Operation skills and tips of CNC lathe
I. Programming skills
Because our factory has high requirements for the accuracy of processed products, the matters that need to be considered when programming are
(a) the processing order of the parts: drilling first and then flat end (this is to prevent shrinkage when drilling); rough turning first and then fine turning (this is to ensure the accuracy of the parts); processing the large tolerance first and finally processing the small tolerance (this is to ensure that the surface of the small tolerance size is not scratched and to prevent the deformation of the parts).
(B) according to the material hardness to choose a reasonable speed, feed and depth of cut, I personally summarized as follows.
1, carbon steel materials choose high speed, high feed, large depth of cut. For example: 1Gr11, choose S1600, F0.2, depth of cut 2mm;
2, carbide choose low speed, low feed, small depth of cut. For example: GH4033, choose S800, F0.08, depth of cut 0.5mm;
3、Titanium alloy choose low speed, high feed, small depth of cut. For example: Ti6, choose S400, F0.2, depth of cut 0.3mm. take my processing a part for example: the material is K414, this material is a special hard material, after many trials, finally choose S360, F0.1, depth of cut 0.2, before processing qualified parts. Programming skills there are many, I personally summarize about so.
Second, the tooling skills
Tool setting is divided into tool setting instrument and direct tool setting. Most of my factory lathe no tool setting instrument, direct tooling, the following tooling skills for direct tooling. First select the center of the right end face of the part for the tooling point, and set as the zero point, the machine back to the origin, each need to use the tool to the center of the right end face of the part as the zero point for the tool; tool contact to the right end face of the input Z0 click on the measurement, tool complement value inside the tool will automatically record the measured value, which means that the Z axis on the tooling is good, X to the tooling for the trial cut on the tooling, with the tool to turn the outer circle of the part less, measuring the value of the outer circle to be turned (such as x for 20mm) input x20, click measure, the tool complement value will automatically record the measured value, then the x-axis is also good; this tooling method, even if the machine tool power off, call restart still will not change the tooling value, can be applied to a large number of long time production of the same parts, during the shutdown of the lathe also do not need to re-tool.
Three, debugging skills
Parts in the program, the need for good knife after the test cut debugging, in order to prevent errors in the program and knife errors, resulting in collision accidents, we should first carry out empty stroke simulation processing, in the machine tool coordinate system in the face of the tool to the right overall translation of the total length of the part 2 – 3 times; then start simulation processing, after the completion of simulation processing to confirm that the program and knife error-free, and then start the processing of parts, the first parts after the completion of processing, the first self-test, to confirm qualified, and then find a full-time inspection check, full-time inspection to confirm qualified after this means that the end of debugging.
Fourth, the completion of parts processing
Parts in the first test cutting is completed, we must carry out batch production, but the first piece of qualified does not mean that the whole batch of parts will be qualified, because in the processing process, due to the different processing materials will make the tool wear, processing materials soft, tool wear is small, hard processing materials, tool wear fast, so in the processing process, we must be diligent and diligent inspection, timely increase and reduce the value of the tool complement to ensure that the parts qualified, to a part For example, the processing material is K414, the total processing length is 180mm, because the material is very hard, the tool wear is very fast in the processing, from the starting point to the end, due to tool wear will produce 10 – 20mm slightly, so we must artificially add 10 – – 20mm slightly in the program. Therefore, we must artificially add 10 – 20mm slightly in the program, so as to ensure that the parts are qualified.
In short, the basic principles of machining: first rough machining, the workpiece to remove the excess material, and then finishing; machining should avoid the occurrence of vibration; avoid the thermal degeneration of the workpiece processing, caused by the occurrence of vibration for many reasons, may be too much load; may be the resonance of the machine tool and workpiece, or may be the machine tool is not rigid enough, or may be caused by the tool dull, we can reduce the following methods We can reduce the vibration by the following methods; reduce the lateral feed and machining depth, check whether the workpiece is firmly clamped, increase the rotational speed of the tool which can reduce the resonance, in addition, check whether it is necessary to replace the new tool. The above is a summary of my years of CNC lathe processing skills.
In addition, in order to safely operate CNC machine tools and prevent collisions with machine tools, I have the following tips.
I often hear people say that if you don’t touch the machine tool, you won’t learn how to operate the machine tool, which is a very wrong and harmful understanding, the machine tool collision is a great damage to the accuracy of the machine tool, and the impact is different for different types of machine tools, generally speaking, the impact is greater for the machine tool that is not very rigid, such as the T6 horizontal lathe we are using now, once the machine tool collision occurs, the impact on the accuracy of the machine tool is fatal. Therefore, for high-precision CNC lathes, collision should be absolutely eliminated. As long as the operator is careful and master certain anti-collision methods, collision can be completely prevented and avoided. The following are a few insights into the anti-collision of CNC lathe: the most important reasons for collision occurrence: one is the wrong input of the diameter and length of the tool; the second is the wrong input of the size of the workpiece and other related geometric dimensions and the wrong initial position positioning of the workpiece; the third is the wrong setting of the workpiece coordinate system of the machine tool, or the machine tool zero point is reset during the machining process, and the change occurs, and the machine tool collision mostly occurs in the machine tool Fast moving process, when the collision also occurs in the greatest harm, should be absolutely avoided. So the operator should pay special attention to the machine in the implementation of the initial stage of the program and the machine tool in the replacement of the time, once the program editing error, the tool diameter and length input error, then it is easy to collision. At the end of the program, the CNC axis of the wrong sequence of retreat action, then a collision may also occur. In order to avoid the above collision, the operator in the operation of the machine tool, to give full play to the five senses, observe the machine tool has no abnormal action, there is no spark, there is no noise and abnormal rattling, there is no vibration, there is no burnt smell. Abnormalities found should immediately stop the program, to be resolved after the machine tool problem, the machine tool can continue to work, in short, mastering the operating skills of CNC machine tools is a gradual process, and can not be achieved overnight. It is built on the mastery of the basic operation of the machine tool, basic knowledge of machining and basic programming knowledge. CNC machine tool operating skills are not static, it is an organic combination that requires operators to give full play to their imagination and hands-on skills, and is innovative labor. At the same time with the hope that this point of my skills and experience can bring a little help to colleagues.