Machining accuracy is mainly used to produce product grades, and 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. fdm prototyping
Machining accuracy refers to the degree to which the actual geometric parameters (size, shape, and position) of the part after machining are in accordance with 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 greater the error, the lower the machining accuracy, and the smaller the error, the higher the machining accuracy. The following is a brief introduction to the methods to improve the machining accuracy of the workpiece:
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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. fdm prototyping
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Second, reduce machine tool error
(1) The rotation accuracy of the bearing should be improved: 1 select high-precision rolling bearing; 2 use high-precision multi-oil dynamic pressure bearing; 3 use high-precision hydrostatic bearing
(2) Improve the accuracy of the bearing parts: 1 Improve the machining accuracy of the box support hole and the spindle journal; 2 Improve the machining accuracy of the matching surface with the bearing; 3 Measure and adjust the radial runout range of the corresponding part to make the error Compensation or offset.
(3) Appropriate pre-tightening of the rolling bearing: 1 can eliminate the gap; 2 increase the bearing stiffness; 3 equalize the rolling element error.
(4) Make the spindle rotation accuracy not reflected on the workpiece. fdm prototyping
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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 transmission ratio should be smaller as the transmission pair is closer to the end;
(3) The accuracy of the end piece should be higher than other transmission parts. fdm prototyping
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Fourth, reduce tool wear
(1) Re-sharpening must be performed before the tool size wear reaches the stage of sharp wear
(2) Use special cutting oil for sufficient lubrication
(3) Tool material should meet the process requirements
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Fifth, reduce the deformation of the process system
(1) Improve the rigidity of the system, especially the stiffness of the weak link in the process system;
(2) Reduce the load and its changes. fdm prototyping
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Sixth, reduce the thermal deformation of the process system
(1) Reduce heat generation and isolation heat source of heat source
(2) Equilibrium temperature field
(3) Adopt reasonable machine tool component structure and assembly standard
(4) Accelerate to achieve heat transfer balance
(5) Control the ambient temperature
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Seven, reduce residual stress
(1) adding a heat treatment process for eliminating internal stress;
(2) Reasonably arrange the process. fdm prototyping
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