Aluminum profile processing error
The degree of agreement between the actual geometric parameters and the ideal geometric parameters after the aluminum profile is processed is the processing accuracy of the aluminum profile. The smaller the processing error, the higher the compliance and the higher the processing accuracy. The processing accuracy and processing error of aluminum profiles are two aspects of a problem.
1. Machine tool manufacturing error
Machine tool manufacturing errors mainly include spindle rotation error, guide rail error and transmission chain error.
2. The error caused by the fixture
In the processing of aluminum profiles, the role of the fixture is to make the workpiece equivalent to the correct position of the tool and the machine tool, so the geometric error of the fixture has a great influence on the machining error (especially the position error).
3. The error caused by the tool
Any cutter will inevitably wear out during the cutting process, resulting in changes in the size and shape of the aluminum profile. The impact of tool geometric error on machining error varies with the type of tool: when using a fixed size tool, the machining error of the tool will directly affect the machining accuracy of aluminum profile parts; for general tools (such as turning tools), machining The error has no direct effect on the processing error.
4. Positioning error
Positioning errors mainly include reference positioning errors and positioning sub-manufacturing errors. When processing aluminum profiles on the machine tool, several geometric elements on the workpiece must be selected as the positioning reference for processing. If the selected positioning reference and design basis are used (the part size is used to determine the size and position of the surface). Benchmark test) is inconsistent, resulting in a baseline mismatch error.
The positioning surface of the aluminum profile parts and the fixture positioning element together form a positioning pair. Due to the inaccurate manufacturing of the positioning pair and the matching gap between the positioning pair, the maximum position change of the workpiece is called the positioning error manufacturing error. The positioning error and manufacturing error will only occur when the adjustment method is used, and will not occur during the trial cutting process.
5. Thermal deformation of the process system
The thermal deformation of the processing system has a great influence on the processing error. Especially in precision machining and long material processing, the machining error caused by thermal deformation can sometimes account for 50% of the total error of the workpiece.
6. Stress deformation of the process system
Workpiece stiffness: In the machining system, if the workpiece stiffness is lower than the machine tool, tool, and fixture, under the action of the cutting force, the deformation caused by the insufficient rigidity of the aluminum profile has a greater impact on the processing error. Tool stiffness: The rigidity of the external turning tool in the normal (y) direction of the surface to be processed is very large, and its deformation can be ignored. The inner diameter of the smaller diameter, the stiffness of the rod is very poor, and the deformation of the rod has a great influence on the machining accuracy of the hole.
Machine tool part stiffness: Machine tool parts are composed of multiple parts. There is no suitable simple calculation method for the stiffness of machine tool components. At present, the experimental method is mainly used to determine the stiffness of machine tool components. The factors affecting the stiffness of machine tool parts are: the influence of joint contact deformation, the influence of friction, the influence of low stiffness parts, and the influence of clearance.
7. Adjustment error
In each process of aluminum profile processing, the process system is always adjusted in one way or another. Since adjustment cannot be absolutely accurate, adjustment errors will occur. In the processing system, by adjusting the machine tool, tool, fixture or workpiece to ensure the mutual positioning accuracy of the workpiece and the tool on the machine tool. When the original accuracy of the machine tool, tool, fixture, and aluminum blank meets the process requirements without considering the dynamic factors, the adjustment error plays a decisive role in the processing error.
8. Measurement error
When a part is measured during or after processing, the measurement method, the accuracy of the measuring tool, the accuracy of the workpiece, and subjective and objective factors directly affect the accuracy of the measurement.
9. Internal pressure
Stress existing inside aluminum profile parts