The selection of CNC lathe tool holders and cutting tools is one of the important contents in CNC machine tool configuration, because the selection of CNC lathe tool holders and cutting tools not only affects the production efficiency of CNC machine tools, but also directly affects the processing quality of parts. Optimizing the tool and tool holder system according to the performance of CNC machine tools or machining centers and centering machines and the characteristics of CNC machining technology can achieve twice the result with half the effort.
1. Classification of tool holders commonly used in CNC machine tools
Compared with ordinary processing methods, CNC processing has stricter requirements on the rigidity, precision, durability and dynamic balance performance of the tool. The selection of cutting tools should pay attention to the structural and technological analysis of the workpiece, combined with comprehensive considerations such as the processing capabilities of the CNC machine tool, the workpiece material, and the process content. Commonly used tool holders for CNC machining are mainly divided into drilling tool holders, boring tool holders, milling tool holders, threaded tool holders and straight tool holders (end mill tool holders and spring chuck tool holders) .
Second, the selection of commonly used tool holders for CNC machine tools
1. Structural form of tool handle
The structural forms of CNC machine tool holders are divided into two types: integral type and modular type. The working part of the integral tool holder for clamping the tool is integrated with the handle used for its installation and positioning on the machine tool. This kind of tool holder has poor adaptability to changes in machine tools and parts. In order to adapt to the transformation of parts and machine tools, users must reserve tool holders of various specifications, so the utilization rate of tool holders is low. The modular tool system is a more advanced tool system, and each tool handle can be assembled through various serialized modules. According to different processing parts and machine tools, different assembly solutions can be adopted to obtain a variety of tool holder series, thereby improving the adaptability and utilization rate of the tool holder.
The choice of the structure of the tool handle should take into account both technological advancement and economical rationality:
① For some simple tools that are used repeatedly for a long time and do not need to be assembled, it is better to be equipped with an integral tool handle, so that the tool has good rigidity and is cheap (such as end mill handles, spring chuck handles and drill handles used to process the outer contour of parts). chuck, tool holder, etc.);
②When processing multi-variety and small-batch parts with frequently changing hole diameters and hole depths, it is advisable to use modular tool holders to replace a large number of integral boring tool holders to reduce processing costs;
③ For many CNC machine tools, especially when the end of the machine tool spindle and the tool changing manipulator are different, it is advisable to choose a modular tool holder. Since the intermediate module (connector) and the working module (tool module) used by each machine tool can be used in common, equipment investment can be greatly reduced and tool utilization can be improved.
2.Tool holder specifications
Most CNC tool holders use 7:24 tapered tool holders, and adopt corresponding types of rivet tightening structures to match the machine tool spindle. Tool handles come in various specifications, with No. 40, No. 45 and No. 50 being commonly used. At present, ISO7388-1983, GB10944-1989, MAS403-1982, ANSI/ASME B5.50-1985, etc. are widely used in our country. When choosing, you should consider the specification of the tool holder to adapt to the machine tool spindle and manipulator.
3. Specifications and quantity of tool holder
The integral TSG tool system includes 20 kinds of tool holders, with hundreds of specifications. Users can choose the varieties and specifications of tool holders according to the CNC machining process of typical parts to be processed, which can meet the processing requirements without causing a backlog . Considering that while the CNC machine tool is working, there are still a certain number of tool holders in the process of presetting or tool grinding, so the number of tool holders is usually 2 to 3 times that of the required tool holders.
4. Matching of knives and handles
Pay attention to the matching of the tool holder and the tool, especially when selecting a tapping tool holder, pay attention to the size of the tap drive square head. In addition, the selection of single-edged boring tools on CNC machine tools can avoid scratching the workpiece when the tool is retracted, but attention should be paid to the position and direction of the tool tip relative to the keyway on the handle: some machine tools require the same orientation as the keyway, while some machine tools require Perpendicular to the keyway orientation.
5. Select and composite tool handles
In order to improve processing efficiency, high-efficiency tools and tool holders should be used as much as possible. For example, a double-edged boring tool holder can be selected for rough boring, which can not only improve processing efficiency, but also help reduce cutting vibration; the selection of a strong spring chuck can not only hold straight-shank tools, but also clamp tools with holes through the post, etc. . For typical workpieces with large batches and complex processing, composite cutting tools should be used as much as possible. Although the compound tool and tool handle are more expensive, the use of compound tool processing on the machining center can combine multiple processes into one process and be completed by one tool, which is beneficial to reduce processing time and tool change times, and significantly improve production efficiency. . For some special parts, specially designed composite tool holders can also be considered.
6. Strengthen tool system management
As the number of CNC machine tools increases, the number of tool holders will increase dramatically. A flexible manufacturing system with 5 to 8 CNC machine tools can have more than 1,000 tool holders. How to make reasonable and effective use of these tools is the key task of tool management. Its content includes: Proposal of toolholder procurement or supplementary plan; Pre-adjustment of tool data; Scheduling and storage of tools; Judgment and control of tool life, etc. How to solve the problem of continuous winding and cutting of chips during grooving with CNC lathe