How to detect the positioning accuracy of a three-axis machining center?

CNC machine tool is the abbreviation of digital control machine tool, which is an automatic machine tool equipped with a program control system. The control system can logically process the programs with control codes or other symbolic instructions, decode them, and express them with coded numbers. After arithmetic processing, the numerical control device sends out various control signals to control the actions of the machine tool according to the drawings. The required shape and size will be processed automatically.

The positioning accuracy of the CNC machine tool can be understood as the motion accuracy of the machine tool. It is very important to ensure the accuracy of workpiece processing. Ordinary machine tools are manually operated, and the positioning accuracy is mainly determined by the reading error, while the movement of the CNC machine tool is realized by digital program instructions, so the positioning accuracy is determined by the CNC system and mechanical transmission error. The movement of each moving part of the machine tool is completed under the control of the numerical control device. The accuracy that each moving part can achieve under the control of the program instruction directly reflects the accuracy that can be achieved by the machined part. Therefore, the positioning accuracy is a very important test. content.

The following is the method of positioning accuracy of CNC machining center:

1. Repetitive positioning accuracy detection of linear motion

2. Detection of linear motion positioning accuracy

3. Reverse error detection of linear motion

4. Detection of the return accuracy of the origin of linear motion

5. Detection of positioning accuracy of rotary table

6. Repeated indexing accuracy detection of rotary table

7. Detection of the return-to-origin accuracy of the rotary table

It should be pointed out that the existing detection of positioning accuracy is measured under the condition of fast and positioning. For some CNC machine tools with a poor feed system, different positioning accuracy values will be obtained when positioning with different feed speeds. In addition, the measurement result of the positioning accuracy is related to the ambient temperature and the working state of the coordinate axis. At present, most CNC machine tools adopt a semi-closed loop system, and most of the position detection components are installed on the drive motor, resulting in an error of 0.01~0.02mm within a 1m stroke. It is not surprising. This is an error caused by thermal elongation. Some machine tools use pre-tensioning to reduce the impact.

The repeated positioning accuracy of each coordinate axis is the most basic accuracy index reflecting the axis. It reflects the stability of the axis's movement accuracy. It is impossible to imagine that a machine tool with poor accuracy can be used in production stably. At present, as the numerical control system has more and more functions, the system error of the movement accuracy of each ejector mark, such as the accumulated pitch error and the backlash error, can be systematically compensated. Only the random error cannot be compensated, and the repeated positioning accuracy It just reflects the comprehensive random error of the feed drive mechanism, which cannot be corrected by numerical control system compensation. When it is found to be out of tolerance, only the feed drive chain can be fine-tuned and corrected. Therefore, if the machine tool is allowed to be selected, it is better to choose a machine tool with high repeat positioning accuracy.

Suitable Materials:

1. Plastic: PVC, ABS, Acrylic, Plastic.

2. Soft Metal: Aluminum, Brass.

If you have parts with high-precision requirements that need to be processed, please contact us, we will provide the most reasonable processing technology and the most favorable price.

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