Fine Grading Refined

April 18, 2013

Having smooth asphalt and road surfaces is not only safer for drivers and pedestrians but it also saves on wear and tear of road at the same time keeping those surfaces from having to be replaced and worked on as much as they were in the past. New technology can make sure the finished product is even better than it has ever been. Qualified and able equipment operators continue to remain vital as well.

Logistics an Important Part of the Mix
Finding skilled operators with the ability to utilize a motor grader to fine grade is a challenge, as Michael Ackerman, motor grader product marketing manager with John Deere Construction and Forestry points out. “Not only do they need the ability to do the final pass, they also need to learn how to handle the material. This involves placement, processing, material moisture, and so forth to make that final grade,” says Ackerman.

Job sites may pose challenges as well. “In order to handle the material, other support equipment such as water trucks, haul trucks, or compaction equipment is required,” explains Ackerman.

“In order for the motor grader operator to be as productive as they can be they cannot wait for this support equipment. Thus, coordinating all the support equipment is a key part of fine grading work and motor graders are most useful for this type of work.”

The process remains twofold. First, motor grader controls allow the operator to accurately control hydraulic functions, particularly the blade raise and lower. This allows the operator to produce finished grade at speeds greater than ever before. In listening and responding to operators, John Deere offers them a choice of controls with their G/GP offerings that both include a steering wheel.

The company’s G offering includes conventional mechanical levers positioned in the industry-accepted pattern on both sides of the steering wheel. The GP offers armrest-mounted actuated controls including a steering lever arranged in the industry standard pattern. The second is the ability to offer grade control systems and enhance the operator’s ability to produce fine grade. The GP offering also comes standard equipped with automated cross-slope control, which allows the operator to hold a consistent slope utilizing one blade lift lever versus two. The operator inputs the desired slope, and the system automatically adjusts the opposite blade lift cylinder to maintain the slope.

In terms of technology, the two main players here are tire technology and grade control systems, each playing a part in high-production finish grading. Tire technology has allowed the operator to produce fine grades at higher speeds by working to eliminate “bounce.” The operator produces a glasslike finish over that of a washboard. Grade control systems continue to enhance the operators’ ability by offering the ability to produce millimeter-accurate finish work.

“John Deere’s “˜open-architecture’ design on our GP models lets the customers employ their favorite brand of grade-control system. GP models come factory-equipped with bulkhead connectors, sensor mounts, electrical wiring harnesses, integrated controls, and exclusive universal moldboard mast mounts. So adding Topcon, Trimble, Leica or other grade-control systems is neat, quick, and noninvasive.

“The operator is a key part in producing fine grading work,” adds Ackerman. “Thus, improving the operator experience is a key to continuing to improve fine grading productivity. Items like operator comfort, visibility, user-friendly systems, etc. will all have an impact on this. Finally, simplifying training on the machine features and grade control systems will make the learning curve much shorter and allow that operator to be more productive sooner.

“Critical to how a motor grader performs is how the machine is balanced from a weight standpoint. John Deere recognizes this and has utilized input from operators that do this type of work every day to develop a well-balanced machine. Another key to how a motor grader performs is horsepower and, more importantly, getting that power to the ground.”

A key part of that is the company’s six-wheel drive offering. These motor graders are able to put the entire weight of the machine and all six tires to work boosting production of the finish grade work completed. Six-wheel drive enables the motor grader to move heavy windrows of base rock to process the material. This processing requires the motor grader to move at higher speeds to get a good rolling action off the blade and ensure proper mixing of the material. The six-wheel drive configuration allows the motor grader to sustain this speed and drive higher productivity on the job site.

“Despite all the technological advances in fine grading, I see no worries for those wondering if their jobs are in jeopardy,” adds Ackerman. “I would say this is not an issue. As I have commented, the operator is integral to fine grading work and will continue to be.”

Keeping up With the Changes
Technology has changed dramatically in the last decade with the advancements in machine and grade control with the GPS and laser control systems, according to Jeff Hulse, product specialist with Case Corp. “These systems improve efficiencies and reduce costs due to fewer passes involved in the fine or finish grading process, which means lower costs in fuel and wear and tear on machinery. Case motor graders can be fit with any of the major brands in the machine control industry.”

Continued advancements in machine control and job mapping, things like integrated GPS in motor graders, simplified setup and operation, as well as smaller base stations and receivers are driving the changes on the this equipment, explains Brad Stemper, Case manager, product sales training “To keep up with all the change out there, Case offers a full line of motor graders and compaction equipment, including both soil and asphalt compaction equip. Several unique features of the Case grader make it an excellent choice for all phases of the grading process.”

The involute multiradius moldboard design provides excellent mixing of material with less segregation of aggregates and fines. The multiradius also requires less horsepower to move the material, which also computes to less fuel consumed. “Case all-wheel-drive graders offer an excellent “˜creep’ feature, which allows for infinite speed adjustments from zero to 3.6 mph, allowing the operator to maneuver around such tight turns and obstacles as curb and gutter when finish grading,” says Hulse.

“Front articulation is another unique feature of Case motor graders,” adds Stemper. “This provides better visibility and control. You know where you’re going just by looking out at the front of the machine. Also, the cab sits back farther, so there’s better visibility to the moldboard.”

Less Need for Workers on the Ground
Michael Salyers, product marketing manager at Komatsu, has been in the machine control business for the last 12 years, working for a GPS distributor. His main focus remains on the machine control portion of operations. Komatsu has partnered with Topcon Positioning Systems, and it also works well with Trimble Positioning.

“Komatsu is integrating the machine control technology in their machines so the blade is controlled automatically,” he says. “Electronic information can be used from the design engineers, plugged into the machine, and this allows the machine to guide itself to the design grade. It’s a major benefit for grading applications in that not only are we doing a lot of the rough grading, but we are fine grading at the exact same time. We’re able to get to grade faster.”

It is also possible to get to grade more precisely than ever before. In the days of stringlines and grade stakes, the operator often had to guesstimate where the grade was between the stakes. He would also have to rework a lot of areas in order to get there, and there was multiple checking going on behind the machine. Sometimes the machine would cut too low, cut too much material out, and the material would be have to be backfilled in that area.

“Whereas at first the operator was in a cut environment or situation, now he’s in a fill situation. Now, in essence, he’s double-handling material, and prior to this technology that would happen often. With integration of the GPS machine control with a machine-both in the grading position and horizontally-the machine is able to both get to grade and it’s going to help prevent those undercut situations where we are going to be cutting out too much material and have to have multiple reworks. The machine is also able to be navigated to the exact location where a feature may be installed, created, or needs to be worked.”

For company owners, the cost of materials continues to increase, according to Salyers. The cost of moving materials continues to increase with fuel costs and the wear and tear on machinery. The less time you can handle machinery the greater your profitability.

With this technology, operators are also able to guide the edge of the blade to the exact back-of-curb and be able to cut the road to the exact width that it needs to be cut. No overcut area is being provided.

“Many times, prior to the development of this technology, the subgrade would be moved, massaged, and they would get it fairly close; there would be highs and lows, dips and valleys,” says Salyers. “What would happen to those dips and valleys is that they would be filled in with the high-dollar material, the concrete and asphalt. In turn, that is costing the state or municipality more money because the contractor is going to get paid by the ton.

“A lot of state entities are now going to a fixed-cost bid project where they’re saying, This is how much money we have, this is what we want to do, the contractor needs to come back and tell us what the design is, what can they do for this. And the state specifies the tolerances, what they want to see, but they’re leaving it up to the design firms to come back to them and say, This is what we can do.”

This is one way the states are saving some money, by being able to complete some of these projects, and a lot of them are requiring machine control, according to Salyers. This is becoming a main portion of the savings: Not only are they working with the tier for engines and those requirements-the mechanical portions of the equipment-but they’re also integrating this new intelligent function that is driving the cylinders, driving the blade, and allowing the operator to have more of a smarter machine.

As with the automotive industry, many of the new dashboard features are being integrated into the construction industry as well. With the automatic blade control, the operator can now get to grade quicker. “Remote job-site management may be possible, where the office is able to monitor the machine’s progress on the job site remotely, being able to do that on multiple machines and getting relayed back to them real-time information so that they know what the production of the machine is in real time.

“Having the most up-to-date information is making the machine more productive than it ever has been. Smoothness is incredibly important when it comes to roadway surfaces, because the smoother it is, the less it will be affected by heavy truck traffic; the pitted road is not going to last as long. Abuse from very small bumps in the pavement radically decreases the life span of the pavement. The smoother the pavement, the longer it lasts. Entities don’t have enough money to continue to rebuild these roads on a frequent basis.”

Every GPS-machine-control manufacturer has kits available that enable users to retrofit any of the existing asphalt surfacing machinery. There are so many machines out there that don’t have machine control. But the ability to take a machine that doesn’t have the controls and install machine controls makes the useful machinery that you had before even more useful. Probably about the only disadvantage you have is that the machine isn’t as fine-tuned as a newer machine.

“But still, the payback we have seen in talking to a lot of customers is that they see payback in 12 to 18 months on the entire system. They’re seeing in about a year the system paying for itself. I’ve even had conversations with many contractors who’ve said they’ve paid it back in that first job. Completing a job without any staking, without any string lines, without any rework, you are reducing a four-pass area to a two-pass area. That’s a 50% reduction in passes. You can really make up a lot of that initial cost very quickly.”

Komatsu has established an ICT division specifically for intelligent machine control, with four members on the team. The models they are integrating with the Topcon technology direct from the factory provide them with an enormous benefit to be able to take on many of the models that are current and simply plug that Topcon equipment in. There’s going to be very little to do on the machinery to make it ready for the 3D positioning for their job sites.

“This can be used on many projects, from a commercial development to a residential subdivision; there are so many uses that it allows the contractor to be productive and move job-site personnel to other tasks on the job, essentially a machine free from any ground support. No one needs to be following this machine or giving them information to grade to on the ground or insuring that the machine is doing what it needs to do. This technology has reduced the number of grade checkers, surveyors.”

Keeping an Inventory
The problem of tight tolerances, especially without the current technology in grading equipment, has been among the greatest challenges, according to Wade Porter, motor grader application specialist with Caterpillar. “Meeting the “˜mm’ accuracies that job specs require is extremely difficult,” explains Porter. “This requires a tremendous amount of skill, some acquired through years of experience and training and some that is just plain natural, like the ability to see grade. These require a motor grader that provides precise, consistent, predictable blade control via superior performing hydraulic systems.

“The design ingredients of the implement hydraulic system are critical. They must be designed specifically for motor grader operations, which is why Caterpillar designs and manufactures its own hydraulic valves, ensuring tight control over design and manufacturing specs for industry-leading results. This is one of the main reasons that contractors are willing to pay a premium price for a new or used Cat grader.”

Obstacles-curbs, medians, light poles, hubs, grade checkers, and other equipment-prove a test on job sites. In addition to increasing stress, causing visibility issues, and increasing time, having to maneuver around obstacles can introduce unwanted machine movement, causing grade change or elevation change of the moldboard as the result of articulated turns.

The various material types used on a job site introduce various challenges, such as rocky versus fine. Inconsistent material types on the same job site can also create headaches for operators, according to Porter. “Compaction and moisture content as well as aggregate moisture have to be optimum to ensure proper compaction-if moisture isn’t optimum, it increases and costs, as it could drive additional material dumps or mixing time.

“Tire type and pressure: radial versus bias, old versus new, tread pattern. All these variables can introduce challenges in finish grade operations. Too stiff of a sidewall can create too much vertical movement. Too soft of a sidewall can cause lateral movement. Inconsistent tire pressures can negatively impact the ability to reach final grade as well.”

Timing matters, as time, of course, is money. The pressure to meet daily square-foot finish adds stress, which creates operator discomfort. Bottlenecks can also create challenges, as material moisture can change over time, so waiting on other support equipment can create challenges. An example of this would be waiting on dump trucks or waiting for the dozer to knock down piles and spread material. Material dumps and spreads and even spreads are key.

“If support equipment isn’t present, the grader must be used to spread the material dumps,” adds Porter. “Depending on how well or how poorly the belly or end-dump driver can effectively spread their loads, could create significant challenges, driving up time and increasing costs.

“Machines well maintained including cutting edges, moldboard slide rails, cylinders, articulation joint, same size tire, same age tire (tread), same tire type all prolong the life of the equipment.  The ability to maintain the wear points on a grader is critical. If wear points are difficult to maintain, work doesn’t get done and may takes longer to get done driving up costs.”

If the grader isn’t maintained properly, the ability to finish will suffer. Caterpillar graders have easily accessible wear inserts with shim-less designs wherever possible to minimize time. Cat’s drawbar and slide rail adjustment points are simple and easy and provide the capability for the operator to make the adjustments in the field, eliminating the need for service truck.

Sometimes grader operators might not know they have to finish until the afternoon, for example, when they are told to head to a different location on the job site. They might need to make some quick adjustments to pull up the slack in these key areas. This is a real advantage with the Cat design. In addition, the cylinder rod mounts need to be kept tight, which is why Caterpillar provides replaceable wear inserts and bushings in the lift cylinders and link bar.

Grading machinery must be the right size for the work. Work in tight areas like parking lots requires a smaller, more agile grader. Working in larger road projects requires heavier graders to spread material faster and in more compact areas, provide greater blade down force.

Too small a blade can create a lot of challenges, according to Porter. “Crumbs flying off the toe, cast materials beyond tandem tires; too long of a blade will be more sensitive to minor corrections laterally.

“A comfortable operator is more productive-period. If fatigue sets in, concentration is negatively affected which can cause safety issues as well as make it much more difficult to meet that tight “˜mm’ accuracy. Cat graders provide simple, intuitive electrohydraulic joystick controls that decrease operator fatigue by as much as 50% and decrease hand/wrist movement by as much as 78% as compared to conventional control systems.”

Operators have to be able to see. They need to be able to see the objects around them-including machines, people, grade stakes, blue tops, curbs, or manholes-for productivity and for safety reasons. Obstacles wreak havoc on a finish grade operator. Any distortion in the window glass can hamper the operator’s ability to finish. This is why many finish grade operators run with the doors or windows open, so they have a clear line of sight to the material/surface they are working. Cat redesigned the M Series cab with angled doors to promote visibility to the work tools as well as the general surroundings.

Technological advancements have been paramount in improving finish grade operations, from machine operation, to project management, to cost savings. However, it can also create certain challenges. Seasoned motor grader operators tend to resist change, so if they don’t adopt this technology, their resistance can be a problem.

“Grader operators also need to understand how to use the grade control systems and be able to troubleshoot them when there is a problem,” explains Porter. “Certain times of the day, satellite signals are down. If a grader operator doesn’t know how to recognize this, their grade accuracy is shot for that time frame. There are many do’s and don’ts associated with technology. If these pitfalls are unknown, a grader operator will suffer dramatically.

Motor graders are finishing machines. Small or mid-size TTT’s (D4-D6) help knock down piles and spread. SSL or BHL help clean up and reach places that a grader can’t reach, such as parking lots in certain areas. Compaction work with roller must be done before final finishing can be done with the grader. Paddle-wheel scrapers with the ability to collect large windrows without scattering material provide compaction, and can also spread material in light areas

“The earliest “grade” technology that I can recall is the SlopeMeter No. 2 level gauge mounted on the front frame of a grader,” adds Porter. “Laser systems were some of the first “˜blade control systems’ to hit the market. Cross Slope and Sonic I believe, were next in line, and then GPS systems came after that (to the best of my knowledge), using satellite communication. The Universal Total Station (UTS) is the latest development out.

“The introduction and advancement of blade control technology has been a game changer. Speed time, fuel savings, accuracy improvements, reduction of resources, reduction of passes, reduced waste, saving money, maximizing asset utilization, less operator fatigue, material savings, jobs done quicker, increased revenue, improved safety, better project management-more competitive bidding, better fleet coordination-communication, reduction in labor time, and the ability to lay jobs out remotely are all benefits from this technology. Cat offers a full suite of Cat Grade Control and AccuGrade systems to complement our motor grader product line. These devices range from simple Cat Grade Control Cross Slope, Sonic, Laser and GPS, all the up to the most sophisticated UTS systems.”

The reduction of external hardware such as masts-as they are designed on most products today-might be something that would improve the equipment, according to Porter. Such external hardware serves as an obstacle, negatively affecting operator visibility and machine versatility (limiting blade reach in some cases). Masts are also targets for theft, and it takes time to remove equipment at the end of the shift everyday and then reinstall it every morning.

Another problem comes from unwanted rotation. Depending on brand and system, certain hydraulic functions can throw off accuracy by as much as 1% to 2%. Most manufacturers of blade control systems use a single mast in conjunction with the grader’s main fall and cross-slope sensors, which are fluid based, so any unwanted rotation or machine listing, for example can throw off the system’s accuracy. “Caterpillar and Trimble are the only manufacturers to offer dual-mast GPS systems that eliminate the need for these fluid sensors,” says Porter. “They in turn increase accuracy and machine versatility.”

Many grade control users don’t realize that single-mast GPS or UTS systems used on motor graders are only at their highest accuracy when the machine has no articulation or wheel lean. These common MG operation practices introduce inaccuracy into single-mast systems that rely on cross-slope sensors to know where the other side of the moldboard is located.

Cat and Trimble dual-GPS systems track both sides of the moldboard, and therefore account for this unmeasured rotation created by articulation or wheel lean. If you are using a single-mast system, remember that, for it to be the most accurate, you must keep your grader in a straight line, with no articulation.

Cat graders are very “vertically” integrated in their design, incorporating such Cat-designed or branded components as engines, transmissions, final drives, hydraulic valves, and hoses. This vertical integration ensures proper design and control for the best quality and reliability.

“We make sure that all hardware and software are properly integrated into the machine, so our dealers have minimal shop time in order to get a grader properly setup prior to delivery. It also gives our customers a one-stop-shop for all their machine and technology needs, saving them time, money, and headaches that come with having to make two phone calls-one for the machine and one for the technology.”

The Cat M Series graders provide the operator with electrohydraulic joystick controls, increasing productivity while improving comfort and decreasing fatigue levels. Machine transmission and steering controls are incorporated in the joysticks so operators never have to take their hands off the controls to operate the grader, making for safer operation. The electrohydraulic technology enables automation of certain hydraulic functions, such as Cat’s articulation return-to-center feature, which returns the grader to a straight frame position with the press of one button. An angled door cab design opens up new lines of site for greater visibility of the work tools, as well as all things around the machine, increasing productivity and improving job-site safety.

Keeping Control Operations Easy
To avoid cost overruns on grading projects it is important to grade various levels of materials accurately. For instance, if 6 inches of concrete is called for in a large building pad, the general contractor is expecting that spec to be fully met; but the subcontractor of the building pad doesn’t want to incur extra costs by placing any more of the most expensive material than required to meet spec. He wants the initial lower cost base materials to be laid down exactly to grade.

“This focus on cost control is one of the main challenges contractors face today, in addition to the challenge of retaining his best people,” explains Gary J. Atkinson, Volvo Construction Equipment’s southeast US district manager for road machinery. “A motor grader operator is regarded as one of the most senior individuals on any particular grading job site. Contractors are taking ever closer looks at the machines they purchase in order to provide their operators with the safest, most comfortable and productive work stations available.

“For example, looking back a few decades, it was virtually unheard of to see equipment with factory-installed air conditioning. Nowadays I can’t recall when we’ve built a motor grader that didn’t have full air conditioning, cab air filtration, and pressurization.

“Beyond that, our machines now come standard with telematics, enabling machine owners to stay in touch with the machines electronically via satellite or cell service direct to their desktop or portable computers. This enables us to coach their operators on techniques to further enhance efficiency and productivity.”

One of the biggest recent advances involves integrating most of the grader’s control functions within the Volvo’s optional joystick controls. This system enables operators to control all blade functions, steering, articulation, transmission gear ratios, forward-reverse, and, when equipped with automatic grade-slope control, also operate those functions from the joysticks.

This is all done without the operator having to take his hands off of the joystick controls, thus reducing the operator’s use of major muscle groups literally hundreds or thousands of times per day. With a conventionally controlled grader, operators reach for the steering wheel, use their hands to actuate the various blade controls, articulation, and wheel-lean levers, and shift the transmission gear ratios and forward-reverse direction.

Beyond the joystick controls, Volvo has taken things to an even higher level with the Memory Gear feature, which enables operators to preset forward and reverse gears and-for repetitive direction changes such as when working a building pad-to shuttle shift directly to those gears without clutching or braking at the end of each cut.

“All combined, it’s an amazingly productive system,” says Atkinson. “Another recent area of focus has been on reducing the amount of tolerances and movement throughout the blade/circle support system. This enables the operator to hold even more precise control, whether operating manually or with automatic blade control, according to Atkinson. These latest systems not only hold tighter tolerances but reduce maintenance costs, contributing to lower operating costs and greater productivity.” 
About the Author

Peter Hildebrandt

Peter Hildebrandt writes about construction, technology, and industry.

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