• Categories:Industry News
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• Time of issue:2019-08-23 16:43
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(Summary description)Under the condition of stiffness, the roughing process takes a larger cutting depth to reduce the number of passes and increase the productivity of the workpiece; the finishing generally takes a smaller depth of cut to obtain a higher surface quality. Influencing the final machining accuracy and machining efficiency of the workpiece, in addition to the reasons of the CNC machine itself, it should also be based on reasonable machining route setting, tool selection and correct installation, reasonable selection of cutting amount, programming skills and rapid control of dimensional accuracy. Aspects are considered comprehensively.

First, programming skills

CNC programming is the most basic work of CNC machining. The pros and cons of workpiece machining program directly affect the final machining accuracy and machining efficiency of the machine tool. It can be started from clever use of intrinsic programs, reduction of cumulative errors in CNC systems, and flexible use of main programs and subroutines.

1, flexible use of the main program and subroutines

In the process of complex mold processing, it is generally processed in the form of multiple molds. If there are several identical shapes on the mold, the relationship between the main program and the subprogram should be used flexibly, and the subroutine should be called repeatedly in the main program until the machining is completed. Not only can the consistency of the processing dimensions be ensured, but also the processing efficiency can be improved.

2. Reduce the cumulative error of the CNC system

In general, the incremental programming is used to program the workpiece. It is the previous one to process the reference. In this way, continuous execution of multi-segment programs will inevitably produce a certain cumulative error. Therefore, in the programming, try to use absolute mode to program, so that each block is a workpiece. The origin is the reference, which can reduce the cumulative error of the CNC system and ensure the machining accuracy.

Machining accuracy is mainly used to produce product grades. Machining accuracy and machining tolerance are terms used to evaluate the geometric parameters of the machined surface. However, the actual parameters obtained by any processing method are not absolutely accurate. From the function of the parts, as long as the machining error is within the tolerance range required by the part drawing, it is considered that the machining accuracy is guaranteed.

Machining accuracy refers to the actual geometric parameters (size, shape and position) after machining the part. You want to learn UG programming to receive learning materials. The group 496610960 can help you to match the ideal geometric parameters. The difference between them is called the machining error. The size of the machining error reflects the level of machining accuracy. The larger the error, the lower the machining accuracy, and the smaller the error, the higher the machining accuracy. Here is a brief introduction to the methods to improve the machining accuracy of the workpiece:

First, adjust the process system

(1) Trial cutting adjustment by trial cutting - measuring size - adjusting the tool's cutting amount - cutting cutting - retrying, and so on until the desired size is reached. This method has low production efficiency and is mainly used for single-piece small batch production.

(2) The adjustment method obtains the required size by adjusting the relative positions of the machine tool, the jig, the workpiece and the tool in advance. This method has high productivity and is mainly used for mass production.

Second, reduce machine tool error

(1) The rotation accuracy of the bearing should be improved:

1 use high precision rolling bearings;

2 using high-precision multi-oil dynamic pressure bearing;

3 using high precision hydrostatic bearings

(2) Improve the accuracy of the accessories with the bearing:

1 Improve the processing precision of the box support hole and the spindle journal;

2 Improve the machining accuracy of the surface matched with the bearing;

3 Measure and adjust the radial runout range of the corresponding parts to compensate or cancel the error.

(3) Appropriate preloading of rolling bearings:

1 can eliminate the gap;

2 increase the bearing stiffness;

3 Homogenize rolling element error.

(4) Make the spindle rotation accuracy not reflected on the workpiece

Third, reduce the transmission chain transmission error

(1) The number of transmission parts is small, the transmission chain is short, and the transmission precision is high;

(2) Adopting the speed reduction transmission is an important principle to ensure the transmission accuracy, and the closer to the end of the transmission pair, the smaller the transmission ratio should be;

(3) The accuracy of the end piece should be higher than other transmission parts.

Fourth, reduce tool wear

(1) Re-grinding must be performed before the tool size wear reaches th