The emergence of CNC machine tools is a great progress in industry, it can better solve complex, precision, small batch, changeable parts processing problems, is a flexible, efficient automated machine tools. Programmers must first process analysis when they use NC machine tools. Whether they are programmed manually or automatically, they need to select the right machine tools, work out the processing plan, determine the processing sequence of the parts, the cutting tools and clamps used in each process according to the material, contour shape and machining accuracy of the workpiece to be processed. Tools and cutting oil. The following is a brief introduction of the problems that need to be paid attention to when choosing CNC machine tools.
First, the basic characteristics of NC machining.
(1) the process content of NC machining is more complicated than that of ordinary machine.
(2) the programming of NC machine tools is more complicated than the compilation of common machine tools. This is because in the ordinary machine tool processing technology do not have to consider the problem, such as the working procedure of the step arrangement, tool point, tool change point and path determination, etc., in the preparation of CNC machining process, but to seriously consider.
Two. Main contents of NC machining process
(1) Select the parts suitable for machining on NC machine tools, analyze the drawings of the parts, define the processing content and technical requirements, and determine the processing scheme.
(2) Designing NC machining processes, such as the division of processes, the choice of cutting tools, fixture positioning and installation, the determination of cutting parameters, the determination of tool path, etc.
(3) adjust the procedure of NC machining process. For example, tool selection, tool changing number and tool compensation.
(4) allocate tolerance in NC machining.
(5) process part of process instructions on CNC machine tools.
Three. The use of special cutting oil.
Generally, in order to clean the finished product easily, the better viscosity should be determined according to the difficulty of processing and degreasing conditions. Some workpiece raw materials will react with chlorine additives, so we should pay attention to the problem of white rust when choosing cutting oil. The cutting oil containing sulfur and chlorine compound additives can ensure the extreme pressure processing performance, and avoid burrs and cracks on workpiece.
Four, commonly used numerical control processing method.
(1) Plane hole parts are usually machined by point position and linear control NC machine tools. When choosing the technological route, the two principles of machining accuracy and efficiency are mainly considered.
(2) rotary parts are usually machined by CNC lathes or grinders.
Considering the machining efficiency: in the lathe processing, usually machining margin is large, must be reasonable arrangement of rough machining route to improve processing efficiency. In practice, it is generally not suitable to use circular instructions, otherwise the empty knife with machining feed speed is too large. A better way is to remove materials from rough cars as soon as possible, and then finish the car.
Consider tool tip strength: low strength cutting tools are often used for machining small grooves on CNC lathes.
(3) When machining planar contour parts with NC milling machine, attention should be paid to the need to use small straight or circular segments to approximate the processed contour when machining irregular curves. When approaching, the workpiece error should be within the qualified range and the number of program segments is less.
These are the problems that need to be paid attention to in NC machining. Through continuous improvement of workpiece raw materials, equipment technology, cutting parameters and so on, the technological level can be greatly improved.
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