Large-sized workpieces such as large rims, discs or gears place special demands on technologists and machine operators. Cutting large surfaces with relatively small widths is sometimes problematic due to stresses that can lead to undesirable deformations and difficulties in achieving part stability. However, proper cnc machining with the right machine tool can optimize the process, guarantee high dimensional repeatability and minimize the risk of errors.
Challenges in CNC machining of large-sized parts.
Hoops with large diameters yet small widths require precise clamping and balancing to avoid vibration during operation.
Machining with suitable CNC lathes allows these tasks to be carried out efficiently, while maintaining stable parameters over the course of successive production runs.
CNC lathe for large-size parts – the genesis of SIM Gdynia’s investment.
In 2021, we decided to expand the technological capabilities of our company by purchasing a CNC lathe that would meet the requirements of large-format machining.
The machine tool was to make it possible to cut parts with a diameter of more than 1 meter and weighing several tons. Such parameters turned out to be indispensable in the production of large-format components used in hydraulic, mining and other heavy industry sectors.
Characteristics and specifications of the GV-1100 CNC machine tool.
The purchased lathe model GV-1100 is equipped with a table with a diameter of 900 mm, which allows the machining of parts with a maximum diameter of up to 1,100 mm. The machine tool is capable of handling workpieces weighing up to 4,000kg, which is completely sufficient for machining parts of considerable dimensions.
At the heart of the machine is a spindle with two gears, offering speeds from 1 to 500 rpm and a torque of up to 10,170 Nm. The 37 kW (continued) / 45 kW (30 min) main drive guarantees smooth operation, even during intensive material removal. An additional advantage is the presence of the C-axis (motor output 3 kW), with which more complex operations can be performed, such as milling outlines on the workpiece.
The lathe has an X axis that allows travel of up to 1,300 mm (in the range -100 ~ 1,200 mm) and a Z axis with a stroke of 900 mm. Depending on your needs, it is also possible to use the W axis, which has a stroke of up to 600 mm. Servo motors of 7 kW (X-axis) and 9 kW (Z-axis) provide adequate dynamics and precision of movements, and the feed rate reaches 12 m/min in the X-axis and 10 m/min in the Z-axis.
The machine is equipped with a tool magazine with a capacity of 12 pieces (taper BT-50), which makes it easier to carry out machining processes without frequent manual tool changes. The maximum tool weight reaches 50 kg, which allows the use of robust cutting heads. The whole machine is controlled by a FANUC Oi-TF Plus system, ensuring high repeatability and positioning accuracy, which for the X and Z axes is ±0.007 mm per 500 mm.
Machining process – stages of operation.
Preparing a workpiece for cnc machining first requires proper clamping and fixing the base. Then the operator selects the optimal cutting parameters, taking into account the dimensions, shape and material of the workpiece and the planned number of cycles.
Due to the large size of the workpiece, it is sometimes necessary to gradually increase the spindle speed or feed rate so as to reduce the risk of vibration. At the final stage, quality control is carried out, including verification of dimensions, shape tolerances and surface evaluation.
Summary.
Cutting large-size parts requires specialized machines that provide power, stability and an adequate working range. The GV-1100 lathe purchased in 2021 allows machining parts with diameters of up to 1,100 mm and payloads of up to 4,000 kg, which has greatly expanded SIM Gdynia’s machining capabilities.
All this makes the machining process for the most demanding large parts run smoothly and allows to achieve the desired quality parameters, regardless of the industry in which the workpieces are finally used.
