Optimum Maintenance for Amazing Machines

Aug. 16, 2014

It’s pretty amazing when you think about it: We can assemble, connect, and torque together thousands of parts made up of glass, plastic, rubber, circuit boards, and several different types of metal. And that once assembled, will result in some incredible piece of machinery that can load and haul and push and compact and cover trash…and make it look easy!

Take for example, machines manufactured by Doosan. While relatively new in the North American marketplace, Doosan has been manufacturing machines since 1935 and is the world’s fifth-largest manufacturer of construction equipment. Say what? That’s right: Doosan’s excavators, articulated trucks, wheel loaders, and other machines are now providing additional options on the heavy equipment menu in North America.

These machines are backed by lots of innovation. The wheel loaders, for example, are made of metal-now there’s an innovation. There are no plastic panels on the doors or plastic fenders. These are solid, get-the-job-done machines. And of course the loaders can be waste-equipped with clean hose routing, special guarding, and solid tires.

Their excavators use solid castings on the pin points of the boom and arm, which are further-strengthened by internal gussets. This allows the machines to be strong-without being overbuilt and overly heavy. Doosan also has designed an ultrahard wear disc at the outside of the bushings, which can be replaced instead of having to rebuild the stick.

Doosan, like all other reputable machine manufacturers, places a lot of emphasis on service and maintenance. The folks who build heavy equipment recognize the importance of good maintenance; they design for it, and they hand it off to the operator at a waste facility…someone like you.

But don’t be fooled! Those machines that weigh 10 or 20 or 50 tons and generate hundreds of horsepower are not invincible. They are, in fact, surprisingly vulnerable to poor maintenance or misuse.

Vulnerability
That’s right! That scraper-which over a lifetime of work might excavate, transport and place 10 billion pounds of soil-can be immobilized by a few ounces of dirt in the wrong place. The engine of a large machine may intake a tremendous amount of air per day. Enough air in fact, to cover an entire football field, 15 feet deep. In dusty conditions, that much air could contain a lot of abrasive dirt.

I remember my grandfather explaining to me, as a kid, how the air-intake system worked on the tractors and other machines we used. Some of those older machines used a simple precleaner (e.g., cyclone dust separator) and an oil bath filter. I remember him telling me-no, warning me-how a tiny leak in that air intake system (something not much bigger than a pin hole) could completely destroy an engine in a few hours.

He told me this with great emphasis so that I wouldn’t forget…and I haven’t.

Still not convinced that these powerful, massive machines are vulnerable? You may be out of touch. Luke Skywalker took out the entire Death Star with one well-placed shot.

But, despite their vulnerability to poor maintenance, these big machines-when handled properly-do the job they’re intended to do.

Credit: Doosan
Why play around with the integrity of your heavy equipment by going cheap on the lubricants?

Perform Basic Maintenance
So, what is your part in regard to keeping machines working? Well, the first part is simple: Perform the basic maintenance recommended by the manufacturer.

Your machine’s manufacturer is the E.F. Hutton of equipment maintenance…when they talk, you’d better listen. Companies that manufacture heavy equipment used at landfills want the machines that you use every day to function with the lowest amount of cost and least amount of downtime. To that end, they have provided the resources you need, primarily in the form of the operations and maintenance manual.

Read the book and follow the instructions. As far as the manufacturers are concerned, what’s good for your machine is good for you…and it’s good for business.

From that standpoint, how might a poor maintenance program affect the functional life of your machines? It reduces their life, yes, but the cause and effect is not always immediately evident.

Most managers would agree that a good maintenance program-one that follows the manufacturer’s recommendations for service intervals, uses high-quality lubricants, and monitors performance with regular oil sampling-would yield maximum machine life. Similarly, those same managers would likely agree that a negligent maintenance program shortens machine life. But what happens in between?

Most machines end up somewhere within that hidden, murky area between a catastrophic failure, and the (ideal) maximum life. We know that mediocre maintenance has a negative impact…but how much of an impact? How in the world can you quantify cost versus benefit when you don’t really know for sure? Well, it’s like falling off a cliff: If it’s high enough to be called a cliff, and if you step off the edge, it really doesn’t matter how high it was…most likely it was too high.

Why play around with the integrity of your heavy equipment by going cheap on the lubricants or stretching service intervals beyond what the manufacturer or your oil sampling recommends.

Good equipment maintenance starts with a good daily routine. Operators should always conduct a pre-trip inspection of any machine before starting it up. Often referred to as a walk-around inspection, these pre-trips include a few very important inspection points. Things like engine oil, hydraulic fluid, coolant, backup alarms, lights, warning systems, brakes…you get the idea.

For your benefit, these items are listed in the manufacturers Operation and Maintenance Manual. For your convenience, you could develop a site-specific daily checklist that includes all of those checkpoints and any others that you deem worthy of daily inspection.

Now you might be thinking that a daily walk-around inspection of your machine is the operator’s responsibility. To a degree, you are right. But that responsibility is shared with the mechanic, who is responsible to see that services happen on time and that repairs are made when needed.

It’s also management’s responsibility. Somebody has to make sure it’s happening, and if you’re the manager, that somebody is you. This is a multistep process, and in order for it to work well you must close the loop. You should make certain of the following:

  • Create the form.
  • Create a policy to make sure the inspections are happening.
  • Train the operators on how to conduct the inspections.
  • Have a system so that the forms get to the right person so that the servicing and repairs are made.

When it’s completed, the system has to have a way to let the operators know that the work has been done and the machine is clear to go back to work.

The manager’s job is to make sure all of these things work and work together as a system. It sounds so simple, but apparently it is not-because more often than you think, it doesn’t happen. Over the last 30 years or so I’ve conducted thousands of operational reviews that included equipment maintenance and operations. In many of those cases (probably over 30%) basic walk-around inspections were not being done. The most recent example of this happened today.

I was conducting an operational review at a waste facility, and I was able to visit with one of the equipment operators for a few minutes. I had previously noticed some obvious issues with his machine, so when I asked him if he did a daily walk-around inspection, it was, I must confess, a loaded question. He said, “Yeah, I kind of walk around and check it out.” I asked him if he had a form and he said no, that they didn’t really have a form, he just kind of looks it over every day. When I pointed out the problems I saw with the machine, he quickly said, “Oh yeah, I forgot to do those things today.”

Credit: Al-jon
Good equipment maintenance starts with a
good daily routine.

If those basic, but vital tasks of conducting a walk-around inspection are not made regular parts of procedure, chances are, they won’t happen. Interesting isn’t it, that those facilities where machine downtime is such a big deal seem to pay so little attention to basic maintenance…interesting.

Well, the good news is that basic machine maintenance is just that…basic. But even so, equipment manufacturers continue to simplify the process, making it more and more-pardon me-idiotproof. This began decades ago with the development of quick-lube systems that allow a mechanic to change oil without pulling a drain plug, and oil sampling that allows you to monitor the condition of the fluids in your machine, and leading up to today’s wireless technology whereby we can monitor the vital signs, in real time, of any machine from the convenience of our office.

Basic machine maintenance has never been easier, which means…no excuses. Don’t make ’em, don’t accept ’em!

Following the manufacturer’s recommendations for maintenance is a critical first step toward having long-lived, dependable machines, but it is still the first step, and if you stop there, you’ll never make it all the way home. In addition to following those basic maintenance protocols, you must also account for job conditions: extremes of temperature, dust, and workload.

Let’s face it, folks, this isn’t rocket science. We’re talking about basics of lube, oil, filter, and good housekeeping. But keep in mind that when we categorize machine maintenance as basic and simple, we do so in the context of it being simple to perform.

How Engines and Lubricants Work
But what happens in the context of design, metallurgy, and thermodynamics is anything but simple.

First, let’s start with a diesel engine. Diesel engines have a very high compression ratio, something on the order of 20:1, and on the compression stroke the air pressure in the cylinder may approach 600 psi with a corresponding temperature of over 500°F. Into this hot, compressed air, the injectors shoot a burst of diesel, which ignites, expands, and forces the piston downward: the power stroke. It is a diesel engine’s high-compression ratio-approximately 3 times higher than a gasoline engine-that makes them so much more powerful. But even so, diesel engines are only about 50% efficient in converting the energy in diesel fuel into mechanical energy. The other 50% is converted into other forms of energy: noise and heat…mostly heat.

That heat must be dissipated quickly by the engine’s cooling system, because if the engine gets too hot, bad things happen. One of the most serious is related to a thinning of engine oil.

Consider that the purpose of various types of lubricants (i.e., engine oil, gear oil or grease) is to form a thin film of lubricant between two moving parts that would otherwise have metal-to-metal contact. That film of oil decreases friction and associated (metal) wear. But that thin film decreases in thickness as the load increases: picture two meshing gears under a very heavy load where the increased force between the teeth compress that thin layer of lubricant.

Now imagine what happens as the oil overheats-perhaps a result of increased friction-and thins down. As it thins (i.e., exhibits a lower viscosity), the film of lubricant between the metal pieces gets even thinner, which causes more friction and…OK, you get the idea.

This same chain of events can begin during hot weather conditions.

Credit: Neal Bolton
Landfills are among the most equipmentdestructive environments on the planet.

Heat
Having had the opportunity to visit landfills in different areas, I’ve found lots of variation in job conditions. When we think of difficult job conditions, most of us think “heat.” And, yes, heat is a big issue, but there’s much more to it.

One summer I was working on a landfill gas venting project in Phoenix, and I’ve got to say it wasn’t just hot: It was hot. Plastic spoons from morning coffee, left on the dashboard of a work truck, would melt into a white blob of molten plastic by lunchtime. The heavy-equipment mechanics worked under umbrellas or at night. They ragged their tools-that is, they placed a rag on their tools every time they set one down…otherwise, it would be too hot to pick back up. Using his infrared heat digital thermometer, one of our Caterpillar mechanics recorded his toolbox (in the shade) at over 130°F.

That was the summer I first heard about Stick Lizards. Similar to the snipes I’d learned about when I was a boy, these were, supposedly, lizards that carried a small stick as they ran across the hot sand. When their tiny feet got too hot, they’d shove the stick into the sand and climb up on it. Then after their feet cooled a bit, they’d jump down, grab their stick, and run on a bit farther.

Well, as you can imagine, that kind of heat impacted more than plastic spoons and the elusive Stick Lizard. It was also very tough on our landfill machines. Internal combustion engines run most efficiently when at their normal operating temperature, usually around 200°F. And on a normal day, your machine’s cooling system can effectively reduce the temperature of the coolant as it passes from the engine, through the radiator.

It’s a simple thermodynamic process: Heat is transferred from the engine to the coolant, and then as the coolant flows through radiator, the heat is transferred from the radiator fins to the ambient air, thereby cooling the system. However, this cooling process becomes far less efficient as the temperature of the ambient air increases. So when the ambient air temperature climbs to well over 100°F, your machine’s radiator becomes less efficient. If you don’t do something to compensate, you’re walking toward the edge of that cliff.

As previously noted, when operated at higher than normal temperatures, engine oil thins and so does that all-important film of lubrication. But something else happens, too. Oil begins to vaporize at a higher rate when it’s hot. That means that some of the more volatile molecules within the oil turn to vapors…and are lost, leaving the remaining oil thicker and harder to pump. Making matters worse, the oil in an overheated engine will more rapidly break down, further thinning and vaporizing. After a while, you’re left with something less than high-quality engine oil. Synthetic motor oil tends to hold up better than conventional oil, but both are negatively affected when subjected to excessive heat.

All of this discussion about high ambient temperatures, internal friction, and the breakdown of oil sounds a bit scary and somewhat out of our hands, like a universal force over which we have no control. Not so.

In most cases, it’s our choices lead us down that dark path of machine failure…or keep us out of the woods. These choices include the basics of selecting quality oils, performing daily monitoring and on-time services, including oil sampling. But there’s more.

Your decisions regarding housekeeping, machine application, even machine selection in the first place, all have an impact on how your machines function.

Dirty machines are bad news: Layers of grease and dust will insulate engines and other components, holding in the heat and starting that cycle of increased thinning oil and increasing friction. Plugged radiators do not allow for proper cooling and are, in my experience, one of the most common contributors to machine overheating, especially when combined with overworking a machine.

When we think of temperature extremes, most often it’s related to heat. But extreme cold temperatures can also have a negative effect on machines.

Credit: LCSWMA
Dust is not your equipment’s friend. Clean filters are.

Cold
Your machine can also be impacted by cold weather. No, we’re not talking about a chilly morning when you wish you’d worn a sweater to work, but rather that extreme cold when engines won’t start and oil won’t flow.

I lived in Montana for many years and had the opportunity to see plenty of examples of how severe cold can affect machines.

Oil doesn’t flow, and diesel can gel, and batteries can lose more than 50% of their cranking power. To prevent these problems, block heaters are plugged in or the entire machine is stored inside to keep it warm.

Mechanics working in extreme cold have issues similar to those who work in very hot weather-similar but different. Tools don’t get too hot to handle, but if you pick up a cold wrench with your warm, moist hands, you might not be able to put it back down. It’s the same principle of the kid who stuck his tongue to the flagpole on a sub-zero day.

Extremely cold weather can create other issues. Soil will freeze solid, sometimes to a depth of several feet. Obviously, this makes it difficult to excavate for cover material. As a preventive measure, some landfill operators will cover their excavation area(s) or soil stockpiles with an insulating layer of mulch.

Operators who aren’t paying attention to this phenomenon can be met with surprises. One operator had been using a D8 dozer to rip through the frozen layer to expose the underlying soil. But he left the dozer parked in that area overnight, and came to work next morning to find his dozer frozen to the damp soil he’d exposed the day before. The dozer was stuck-solid-just as if it had been parked on freshly poured concrete. Not wanting to leave it for the next Chinook wind, he got a dozen or so 25-foot lengths of heat tape-like you’d use to wrap your water pipes to prevent them from freezing. He placed several runs of heat tape on the ground, encircling the area immediately adjacent to the tracks. The heat tape was covered with straw bales, then the entire machine was covered with a heavy-duty tarp. Finally, after several days of running a generator (for the heat tape), the ground had thawed enough to free the dozer.

Extreme weather conditions can-and do-have an impact on machine performance, and in order to compensate, you must understand how your machines are affected. First, as we’ve discussed, you must be even more diligent in regard to following your preventive maintenance program.

But when it comes to keeping your machines in great shape, there’s more to it than grease, oil and regular services alone.

That brings us to the issue of operations. Assuming that all the other maintenance factors we’ve discussed are in order, machines that are operated within the limits of their design, will-except under extreme conditions-function well, do their job, and just keep on keeping on.

The operations factor is one of the most overlooked aspects of keeping your machines up and available, overlooked perhaps because it requires that we step back and take a broader look at the overall system. We’ve found that a high percentage of maintenance problems originate with the use of the wrong machine for the job…or the right machine used improperly.

Credit: Doosan
Give your ADTs some TLC as well.

Wrong Machine
At one landfill, a D6 dozer was trying to do the work that was really more in line with a D8 dozer: push transfer truck loads. As a result, the D6 was constantly overloaded and lugging, not to mention half-buried in garbage.

Similarly, pushing steeply uphill, pushing oversize loads, or doing work that a machine was simply not designed for will definitely impact a machine’s performance and its effective life.

Inefficient Technique
Another thing we commonly encounter during operational reviews is machines working too many hours at tasks that they shouldn’t even be doing. Bulldozers, for example, which are pushing trash from the tipping pad to the active face…then spending twice as much time performing unnecessary cleanup pushes, back-blading, and general “keep busy” tasks.

Similarly, one of the most critical tasks performed by landfill equipment is the process of waste compaction. A lot has been written about how to effectively compact trash and why it’s so important to do so. But even here there are choices and special techniques known only by those who spend their working hours in the cab of a compactor, processing load after load of similar, but different, types of waste.

Matching the machine to inbound tonnage, even to the type of inbound tonnage, is key. Along that line, when selecting a landfill compactor, consider the soil type and climate. If your landfill has noncohesive soil, a machine with very large teeth and a dense placement pattern on the drum makes sense. Generally, more teeth into the trash equates to better compaction. Under those conditions, cleaner bars (to keep the drum clean) may be less important because the sandy soil does not tend to pack between the teeth.

Conversely, at a landfill with cohesive soil (i.e., clay), there may be more problems with wheel packing. In those conditions, it’s important to select a wider tooth placement pattern-or a machine that has a good cleaner-bar design.

Where wheel plugging is a problem, having a machine with very effective cleaner-bars, such as TANA or Bomag, provides important benefits.

Matching the size of the compactor to the inbound tonnage is a little bit art and quite a bit science. This is evidenced by the wide range of landfill compactors currently available. TANA alone produces five different models. Another dozen or so are offered by Caterpillar, Bomag, Aljon, and CMI.

Credit: Neal Bolton
From rags to cables and beyond-if you can imagine it, it can gum up your works.

Each of these models represents many millions in R&D, design, and manufacturing setup. Obviously they don’t do this for fun, but because they recognize that different landfills have different needs, yet all focus on achieving the highest possible waste density. So, while preventive maintenance and machine life play leading roles, in the landfill business, airspace is still king.

That is exactly why there are also a number of companies that take things a step further. Companies like Terra, MacPactor, and Caron manufacture wheels, teeth, and other attachments specifically for landfill compactors. When it comes to selecting landfill compactors, wheels, and teeth, having choices is not the issue-there are plenty. The issue is being able to sort through those choices and make the right decision in terms of make, model, and options…and, ultimately, how the machines are utilized. All things considered, the lube, oil, and filter aspect of machine maintenance really is the easy part.

Keeping your machines in tip-top shape requires a solid commitment to daily maintenance. But it takes more than that, because there’s a lot happening beneath that layer of orange or yellow paint. The more you know about how machine usage and environmental conditions affect your machines, the better your decisions will be in regard to maintenance.

About the Author

Neal Bolton

Neal Bolton is a civil engineer with 37 years of experience in heavy construction and landfill operations. He recently presented a four-part webinar series, “Process Improvement for Solid Waste Facilities,” through Forester University.

Photo 39297166 © Mike2focus | Dreamstime.com
Photo 140820417 © Susanne Fritzsche | Dreamstime.com
Microplastics that were fragmented from larger plastics are called secondary microplastics; they are known as primary microplastics if they originate from small size produced industrial beads, care products or textile fibers.
Photo 43114609 © Joshua Gagnon | Dreamstime.com
Dreamstime Xxl 43114609