Dig Smarter, Not Harder

March 1, 2011
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While grade control is prevalent in the grader/dozer market, its acceptance on the excavator front is still an emerging trend. However, with the further “ruggedization” of machine-control systems, excavator-specific use is definitely on the rise. As more greenfield projects are created (and as the economy continues to recover), industry leaders are predicting excavator grade control as the next big game-changing competitive edge in a variety of applications-most notably in utility work, where its current use is estimated at 15% of all projects being quoted.

Excavator grade control delivers a host of benefits-from a big, big productivity payoff to major reductions in labor, material, and fuel costs-as well as minimized site delays, improved job-site safety, and, importantly, the ability to eliminate costly overexcavating. And, from a far more bottom-line standpoint, one contractor says, “My simple entry-level unit sticks anywhere I place it on the boom. It gives me no back talk; no complaints about the heat or the cold; takes no bathroom breaks; receives no phone calls; doesn’t ask me to change the radio station; works for peanuts-just a couple of batteries-and it keeps me from jumping in and out of the excavator to check the grade. It’s paid for itself many times over.”

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Manufacturers Stress Education
The makers of today’s major GPS machine-control and laser-guidance systems stress the importance of education. Contractors may not readily see the benefits of excavator grade control in general earthmoving applications, as opposed to its more obvious advantages in dredging projects, for example.

Nick Guadagnoli, product-marketing manager for Leica Geosystems machine control, points to machine utilization as a top benefit. “Outfitting an excavator with machine control allows the machine to be used for the whole operation, while eliminating multiple machines performing the same tasks. Also, unlike a dozer or grader, the excavator will tackle work in soft materials or in hard rock, allowing the operator to get to grade all with one machine,” he says, adding that excavator grade control also eliminates offset stakes and the need for a grade checker, allowing the contractor to reallocate resources-both staff and other machines-to areas of the project where their utilization rate is much higher. “Using machine control on an excavator turns the machine into a production tool that improves the bottom line by reducing rework, reducing machine idle time, and opening up new ways to utilize the excavator. The result is reduced wear and tear on the bucket and the rest of the machine; reduced fuel usage; and an increase in machine utilization,” he says.

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Tony Vanneman, construction-marketing manager for Topcon, explains that new sensor technologies have readied machine control for the excavator arena. He says that the previous generation of sensor technology wasn’t rugged enough for the hydraulic excavator environment, and did not offer enough repeatability as to the degree of accuracy pass after pass, and day after day. Plus, when one considers the motions of the excavator’s boom, stick and bucket-combined with the 360-degree movement of the machine-it is clear that the excavator would require a different sensor technology than that developed in past years.

Today’s new sensor technology (three-axis gravitational tilt sensors which “talk” to one another) is far superior, says Vanneman, and is robust and ready for use with excavators, regardless of the weather conditions and the level of abuse. The tilt sensors are placed on the excavator body, boom, stick and bucket and continuously calculate the distance from the cab to the bucket teeth.

Topcon’s 2D systems for excavators comprise non-GNSS (Global Navigation Satellite System) sensors and can detect various physical references, such as the existing surface, a hub, a previous cut or a rotating laser. The operator can choose a reference and enter a cut or slope depth. The system allows the operator to create multiple elevation or slope designs and cut to the design without the need to establish a reference.

For 3D grade control, the 3D GNSS sensors pinpoint the location of the bucket teeth relative to the slope. For example, Topcon’s X63 grade-control system, which is designed specifically for excavators, consists of four temperature-compensated 360-degree CAN-based tilt sensors that measure angles from the cab, boom, stick, and bucket; a GX-60 color touchscreen control box; two GPS+ antennae; and a GPS+ receiver. As the excavation proceeds, the operator views the machine’s exact position on the site, as well as the bucket’s position at any given moment.

As to its benefits of these systems, Vanneman stresses the virtual elimination of overexcavation as number one. “By preventing over-digging, the contractor obviously cuts costs in fuel, labor and wear and tear. But the substantial benefit is material costs savings by not wasting money on excess bedding material for example,” he says. “So when the project calls for 6 inches of bedding material, that’s what you end up with-and the very common and significant cost overruns in materials and material handling are eliminated. That’s why these systems pay for themselves so quickly,” he says.

Guadagnoli says that today’s machine control and guidance systems are designed to make it extremely easy for contractors to apply them to excavators. He suggests the Leica PowerDigger 2D excavator guidance system as a good place to start. “There is little to no learning curve-only the amount of time it takes for the operator to get comfortable with the full-color graphical interface which projects an image of the bucket in real time as they make adjustments to the bucket position. The system allows multiple elevations and slopes to be constructed at any orientation, without resetting the machine or laser height reference,” he says, adding that the system offers a new PowerDriller function that’s designed to maintain verticality for excavator drilling attachments.

Leica PowerDigger 2D features a PowerSnap technology that allows contractors to use the same control panel on an excavator, dozer, or grader. As a cable-free system, users can swap control panels between traditional grade and slope, and 3D machine controls as the job demands. Contractors can manage their grade control investments as their business grows with affordable upgrades all the way up to 3D GPS technology, according to Leica.

Tim O’Brien, marketing manager for Case Construction Equipment, agrees that the advantages of excavator grade control are speed, accuracy, and quality control. “Among the market forces driving the adoption of this technology is the pressure on contractors to reduce labor costs and to accept smaller projects to keep revenues flowing,” he says, adding that Case dealers can provide its customers with machine control and guidance systems through third-party vendors.

“Large contractors really can’t afford not to upgrade to this technology. The cost savings are too great to ignore, and the competitive risk of not using the technology is too great,” says O’Brien. “We’re not seeing this technology in residential excavation applications yet. However, it would be very important on the large-scale foundation excavations for commercial and industrial projects, and trenching for pipeline projects.”

RFPs for large jobs, says O’Brien, are starting to require machine control capabilities. “Overall, we’d estimate that 15% of large utility projects are using excavators equipped with machine control-not only to get to the right grade at the bottom of the trench, but to ensure safety by keeping workers out of the trench and away from working machines. Also, clients want verification of work done to within one-tenth of an inch of the plan-and excavator grade control technology provides verification of meeting engineering specs,” he says.

Kent Pellegrini, global excavator specialist for Caterpillar Inc., says that today’s larger contractors have the advantage of working multiple machines as one system. “When you have an excavator, a dozer, a grader, a backhoe, and a wheel loader all grade-control ready, they can work as a system. They all work together, each with a computer chip, and each downloading a site map. It is amazing what a system like this can do,” he says.

Caterpillar AccuGrade has been available for several years on the company’s dozers and motor graders but was just integrated and available as factory ready on its excavators in 2007. When Caterpillar launches the North American debut of its new E Series excavators at ConExpo 2011, customers will find position-sensing cylinders as standard on the new units. “So when a contractor selects a grade-control package, the stick cylinder will be a position-sensing cylinder versus potentiometers that were used previously,” says Pellegrini. He explains that when potentiometers were used on the bucket linkage, they were subjected to potential damage when down in the hole or when slinging heavy debris. “Having these position-sensing cylinders as standard will cut dealer installation costs. Our goal is offering a continually improved, integrated system and a “˜one-stop shop’ for all aspects of the machine,” he says.

Excavator Grade Control at Work
H&M Excavating of Kelowna, BC, operates GPS-equipped dozers, graders, and excavator and reports productivity increases of up to 40%. The company uses a Topcon 3D system on a Hyundai 290 excavator. Recently, this matchup worked effectively when doing site grading, roadwork, and underground utilities for a nine-lot subdivision cut into a hillside. The job site was tight, with lots that step up and down and a 12% grade road leading into it. If the project had been conventionally excavated, the stakes alone would have posed numerous obstacles, says the company.

The machine-control systems allowed H&M to easily make the changes required to go from rough grading to lot grading. As new engineering data came in, the lot grading information was merged into the model and the revised data was e-mailed to the job site, downloaded to a card, and transferred into the machine. The operator was then able to switch from rough grading to digging basement elevations with very little difficulty. Because H&M was able to complete finished lots with elevations within 1 to 2 inches, the contractor could come in and start building immediately.

Utility work on the site included a retention pond, dry well, rock pit, water lines, and sanitary sewer, all of which were built into the model plan. When it came time to excavate for the water line, the operator would simply flip to that particular model and would know exactly where to dig. The pipe crew would come in behind them, and sanitary and storm crews would then follow up with lasers and stakes of their own-but basically the excavator already had already done the work for them, according to H&M.

The move to machine control, particularly on the excavators, presented an initial reluctance to change on the part of the operators. But H&M management says that shortly after adopting the technology, the operators didn’t want to return to conventional methods. They had found that it took a lot of stress and guesswork out of the job, as well as keeping the project far ahead of schedule.

Ebert Construction Co., Wamego, KS, is using 3D machine-control systems on its excavators to help reshape 2.5 miles of the channel at Soldier Creek, which is contained by two parallel levees spaced 300 feet apart. A major flood in 2005 eroded the creek banks and this project will repair the damage, helping to prevent further flooding upstream of the repaired area. Ebert has engaged a fleet of earthmoving equipment to remove 350,000 cubic yards of earth from the side slopes and take them to waste areas behind the levee. Some 170,000 cubic yards are being moved from cuts to fills on the slopes

Two Komatsu hydraulic excavators, a PC400LC and a PC300LC, are each fitted with a PowerDigger 3D machine-control system from Leica Geosystems, and are being used to shape the side slopes. Each slope is designed with an upper and a lower bank, both on a 3:1 slope and separated by a gentler 10:1 slope.

Ebert has a GPS base station at the job site, and it continually corrects satellite signals sent to the dual receivers on the excavators. Each excavator has three sensors mounted on it-one each on the boom, stick, and bucket. The sensors and the GPS system feed information to the onboard computer about the bucket’s locations-in two, or three dimensions-to the design template.

Jim Ebert, project manager for the contractor, says the Leica PowerDigger 3D systems improve the excavators’ efficiency because no grade checking is needed. He further states that the systems save Ebert $40,000 a year by eliminating the grade checker. The Power Diggers’ screens show the operators the cuts and fills on a continuous basis. “Plus, we can work underwater without having a grade checker climb into the water,” he says.

“The Leica Geosystems GPS takes the guesswork out of grading for the operators,” says Trent Ebert, project superintendent. “And there’s no more calling us to say the stakes got run over by a dozer. There’s no downtime. Nobody has to watch the operators; they can dig, back up, find the next place to cut, and keep on going.” Due to these efficiencies, Ebert estimates that the company will boost its productivity and beat its scheduled completion date by up to 15%.

Excavator Grade-Control Training
“Training is not a challenge when you have a reliable, highly skilled dealer to call upon. Leica Geosystems offers many training options at different price points through our dealer network. We also offer computer simulators that allow an operator to get comfortable with the way the software looks and reacts in a non-production environment,” says Guadagnoli.

Vanneman says that Topcon also stresses training with the local dealer. “We also offer Topcon University, and we can supplement dealer training with online training classes and classes at our facility or in the field. We are a huge advocate of the team-teaching concept with the operator, the grade setter, and the foreman all there for the training. That way everybody is reading from the same page, and that eliminates any finger pointing,” he says.

“Training usually takes two to three days, and we take it step by step,” says Ryan Neal, connected worksite demonstrator instructor for Caterpillar, Inc. “The challenge is getting people to trust the system. First of all, it’s hard for them to quantify how they are going to make money with it. Many think the old way is the good way. But once they use it, they don’t want to do without it. It makes a good operator a great operator. But there is always that learning curve and there will always be that slight lag of unproductive time, and that scares people. But once they get over that hurdle, there is no going back,” he says.

A Competitive Edge
With headquarters in Hamden, CT, Sweeney Excavation reports that it is the first in its state to incorporate GPS technology on its excavators, having done so in early 2006. Owner Robert Sweeney describes his company as a dedicated Volvo user, with six units in his fleet-each so very well supported, says Sweeney, by a longtime Volvo dealer partner, Tyler Equipment Corp. of East Longmeadow, MA. His Volvo EC290B excavator is equipped with a Trimble SiteVision GPS system, and he has five other Trimble systems applied to dozers and graders. The company has evolved from the use of GPS base stations to networking its fleet via a modem and a broadcasted signal to each of its machines on the site.

“Combining GPS technologies with excavators pays back every day if you implement it correctly with a well-trained operator,” says Sweeney. “A good operator can visualize, but you have to give him the vision. The vision is now in the cab of the machine. He can be anywhere on a construction site and know exactly what he is going to build and where he is going to build it. It’s all about improving ourselves for our customers. We can complete our projects far more quickly and accurately, and with less people. The future looks bright for the expansion of these technologies on excavator fleets.”

Crunch the numbers on the costs of every aspect of over-excavation. It’s a no-brainer that machine control and guidance-particularly on the excavator-is a game-changer. Think of it as a marketing tool that can be used as leverage. You have technology that will eliminate costly errors. Your competitor does not. Who has the edge?