The reasonable selection principle of the cutting amount of vertical machining center working is: rough machining is generally based on improving productivity, but economy and processing costs should also be considered; semi-finishing and finishing should be taken into account on the premise of ensuring the quality of processing Cutting efficiency, economy and processing cost. Determine the specific cutting parameters according to the machine tool manual and actual use experience.
1. Cutting depth t. When the rigidity of the workpiece and the tool permits on the machine tool, the machining allowance is t, which is an effective means to improve production efficiency. In the processing process, in order to ensure the processing accuracy and surface roughness of the workpiece, a certain margin should usually be reserved. The finishing allowance of CNC machine tools can be slightly smaller than that of ordinary machine tools.
2. Cutting width L; usually L is directly proportional to the tool diameter and inversely proportional to the cutting depth. In economical CNC machining, the value range of L is usually L=(0.6~0.9)d.
3. Cutting speed v. Increasing the value of v is also a way to improve productivity, but v has a close relationship with tool durability. The tool durability decreases sharply with the increase of v, so the choice of the value of v mainly depends on the tool life. In addition, the cutting speed is related to the processing material. For example, when milling alloy steel 30CrNi2MoVA with an end mill, the cutting speed can reach 8m/min; when milling aluminum alloy with the same end mill, v can be 200m/min.
4. Spindle speed n (r/min). The spindle speed is usually determined by the cutting speed v. The control panel of CNC machine tools is generally equipped with a spindle speed difference (double speed) switch. During the processing, the spindle speed can be adjusted in full.
5. Feed speed vF. Choose vF according to the requirements of part machining accuracy, surface roughness, tool, workpiece material, etc. Increasing vF can also increase productivity. In the case of lower requirements for processing the surface, the material is more selectable. The utility model can also be manually adjusted through the trim switch on the machine tool control panel, but the maximum speed is limited by factors such as the rigidity of the equipment and the performance of the feed system.
Due to the wide application of CNC machine tools in production practice, CNC programming has become an important subject of CNC machining. During the machining process, when NC programming is carried out, the selection of the tool and the determination of the cutting amount should be carried out in time. Therefore, in order to ensure the processing quality and efficiency of parts, programmers must be familiar with the selection method of cutting tools and the principle of determining the amount of cutting, give full play to the advantages of CNC machine tools, and improve the economic efficiency and production level of the enterprise. In the process of CNC machining, the selection of cutting tools and the determination of the amount are an important issue, which not only affects the processing efficiency, but also affects the processing quality. Due to the development of CAD/CAM technology, numerical control processing, especially the connection between microcomputer and NC system, provides the possibility to directly use CAD design data. Design, process design, programming, etc. are all completed by computer, usually without special The process file output.
