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The latest milling machine technology can maintain tight tolerances and increase production, while reducing the demand for workers.
New milling machine technology allows you to achieve tighter tolerances, maintain high productivity and avoid placing new demands on milling personnel. Tom Chastain, Wirtgen American Milling Product Manager, said: “The new generation of slope control, milling drum technology and a new operating system make it easier to increase productivity than in the past while achieving higher quality.”
The process of setting up cutting and monitoring machines has also been simplified. “Compared with older generation equipment, on-board diagnostics, simple slope control settings and automatic calibration procedures greatly reduce the operator’s responsibilities,” said Kyle Hammon, Astec’s technical sales manager.
In order to maximize output and surface quality, the milling machine must be able to detect the changing load on the machine and react accordingly. Astec’s goal is to maintain high-quality milling patterns while maximizing output and protecting machines and workers. This is where the latest technology comes into play. Some models of new milling machines have an operating system that allows the operator to choose between milling modes​​. This allows the operator to control the mode.
“You can tell the machine what knife and drum line spacing you have and what pattern quality you want to achieve,” Chastain said. These settings can even provide insight into the cutting tool you are using. “The machine calculates this information and determines the speed of the machine, the speed of the cutting drum, and even the amount of water. This allows operators to maintain their production lines and convey materials while the machine does the rest.”
In order to optimize production and surface quality, milling machines must be able to detect changing loads and react accordingly. “Engine load control and traction control systems are in place to keep the machine running at a constant speed and to prevent sudden changes in working speed from causing defects in the milled surface,” Harmon said.
“An active load management system like Caterpillar’s load control allows the operator to push the machine to its maximum capacity without the risk of machine stalling,” said Jameson Smieja, Caterpillar’s global sales consultant. “This can significantly increase the productivity of the machine by guessing how hard the operator pushes the machine.”
Caterpillar also provides cruise control. “Cruise control allows the operator to store and restore the target milling speed by pressing a button, thereby helping the operator maintain a consistent pattern throughout the project.”
Functions such as load control ensure the most efficient use of available engine power. “Most cold planers allow operators to choose the engine and rotor speed they want to cut. Therefore, in applications where speed is not the primary consideration or trucks are restricted, operators can choose lower engine and rotor speeds to reduce fuel consumption. ,” Smieja explained. “Other functions such as idle speed control allow the machine to decrease to a low idle speed when stopped, and only increase the engine speed as needed when certain functions are activated.”
Wirtgen’s MILL ASSIST machine control system helps operators optimize the results of the milling process. Wirtgen Wirtgen focuses on increasing operating costs. “The latest version of the machine is more economical in terms of fuel, water and tool consumption, while [reducing] noise levels,” Chastain said. “Having an operating system that informs the machine of what we are trying to achieve, as well as a new two-speed transmission, allows the machine to run at its best, while also monitoring consumables.”
Tool holders and teeth have also been developed. “The updated cutting technology gives us more confidence in our milling performance and smoothness,” Chastain said. “The newer carbide tools, as well as the current PCD or diamond tools, allow us to mill longer with less wear. This means that we don’t stop often, we will keep this for longer. A quality model. These latest innovations in cutting technology and higher machine performance allow us to achieve quality and material output.”
The popularity of diamond cutting bits continues to grow. According to Caterpillar, these drill bits have a life span of 80 times longer than carbide drill bits, which can significantly reduce downtime.
Astec “This is especially true in demanding applications where carbide drill bits must be replaced multiple times a day,” Smieja said. “In addition, diamond drill bits tend to remain sharp throughout their life cycle, which enables the machine to produce consistent milling patterns and maintain higher cutting efficiency, thereby increasing productivity and saving up to 15% in fuel.”
Rotor design is essential to ensure the expected results. “Many rotor designs have varying degrees of cutting tooth spacing, allowing the operator to obtain the pattern texture required for the final milled surface while removing as much material as possible,” Smieja said.
By reaching the target level for the first time and eliminating rework, a milling machine equipped with the latest level control technology is expected to significantly increase productivity, so that the initial investment cost can be quickly recovered.
“Thanks to modern grade control systems, today’s milling machines can be very precise and produce smooth contours,” Smieja said. “For example, Cat cold planers come standard with Cat GRADE, which has slope and slope functions, providing versatility and flexibility for any number of applications. Whether the goal is targeted depth removal, milling to improve smoothness, or Milling to precise design contours, Cat GRADE can be set and adjusted to achieve the best results in almost all applications.”
Slope control has been improved to make it easier to achieve consistent depth and/or slope. Chastain said: “Simplified but state-of-the-art technology provides operators with fast and accurate responses, while also reducing their work pressure.”
“We are seeing more and more 3D technologies entering the milling industry,” he added. “If the settings are correct, these systems work well.” The averaging system uses sonic sensors to average machine lengths or longer cutting depths.
Complicated work is conducive to 3D slope control. “Compared with standard 2D systems, the 3D slope control system enables the machine to mill with higher precision,” Hammon said. “In more complex projects that require different depths and lateral slopes, the 3D system will automatically make these changes.
“The 3D system really needs to create a digital model based on the road data collected before the milling operation,” he pointed out. “Compared with traditional 2D operations, building and implementing digital models on a milling machine requires more work in advance and additional equipment.”
CaterpillarPlus, not every job is suitable for 3D milling. “While 3D milling provides the best accuracy relative to design specifications, the technology required to achieve that accuracy requires significant investment, as well as additional site management that is only suitable for special applications,” Smieja said.
“Workplaces with good sightlines, controllable distances, and minimal interference to 3D control stations (such as airports) are good candidates to benefit from 3D slope control, which helps meet strict regulations,” he said. “However, 2D slope control, with or without chords, is still an effective way to meet many of today’s milling specifications without the need for additional hardware.”
Orange Crush LLC is a Chicago-based general contractor responsible for a series of projects, including asphalt and concrete road construction and excavation. It paves roads and subdivisions as well as commercial real estate.
“We can use six asphalt plants in the Chicago area,” said Sumie Abdish, the general manager. “We have five grinding groups and seven grinding machines (milling machines).”
With the help of SITECH Midway, Orange Crush chose to install the Trimble 3D master control system on its latest Roadtec RX 700 milling machine. Although 3D milling is relatively new, the contractor does have extensive experience in 3D paving.
“We first equipped our pavers because we were almost done on the toll road [project],” Abdish said. But he thinks the best way is to start with a milling machine. “I firmly believe in starting from scratch. I think you’d better do 3D milling first, and then laminate the milled materials together.”
The 3D total station solution allows stricter control of all aspects from output to accuracy. This has indeed proved beneficial to the recent Norfolk Southern Railway Yard project in Englewood, Illinois. Orange Crush must maintain strict grades, and the 3D total station technology eliminates the need to constantly draw numbers in front of the rolling mill and constantly recheck work.
“We have a person behind the mill with a rover, there is a little extra cost, but it’s better than having to go back because we missed two or three out of ten results,” Abdish commented.
The accuracy of the Astec system has been proven to be correct. “It got the money score the first time,” Abdish said. “Your output in this application has increased by 30%, especially when you have a variable depth milling machine and you maintain a certain altitude and slope in each position.”
The technology does require a lot of investment, but the payback can be very fast. Orange Crush estimates that it has recovered nearly half of its technology investment in the Norfolk South project alone. “I will say that by this time next year, we will pay for the system,” Abdish predicted.
The site setup usually takes about two hours with Orange Crush. “The first time you go out for a measurement, you have to calculate two hours in the morning and calibrate each time you transfer the machine from one job to another,” Abdish said. “Before you send the truck there, you must get the machine there a few hours in advance.”
For contractors, operator training is not a daunting challenge. “It’s not as big a challenge as I thought,” Abdish recalled. “I think the learning curve of a paver is longer than that of a polisher.”
The person in charge of measurement/machine control guidance is responsible for setting up each job. “He will go out to control every job, and then work with SITECH to make the first measurement of the machine,” Abdish said. Keeping this person up to date is the most important part of the training. “The actual staff immediately accepted it.”
Thanks to the positive experience gained, Orange Crush plans to expand its 3D milling capabilities by adding the Trimble system to the recently acquired Wirtgen 220A. “When you have a project, you have something that will keep you in strict hierarchical control, which is just an idea,” Abdish said. “This is the biggest thing for me.”
The increased degree of automation and simplified control means that staff do not have to press buttons frequently, thereby reducing the learning curve. “By making the operation control and slope control user-friendly, novice operators can use the new machine more easily, instead of the 30-year-old machine that requires a lot of skill and patience to master,” Chastain said.
In addition, the manufacturer provides unique features that can simplify and speed up machine setup. “The sensor integrated into the machine allows the use of Caterpillar’s'zeroing’ and’automatic cut transition’ functions to simplify setup,” Smieja said.
Wirtgen’s leveling technology can adjust the height, depth and spacing to obtain extremely accurate results and reduce the workload of the operator. Wirtgen reset can quickly bring the machine back to the initial “scratch height” so that it is ready for the next cut, Smieja explains. Automatic cutting transitions allow the operator to program in predetermined transitions of depth and slope within a given distance, and the machine will automatically create the required contour.
Smieja added: “Other features, such as a high-quality camera with cutting edge guides, make it easier for the operator to align the machine correctly at the beginning of each new cut.”
Minimizing the time spent on setup can increase the bottom line. “Using the latest technology, setting up the milling machine to start has become easier,” Chastain said. “The milling staff can set up the machine for operation in a matter of minutes.”
The color control panel of the Roadtec (Astec) milling machine is marked with a clear label, which is simple and straightforward to operate. Astec technology also improves safety. “The latest features implemented for the Astec CMS milling machine are safety related,” Hammon said. “If a person or a larger object is detected behind the machine when reversing, the rear object detection system will stop the milling machine. Once the person leaves the detection area, the operator can reverse the path of the machine.”
However, even with these advancements, milling is still one of the applications that operator skills are difficult to replace. “I personally think that milling always requires human factors,” Chastain said. “When things are going well, the operators can feel it. When things are not right, they can hear. It helps a lot to make these machines safer and easier to operate.”
Preventing downtime keeps the milling project on track. This is where telematics technology changes the rules of the game.
“Telematics is a powerful tool for reducing downtime and collecting performance data in real time,” Hammon said. “Production data, fuel consumption and idle time are a few examples of information that can be obtained remotely when using a telematics system.”
Astec provides the Guardian telematics system. “The Guardian telematics system allows two-way communication between the machine and the end user or approved service technician,” Hammon said. “This provides a higher level of maintainability and data collection on each machine.”
When there is a problem with the milling machine, it needs to be identified and repaired as soon as possible. Chastain said: “The new milling machine should not only simplify the operation, but also simplify the diagnosis and troubleshooting of these machines.” Machine downtime is even worse.”
Wirtgen has developed a system to proactively notify users of potential problems. Chastain said: “These new machines will notify the operator when some equipment is not turned on, inoperable, or just turned off by mistake.” “This is expected to reduce the number of holes [already] set up on the road in the past few years.”
Wirtgen has also established redundancy on its milling machine to reduce downtime. “When we did fail, there was a built-in backup, so the milling machine could continue to run without sacrificing quality or production,” Chastain said.