Comparison of machine tool layout
The plane where the two guide rails of a flat bed CNC lathe are located is parallel to the ground plane. The plane where the two guide rails of an inclined bed CNC lathe are located intersects with the ground plane, forming an inclined plane with angles of 30°, 45°, 60°, and 75°. From the side of the machine tool, the bed of a flat bed CNC lathe is square, while the bed of an inclined bed CNC lathe is a right triangle. Obviously, under the same guide rail width, the X-direction slide of the inclined bed is longer than that of the flat bed. The practical significance of its application in lathes is that more tool positions can be arranged.
Comparison of cutting rigidity
The cross-sectional area of an inclined bed CNC lathe is larger than that of a flat bed of the same specification, that is, it has stronger bending and torsion resistance. The tool of the inclined bed CNC lathe cuts downward from the oblique upper part of the workpiece. The cutting force is basically consistent with the gravity direction of the workpiece, so the spindle runs relatively smoothly and is not easy to cause cutting vibration. When the flat bed CNC lathe is cutting, the cutting force generated by the tool and the workpiece is 90° to the gravity of the workpiece, which is easy to cause vibration.
Comparison of machining accuracy
The transmission screw of the CNC lathe is a high-precision ball screw. The transmission gap between the screw and the nut is very small, but it does not mean that there is no gap. As long as there is a gap, when the screw moves in one direction and then drives in the reverse direction, it is inevitable to generate a reverse gap. The reverse gap will affect the repeat positioning accuracy of the CNC lathe, thereby affecting the machining accuracy. The layout of the inclined bed CNC lathe can directly affect the gap of the ball screw in the X direction. The gravity directly acts on the axial direction of the screw, making the reverse gap during transmission almost zero. The X-direction screw of the flat bed CNC lathe is not affected by the axial gravity, and the gap cannot be directly eliminated. This is the innate precision advantage that the design brings to the inclined bed CNC lathe.
Chip removal capacity comparison
Due to gravity, the inclined bed CNC lathe is not easy to produce entangled tools, which is conducive to chip removal; at the same time, with the central screw and guide rail protection sheet metal, the chips can be prevented from accumulating on the screw and guide rail. Inclined bed CNC lathes are generally equipped with automatic chip conveyors, which can automatically remove chips and increase the effective working time of workers. It is difficult to add an automatic chip conveyor to the flat bed structure.
Automatic production comparison
The increase in the number of tool positions of machine tools and the configuration of automatic chip conveyors are actually laying the foundation for automated production. One person guarding multiple machine tools has always been the direction of machine tool development. The inclined bed CNC lathe is equipped with a milling power head, an automatic feeding machine or a manipulator, automatic loading, and one-time clamping to complete all chip cutting processes, automatic unloading, and automatic chip removal, which becomes an automatic CNC lathe with extremely high work efficiency. The structure of the flat bed CNC lathe is at a disadvantage in terms of automated production. Although the inclined bed CNC lathe is more advanced than the flat bed CNC lathe in all aspects, its market share is far behind. Flat bed CNC lathes are easy to produce and occupy more than 90% of the CNC lathe market share.
