A little carelessness in the machining process of machine tools will cause errors. Do you have a clear understanding of the machining processes that are easy to cause machining errors?
1. Manufacturing error of production machine tool itself
Six machining processes that are easy to affect machining errors
The manufacturing error of the production machine tool itself mainly includes spindle rotation error, guide rail error and transmission chain error.
Spindle rotation error refers to the variation of the actual rotation axis of the spindle at each instant relative to its average rotation axis, which will directly affect the accuracy of the workpiece being processed. The main causes of spindle rotation error include spindle coaxiality error, bearing error, coaxiality error between bearings, spindle winding, etc. The guide rail is the benchmark on the machine tool to determine the relative position relationship of each machine tool component, and it is also the benchmark of machine tool motion. The manufacturing error of the guide rail itself, the uneven wear of the guide rail and the installation quality are important factors causing the guide rail error. Transmission chain error refers to the error of relative motion between transmission elements at both ends of the transmission chain. It is caused by the manufacturing and assembly errors of each component link in the transmission chain, as well as the wear in the process of use.
2. Positioning error
Positioning error mainly includes reference misalignment error and positioning pair manufacturing inaccuracy error. When machining the workpiece on the machine tool, several geometric elements on the workpiece must be selected as the positioning datum during machining. If the selected positioning datum does not coincide with the design datum (the datum used to determine the size and position of a surface on the part drawing), the datum misalignment error will occur
The workpiece positioning surface and fixture positioning elements together form a positioning pair. The maximum position variation of the workpiece caused by the inaccurate manufacturing of the positioning pair and the matching gap between the positioning pairs is called the inaccurate manufacturing error of the positioning pair. The inaccuracy error of positioning pair manufacturing will occur only when the adjustment method is used, and will not occur in the trial cutting method.
3. Adjustment error
Machining error
In every process of machining, the process system must be adjusted in one way or another. Because the adjustment cannot be absolutely accurate, there is an adjustment error. In the process system, the mutual position accuracy of workpiece and tool on the machine tool is guaranteed by adjusting the machine tool, tool, fixture or workpiece. When the original accuracy of machine tools, cutting tools, fixtures and workpiece blanks meet the process requirements without considering dynamic factors, the adjustment error plays a decisive role in the machining error.
4. Geometric error of tool
Any tool will inevitably be worn in the cutting process, which will cause the size and shape of the workpiece to change. The influence of tool geometric error on machining error varies with the types of tools: when using fixed size tools for machining, the manufacturing error of the tools will directly affect the machining accuracy of the workpiece; For general cutting tools (such as turning tools), the manufacturing error has no direct impact on the machining error.
5. Geometric error of fixture
The function of fixture is to make the workpiece equivalent to the tool and machine tool have the correct position, so the geometric error of fixture has a great impact on the machining error (especially the position error).
6. Measurement error
When parts are measured during or after machining, the measurement accuracy is directly affected by measurement methods, measuring tool accuracy, workpiece and subjective and objective factors.
(Editor: we are Shenzhen perfect precision products Co., Ltd., specializing in providing laser cutting, bending, stamping, spinning, welding and other high-quality sheet metal processing services. With 15 years of experience and a 3000 square meter factory, we have an experienced engineering team, with iso9001:2015 quality system and imported machines from the United States and Japan. You can send us inquiries below.)