn and effectively use this technology in the completion of daily routes and in troubleshooting equipment issues. Ultrasound tools are also used in identifying issues that produce sound emitted with conditions of interference, rubbing and knocking. Dramatic reduction in the overall use of facility air compressors can also be accomplished by routine use of ultrasound to lead programs aimed at reducing and/or eliminating small air leaks throughout the plant.

Infrared Thermography

New cameras are less expensive, smaller and easier to use, and, therefore, are more useful in the day to day monitoring of equipment. A trained 1st level Thermography technician can frequently scan electrical panels, motors, gearboxes and other critical heat sensitive equipment. This is another tool that, when combined with the other PdM technologies, provides an umbrella of coverage that improves overall equipment reliability and can, when properly used, significantly reduce unwanted events. Today’s cameras are a better investment because they are intuitive, require little training and provide information that is closely related to the real time functioning of the equipment. Problems detected through digital imaging can now be immediately addressed rather than waiting for reports that arrive weeks or sometimes months later – too late to prevent the failure.

Vibration

The principles of monitoring the health of plant machinery by monitoring equipment vibrations are well proven and straightforward.  All operating machines vibrate to a certain extent, but, since an increase in vibration almost always precedes deterioration in operating conditions, it is possible to gain valuable information concerning a machine’s condition by monitoring its vibration levels. Vibration analysis is used more for long term detection and equipment or parts failure analysis than in the day to day operation. The results of an ultrasound or an infrared reading that identifies a hot bearing finding on a daily route may result in the use of vibration analysis to determine the source of the sound or heat. Vibration technology falls more in the deterministic rather than the predictive category, because it’s possible through wave form analysis with today’s software packages to accurately pinpoint the source and the problem.

Lubrication

Most bearing experts will tell you a major cause of premature bearing failure is poor or nonexistent lubrication. Auto-lubrication devices are used to ensure that each lubricated bearing point is always properly lubricated.

The first step in this process is to review the equipment drawings and make sure that all lubrication points are identified. The next step is to determine the correct lubrication for each type of bearing; fill your automatic lubrication system with the correct lubricant and set the lubrication time period correctly for type and size of bearing. Electro-luber’s are used throughout the facility and monitored by the technician while completing the daily route. A lubrication level mark is placed on the side of the dispenser; the technician automatically changes it out when the level in the dispenser is below the mark. Auto-Lubers eliminate the need to issue lubrication PM’s; we set it up once and the daily route will manage the system.

Scheduling

Where some companies choose to use specially trained experts to implement their CbM or PdM, we chose to involve everyone. Standardizing the work into small, consistent and dedicated components is the key for us. 

Proper scheduling goes hand in hand with standardized work. Each technician assigned to an area is given a standard route to cover.

The breakout looks something like this:

Day 1 - Visual Inspection

Day 2 - Ultrasound

Day 3 - Vibration

Day 4 - Infrared

Day 5 - Visual

Scheduling is also critical to assure the best utilization of tools and to free personnel to complete their routes without interruption.

Summary

Predictive Maintenance at Dell includes standardized scheduled routes performed by all maintenance technicians. Routes utilize visual inspection, ultrasound, vibration, and infrared. Technicians are assigned to an area and given short duration, dedicated routes to complete. Scheduling is key to assure equipment, tool and technician availability.

PdM, along with the best of Preventative and Reactive maintenance are core components to our program. Through Predictive Maintenance, we promote a proactive culture that finds and prevents issues rather that waits and fixes problems.

Mark Burgett serves as senior manufacturing engineering manager, Texas Operations for Dell. In this role, he is responsible for manufacturing process engineering, factory automation, factory controls and maintenance engineering for Dell’s operations in Central Texas. Mark has 20 years of manufacturing and technology experience. He joined Dell in 1997 as a quality engineer and has served in a variety of engineering and management roles. In 2005, following assignments in test engineering, Mark moved into the role of senior manufacturing engineering manager.

Prior to Dell, Mark worked at Texas Instruments in Dallas. Mr. Burgett holds a bachelor’s degree in mechanical engineering from Kansas State University and a master of business administration degree from Southern Methodist University.