Operation methods and skills of the hottest CNC ma

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Operation methods and skills of CNC machine tools

as for the classification of many domestic operators who are just engaged in CNC machine tools at present, a large number of operators are technical workers who have previously engaged in the operation of general manual machine tools or semi-automatic machine tools. They are very familiar with machining, but they are relatively unfamiliar with the programming of CNC machine tools; There are also students who have just graduated from the mechanical college. They are familiar with the knowledge of mechanical processing, the theory of numerical control processing and programming, but they lack, such as: bell type furnace annealing with nitrogen (or nitrogen hydrogen mixture) protection for raw materials and advanced, fast and automatic thickness measurement continuous rolling technology; The stamping of small and medium-sized chain pieces adopts multi piece, multi station high-speed progressive die; The heat treatment adopts the new technology of controllable atmosphere quenching, carbonitriding and propane gas carburizing; Practical machining experience in adopting new chromizing process for pin shaft; There are also many operators who have never been exposed to machining and programming, so it is very difficult for them to learn the operation of CNC machine tools. For those who are beginning to learn CNC machine tools, it is very important to master certain operating skills of CNC machine tools. On the one hand, they can avoid machine tool collision accidents, resulting in machine tool damage; Second, in a relatively short time, it can quickly improve the operator's CNC machine tool operation skills, be competent for their own work, and create economic benefits for the unit. This paper introduces some theoretical knowledge of the operation skills of CNC machine tools, especially for those operators who have just come into contact with CNC machine tools, hoping to have some reference significance for the operators who have just engaged in CNC machine tools

first of all, the operator needs to have a comprehensive understanding of the CNC machine tool. Understand the mechanical structure of the machine tool: understand the mechanical structure of the machine tool; Master the shafting distribution of the machine tool; More importantly, we should firmly grasp the positive and negative directions of each NC axis of the machine tool; It is necessary to master the functions and use of various parts of the machine tool, such as the principle and function of a simple pneumatic system and the working principle and function of a simple hydraulic system; In addition, it is necessary to master the working principle and function of each auxiliary unit of the machine tool, such as the working principle, function and use method of the tool magazine, cooling unit, voltage regulator, electrical cabinet cooler and other units, as well as the working principle, function and use method of each safety door lock of the machine tool

firmly grasp the functions of each operation button of the machine tool: know how to execute the program; How to check the workpiece processing state after suspending the program, how to resume the program after resuming the suspended state, and how to stop the program; How to change the program before executing it, and so on

know what kind of operating system your machine tool is; Simply understand the control principle and working method of CNC system; What kind of working language is used in the system, the software used in machine tool processing and the language used. If the operator does not understand the language or the professional vocabulary of the language, then professional training is required. During the training, he needs to carefully take notes. What Chinese meaning each vocabulary in the machine tool software represents must be memorized and mastered, so that the machine tool can be used correctly in the future. In addition, operators also need to learn and master the general operation alarm sentences during training, and know what the Chinese means, how to solve problems, and how to eliminate false alarms. In addition, if the operator has the energy and ability to allow, he can learn and master this kind of language, which will be of great help to improve the machine tool operation skills in the future

secondly, it is necessary to master the manual or automatic operation of the NC machine tool and the movement of each NC axis of the machine tool. The operator must reach the state that practice makes perfect, so that he can retract and release freely in any case; In case of collision or failure, the operator can correctly and timely deal with the problem, and the operator will form a conditioned reflex and decisively take braking measures. In addition, the operator should be very familiar with the processing program of CNC machine tools; You should be very familiar with what kind of process and operation, and what kind of action the machine tool should have. When the machine tool executes the program, you can know at the first time whether the action of the machine tool is correct and whether braking measures need to be taken. In addition, every novice operator has more or less some fear in the early stage of operating the machine tool, fearing that the machine tool will collide with the knife and machine. Only after the operator has mastered the operation of CNC machine tools, can he overcome similar fear and learn to master higher CNC machine tool operation skills on this basis

third, it is necessary to master the program, the parameter compensation of each process and the compensation of the diameter and length of the cutter or grinding wheel. First, after training, master the programming language, programming method and parameter compensation method of the NC machine tool you want to operate. Now most advanced CNC machine tools are equipped with PC workstations for programming or simulation. Then beginners can first learn the simulation of software and machine tool cutting on the workstation. In the process of learning programming, we should not only pay attention to the simulation results, but also learn the process of simulation processing. We should understand what kind of cutting tools or grinding wheels are needed for the processing of workpieces, and what kind of motion path the NC axis of the machine tool completes the cutting process; When the machine tool performs a specific process processing, the position and direction of the movement of the relevant parts in the machine tool; Pay attention to the movement direction and cutting direction of each axis during machining, including how to feed and withdraw the tool, and pay attention to the fast forward speed and displacement of each step during machining, and the speed and displacement of each step during machining. When processing through simulation software, pay attention to the correct input of all parameters in the simulation process, and do not input carelessly because of simulation, which may lead to incorrect simulation processing results; Or cause collision accidents during actual processing in the future, or parts are scrapped. If the simulation software has the function of anti-collision test, it is necessary to use this function to check the correctness of programming. In addition, the operator needs to pay special attention: simulation processing is only a theoretical result, which does not mean that the machine tool will not collide in the actual cutting process, nor does it mean that qualified products can be processed. The purpose of simulation is to save programming time, improve the actual utilization of machine tools, and reduce the debugging time when processing workpieces, which does not represent the actual part processing. The completion of perfect workpiece processing is inseparable from the wisdom and sweat of CNC machine tool operators

fourth, the processing skills in the actual processing process should be carefully prepared. First read the drawing, confirm the position of the workpiece to be processed, confirm the accuracy tolerance of the part of the workpiece to be processed, and then process the program. Prepare the workpiece, cutter or grinding wheel required in the processing, the testing instruments required in the processing, and the auxiliary tooling and fixtures required in the processing

when machining the first workpiece, the machine tool should use the single step working state for trial cutting. When the machine tool program calls a new tool or grinding wheel, it should first set the tool and check whether the program action is correct

during workpiece processing, try to adopt one-time clamping to complete workpiece processing; If the second clamping of the workpiece is required for measurement or other reasons, it is necessary to ensure the unification of the positioning and processing benchmark of the second clamping and the first clamping. If the amplifier range transformation, data collection, data transmission, experimental mode selection and LCD display of the whole machine adopt the automatic positioning device of the machine tool, it is necessary to maintain the measurement speed consistency of the automatic measurement system. When testing the machining accuracy of the workpiece, it is best to complete it on the machine tool, which can reduce the positioning error of the secondary clamping. In addition, when the machine tool is processing some parts of the workpiece, the accuracy requirements of its dimensional tolerance are high, the operator needs to check the accuracy after each processing, and then go to the next position of the workpiece after passing the inspection; If the shape of a part on the workpiece is processed and synthesized from two or more directions, the processing in each direction will affect the position or shape tolerance of the shape of the part. Then the direction that has less impact on the accuracy of the workpiece should be processed first, then the direction with higher tolerance requirements of the workpiece should be processed, and finally repeated processing, and finally approaching the required accuracy. If the workpiece cannot be measured by using standard measuring instruments on the machine tool, and the workpiece cannot be removed from the machine tool for measurement, otherwise the machining accuracy of the workpiece will be affected, special caliper, plug gauge, gauge and other means can be used to detect. If the machine tool software has a measurement function, the machine tool itself can be used to measure the workpiece. After finishing the processing of the whole workpiece, the workpiece shall be comprehensively inspected

for the processing of batch workpieces. After the initial program debugging is completed, the processing program needs to be optimized. The basic principles of optimization are as follows: the premise of ensuring machining quality, optimizing cutting parameters, such as feed speed, tool or grinding wheel speed, transverse feed, machining depth, etc; Optimize the processing steps, optimize the processing benchmark, improve the processing efficiency, use high-life tools or grinding wheels, and reduce the number of tool changes or wheel corrections; Establishing a reasonable mathematical model of machining procedure, an effective and reliable program, reasonably setting the allowance and times of rough and finish machining, and using appropriate forming tools or grinding wheels have a significant effect on improving efficiency and ensuring machining quality

for ensuring the processing quality of the processed workpiece, the following aspects should be paid attention to: heat the machine tool for a period of time during processing, maintain the thermal balance of each mechanical axis of the machine tool during operation, try to keep the temperature of the processed workpiece stable during the processing of the machine tool, and try to maintain the cold and heat balance of the working head, machine tool spindle, lead screw guide rail, grating ruler, tool collet or grinding wheel connecting rod. If the machine tool uses cooling oil and coolant, its temperature should be kept constant. The temperature of coolant is one of the important factors that affect the accuracy of workpiece processing. Next, the constant temperature of coolant should be ensured through the cooling system of the machine tool

generally, the factory needs to shut down at night and restart the machine the next day, so the machine tool needs to be warmed up before working every day. In order to improve the utilization rate of machine tools, there are two methods to realize machine tool processing. First, slightly modify the original program after startup, and make a compensation amount away from the workpiece in all processing procedures. Then, during the processing process, the correction value of the machine tool will be changed according to the measurement results. When the machine tool is in the heat balance state, the correction value may not need to be changed again. Another method is to process the parts with large tolerance on the workpiece for a period of time after starting up, and then process some parts with high tolerance on the workpiece after the machine tool reaches thermal balance after a period of time; Or rough machining with the machine tool first, and then finish machining of the workpiece after the machine tool reaches the thermal balance

for a workpiece with multiple benchmarks and multiple sizes with high accuracy requirements. Then a datum on the workpiece should be processed first, and only one or two dimensions should be defined, but the position with high dimensional accuracy requirements should be added first for the position with multiple dimensions on the same datum

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