Production of commercial vehicles has been expanding steadily in recent years, with manufacturers in emerging economies needing new capital equipment and new production technologies to address the rising demand for semi-trucks and agricultural machinery, supplying the expanding construction and agricultural sectors in their regions. The competition to supply that demand is growing too, as new manufacturers (notably in China) establish the necessity of producing parts at affordable cost.
For suppliers to the commercial vehicle market, production planners are under pressure to deliver quality parts at low cost. The future of commercial vehicle production lies in being faster, more energy efficient and increasingly flexible.
EMAG’s VL 8 vertical pick-up turning machine for workpieces up to 400 mm diameter offers a high-efficiency approach to finishing large-dimension castings for commercial vehicle components.
Large vehicles call for large components, but manufacturing of especially large and heavy components (e.g., powertrains for semi-trucks, excavators, or buses) poses particular challenges. How can a large clamped component be machined economically and, at the same time, with the highest precision? How does the demanding task of handling such components not result in an unmanageably long production process?
The VL 8 vertical pick-up turning machine, the latest from EMAG’s machine experts, provides the answers to these challenges. All the advantages of the VL series have been transferred directly to a machine specially designed for the handling of large components, in which a number of different turning and milling operations are carried out in a single closed-loop production process. Integrated automation ensures quicker production times, and the vertical layout a high degree of process integrity where chip flow causes no problem. Subcontractors and component suppliers benefit from short idle times, high component quality, and reduced unit costs.
The basic design of the VL 8 follows closely the preceding entries in the VL series. Sturdy construction, dynamic axes, and simple operation are the main characteristics. These machines are based on a completely new machine concept that allows for a variety of production technologies for soft and hard machining to be combined, achieving a very attractive price-performance ratio. Among the design details:
• The machine base is formed from a polymer concrete called Mineralit that ensures vibration resistance and promotes better tool life and machining quality.
• The front of the machine base features a compound slide to carry the vertical main spindle that dynamically traverses the Z- and X- axes.
• With a chuck diameter of 500 mm, the pick-up spindle accepts workpieces up to 400 mm diameter.
• The machining process uses a 60-kW main spindle, with a torque rating of up to 1,220 Nm and speeds of up to 2,850 rpm.
• The turret accommodates 12 turning or, optionally, 12 driven drilling and milling tools. Workpieces are loaded into the carrier prisms of a conveyor belt and positioned via NC axis.
The pick-up spindle collects the workpieces from the lateral conveyor belt and takes them to the machining area. Short travel distance ensures minimal chip-to-chip times. A highly flexible machining process allows for the use of a large variety of tools. It is also possible to link up two machines and a component turnover station to create a flexible production cell — to machine the first and second sides of a workpiece completely in one cycle, for instance. Additionally, the integration of a Y-axis in the turret allows for the “off-center” machining of more complex geometries.
Other features have been developed to ensure precision during the machining process. For example, the spindle is designed iwth short distances between the bearings and high-precision separable bearings in a tandem-O-tandem arrangement and support bearings with length compensation at the spindle end, providing for a particularly sturdy construction – which is important basic condition for micrometer-precision turning processes.
Precision is maintained through the integration of an inspection process into the cycle sequence. The required probe is installed outside the machining area and checks the workpiece while it is still clamped. Any corrective data is sent to the CNC control and the process is adjusted accordingly. This guarantees consistently high precision even during automatic operation. All service units are easily accessible and with an operator to turret distance of just 400 mm tool changes quick and easy.