Wirtgen W 250i high-performance cold milling machine for limitless milling performance débuts at Conexpo 2014
Wirtgen's W 250i – the company's most powerful cold milling machine – is making its début on the North-American market at Conexpo. The machine being exhibited in Las Vegas is equipped with an extra-large milling drum unit for a working width of 12’ 6” (3.80 m), offering a good 70 percent increase in milling width over a standard machine and consequently a remarkable increase in milling performance. It also sports a camera system and the Vacuum Cutter System (VCS). High rates of productivity, maximum cost efficiency and the eco-friendly i-machine technology of the W 250i make it the top player in its performance class.
Broad range of applications on large job sites
The strength of the W 250i lies in its ability to mill large job sites on motorways or airports at top speed. The Wirtgen large milling machine can remove asphalt layers with a milling depth of up to 14” (350 mm) and hard concrete surfaces at a high advance rate. In addition to removing complete roadway sections in a single pass, individual layers can also be removed extremely economically. The W 250i performs impressively in all of these applications, and not only due to the high advance rate and maximum milling output its tremendous engine power permits. Above all, the intelligent WIDRIVE machine management system, the three selectable milling drum speeds and the Dual Engine Concept keep the operating costs exceptionally low for a cold milling machine in this performance class. As a result of the Dual Engine Concept, the W 250i essentially unites two machines in one: on the one hand, there is the high-performance milling machine with the full power of its two engines and 1,005 PS, while on the other hand, the customer also benefits from a cost-efficient mid-range milling machine that can operate with the 608 PS power of one engine to economically remove softer asphalt surface courses or porous asphalt, for example.
Optimum adaptation to job site requirements with three milling drum speeds
In order to optimize fuel consumption, milling output and the overall efficiency of the W 250i large milling machine, the machine operator can set the most suitable milling drum speed for the job at hand directly from the operator's platform via a selector switch. This means that the ideal milling output can be achieved even in the event of highly divergent requirements by directly switching to the optimal speed during the milling process. In the case of standard milling jobs, such as the removal of a surface course, the W 250i operates with the medium milling drum speed of 1,800 rpm, also producing the milled material in favourable particle sizes. When removing thin surfaces at the maximum advance rate, the high milling drum speed of 2,000 rpm is selected, producing a superior milling texture. In order to achieve maximum milling output while keeping the costs low, the lowest speed of 1,600 rpm is the right choice for complete removal as it guarantees reduced fuel consumption and low cutting tool wear. On the whole, the three selectable milling drum speeds ensure a favourable balance of operating costs.
Six milling widths available
The standard milling width of the W 250i is 7’ 3” (2.20 m). This can be optionally extended by fitting the machine with additional milling drum units for working widths of 8’ 2” (2.50 m), 10’ 2” (3.10 m), 11’ 6” (3.50 m), 12’ 6” (3.80 m) or even 14’ 5” (4.40 m). For milling drum units with working widths greater than 7’ 3” (2.20 m), the W 250i is equipped with extension elements. In the case of a milling width of 7’ 3” (2.20 m), a machine version is also available with FCS Light. The tried and tested FCS Light quick-change system for milling drums allows a wide variety of different milling operations to be carried out by using different milling drums. The large milling widths are particularly suited for efficiently removing surface courses extending over a large area. For example, up to 20,000 square metres can be removed in a single work shift using a 12’ 6” (3.80 m) wide milling drum unit.
Simple operation thanks to smart technology and perfect ergonomics
The operating concept assists the machine operator in his work and provides him with all the information he needs to know. Alongside the intuitive operating concept, the multifunctional control display is another highlight, operating as a practical information hub: it can be swung to the left or right of the operator together with the LEVEL PRO control panel and displays operating statuses and servicing data in an easily comprehensible way. The control display provides user-friendly diagnostic options with clear graphics for identifying the source of any problem. Another handy function is the logging of job data: at the end of the day, the log, for example, can show how many trucks have been loaded and the overall tonnage that was achieved.
The number of control elements has been minimized in the W 250i, as Wirtgen's machine management system WIDRIVE already handles many tasks for the operator in automatic process chains. For this reason, it is easy to learn how to operate and control the W 250i. The logically arranged operating function groups with language-neutral symbols further enhance comprehensibility. An optional camera system with two or six cameras is also available to facilitate checking the working areas. The operator can view as many as six working areas on the control display.
Automatic machine alignment using PTS
The PTS system automatically aligns the W 250i parallel to the road surface. PTS stands for Parallel To Surface. The system ensures simple, accurate operation of the machine in demanding profiling jobs. PTS also assists the operator with positioning the machine in the milled cut to initiate the milling process. In automatic mode, the system takes care of all the steps that the operator would otherwise need to select manually one after another. The need for tiresome manual correction is eliminated. The operator activates the LEVEL PRO level control system at the flick of a switch, and all four crawler track units of the large milling machine are lowered simultaneously at high speed. When the milling drum unit reaches the surface to be milled, the lowering speed is reduced and the milling drum slowly penetrates the material down to the set depth. The automatic process helps to prevent excessive cutting tool wear or even tool failure when commencing the milling operation.
The same applies when the W 250i is aligned transverse to the direction of travel. In many cases, cold milling machines need to overcome significant differences in height when being moved into or out of the milled cut. The integrated 4-fold full-floating axle balances out all four track units quickly and reliably to reduce the machine’s lateral inclination to a minimum. This lends a high degree of stability to the large milling machine whilst the operator enjoys a pleasant driving experience.
ISC: Intelligent speed control ensures maximum traction
The ISC system, which is short for Intelligent Speed Control, truly comes into its own in highly demanding milling jobs. Just like the traction control system of a car, ISC prevents crawler track slip and ensures perfect traction of all track units to achieve maximum milling performance. This, in turn, reduces track pad wear. When negotiating bends, the ISC system automatically increases the speed of the outer crawler tracks depending on the steering angle. As a result, even extremely narrow bends can be milled using the all-track drive. Automatic adjustment of the advance rate to match the diesel engine load always ensures maximum performance yet quiet operation of the machine.