Four shots every 28 days. It couldn’t get any simpler than that, right? At least I thought so at first.
Two years ago, when I was asked to manage our facility’s machinery lubrication program, I had limited experience with lubrication. My manager suggested I refocus the program on the basics; which I agreed was a reasonable starting point. Several preceding engineers had established our facility’s excellent program; plus I had good technical resources reporting to me from whom I could learn. I must admit that at first, I thought of lubrication as a menial task, as many do. My attitude quickly changed as I realized the importance of lubrication in a manufacturing facility.
Advanced Glassfiber Yarns is a 59-year old textile mill in Huntingdon, Pennsylvania, which produces a variety of fiberglass yarns and continuos fiberglass mat. Our equipment varies in size and age, but much of it is specialized state-of-the-art equipment. The nature of our process exposes a large amount of the equipment to a wet, abrasive (glass) environment. We also have a wide range of equipment operating speeds within our facility. We have slow moving conveyor rolls running at less than 50 rpm, and high-speed spindles that run at more than 6000 rpm. We also have equipment that resides outdoors (exposed to Pennsylvania winters), and some equipment subjected to temperatures greater than 350°F (177°C).
A large portion of the program in our facility involves the application of grease. Although we have some automated lubrication systems, because of the nature of our process, most of our grease applications are performed manually with grease guns. A lubrication database was developed by one of the preceding engineers who calculated the amount of grease required for each piece of equipment and the equivalent number of pumps (shots) of a grease gun required to achieve this amount. Although it seems basic, the grease gun is a good place to start to learn lubrication practices.
The grease gun is an effective tool for moving grease to a point of application, though it is often taken for granted. The most common styles of grease guns include the lever, pistol-grip, hand grip, air-powered and battery-powered. The lever style is the most economic and widely used of all the grease guns.
Air-powered Grease Gun
Lubrication technicians need to know the output per stroke of the grease gun in order to know how much grease is added each time a piece of equipment is lubricated. Grease guns vary in the amount of grease pumped per stroke, from one to three grams of grease or higher. The actual output can vary depending on the age of the grease gun. One of the technicians informed me that although our lubrication database stated the number of strokes required to relubricate each piece of equipment, there were many different brands and models of grease guns in use throughout our facility. Maintenance personnel in each process department purchased various grease guns over the years, without designating one particular model or type as a company standard. Individuals simply ordered whatever was available and looked good at the time.
We performed an audit of our facility to determine exactly how many and what types of grease guns were in use. We found that we had 33 grease guns that ranged from 0.56 to 3.10 grams per pump. The audit revealed that we had a uniformity problem that needed to be addressed, and we wanted to do so correctly.
The first step was to contact a local vendor and arrange an in-house training session on grease guns. This allowed us to ask questions and learn as much as possible before formulating a corrective action plan. There are many companies selling high-quality, dependable industrial grease guns. Two of the largest are Lincoln and Alemite.
Some factors to consider when establishing standard grease guns for your facility include:
Another factor to consider is the type of grease fittings used in the facility. Most fittings have a ball check in the head of the fitting, which prevents dirt from getting to the bearing. The spherical contour of the fitting head provides a ball-and-socket joint between the fitting and the hydraulic coupler of the grease gun. The most common fitting is the hydraulic fitting, available in standard and metric sizes.
Hydraulic fittings are available in threaded, thread-forming, rivet and drive styles. They are available in different angled configurations and a wide variety of extension lengths to allow you to position the fitting for easy access with a grease gun on different types of equipment. Other common types of fittings include button head, flush (where protruding fittings cannot be used), pin, pressure relief and vent. There are also hydraulic shut-off fittings that shut-off at specified pressures to prevent overlubrication and blowing out bearing seals. Each application needs to be examined to determine the correct fitting and which style of grease gun and coupler is needed.
Grease gun fittings and accessories can enhance a lubrication program in several ways. Caps help keep contaminants out of the fitting and the bearings. Paint markers or colored labels (such as dots) can be used to identify the proper grease to use on a fitting. It is important to ensure that the proper grease is used on the equipment in your facility.
To prevent the accidental lubrication of bearings with an incompatible grease, we are considering using button head fittings on lubrication points in our facility that require a polyurea grease to eliminate the possibility of adding the wrong product. We are also examining standard hydraulic fittings on lubrication points that require lithium grease. Again, do not overlook the basics and the chance for improving the tribology program at your facility.
Lever-style Grease Gun
After careful consideration, we selected a lever-style grease gun for most of our manual grease lubrication tasks. We also found it necessary to use a hand-grip style grease gun on certain equipment in one area of our facility. Because of the location of the hydraulic fittings, it is necessary to hold a flexible extension on the fitting with one hand while pumping the grease gun with the other hand. The lever-style grease gun disperses 1.28 grams of grease per pump while the hand-grip style disperses 0.86 grams per pump.
The next step was to replace the old grease guns with the new grease guns. To make sure the old grease guns were completely removed from service, we gave them to craft personnel to take home for personal use. This made a number of employees happy and helped to gain acceptance for the distribution of the new grease guns. Buying all new grease guns also allowed us to mark the new grease guns with colored labels, identifying what grease to use with each gun.
Strategic Work Systems (www.swspitcrew.com) offers a shrink-tube sleeve made of polyolefin to fit over a cartridge grease gun after affixing labels. The sleeve is attached by using a heat gun to shrink the tube, which is resistant to chemicals and oils and provides an easy-to-grip surface. Remember that it is important to identify the type of grease to be used in each grease gun.
A basic step that is often overlooked is training the lubrication technician on the proper use of the grease gun. A high-pressure grease gun delivers pressure up to 15,000 psi. Most bearing seals will rarely handle more than 500 psi. A grease gun in the hands of an untrained technician can compromise the bearing’s seal and lead to early failure. The compromised seal invites dirt or other foreign materials as well as overlubrication due to little or no back pressure.
Safety training can also be a factor when using a needle-point applicator to disperse grease to certain types of fittings. If the needle slips off the grease point and punctures the hand or finger, grease can be forced into the skin. This can cause the punctured area to become swollen, stiff, and even gangrenous, which could lead to amputation. This is why grease gun injuries require immediate medical treatment. Remember to use caution when using needle-point applicators on grease guns.
Some common tips for using a grease gun:
Always make sure the dispensing nozzle of the grease gun is clean before using.
Manual grease guns have their place in industry. They have a few disadvantages, the chief of which is poor control that can lead to over- and underlubrication. Grease guns also present a higher risk of inducing contaminants. However, they do have advantages, such as low cost, ease of use once the technician is properly trained, and allowing the technician to inspect the equipment during lubrication tasks. Just remember not to overlook the basics, no matter how simple it may seem.