At present, the common locking mechanism of turning and milling machine tools is a three-tooth disc. Because the three-ring structure is positioned in the axial and radial directions at the same time, six degrees of freedom are limited, while the original spindle has limited five degrees of freedom, so there are five degrees of freedom over-positioning. The advantage is that very good stiffness can be obtained, but the requirements for the machining accuracy of the parts and the assembly accuracy of the parts will be greatly improved, and higher requirements are put forward for the manufacture and assembly of the parts. The position of the three-toothed disc locking mechanism in the turning and milling five-axis head has a great influence on the machining performance, and there are usually two forms. One of the turning and milling compound machine tools is installed at the front end of the front bearing of the main shaft. In this way, the locking position is close to the turning force point, which is very beneficial to heavy cutting and vibration cutting; in addition, the hydraulic clamping mechanism of the three-tooth disc has a vibration damping effect, which is beneficial to the cutting of long shanks. The other is installed at the rear end of the front bearing of the main shaft. In this form, when milling, the distance between the force point of the tool and the front bearing of the main shaft is short, which is conducive to milling, and is very beneficial to improve the rigidity of boring and milling and improve the surface processing quality.
The three-tooth plate is installed at the front end of the front bearing of the main shaft, which is relatively easy to assemble; the three-tooth plate is installed at the rear end of the front bearing of the main shaft, which is difficult to assemble and not conducive to maintenance. The angle recognition mechanism that generally realizes the orientation of the main shaft cannot be used for turning and milling five-axis heads because of its large size.
One of the important directions of turning and milling machine tools. Composite machine tools also include various forms such as turning-milling composite, turning-milling-grinding composite, milling-grinding composite, cutting and 3D printing composite, cutting and ultrasonic vibration composite, laser and stamping composite, etc. Functional, can complete multiple tasks in one clamping, improve processing efficiency and processing accuracy.
The upper center of the turning and milling machine tool is a five-axis linkage machine tool that is mainly based on turning, supplemented by milling, boring, drilling and tapping. There are at least 3 linear servo axes and 2 rotary servo axes, namely X/Y/Z axes and B/C axis. The turning-milling machining center can complete all or most of the operations in one clamping of the workpiece.
Foreign turn-milling machining centers have developed to a relatively mature stage, and many new technologies (such as linear motors, torque motors, built-in motors, and power turrets with built-in motors) have been successfully applied to turn-milling machining centers. , and most of them have realized modular design, which can “assemble” corresponding machine tools in time according to market needs. Domestic turning-milling machining centers started late, and some key technologies (such as torque motor-driven B-axis, built-in motor turning spindle, built-in motor tool power spindle, high-torque mechanical tool power spindle and single servo Although technologies such as power towers have begun to be applied, no breakthrough has been made so far. Compared with foreign turning-milling machining centers,
The domestic level gap is still very large, mainly in the following aspects:
(1) The performance indicators of machine tools are low. The parameters such as acceleration, fast travel speed, spindle power, torque, positioning accuracy and repeat positioning accuracy of machine tools are generally lower than those of foreign manufacturers. The overall level of domestic turning-milling machining centers is comparable to similar foreign products. Not on a level yet.
(2) The reliability needs to be improved. The failure rate of domestic turning-milling machining centers is relatively high, which is one of the most strongly reported problems by users. In particular, the early failure accounts for a large part, and the general user can only operate normally after half a year of use, which affects the recovery speed of the user’s initial investment.
(3) The product series needs to be improved in terms of machine tool specifications. Domestic new product development, shortening the delivery period, reducing manufacturing costs, meeting individual needs and expanding market share will certainly help. Therefore, my country’s machine tool industry should also pay attention to and implement the modular design of machine tools as soon as possible.
Turn-milling machining centers are basically single product specifications, lacking a complete product spectrum, and cannot meet the needs of the market. Only Shenyang Machine Tool’s HTM series (original SSCKZ series) has complete product specifications, which can meet the needs of users with different specifications.
(4) Insufficient software functions In terms of software functions, the turning and milling compound machining centers of foreign manufacturers have online detection functions, online real-time monitoring of tools and adaptive control functions, tool life management, automatic tool setting functions, temperature compensation functions and powerful CAD/ CAM automatic programming function, etc. However, the software functions of the domestic turning-milling machining centers are very limited, and generally only have the function of online tool detection, automatic tool setting and CAD/CAM automatic programming.
(5) The appearance design and manufacturing level need to be improved. The appearance design of foreign turning-milling machining centers takes into account the rationality and economy of function, structure, and process, and realizes the unity of product internal quality and external quality. The composite machining center has obvious shortcomings in this regard.
The rough machining of the turning-milling machine tool is to quickly remove the blank allowance. During rough machining, a large feed rate and a large depth of cut should be selected to remove as many chips as possible in a short time. Rough machining does not require high surface quality, and the blunt standard of the tool is generally a significant increase in cutting force. Litz horizontal machining center is the standard of the wear width VB of the flank.
The turning-milling machine tool refers to the machining center with the spindle axis parallel to the worktable, which is mainly suitable for machining box-type parts. His working principle is that after the workpiece is clamped once on the machining center, the computer can automatically select different tools, automatically change the spindle speed of the machine tool, and complete the multi-process processing on multiple surfaces of the workpiece in turn. The advantage of the precision horizontal machining center is that it can greatly improve the production efficiency, but it occupies a large area and has a high cost.
Selection points of turning and milling compound machine tools
1. Specifications include the size of the processing space, the spindle speed range, the feed speed range, the size and range of the standard tool, the capacity of the numerical control device and the number of optional accessories.
2. The performance includes static accuracy, machining accuracy, moving accuracy, positioning accuracy, thermal deformation and anti-vibration performance.
3. Others include adaptability to the system, convenient maintenance, system and safety, etc.
The working principle of Tsugami turning and milling compound machine tool
After the workpiece is clamped once on the machining center, the digital control system can control the machine tool to automatically select and replace the tool according to different processing procedures, automatically change the machine tool spindle speed, feed rate and the movement path of the tool relative to the workpiece and other auxiliary functions. , to complete the multi-process processing on multiple surfaces of the workpiece in turn. And there are a variety of tool change or tool selection functions, so that the production efficiency is greatly improved.