Influence of Machining Errors on the Quality of Straight Round Flexible Hinges_Hinge Knowledge_Talls1

Expanded

The flexible hinge is a highly versatile mechanism that utilizes the micro-elastic deformation and recovery characteristics of metal. It acts as a micro-positioning high-resolution transmission mechanism, widely used in various fine-tuning devices, precision positioning platforms, photolithography and scanning detection microscopes, and more. Due to its integrated processing and molding, it possesses unique characteristics such as no mechanical friction, no mating space, no lubrication, and high motion sensitivity.

However, there are several factors that can affect the working performance of flexible hinges. When designing flexible hinges, certain assumptions are made, such as assuming that only elastic deformation occurs at the hinge while the rest is considered as a rigid body. It is also assumed that only corner deformation occurs during work, without expansion or other deformations. Additionally, the hinge itself has inherent defects, such as the center of rotation not being fixed, stress concentration, stress magnitude changes with the position of the joint, and the influence of the environment on the material.

In structural design, the coupling displacement of the corner and the straight line can be caused by processing errors between the combinations of several hinges and connecting rods. This can result in the motion deviating from the ideal track. Extensive literature has analyzed the error sources of flexible hinge mechanisms, discussing material performance, size design, vibration, interference, machining errors, and more. These studies provide valuable insights into the sensitivity of each variable error and the coupling of the displacement mechanism caused by manufacturing errors.

This paper aims to analyze the three types of machining errors of the straight circular flexible hinge and derive the stiffness calculation formula when these errors are present. The dimensions of the hinge and the error parameters are used to calculate the stiffness and verify the results through finite element analysis (FEA). This analysis provides valuable information for the parameter design and processing of the hinge.

The three types of machining errors analyzed in this paper include the positioning error of the notch arc in the y direction, the positioning error of the notch arc in the x direction, and the perpendicularity error of the center line of the notch arc. Each error type is analyzed separately, and the stiffness errors are calculated based on the error coefficients and hinge parameters. The stiffness error formulas are then compared and verified through FEA simulations.

The results of the numerical analysis and FEA simulations show good agreement. The stiffness error curves obtained under different hinge parameter values demonstrate that the error coefficients significantly impact the stiffness. The positioning errors in the y and x directions have a considerable influence, while the perpendicularity error also affects the stiffness. By understanding these errors and their effects, efficient design and machining processes can be implemented to minimize their impact on the flexible hinge.

In conclusion, the machining errors of straight round flexible hinges have a direct impact on their stiffness performance. This paper provides a comprehensive analysis of the three types of machining errors and presents stiffness calculation formulas for each error type. The results are verified through FEA simulations, highlighting the importance of controlling positioning errors and perpendicularity errors in order to optimize the performance of flexible hinges. The findings of this study can serve as a valuable reference for design and manufacturing processes in various industries.