The selection of tools is carried out in the state of human-computer interaction of NC programming. The tools and tool holders should be selected correctly according to the processing capacity of the machine tool and the performance of the tool materials, the cutting amount of the machining process and other related elements. The general principle of tool selection is: easy installation and adjustment, good rigidity, high durability and precision. Under the premise of meeting the processing requirements, try to choose a shorter tool holder to improve the rigidity of the tool processing. The specific selection method has the following 4 points.
(1) When selecting a tool, the size of the key tool is adapted to the surface size of the workpiece to be processed. In production, end mills are often used for processing the side contours of flat parts: when milling planes, carbide insert milling cutters should be selected; when machining bosses and grooves, acetylene high-speed steel milling cutters should be selected; rough surface or rough machining When drilling holes, rice milling cutters with carbide inserts can be selected; when adding some three-dimensional and varying bevel outline shapes, ball-end milling cutters, ring milling cutters, cone milling cutters and disc milling cutters are often used.
(2 /) When performing free-curved and / (mold /) machining, in order to ensure the machining accuracy, the cutting line spacing is generally close to the tip, and the cutting speed of the end of the ball head tool is zero, so it is often used for the surface finishing. Flat head tools are superior to ball head tools in terms of surface plus quality and cutting efficiency. Therefore, as long as undercutting is ensured, whether it is rough machining or curved surface finishing, priority should be given to flat head tools. In addition, the durability and accuracy of the tool are extremely related to the price of the tool. In most cases, although the choice of a good tool increases the cost of the tool, the resulting improvement in processing quality and processing efficiency can greatly reduce the overall processing cost.
(3 /) On the machining center, various tools are installed on the tool magazine respectively, and the tool selection and safety operation can be performed at any time according to the program regulations. Therefore, a standard tool holder must be used for drilling, hammering, expanding, milling and other processes The standard tools used are quickly and accurately installed on the machine tool shaft or tool magazine. The programmer should understand the structure size, adjustment method and adjustment range of the tool holder used on the machine tool, so as to determine the radial and axial dimensions of the JJ tool during programming. A few days ago, the machining center in China adopted the TSG tool system. Its tool handles have two types: straight handles / (3 specifications /) Lijiao handles / (4 specifications /), which includes 16 types of tool handles regardless of purpose.
(4 /) In the process of economical numerical control machine tools, because the sharpening, measurement and replacement of tools are mostly carried out manually, it takes a long time to assist, so the order of the tools must be arranged reasonably. In general, the following principles should be followed:
- Reduce the number of tools as much as possible:
- After a tool is clamped, all processing steps that can be performed should be completed;
- JJ tools for roughing and finishing should be used separately, even tools of the same size and specification; Mill first and then drill:
- Finished surface finishing first, then two-dimensional contour finishing:
- When possible, the automatic tool change function of the CNC machine tool should be used as much as possible to improve production efficiency.