Really! Is there a big difference between CNC machine tools and ordinary machine tools? Before explaining this issue, let’s talk about the modern mechanical parts processing methods.
There are many methods for processing mechanical parts in modern mechanical manufacturing. In addition to cutting, there are also casting, forging, welding, stamping, extrusion, etc. However, all parts with high precision requirements and fine surface roughness requirements generally need to be processed by cutting on machine tools. Traditional machine tools usually include supporting parts, speed change mechanism, feed mechanism, spindle box, tool holder, lubrication and cooling system, etc., while CNC machine tools are developed on the basis of traditional machine tools. The processes and structures of the two are similar, but CNC machine tools are mainly produced through programs, and there is no or little human intervention during the processing. The following is a brief introduction to the differences between CNC machine tools and traditional machine tools:
- Structural composition of CNC machine tools
The basic composition of CNC machine tools includes processing program carrier, CNC device, servo drive device, machine tool body and other auxiliary devices. Each component is controlled by the CNC system, including CNC system, main transmission system, feed servo system, cooling and lubrication system, etc.:
(1) Control system The center of motion control of CNC machine tools executes CNC processing programs to control machine tools for processing.
(2) Auxiliary devices such as hydraulic, pneumatic, lubrication, cooling systems and chip removal, protection and other devices.
(3) The spindle box includes the spindle box body and the spindle transmission system, which is used to clamp the tool and drive the tool to rotate. The spindle speed range and output torque have a direct impact on the processing.
(4) The feed servo system consists of a feed motor and a feed actuator, which realizes the relative movement between the tool and the workpiece according to the feed speed set by the program, including linear feed movement and rotational movement.
(5) The machine tool base usually refers to the base, column, beam, etc., which is the foundation and frame of the entire machine tool.
- Advantages of CNC machine tools over traditional machine tools
(1) The structure of CNC machine tools is simpler
The mechanical structure of some typical CNC machine tools is mainly composed of basic parts, main transmission system, feed transmission system, rotary table and other mechanical functional accessories. The mechanical structure of CNC machine tools, first of all, from the perspective of digital control technology characteristics, since the servo motor is used in the CNC machine tool, the digital technology is used to realize the direct control of the working sequence and motion displacement of the machine tool actuator. The gearbox structure of the traditional machine tool is cancelled or partially cancelled, so the mechanical structure is greatly simplified.
(2) Functional integration of CNC machine tools
Digital control systems also require mechanical systems to have higher transmission stiffness and no transmission gap to ensure the execution of control instructions and the realization of control quality. At the same time, due to the continuous improvement of computer level and control ability, it has become possible to allow more functional components to perform various auxiliary functions required on the same machine tool at the same time. Therefore, the mechanical structure of CNC milling machines has higher integrated functional requirements than traditional machine tools.
(3) CNC machine tools have higher precision and efficiency
From the perspective of the development requirements of manufacturing technology, with the emergence of various new materials and new processes, as well as the demand for cost reduction in market competition, metal cutting processing is moving towards higher cutting speed and precision, higher production efficiency and more reliable systems. This requires that CNC machine tools developed on the basis of traditional machine tools have higher precision, faster drive power, better mechanical structure stiffness, more reliable operation, and can achieve long-term continuous operation and as little downtime as possible.
(4) Standardization of CNC machine tool accessories
With the continuous accumulation of various machine tool process data, the basic parts of CNC machine tools, including the bed, column, beam, workbench, base and other structural parts, as well as supporting tools, fixtures, cutting oil, etc., are developing in the direction of standardization and processization, solving the problem of universalization of machine tool equipment.
