Views: 1 Author: Site Editor Publish Time: 2021-05-28 Origin: Site
Fixture and cutting tool are very important in NC machining. The correct choice will directly affect the machining efficiency and quality. Fixture selection should have enough accuracy, stiffness and reliable positioning datum. Tool selection should also consider the processing capacity, process content and workpiece material of lathe. In the selection of fixtures and tools, we must first understand the specific characteristics of various fixtures and tools, and select fixtures and tools according to the specific situation.
1. Clamping and positioning of workpiece
Workpiece positioning is the first step of machining operation, which is directly related to the accuracy and efficiency of machining. When positioning a workpiece, the first step is to select the positioning datum (the positioning datum is directly related to the machining size and accuracy of the workpiece). There are mainly two kinds of rough datum and fine datum, which need to ensure the unity of design datum, process datum, measurement datum and programming remote point. When designing the clamping scheme, the clamping quantity should be reduced as much as possible. Selecting NC turning fixture is an important part of clamping scheme. Four jaw single action chuck and three jaw self centering chuck can be used for clamping shaft and other rotary parts; The disc parts can effectively clamp the adjustable jaw chuck or the fast adjustable chuck; In addition to considering chuck, more jobs with higher requirements will choose to make special tooling for auxiliary processing, or consider leaving allowance for upper grinder grinding.
2. Select turning tools and determine cutting parameters
Numerical control tool is the main part of turning. The adaptability of workpiece, numerical control machine and tool should be considered comprehensively when selecting tool. The tool with large diameter should be selected as far as possible, which will increase tool life and improve production efficiency. CNC machine tools require turning tool material to meet the requirements, not only to ensure the hardness, thermal conductivity, strength and other physical indicators of tool material, but also to consider the economy of processing tool.
The shape of the cutting tool should refer to the contour map of the workpiece to be machined and its accuracy requirements, and also choose the tool with large diameter or forming tool, so as to improve the turning efficiency and prolong the life of the tool.
Also pay attention to the control of cutting parameters. It is necessary to pay attention to the operation parameters of each process, and then control the NC programming data. In the process of NC programming, the cutting parameters should be determined to make the cutting depth (back feed), cutting speed (spindle speed) and feed speed (feed) adapt to each other, so as to improve the efficiency of NC turning and obtain the ideal surface roughness.
The above are some ideas and suggestions for CNC lathe fixture and tool selection. In actual processing, we should not be afraid of hard work and trouble. Combined with comprehensive analysis of various factors, and constantly try, optimize and summarize, we believe that we will soon become the "old driver" of CNC lathe processing industry.