Programming skills 

1） Processing sequence of parts: drilling first and then flat end (this is to prevent shrinkage during drilling); Rough turning first, then fine turning (this is to ensure the accuracy of parts); The first machining tolerance is large, and the last machining tolerance is small (this is to ensure that the small tolerance dimension surface is not scratched and prevent the deformation of parts).

2） According to the hardness of the material, the reasonable rotation speed, feed rate and cutting depth are selected

1. Carbon steel material selection of high speed, high feed, large cutting depth. For example: 1gr11, select s1600, f0.2, cutting depth of 2mm;

2. Cemented carbide choose low speed, low feed, small cutting depth. For example: GH4033, select S800, f0.08, cutting depth 0.5mm;

3. Titanium alloy has low speed, high feed rate and small cutting depth. For example: ti6, select S400, f0.2, cutting depth 0.3mm.

Skills of knife setting

Tool setting is divided into tool setting instrument and direct tool setting. Most lathes have no tool setting instrument, which is direct tool setting. The following tool setting skills are direct tool setting. First, select the center of the right end face of the part as the tool setting point, and set it as the zero point. After the machine returns to the zero point, each tool that needs to be used will set the center of the right end face of the part as the zero point; When the tool contacts the right end face, input Z0 and click measure, the measured value will be automatically recorded in the tool compensation value, which means that the z-axis tool setting is good, the x-axis tool setting is trial cutting tool setting, and the outer circle of the part is less with the tool. Input X20 to measure the outer circle of the part to be turned (for example, X is 20mm). Click measure, the tool compensation value will automatically record the measured value, and then the x-axis is also good; This tool setting method will not change the tool setting value even if the machine tool is powered off, and it can be applied to mass production of the same part for a long time, during which turning off the lathe does not need to reset the tool.

Debugging skills

After the part is finished, the test cutting and debugging is required after the tool is finished. In order to prevent the error and error of the tool alignment and the collision accident, we should carry out the simulation processing of the empty travel in advance, and shift the tool to the right in the coordinate system of the machine tool by 2-3 times of the total length of the parts; Then start the simulation processing. After the simulation processing, confirm the procedures and correct the tool. Then start processing the parts. After the first part is processed, self check and confirm the qualified part. Then, find the full-time inspection and check. After the full-time inspection is confirmed to be qualified, the commissioning is finished.

Finish the machining of parts

After the trial cutting of the first part is completed, the parts will be produced in batches. However, the qualification of the first part does not mean that the whole batch of parts will be qualified, because in the process of processing, due to the different processing materials, the tool will be worn. The processing materials are soft, the tool wear is small, the processing materials are hard, and the tool wear is fast. Therefore, in the process of processing, it is necessary to check frequently and increase and reduce the tool compensation value in time, Ensure the parts are qualified.

In a word, the basic principle of machining: rough machining first, remove the surplus material of the workpiece, and then finish machining; Vibration should be avoided during machining; There are many reasons to avoid the thermal denaturation of the workpiece during processing, which may be the excessive load; It may be the resonance between the machine tool and the workpiece, or it may be the lack of rigidity of the machine tool, or it may be caused by the tool passivation. We can reduce the vibration by the following methods; Reduce the cross feed and machining depth, check whether the workpiece clamping is firm, increase the speed of the tool, the latter can reduce the resonance by reducing the speed, in addition, check whether it is necessary to replace the new tool.

In addition, in order to operate the CNC machine safely and prevent collision, I have the following experience:

It is often said that if you don't touch the machine tool, you can't learn how to operate the machine tool. This is a very wrong and harmful understanding. Machine tool collision is a great damage to the accuracy of the machine tool, and it has different effects on different types of machine tools. Generally speaking, it has a greater impact on the machine tools with weak rigidity.

Once the machine tool collides, the impact on the accuracy of the machine tool is fatal. Therefore, for high-precision CNC lathe, collision must be eliminated. As long as the operator carefully and master certain anti-collision methods, collision can be completely prevented and avoided.

The main reasons for collision are as follows: first, the input error of tool diameter and length; Second, the size of the workpiece and other related geometric dimension input error and the initial position of the workpiece positioning error; Third, the workpiece coordinate system of the machine tool is set incorrectly, or the zero point of the machine tool is reset in the process of processing, resulting in changes. Most of the machine tool collisions occur in the process of rapid movement of the machine tool. At this time, the collision is also the most harmful and should be absolutely avoided.

Therefore, the operator should pay special attention to the machine tool in the initial stage of executing the program and when the machine tool is changing the tool. At this time, once the program is edited incorrectly and the tool diameter and length are input incorrectly, it is easy to collide. At the end of the program, if the action sequence of NC axis is wrong, collision may also occur. In order to avoid the above collision, the operator should give full play to the function of the five senses when operating the machine tool, and observe whether the machine tool has abnormal action, sparks, noise, abnormal sound, vibration and burning smell.

In short, mastering the operation skills of CNC machine tools is a step-by-step process, which can not be achieved overnight. It is based on mastering the basic operation of machine tools, basic machining knowledge and basic programming knowledge. The operation skill of CNC machine tool is not unchangeable, it is an organic combination that requires the operator to give full play to his imagination and practical ability, and it is an innovative labor.