Your Reliability Engineering Professional Development Site
The work order report is the maintainer’s opportunity to advise the engineer what problems exist with equipment out in the plant.
It can also provide an accurate record of what was found during the repair. This makes it important that work order reports are completed in detail and are reviewed by managers and engineers.
Keywords: CMMS, computerized maintenance management system, breakdown, corrective, work order, implementation. [Read more…]
Book being reviewed is “Maintenance Planning and Scheduling Handbook 3/E
Keywords: maintenance planning, scheduling, planner, performance, productivity, planner. [Read more…]
Polyethylene is one of the most commonly used engineering plastics.
Its chemical resistance properties and ease of fabrication make it popular in the chemical industries. Its molecular structure provides the key to its versatility.
Keywords: HDPE, long chain macromolecule, thermoplastic, plastic welding. [Read more…]
Valves can be used to both isolate and regulate liquid and gas flow.
Valve used for isolation duties must provide secure, tight shut-off. Consideration must be given to the nature of the process chemical, the quality of sealing and the impact of outside environmental occurrences.
Keywords: bubble tight, design pressure, leakage rate, fire rated, differential pressure. [Read more…]
One method to provide a formal means of appraising people’s performance is by using performance reviews. The employee and manager together use a structured check sheet to work through keys duties of the employee.
They address both the good, and not so good, aspects of performance. The end result is an unbiased assessment of the employee’s current performance and a plan to improve it over the coming year.
Keywords: rating scale, verifiable, performance standards. [Read more…]
Chain drives are used when precise speed ratios are required between the driver and driven shafts. A chain drive allows no slippage. An example is on a gearbox driving a conveyor. Chain drives are also used when a large amount of power is required through the drive. For example the drive on large rotating kilns. [Read more…]
Historically numbers have been used to represent the work type.
As numbers are not a universal human method of description, the work type is also described using words.
The proper choice of words is critical if classification errors are to be minimized.
Keywords: CMMS, computerized maintenance system, breakdown, corrective, work order, implementation. [Read more…]
When spares cannot be purchased easily it becomes necessary to manufacture your own.
Local fabricators, foundries and machine shops can often make the item if you provide them with a design and specification.
Keywords: casting, reverse engineering, metallurgy, original equipment manufacturer, second hand. [Read more…]
When equipment breaks unexpectedly it is good practice to investigate why it happened so that the root cause can be rectified and the problem prevented from again happening.
There are no mysterious causes, only poor systems or system failures. It is not often that people intentionally sabotage plant and equipment.
By analyzing why a thing happened the lesson can be absorbed and changes made to business systems to reduce its probability of reoccurrence.
In this article, four equipment failures are reviewed and investigated to determine their cause and the resulting necessary changes.
Keywords: root cause failure analysis, failure mode. [Read more…]
The efficient use of men, materials and external resources requires coordination and preparation.
When a job starts everything needed to do the job must be at hand and must be right to use. The maintenance planner does the preparation required prior to the start of a job.
The planner’s focus is to prepare everything needed to execute a job through to its successful completion and have it ready and on-hand before the job starts.
How well the planning job is done directly affects how efficiently the men do the work and how long it takes for it to be done.
Keywords: job scheduling, breakdown work. [Read more…]
The very best asset managers have maintenance under control.
Their entire organization’s systems and methods are tuned to preventing unplanned stoppages. They only do that which has first been thought through and prepared for.
But most importantly they understand the key factor to excellent asset care and work toward it continuously and energetically.
Keywords: preventative maintenance, reliability-centered maintenance, RCM, total productive maintenance, TPM. [Read more…]
Weld preheating is the purposeful application of heat to warm metal to a desired temperature prior to welding.
Preheating slows down the cooling rate of the weld and gives the metal more time to form a good microstructure, release internal stresses and dissipate hydrogen from the weld.
Keywords: thickness, weld puddle, cooling rate, temperature. [Read more…]
When a bolt and nut is tightened to draw the bolt head and nut together it stretches the shank, deforms the threads and loads the object trapped between the bolt head and nut.
The bolt shank acts like a spring being pulled apart and it tries to return to its unloaded condition.
The amount of tension developed in the shank is dependent on the number of turns of the nut.
The size of the torque required to turn the nut has little to do with the tension applied to the bolt shank.
Rather the amount of torque needed to turn the nut reflects the slipperiness of the threads.
Keywords: bolt tension, yield stress, the coefficient of friction.
This article covers some of the problems that can occur with bucket elevators and provides possible remedies.
Bucket elevators lift bulk materials from one level to another.
They are used on powders, granules, grain, chip shaped products and lumpy materials.
They function well when designed properly for the duty, and used as designed. [Read more…]
Many equipment breakdowns and stoppages occur because of improper clearance between holes and shafts.
The shaft is too tight in the hole; the center of the hole is not at the center of the shaft making it off-center; one part is loose on another and slips out of place or does not seal as it should. [Read more…]