Intelligent cutting technology from Wirtgen cuts milling costs

Cost pressure and pressure to perform are tremendously high in any project using cold milling machines for the rehabilitation of roads. Machine users are not only supported by innovative machine technology and high machine availability, but the powerful “heart” of each cold milling machine – the milling drum assembly with all those components that are part of the cutting technology – is of prime importance for success on the job site. “Cut costs while keeping quality high” is the maxim of technology leader Wirtgen who has been developing economical solutions in cutting technology for customers for about 45 years, covering a broad range of milling applications. The company makes full use of any potentials offering themselves for reduction of the operating costs, focusing not only on the standard milling drums but also on special milling drums with larger working widths or the so-called eco cutters which are fitted with a smaller number of cutting tools – both options help customers improve the performance of their machines while cutting costs at the same time.

Rehabilitating surface courses quickly with special drums at large working widths

In the large milling machine class, drum units in “XXL size” in particular have stood the test in day-to-day operation. A range of special milling drums offering milling widths of up to 4.40 m is on offer for Wirtgen’s high-performance milling machines with milling widths of 2 m or more. Milling contractors are making increasing use of these powerful special drums to complete large-scale surface course rehabilitation projects within a short period of time. Operating costs of the cold milling machine are reduced while costs of wear and tear at the cutting tools minimized at the same time.

Tremendous performance rates are realized in particular when milling surface courses at the standard milling depths of 4 to 5 cm. They are due to the larger working widths offered by the special drums when working at the same advance speed and cannot be achieved when using drums of standard milling widths. Apart from offering increased performance rates, the special drums create a milling texture that is every bit as precise as that of standard drums. As a result, the initially higher investment in a special milling drum assembly will pay off quickly after just a few milling contracts.

Milling width of 4 m makes short work of rehabilitation on feeder road

In this particular case, contractor SVB Asphalt Fräse GmbH used the most powerful Wirtgen cold milling machine, a W 2200 with an engine rating of 671 kW, on a heavily frequented federal road. Rehabilitation of the surface course was to be carried out in one single nightshift. Using the special milling width of 4 m enabled one directional lane at a time to be milled off in a single machine pass. Altogether, 22,000 m² were removed at a milling depth of 5 cm in a single working shift.

The facts are speaking a clear language: the milling operation was completed quickly in the course of one night, so that traffic flowed smoothly again on this feeder road to the A8 motorway in the early hours of the following morning. Using the large milling drum unit results in a significant gain of time as there is no need for the cold milling machine to work the road in several passes, which completely dispenses with the time usually required for turning and repositioning the machine. Had a milling drum with a standard working width of 2.20 m been used, as many as two passes would have been needed for removing the pavement on one single directional lane.

Over and above the time factor, the machine’s highly efficient operation considerably reduced the costs of fuel and operating materials like oil and water and, not least, the costs of wear and tear on the machine and in particular on the cutting tools. Such a project can therefore be completed at a highly positive total cost balance.

Significant time and cost benefits also result in terms of job site logistics. Subsequent sweeping operations can begin immediately following removal of the pavement on the first lane. In addition, asphalt pavers and rollers can take up their work of paving and compacting the new asphalt surface course immediately after completion of the milling operation, helping to keep the logistics chain lean and going with the flow.

Complete removal even in hard materials with powerful eco cutters

The eco cutters developed by Wirtgen are yet another attractive alternative to the use of standard milling drums. These intelligently designed new milling drums achieve maximum milling performance at minimum costs. The special eco cutters are fitted with a reduced number of point-attack cutting tools at increased tool spacings. It is precisely that optimized tooling, however, which ensures the highest possible area performance. For fewer cutting tools are synonymous with reduced cutting resistance and thus faster machine advance rates.

Eco cutters are generally equipped with around 35% fewer cutting tools than standard milling drums. Expressed in terms of cost, the machine user has significantly lower tool costs per cubic metre of pavement milled. Numerous operations have shown that the area performance of eco cutters surpasses that of standard milling drums by around 20%.

Eco cutters are the ideal choice for the complete removal of pavements on a large scale, both in asphalt and in harder materials, such as concrete. This was demonstrated in a construction project involving the removal of a concrete pavement. Milling contractor Enrico Feind e.K. used a W 2000 from Wirtgen to mill off concrete with a light steel reinforcement. It was only the use of an eco cutter with a tool spacing of 25 mm that enabled the hard material to be removed economically at a milling depth of 25 cm and to be directly loaded into trucks. The alternative option would have been the cost-intensive and machine-intensive removal of the concrete using an excavator, followed by subsequent crushing. Incidentally, the tried and tested eco cutters are on offer for all Wirtgen cold milling machines with front-loading conveyor system and a working width of 1 m or more.