A grease gun is a common workshop and garage tool used for lubrication. The purpose of the grease gun is to apply lubricant through an aperture to a specific point, usually on a grease fitting or 'nipple'. The channels behind the grease nipple lead to where the lubrication is needed. The aperture may be of a type that fits closely with a receiving aperture on any number of mechanical devices. The close fitting of the apertures ensures that lubricant is applied only where needed. There are three types of grease gun:1.Hand-powered, where the grease is forced from the aperture by back-pressure built up by hand cranking the trigger mechanism of the gun, which applies pressure to a spring mechanism behind the lubricant, thus forcing grease through the aperture.2.Hand-powered, where there is no trigger mechanism, and the grease is forced through the aperture by the back-pressure built up by pushing on the butt of the grease gun, which slides a piston through the body of the tool, pumping grease out of the aperture.3.Air-powered (pneumatic), where compressed air is directed to the gun by hoses, the air pressure serving to force the grease through the aperture. Russell Gray, inventor of the air-powered grease gun, founded Graco based on this invention.[citation needed]The grease gun is charged or loaded with any of the various types of lubricants, but usually a thicker heavier type of grease is used.It was a close resemblance to contemporary hand-powered grease guns that gave the nickname to the World War II-era M3 submachine gun.

While anatomy is commonly associated with biology and medicine, this article does not include the study of the human body. However, the typical illustrative methods used for detailed examination and analysis of bodily features have always been an effective learning tool in the classroom. The anatomy lessons within Machinery Lubrication will apply these same methods for various topics within our industry.In this issue, the grease gun will be dissected to uncover all of its component characteristics. In addition, several other related topics will be discussed, such as common grease gun disorders, symptoms of incorrect greasing volume or frequency and best practices for using a grease gun.Types of Grease Guns

Types of Grease GunsIts fundamental that grease is used as a lubricant because it clings to a machines moving surfaces without easily leaking away like oil. For this reason, the filling and refilling of grease in grease-lubricated machines must be treated differently than that of oil-lubricated machines. Therefore, it is essential that the proper grease gun operation is understood and managed by lubrication technicians for bearing and machine reliability. Simply knowing the signs of overgreasing and undergreasing and how often to reapply can go a long way in extending machinery life.Connectors, Adapters and Couplers

A grease gun may come with the standard connection adapter such as a hydraulic coupler, but there are several variations depending on the application. The standard hydraulic coupler is the most commonly used and most applicable. A 90-degree adapter is ideal for fittings in confined areas that require a 90-degree bend. A needle-end adapter provides a thin, precise amount of grease for tight places, while a three-jaw swivel coupler offers a variety of locking positions for different applications.Flexible Hose vs. Fixed TubeThe decision to use a flexible hose or a fixed tube depends on the machines grease-fitting type and ease of location, as well as the type of grease gun used. For example, a hard-to-reach location would benefit from a flexible tube. On the other hand, lever-style grease guns require both hands to pump the grease and would favor the fixed-tube alternative.AccessoriesGrease gun meters can be retrofitted onto a grease gun to help optimize lubricant consumption. Plastic caps provide benefits such as preventing corrosion and debris. They also can be color-coded so that cross-contamination does not occur. Other accessories such as sonic/ultrasonic devices are also available.Grease Fittings

Grease fittings have several names such as a Zerk fitting, grease nipple or Alemite fitting. This is the lubrication point where the grease connector is attached. The standard hydraulic grease fitting is most commonly used for standard applications. It can be either upright or angled. The button-head fitting is ideal for good coupler engagement when large volumes of grease are being added. A flush-type grease fitting is preferred when space is limited for standard protruding fittings, while the pressure-relief vent fitting helps prevent higher pressures that could lead to damaged seals.Machine Health Risks Associated with Grease GunsHigh Grease Gun PressureA high-pressure manual grease gun is designed to deliver from 2,000 to 15,000 psi. Applying too much pressure while greasing will damage the bearing seals, which rarely handle more than 500 psi. Symptoms of high grease gun pressure include collapsed bearing shields, damaged bearing seals, grease driven into electric motor windings, and safety and environmental issues.Regreasing FrequencyManaging regreasing frequencies to optimal conditions is necessary to avoid long-term machine health problems. If the frequency is too long, symptoms may include lubricant starvation, which promotes wear, friction and grease contamination. If the frequency is too short, excessive grease consumption and safety and environmental issues may occur.Overgreasing and UndergreasingIt is important to know the exact amount of grease necessary for your greasing application to avoid overgreasing or undergreasing. Symptoms of overgreasing include damaged seals and motor windings, environmental issues, and fluid friction, which leads to increased heat generation, higher grease oxidation rates and higher energy consumption. Symptoms of undergreasing include bearing starvation, which results in friction wear and increased contamination.How Output is MeasuredIt is common for maintenance departments to have a wide variety of grease gun types, makes and models. This can cause grease-related disorders due to cross-contamination and inaccurate knowledge of each grease guns output per stroke. Grease guns are known to vary in the amount of grease that is output from 0.5 grams to more than 3 grams. This inconsistency depends on factors such as the type, model and age of the grease gun.

To overcome this problem, it is necessary to calculate the amount of grease that is released from a grease gun per stroke. To do this, use a calibrated scale and consistently pull 10 strokes of grease onto the scale. Once this value is known, divide by 10.

Grease Gun Best Practices Calculate the proper amount of grease needed for the relubrication of bearings based upon the calibrated delivery volume of the selected grease gun. Use a vent plug on the relief port of the bearing to help flush old grease and reduce the risk of too much pressure on the bearing. Use extreme caution when loading grease into the grease gun to ensure that contaminants are not introduced. If using a cartridge, be careful when removing the metal lid so that no metal slivers are introduced into the grease. Make sure the grease gun is clearly marked to identify the grease with which it should be charged. Do not use any type of grease other than that which is identified. Always make sure the dispensing nozzle of the grease gun is clean before using. Pump a small amount of grease out of the dispensing nozzle and then wipe the nozzle off with a clean rag or lint-free cloth before attaching it to the grease fitting. Clean the grease fitting of all dirt before attaching the grease gun. Inspect and replace damaged fittings. It is helpful to use grease-fitting caps to keep them clean, but still wipe fittings clean before applying grease. Ensure that the proper grease is used at every grease point. Applying the wrong grease can cause an incompatibility problem, which can quickly cause bearing failure. Lubrication points should be clearly identified as to which grease is to be used. This can be done with colored labels, adhesive dots or paint markers. Grease guns should be stored unpressurized in a clean, cool and dry area and in a horizontal position to help keep the oil from bleeding out of the grease. Grease gun clamps make storage easy and organized. Also, cover the coupler to keep it free from dirt and contaminants. Calibrate grease guns regularly to ensure the proper delivery volume.

Grease Gun Best PracticesWhen lubricating equipment with a grease gun, it is important to know precisely how much lubricant needs to be applied per cycle and how much lubricant the grease gun will produce per shot. Grease guns can produce between 1 gram and 1.5 grams per shot. This can result in significant overlubrication per point unless the output is known.Grease guns are capable of producing several thousand psi per stroke. This kind of pressure can certainly blow out bearing seals and shields. If a careless approach is taken when using the grease gun, then it is highly likely that the equipment will be overpressurized and overlubricated. When this occurs, particularly with a bearing, then the likelihood that the bearing can see its rated lifecycle is greatly reduced.Whether the gun is filled with oil or grease, the practitioner should be precise with the use of the gun, beginning with an analysis of the bearing dimensions and calculation of the required amount of grease per cycle, followed by an analysis of the amount of output per cycle of the gun.When working the grease gun lever arm, never hold the nozzle onto the grease fitting. Also, when cycling the lever arm, be conscious of the risk of overpressurization and do not force the lever arm if there is strong back pressure.Use the following tips to maintain your grease guns and fittings. Wipe the fitting before use to clear debris. Use a clean shop rag or lint-free cloth to clear debris. Inspect the grease fitting. Replace defective or damaged fittings. Where possible, standardize on fitting type. Conspicuously mark the grease fitting with the type of grease being used. Avoid changes where possible. Learn the proper grease gun operation and know the delivery volume per shot. Have grease guns calibrated occasionally to ensure proper volume delivery. Some grease guns develop pressure up to 15,000 psi. Exercise caution to avoid overpacking and/or seal damage. Keep guns clean, avoiding laying them on dirty surfaces. Repack on a clean bench using a gun loader fitting. Keep grease guns covered when not in use. Exercise caution to ensure safety. Make changes such as piping out the fitting to avoid danger. When repacking grease guns from a pressure line, wipe down the fitting and the pressure line to prevent contamination. When repacking with tubes, move to an environmentally controlled area, such as a control room, to replace the tube.

Greasing with AccountabilityMost grease-lubricated bearings fail to reach their life expectancy. This statistic is due to a number of reasons, one of which is the manual grease route, which unfortunately has properties similar to human beings. Man is not faultless either as an individual or as a group and makes errors regularly. Automatic Greasing

To date, one of the objectives of maintenance departments has been to replace all manual greasing with automatic lubrication systems. Automatic systems offer several advantages: Greasing with the correct amount of lubricant significantly reduces the consumption of grease when compared to traditional manual greasing. Several cases have reported grease consumption was reduced by 30 to 50 percent. Not only has this been documented by various automatic systems manufacturers, but an article in the Swedish magazine Underhll and Driftskerhet (Maintenance and Reliability, February 2000) and a case study from VTT (Technical Research Center of Finland) carry convincing evidence. Automatic grease lubrication that provides reliable cycles and correct lubricant discharge may reduce the number of bearing failures by approximately 50 percent, which is supported by the VTT report. The automatic systems are closed, ensuring grease is isolated from the environment when it transfers from the lubricant reservoir to the bearings (no contaminated zerks). Automatic lubrication that is correctly designed, installed and maintained is reliable; therefore the impact of the human factor is virtually eliminated. Unfortunately, the cost of implementing the system may be a hindering issue. When installed in process industries, automatic lubrication is costly - roughly estimated between 380 to 760 USD (300 and 600 EUR) per lubrication point. Current Manual Greasing

Manual greasing is a daily task performed in process industries worldwide. It is carried out with simple tools, as a low-priority, routine task without status. This is industrys standard practice to date! Unfortunately, the problem with manual greasing is the frequency of faults. Manual lubrication is performed by human beings and humans make mistakes. Aviations View of Mistakes

In some human activities, such as aviation, mistakes cannot be tolerated. Aviation demands specific routines and systems, which are created to increase safety and eliminate (or minimize) the human element where possible. Aviation has adapted to the following conclusions: Human beings make mistakes; and mistakes cost money and may cost lives. What are the similarities between the aviation industry and lubricating with grease? Both are large-scale routine activities performed daily by various people. In both activities, mistakes result in expensive consequences ruled by natural law. What are the differences between the aviation industry and lubricating with grease? In the aviation industry, the potential consequences of human mistakes are obvious, immediate and may risk lives. In greasing, the consequences are costly and lives are very seldom at risk when we fail to lubricate. Unfortunately, they are not immediately obvious. Hidden Mistakes Lead to Costly Consequences

The grease in a rotating bearing works only for a limited time and must be replenished while the lubrication film in the bearing is still in good condition. If the grease in a bearing is not replenished in time, heat, oxygen in the air and mechanical stresses will degrade the oil and adversely affect the strength of the lubricating film. This will result in the initiation of a bearing failure, which will reduce the life of the bearing. An obvious problem is that one is never aware that he may have missed lubricating a bearing. A working bearing that has not been lubricated for more than a month can still function without problems, and may not show any obvious symptoms of deterioration. When the bearing finally fails, it will be filled with good grease and no signs of a missed lubrication event will be present. Since the bearing was missed, several successful relubrication events have been made. Therefore, the life of the bearing was reduced and acceptance of the shortened life becomes the norm.Being unaware of the mistake prevents corrective actions to manual greasing from being implemented, which leads to the following conclusions: Human beings make mistakes, and mistakes cost money. The mistakes made by the lubrication technician are not immediately apparent. The mistakes unfortunately remain; otherwise a large difference would not be evident when manual greasing is replaced by automatic, as outlined in the VTT report. The lubricating film must remain perfect around the clock to prevent breakdowns in the bearings. In the past, manual greasing was inferior to automatic lubrication when attempting to maintain uninterrupted production of a mill. Statistics of Manual Greasing

Manual greasing is performed so often it must be looked upon as a statistical phenomenon. At our mill, we perform approximately 100,000 grease replenishments of bearings through zerks per year. If our team of lubrication technicians exhibit superior performance and do not miss more than one nipple per 1,000 nipples, statistically there will be 100 missed bearings per year. These missed bearings are expected to cost the mill 126,000 USD (100,000 EUR) in increased maintenance costs and lost production. So, there is definitely a problem! If the error level is decreased by a factor of 10, the mistakes will cost 12,586 USD (10,000 EUR) per year. Furthermore, if the level is decreased 100 times, the cost comes down to 1,259 USD (1,000 EUR) per year, which is acceptable. How can the error level be decreased by 100 times? Overgreasing: A Solution or Problem?If bearings are unnecessarily greased twice as often, some nipples can be missed without any perceived problem, because the missed bearings will, in all probability, be greased the next time. If one bearing per 1,000 is randomly missed, the risk of the same bearing being missed consecutively is one in a million. Greasing at half the optimum intervals offers a solution to the problem of randomly missed zerks. But will equipment then be overgreased? Overgreasing is considered to be one of the main causes of grease-lubricated bearing failures. Greasing at half the required interval demands a great deal of work and is bad practice. Electronic Greasing Aids: A Better Solution?The lubrication technician is provided with a handheld aid to use during the greasing route that indicates how much grease each lubrication point needs. As greasing occurs, the aid automatically reads the lubrication point number and registers the amount of grease pumped into the bearing. It also stores all of the data. If the lube tech should miss one or more lubrication points, he will be alerted to this when the greasing route data is downloaded to a computer. He can then return and finalize the greasing route by lubricating the missing points. Not a single lubrication point will be missed. A professional lubrication technician using the new aid will guarantee this! The correct procedure no longer depends on the skills of specific individuals. It can be accomplished by substitute lube techs, who may be standing in due to sickness or holidays. During a greasing route, the new handheld tool will automatically register which lubrication points have been greased, when they were greased and the quantity they were greased with. At the base, the computer will show which lubrication points need to be greased to finalize the lubrication route. Guaranteed lubrication cycles will be achieved with statistic certainty, providing higher profit margins for the mill. The SystemThe system that met our requirements was a radio frequency identification (RFID)-based manual greasing system, where each lubrication point is equipped with a special grease nipple combined with a transponder. With a built-in antenna, the grease meter communicates with the transponder (Figure 1).

Figure 1. Grease Nipple with Transponderand Hydraulic Coupling with AntennaIn addition to the RFID unit and its antenna, this system has a metering module that calculates the grease quantity pumped into the grease nipple. The grease meter is also equipped with intelligence and storing capacity (Figure 2).

Figure 2. The Grease MeterThe entire system is controlled by a computer managed by lubrication technicians (Figure 3). The grease meter is connected to the computer via a communication and loading unit.

Figure 3. A Lubrication TechnicianControls the SystemHow Does it Work?When its time to lubricate, the lubrication technician loads the current grease route into the grease meter, then walks his route and performs the necessary tasks. For each lubrication point, the meter displays the amount of grease the bearing needs and how much it receives. The lube tech returns to the base and connects the grease meter to the computer. The stored information is downloaded to the computer, and the time of the download operation is simultaneously registered. The computer display immediately shows the status of the lubrication points in the grease route. It appears as a list with different colors for greased and nongreased lubrication points. The Economic BenefitsThe economic impact of greasing efficiently depends on three factors: 1. The number of mistakes made by lubrication technicians. 2. The physical consequences of missing a lubrication point. The more accurate greasing intervals, the greater the impact will be. 3. How much overgreasing is reduced when the correct amount of grease is applied at optimal intervals. The first factor is difficult to estimate and depends on the organization and its personnel. The author estimates it to be one in 1,000, but likely more for most mills. With the electronic aid, this could decrease by at least a power of 100; meaning that the number of missed points will be less than one in 100,000. The second factor is more easily estimated because it depends only on those powers of nature which have a degradable effect on lubricants. The author estimates it to be a ratio of 1:3, assuming a defective lubrication film will appear in one-third of the missed bearings. These bearings will have to operate on the defective lubrication film until the next lubrication route. This figure is presumably conservative. If the current number of missed bearing is one in every 1,000, then it would be expected that 100 would be missed in every 100,000. By applying the electronic aid, this can be reduced from 100 to one. From this, it is apparent that the electronic aid could prevent 99 bearings from being missed. Of these 99, it is estimated that one-third would have premature wear resulting from the missed relubrication event. This means that we can prevent at least 30 premature bearing breakdowns yearly by decreasing the human factor. The improved reliability and the decreased maintenance costs can be estimated to several hundred thousand USD per year. This will also result in an improved environment (decreased grease consumption and waste handling). Profits will also increase from reducing overgreasing which SKF Reliability Systems estimates as one of the main causes of bearing failures in this type of industry. According to SKF, we can also save another hundred thousand USD per year from reducing overgreasing. The investment for the whole mill amounts to approximately 204,508 USD. The described system (LubeRight) has been invented and developed by the Swedish company Assalub. to Operate a Grease Gun Safely

All machinery must be lubricated to ensure smooth operation and to maximize equipment life. From manufacturing to farming to wind energy applications, grease guns are one of the most common ways to achieve proper lubrication. Although use of grease guns is widespread, these tools deserve respect and should be used in accordance with the manufacturers safety guidelines to avoid injury.There are four main types of grease guns on the market: manual, battery-operated, air-powered and AC electric. Each type has its own specific set of guidelines, but many general rules are applicable to all, such as training, proper tool use and care, work area safety and personal safety.Manual Grease GunsManual grease guns include lever-action and pistol-grip models. These popular tools are widely used and are the most economical type of grease gun. Manual grease guns can achieve pressures up to 10,000 pounds per square inch (psi), while plug-valve sealant guns can reach 15,000 psi.Battery-operated Grease GunsBattery-operated grease guns are ideal for speeding up routine lubrication tasks. Using this type of grease gun can also help to minimize operator fatigue. These grease guns are rated anywhere from 6,000 to 10,000 psi, depending on the model.Air-powered Grease GunsAir-powered or pneumatic grease guns use compressed air to apply pressure to an air piston, which drives the grease piston and forces lubricant out of the coupler into a grease fitting. By depressing the guns trigger, a steady flow of lubricant is dispensed. Typically, pneumatic grease guns are rated up to 6,000 psi.AC Electric Grease GunsAC electric or corded grease guns provide a consistent flow of grease and are often used as an alternative to air-powered tools. AC electric grease guns generally are rated up to 7,000 psi.TrainingEffective lubrication requires specific training, ranging from the actual physical activity of applying the lubricant to the effects of misapplication, including spills and damage to machinery. The operator should be trained on each piece of equipment to be lubricated, as well as each grease gun that will be used to accomplish the task.

Some general rules of lubrication also should be considered, said Alemite senior product manager Americo dos Santos. Do not apply lubricants to a machine in operation unless the fittings are located in a safe place. Never reach over, under, through or past moving parts of the equipment to complete your task. You should maintain proper footing and balance at all times to facilitate better control of the tool in unexpected situations.Proper Tool Use and CareWhether you are using a manual, battery-operated, air-powered or AC electric grease gun, the high pressure developed by the tool should be considered. High pressure can develop in different ways. A common situation when high pressure is created involves what is known as a frozen fitting. When a fitting is not lubricated for an extended period of time, the grease in the line may cake. Mineral or vegetable oil in the grease gets consumed and leaves a waxy, soap-like base. This soap thickener is what makes grease a semi-solid. Common soaps include calcium stearate, sodium stearate and lithium stearate, as well as mixtures of these components.High-pressure injection injuries may be caused by accidental injection of grease through the skin and into the underlying tissue. Generally, fingers or hands experience this type of injury, which is most likely to occur when a hose ruptures. Also, some lubrication applications require needle-type accessories that can lead to an injury if used improperly.An injection injury may be very small and essentially painless, and the injured person may be tempted to continue working, explained dos Santos. However, if you receive any type of injection injury, you should seek medical attention immediately. The lubricant will need to be removed and treatment initiated to prevent infection. If possible, provide the medical technician with the brand of grease or oil involved so that the manufacturer can be contacted regarding the possible toxicity of the lubricant.Safety features are available and precautions can be taken to minimize the risk involved in using high-pressure grease guns. The key is to use the right tool for the job. Do not improvise or change the grease gun configuration for any purpose other than that which it was intended.It is critical that all of the components utilized are rated for the amount of pressure being applied, so you should use only hoses specified by the grease gun manufacturer. For example, if your grease gun is rated at 10,000 psi and your hose is only rated at 1,500 psi, the situation can become hazardous very quickly.It also is essential that you inspect the hose between the grease gun and the coupler before each use, dos Santos stressed. If there are any signs of wear or damage on the hose, do not use it.When a grease cartridge is loaded into the grease gun, the follower rod should be securely latched to the end cap so it doesnt spring back unexpectedly. Use care when removing the pull-tab on the cartridge to prevent getting cut by the tabs sharp edges. In addition, always aim the grease coupler away from your body when loading and priming the grease gun. You dont want to take any chances that grease may get into your eyes.

Battery-operated grease guns have a few safety guidelines of their own. For instance, the power switch should be in the off position before inserting the battery pack. The battery pack should always be disconnected from the grease gun before changing accessories or unscrewing the grease cylinder from the gun. Never attempt to open the battery pack or expose it to water.When not in use, keep the battery pack away from metal objects such as paper clips, coins, keys, nails, screws or other small items that can make a connection from one terminal to another. Under abusive conditions, liquid may escape from the battery and should be avoided. If contact with this liquid occurs, flush with water. If the liquid contacts your eyes, seek medical attention.When using a battery charger, use only the charger specified by the manufacturer. Ensure that the cord is situated so it will not be stepped on, tripped over or otherwise subjected to stress. Do not operate the charger with a damaged cord or plug, or if it has received a sharp blow or been dropped. You should also refrain from charging batteries or using any electrical (corded) grease gun in damp areas.Other workplace practices involve operating, caring for and servicing your grease gun, dos Santos noted. Always read and follow the manufacturers instructions before using your grease gun. Avoid kinking hoses, as this can weaken them and make them more susceptible to ruptures. Be sure to label your grease gun so that you can identify the type of grease in that particular gun. Also, you should wipe grease fittings and the grease coupler clean before connecting to prevent contamination.Battery-operated, air-powered and AC electric grease guns can build extreme pressures, which may not be evident to the user. Therefore, extra caution should be taken with these tools. Never exceed the maximum input air pressure on pneumatic tools. Most of these grease guns run at a 40-to-1 grease pressure to air ratio, so substantial pressure is created with a relatively low input air pressure.Keep grease guns clean and avoid placing them on dirty surfaces. All repairs should be performed by a qualified technician who uses only original replacement parts. Finally, when lubrication tasks are performed, grease often gets on your hands, so be sure to wash them to remove any chemical residue.Work Area Safety

Regardless of the type of grease gun you choose, it is important to keep your work area clean and well lit. Cluttered and dark areas invite accidents of many kinds. Oil or grease spills on floors, catwalks and ladders can cause serious falls and fire hazards. Wipe up lubricant spills immediately or use absorbent drying pads or granules. Sources of lubricant leaks should be repaired to maintain a safe environment.If you are using a power tool, make sure that the area is free of flammable liquids, gases or dust, which may be ignited if the tool creates a spark, dos Santos added. In addition, power tools should not be exposed to rain or wet conditions, and care should be taken to prevent cord damage, as this can increase the risk of electric shock.Minimize distractions, such as bystanders, while operating your grease gun, as they may divert your attention from the task at hand. Never play around with or use a grease gun for practical jokes.Personal SafetyIt is recommended that you wear personal protective equipment including safety glasses, gloves and non-skid shoes or boots to help prevent injury. Refrain from wearing jewelry or loose or torn clothing that could become caught in moving parts.Stay alert while using a grease gun. You should never operate any tool if you are tired or impaired by alcohol or medication, as a moment of inattention may result in serious personal injury.By utilizing sound procedures, training and appropriate tool use and care, you can maximize potential bottom-line benefits received from proper grease gun lubrication techniques while maintaining worker safety.The Dangers of OvergreasingWhen it comes to regreasing bearings, more is not always the better option and actually can be a costly mistake. Instead, greasing should be set on a frequency with proper calculations used to determine the amount of grease needed at each relubrication. The determining factor for the amount required is based on the dimensions of the bearing or the bearing housing.Overgreasing can lead to high operating temperatures, collapsed seals and in the case of greased electric motors, energy loss and failures. The best ways to avoid these problems are to establish a maintenance program, use calculations to determine the correct lubricant amount and frequency of relubrication, and utilize feedback instruments.

Too much grease volume (overgreasing) in a bearing cavity will cause the rotating bearing elements to begin churning the grease, pushing it out of the way, resulting in energy loss and rising temperatures. This leads to rapid oxidation (chemical degradation) of the grease as well as an accelerated rate of oil bleed, which is a separation of the oil from the thickener. The heat that has been generated over time along with the oil bleed eventually will cook the grease thickener into a hard, crusty build-up that can impair proper lubrication and even block new grease from reaching the core of the bearing. This can result in accelerated wear of the rolling elements and then component failure.Seal damage is another negative side effect of overgreasing. Grease guns can produce up to 15,000 psi, and when you overgrease a bearing housing, the lip seals can rupture, allowing contaminants such as water and dirt to gain access into the bearing housing. Keep in mind that lip seals usually fail around 500 psi. This excessive pressure can also damage single and double-shielded bearings, causing the shields facing the grease supply to collapse into the bearing race and leading to wear and eventually failure. When too much pressure is generated from a grease gun due to overgreasing, it is easy for the hard, crusty grease formed from heat (high operating temperatures) to be broken apart and sent directly into the bearing track.Overgreasing electric motor cavities has the same effect as with any bearing application except that grease can reach the motor windings. When filled completely with grease, an electric motor bearing will generate excessive heat due to churning. This results in energy loss as well as an accelerated rate of oil bleed and hardening of the grease thickener. Again, the high pressure applied from a grease gun can result in grease finding its way between the shaft and inner bearing cap and pressing into the inside of the motor. The result over time is the coating of the electric motor windings with grease, which leads to both winding insulation and bearing failures.Setting up a maintenance program is key to solving the problem of overgreasing. Each lube point, whether it be a bearing housing or electric motor, should be tracked as an asset, and records kept for scheduling planned maintenance or inspections of the asset. While the initial setup of a maintenance system may take some time and hard work, the end results will have a major impact.Once you have planned the scheduling of the assets, you will need to determine the timing and amount of grease (volume) that should be applied at each point. The volume can be calculated with a simple equation (ref. SKF):G = 0.114 x D x BWhere G = the amount of grease in ouncesD = the bore diameter in inchesB = the bearing width in inchesNext, calibrate all grease guns in use and train the technicians on the proper procedures of usage. Calibrating a grease gun is very simple. All you need are the grease gun and a postal scale. Determining the weight in ounces per full stroke (shot) of the grease gun will allow you to identify the number of shots it takes to equal 1 ounce of grease. This will help you establish the right volume needed to ensure you are delivering the precise amount at each use.After you have determined the correct volume, its time to establish the proper frequency. There are several methods for estimating a regreasing frequency, including multiple calculators, tables and charts. The major factors in determining frequency are load, operation time, type of bearing, speed, temperature and environment.Feedback tools can also be beneficial for fine-tuning your frequency. For example, ultrasonic instrumentation is one of the best ways to optimize the correct frequency and help you set up your maintenance program.Establishing appropriate procedures and inspections during relubrication is another important part of a maintenance program. Some basic steps include: Cleaning areas around the fill and relief fittings. Ensuring the grease relief valve moves freely or the drain plug is removed. Checking to be sure the relief passage is clean from any hardened grease that may be blocking grease from exiting. Greasing the bearing cavity with the correct calculated volume of grease while slowly adding each shot to minimize excessive pressure build-up. Allowing the motor to run during and after greasing to expel any excess grease. This should be done before re-installing the purge port or bottom grease relief valve and cleaning the area of any excess grease.Tips to Control Overgreasing Discontinue greasing when you feel abnormal back pressure. Always make sure exhaust ports are cleaned out from any debris or old, hard crust that could be blocking the passageway. Consider installing grease guns with pressure gauges, shut-off grease fittings or relief-type vent plugs. Slowly pump grease into bearings every few seconds. Using a quick-lever action could cause seal damage and not allow the grease to distribute throughout the bearing correctly.10 Lubrication Best Practices for Improved Equipment ReliabilityLubrication has a direct effect on equipment reliability. If you have a good lubrication strategy, you will improve your plant and equipment uptime. For any given plant, there are a number of important steps that, if implemented, will increase equipment reliability. The following 10 lubrication best practices can help companies achieve the optimal result in maintenance costs compared to production reliability. 1. Assessment/BenchmarkingIn this process, you assess the things that you do right as well as the things you need to do better.2. Organization and PlanningThis step is about ensuring that all lubrication tasks in the plant are completed at the right time with the right lubricant and the right quantity while using the right processes. For this, most companies use software to control and report the activity.3. IdentificationTo ensure that the right lubricant is added to a piece of equipment, a labeling system is needed. This is driven by the fact that in large plants multiple types of lubricants are used. Lubricants are complex chemical compositions and are often very incompatible, so to avoid errors of mixing lubes and to support industry standards, particularly in the food-grade industry, a good labeling system is necessary.

A good labeling system can help ensure that the right lubricant is added to a piece of equipment.4. Cleanliness ControlOil contamination is a major source of component wear and equipment failure. Therefore, it is important that only clean lubricants are used in the equipment operation. Cleanliness-control centers ensure that the lubricant is stored safely, is clean and is transferred in a contamination-free environment.Best practices for cleanliness control include: Only use fully sealed containers. Fit air breathers to all containers to prevent the ingress of water and contaminants from the atmosphere. Filter all oil to get it very clean. Only use contamination-free containers, i.e., containers that will not generate contaminants.An example of a cleanliness-control center.5. In-plant DispensingOpen and dirty dispensing containers can be a source of contamination entering the machine. Dispensing equipment must be safe, clean and closed. It also should be efficient, easy to use and adapted to the applications being filled. Make sure the containers are well-identified so no mistakes occur, regardless of who uses them.

These multi-colored dispensing containers are fully sealed, easy to use and rust free.6. Grease Lubrication ToolsAdding grease to a machine accounts for the majority of lubrication jobs. Therefore, its essential to have tools that are efficient and practical. Grease guns should be color-coded to ensure that the right lube gets in the right application. Color-coded grease guns, with one color for each different grease, can help in this regard.7. Contamination ControlControlling the contamination of oil inside the equipment is also critical. The international standard for measuring this is ISO 4406. Online and offline filtering systems are used to clean up the oil, while breathers or air conditioners are utilized to protect the lubricant.

An example of a small mobile filter cart.8. Oil AnalysisAnalyzing the oil in an application is an important part of a lubrication strategy. By measuring against ISO 4406 standards, the oil can be kept at the right cleanliness levels. Additionally, chemical analysis of the oil will determine if it is fit for further use.9. Environmental ControlIf spilled, lubricants can contaminate the environment. Therefore, most maintenance strategies today work to prevent such contamination from occurring. This is also a key ingredient in world-class manufacturing standards.10. Knowledge ManagementManagement of knowledge is becoming critical in industry today, particularly within the maintenance sphere. Maintenance workers must be skilled in the benefits of good lubrication practices. Additionally, with the growing awareness of the benefits of employing reliability-based maintenance strategies, the basic training of personnel should be raised to that of the reliability techniques employed by best-practice organizations.Dangers Associated with Implementing Best PracticesImplementing reliability-based strategies that are successful over the long term is not an easy task. Many strategies fail because they are seen as projects and not as processes to change the work culture of those involved.

Effective implementation requires the existing culture within a plant to be changed so the processes are accepted, followed and sustained.While cultures can be changed, to achieve this requires an understanding of the causes of failure and how to prevent these factors from coming into play during the implementation process.Addressing the need to change the way employees work will provide a higher success rate for any project and ensure the new way of working will be sustainable over the long term.