The Art Of Dozing

While bulldozers are tough machines capable of moving mountains of rock or sand, fleet managers need to select the correct machine configuration and ensure that operators are using the right technique for optimum productivity on site.

In Saudi Arabia, with major housing developments being built around the country as part of the Vision 2030 drive to boost home ownership, with two thirds of Saudis under the age of 35, bulldozers are key to clearing and levelling sites before construction. The dozer is often one of the first pieces of equipment on-site, says Ahmed A Fathullah, Regional Sales Manager at Zahid Tractor, the Caterpillar dealer for the kingdom, who says that demand for major housing developments and new cities expansion will also continue to drive demand for new roads construction and building material. The mining business is picking up, with increased demand for large dozers from mines and quarries, says Fathullah. Due to pandemic-related travel restrictions there are fewer operators available, which has pushed up demand for rentals.

The Cat D9R is the top-selling unit in the central region, with the D8 and D10 also widely used. The D8R configured for waste handling is a popular machine for waste managing applications, such as municipal landfills, says Fathullah. It features large tracks, improved plate capacity to reduce ground pressure, and a large-capacity blade. "For waste management, Cat installs a very effective package to improve the life of the undercarriage and add guards for the transmission, undercarriage and engine, which prevents debris entering the engine,” says Fathullah.

Durability, ease of maintenance and effective after-market support are important features for bulldozer customers, he says. For large projects, that means the option to have technicians on-site and regular visits from service teams, to ensure that machines are reliable and have maximum up-time, especially on remote job-sites. The machines are able to work through demanding desert conditions, he says: "We are always working with customers and Caterpillar to continuously improve the product and its configuration, including for special applications. Our customers are highly experienced and have very high demands for their machines, which we are able to meet.”

One key design feature on Cat dozers is the elevated high sprocket, which gives the machines their distinctive profile. On the D9R, the elevated sprocket and fully suspended undercarriage work together to increase traction and create a smoother ride for operators, while the elevated sprocket design transfers implement shock loads to the mainframe, isolating final drives, axles and steering components from harsh impacts and resulting in higher production and longer component life. The Bogie suspension also allows the track to conform to ground conditions, providing up to 15% more ground contact, especially in hard, uneven terrain, while an undercarriage idler guard provides additional wear protection from abrasive material.

Customer and operator training is also an important aspect of maximising productivity, including techniques like slot dozing, says Fathullah, and Zahid Tractor carries out regular training with customers. Onboard machine control technology that can improve dozer accuracy is also of interest to contractors, but is not yet widely used. Improved accuracy can be a requirement on projects with very high technical standards or a complex design, such as an airport, stadium or golf course.

Fathullah says the firm receives enquiries on machine control, and believes demand will grow as operating costs continue to increase and designs become more sophisticated. "We believe that demand for this solution will increase in the near future,” he says.

Bulldozers are widely used in waste management applications.

Made in Japan

Known for its quality, bulldozers are one of the core product lines for Komatsu, the second largest equipment manufacturer in the world by revenue. Top selling models in the Middle East include the D155A-6, widely used for construction projects and in rental fleets; and the larger D275A-5R and D375A-6R models for the quarry and mining segment, said Jehad N. Jayyousi, Assistant Manager – Marketing at Komatsu Middle East.

The Komatsu bulldozers sold in the GCC are all produced in Japan, and all major components are built in-house, ensuring they're optimized to work together and have undergone strict quality control checks, and meaning that all the service can be done by the distributor (rather than a customer needing to contact different suppliers as when machines are built with component from multiple brands), says Jayyousi. "If you talk to any customer, the first word that he associates with Komatsu is quality – we build high-quality and very durable machines.”

The Komatsu bulldozers feature the low-drive system, part of the design philosophy behind them. "The key feature of the low drive is that the machine's center of gravity becomes low. This improves the machine stability and the dozing and ripping performance,” explains Motoyasu Kakita, Manager, Product Marketing at Komatsu Middle East.

Komatsu offers a range of different blades for its dozers.

Another feature on the D275A-5R and other mining dozers is automatic control of machine speed to prevent excess shift slip, says Kakita. The newly designed powertrain electronic control system features an Electronic Controlled Modulation Valve (ECMV), which automatically adjusts clutch engagement depending on travel conditions, and controls steering clutches and brakes in response to the conditions.

For example, when dozing downhill, the ECMV automatically controls steering clutches and brakes depending on incline of machine or degree of load, reducing counter-steering and producing smooth dozing operation. The overall effect is to improve the operator experience, increase productivity and accuracy of the grade, and reduce fuel consumption and unnecessary wear on the shoe, says Kakita.

One of the biggest variables on any site is ground conditions. "The rule of thumb is that we will choose the narrowest shoe possible that provides enough flotation,” explains Jayyousi. "A long, wide track will increase flotation and help the bulldozer work, but on a rocky site it will also increase wear because you are increasing the contact area.”

The material to be moved also affects blade selection. Komatsu offers different blade types, including the U-blade for maximum shifting (used with lighter materials) and the straighter S blade for highest penetration. The firm frequently recommends the SU blade, which offers a balance between penetration force and capacity. Another option is the Sigma Dozer with a Sigma-shaped blade, as in the Greek letter Σ. Rather than material being spilled around the side of the blade, the Sigma Dozer blade's patented design heaps it up in the center for improved rolling, allowing the machine to move more material and use less fuel.

Informing customers of the best options for a specific project or location is also part of the service. Komatsu's application engineers visit a site to study a project and the amount of material that needs to be moved, in order to provide a fleet recommendation. Designing a more efficient work plan for a customer often decreases operating costs.

For a municipal job in Ras al Khaimah on which a large amount of sand needed to be moved – mainly cut and fill – the recommendation from the application engineer was to use the slot dozing technique. Komatsu arranged operator training for over 50 operators to ensure they became familiar with the technique, whereby each trip is made in the same path and the material pushed into the slot is retained in front of the blade, meaning bigger loads can be handled. It resulted in significant savings for the client, in both fuel and machine hours. When buying a new machine, customers typically look at total cost of ownership, which includes initial price, owning and operating costs, productivity and resale value. Operator comfort is also increasingly important for contractors in our region, a trend that plays to Komatsu's strengths, says Jayyousi. "In our D155A-6, we can achieve the formula of the lowest cost of ownership.”

Komtrax, Komatsu's telematics system, monitors machine location and health, alerting machine owners when error codes are detected. It also helps technicians to plan maintenance or repairs, and bring the right tools and spare parts when there is a fault. "In a nutshell, Komatsu dozers are leading the market in addition to a considerably high resale value,” says Jayyousi.

Improved driver training can result in big savings on fuel.

High Drawbar Pull

In its factory in Poland, Liugong Dressta Machinery produces a large range of bulldozers. The large TD-25 and TD-40 models are its two main machines sold in the Middle East. Both machines were relaunched as face-lifted machines in recent years, with a number of product improvements, most noticeably an updated cab with ROPS and FOPS integrated into the cabin structure rather than external, meaning increased visibility and safety for the operator, says Product Director Erçin Güleryüz.

Another feature of the dozer range is the high-capacity fuel tank, which on remote job-sites is especially efficient as it reduces the number of fill-ups required, allowing refuelling to be synched with shift changes.

The TD-40 is Dressta's biggest dozer. Key productivity features include large blades and high drawbar pull, for a high push load that bolsters productivity. The effectiveness of its ripper is boosted by high hydraulic power and its heavy weight.

The 41.5-tonne operating weight TD-25 is widely sold throughout the Middle East for road projects and desert landscaping, as well as oil & gas. The dozer can be fitted with wide track shoes that allow it to be used on very soft ground material, such as desert. Machines are fitted with a special cooling package for machines sold into the Middle East, so that it can operate even at the highest recorded ambient temperatures, says Güleryüz.

"The key features of our machine are drawbar pull and capacity of the blade, which allows customers to move more material quicker, meaning higher productivity, which is the most important aspect of a dozer as it is used on a project," he says, adding that a new mid-weight machine is also upcoming.