Steeling Up Track Life

With undercarriage components contributing up to 50% of the owning and operating (O&O) cost of a large earthmover, there is a big opportunity for you to increase profitability by investing in the latest technology - both in terms of hardware and management tools. But the results will really depend on where you're operating and how you currently manage your undercarriage.

Reducing sliding friction and increasing component durability can increase undercarriage life. "Weight, motion and stress are what cause wear," says Dan Drescher, product marketing manager for crawlers, Deere & Company. "A larger component can take more of that than a smaller component."

As such, Deere & Company has increased the size of several major components. "We are using larger rails, a little larger bushing, larger pins," says Drescher. "But as far as wearing, it would be the bushings and rails that would be the big drivers. There is more surface area and a little more weight there."

Fewer pin and bushing turns
Pin and bushing turns have traditionally allowed you to maximize your undercarriage investment. The alternative is to run the undercarriage to destruction, which can be much more costly.

But you need to identify the appropriate time to make these turns. "If you go too long, then of course you lose that opportunity," says Drescher. The longer you can go between pin and bushing turns, the more money you can potentially save.

Deere & Company's SC-2 extended life bushings are intended to maximize undercarriage life and extend the time between pin and bushing turns. SC-2 is actually a coating process applied to the bushing. The coating is sprayed on with the aid of robotics, then fused to the bushing by heating it in a hydrogen furnace.

This coating adds strength. "What SC-2 gives you is a super-hardened coating that can actually flex on impact. So it doesn't break, but it still wears very long," says Drescher.

Flex is important in undercarriage components. "If the coating doesn't flex a little bit, then it could fracture," says Drescher. "You get accelerated wear and a broken component."

The SC-2 undercarriage is managed like a conventional undercarriage - you just run it to a higher hour level before turning the bushings. Its lower maintenance cost makes return on investment especially rapid in harsh environments. "In the abrasive Florida marketplace, SC-2 lowers your operating expense by about 35%," says Drescher. "Return there would be significantly faster than it would be in someplace like Ohio or Iowa, where they have loamy conditions and you are going to get 4,000 to 5,000 hours on your undercarriage without SC-2."

Of course, not all technology to extend undercarriage life is hardware related. For instance, Deere & Company has taken advantage of the new electronic transmission controls to limit operator-induced wear.

"On the crawler products, the transmissions are electronically EH controlled," says Drescher. "That allows you to program in adjustable reverse gear ratios. In a lot of applications, you can slow down your reverse speed independent of your forward speed. It does save on undercarriage wear, because on anybody's undercarriage - at least on the bushings - you [generate] wear twice as fast in reverse as you do in forward."

Less sliding = less wear
Caterpillar actually eliminates the need for pin and bushing turns with the SystemOne undercarriage on its D3 to D6 dozers. "From the standpoint of reducing the owning and operating costs, it has really saved customers a significant amount of money because they don't have the bushing turns," says Tom Neeley, sales support manager, Caterpillar. "In addition, they are getting longer wear life. We have customers who have almost doubled the life."

The SystemOne track uses high-tech cartridges to hold the links together. Unlike a conventional pin and bushing design, the cartridge design doesn't depend on the link interface to remain sealed. The factory-sealed cartridge joints are laser welded, which prevents loss of seal compression and reduces the likelihood of leaks.

The cartridge design offers other benefits, as well. "For years, we have talked to customers about operating in reverse," says Neeley. "In reverse with a standard undercarriage, the bushing will slide in the sprocket." But SystemOne is much more forgiving. "With the SystemOne undercarriage, the bushing engages and the links will move around the bushing, so it is not sliding. Thus, it is not causing wear on the bushing."

Sprocket life has also increased dramatically. "The sprocket segment itself did not change in design. But given the fact that the bushing is no longer sliding on the sprocket, you can go through two chains before you would have to replace a sprocket segment," says Neeley. "The same is true for the idler. That is a major savings."

SystemOne is also more tolerant of tight track. "Tight track is still bad, but it is not as detrimental," says Neeley.

The cartridges still allow the track to be removed for tractor repairs. SystemOne does not require a master link; the chain may be opened up using your own portable press or one from the dealer. It can be disassembled at any one of the box sections. "There is a master link that is available through the parts department," says Neeley. "It will soon be introduced on the machines at the factory."

Of course, the cartridge design is only one component of SystemOne. The whole undercarriage was redesigned from the ground up. All of the links - inside, outside, left and right - are exactly the same. Orientation is the only difference. "Because that link is a straight link, it is a stronger link," says Neeley. "It can withstand a lot more stresses than the offset link."

Rollers feature an increased flange diameter. According to Caterpillar, this provides optimum guiding and allows roller life to be extended to match chain life. In addition, the center tread idler contacts only the bushings and not the links, which eliminates link scalloping. The idler will also last longer because it contacts a rotating bushing instead of a link rail.

Overall, Caterpillar claims the SystemOne undercarriage can cut O&O costs 35% to 70%, and increase life expectancy by 50% or more.

A cost-effective choice
Most manufacturers continue to offer traditional undercarriage components, since the newer technologies may not make sense in every situation.

"We still offer sealed and lubed undercarriage for the non-abrasive areas," says Drescher. "It is a lower cost. Of course, you get a little less life, but it depends on where you are in your machine lifetime. If you are going to keep the tractor quite a bit longer, you might go with another SC-2 package. If not, you may put something else on that readily fits on the same track frame. There are no modifications necessary to do that."

The newer technology does require a higher upfront investment. "If I am going to do a retrofit from the standard undercarriage to the SystemOne, I am looking at an approximately 30% (premium), plus or minus a little bit depending upon the model size," says Neeley.

But if you are going to operate the machine for any length of time, this cost premium is quickly recovered. "We have seen people cut their cost per hour in half, even though they have spent 30% more for that undercarriage," Neeley points out.

Advanced undercarriage management
Effectively managing your undercarriage will help you to extend component life no matter what system you are using. "We have a lot more user-friendly management packages for undercarriages than we had even a couple of years ago," says Drescher.

Neeley agrees, "The tools are significantly different than what we started with when Caterpillar began our Custom Track Service (CTS) in 1959."

One of the most recent tools is an ultrasonic measurement device. "Instead of having to take calipers or take measurements with old hand tools, [dealer service technicians] can do it a little quicker with this ultrasonic tool and come up with results faster for the customer. It will tell them where they are in the process," Drescher explains. "And that tool will link to our Parts Expert program, which gives the customer a printout of where he is at."

There can be other advantages, as well. "The benefit of the ultrasonic tool is it pairs up with our undercarriage management software to download right to a distributor's product support laptop," says Mike Kunin, manager, undercarriage, Komatsu America Corp. "It does the calculations for them and produces an hours remaining wear report."

This ability to quickly assess wear can boost productivity. "If the manual measurements take 30 minutes, and the ultrasonics take 10 minutes, the customer has just saved a third of an hour he has taken his tractor down," says Kunin.

Ultrasonics also take less preparation. "You don't need to clean out the tracks," says Kunin. "You need a space of clean metal about the size of a quarter. So a scraper, a wire brush, allows you to do it a whole lot faster."

Recording measurements is also easier because you don't have to set the tool down to write down each measurement. "The ultrasonics allow you to do 200 measurements and download them all at the same time," says Kunin.

The margin of error is about the same, whether you measure the track manually or use an ultrasonic tool. "We have two different sets of specs," says Kunin. "We have a manual set of specs and an ultrasonic set of specs." Once someone is proficient in using either method, the accuracy level is going to be comparable.

"The most important measurement on the undercarriage is the bushing," Kunin continues. "That's the wear-out point. Once you do the bushing turn, you are on the run-out." That's why product support reps often shoot the bushing with the ultrasonic tool to determine the turn point and the life.

Komatsu is now in the process of taking the next technology leap by tying its undercarriage management technology with KOMTRAX. This web-based GPS equipment management solution provides critical machine data at your fingertips 24 hours a day. "KOMTRAX technology gives us the benefit of knowing how many hours are being put on a machine - and not just idle hours, but how many travel hours," says Kunin.

Today, product support reps measure the undercarriage life, then estimate the bushing turns or replacement schedule based on utilization estimates. "KOMTRAX gives us the ability, along with our software, to monitor if that utilization goes up or down," says Kunin. "Then we can start looking at working hours. You know the undercarriage is not going to get used at all when [the machine] is idling; we are not counting that as wear. The only thing that is going to wear out the undercarriage on a dozer is back and forth."

The objective is to manage the undercarriage as cost effectively as possible without wasting valuable time. "We are using [KOMTRAX] as a tool of predictability," Kunin states. The goal is to catch the undercarriage at 90% or 95%, but before bushings are worn to the point they can't be turned. So the undercarriage world is constantly changing with new products and management tools. And we have heard there is even more on the way. Stay tuned!

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