Machining precision controlling method for plane surface assisted by SPDT

In traditional processing mode, a given lathe and a set of fixed processing system can only produce a predetermined precision part. This article proposes a machining method that can control the surface precision of machining plane parts, and four gaskets with different accuracy requirements are processed on the same slow tool servo single-point diamond lathe for experimental verification. Then, the Peak Village (PV) value and surface topography of the processed parts were measured using the surface profiler Taylor Hobson PGI 1240 and Keyence VR-3200, respectively. Through the processing and analysis of the measured data, the maximum deviation between the PV value and the given PV value is 2.4 µm, the minimum deviation is 0.4 µm. And the PV value obtained by calculating the helical spacing measured by surface topography according to the method in this article is approximately equal to the measured PV value, so the correctness of the machining method is verified. Therefore, the machining method can control the surface accuracy of machining parts accurately according to the required accuracy.

Modeling and optimization of material removal influenced by sliding velocity in polishing

The high-precision part surfaces are usually finished by the corrective polishing to improve the surface form accuracy. This article proposes a new method to model and optimize the material removal in the polishing process. This method assumes that the material removal rate in polishing follows the Preston’s equation, and the material removal profile is obtained by integrating the material removal index along the tool path at each unit area of the tool/workpiece contact. The focus is on the effect of the sliding velocity on the material removal profile. Results indicate that the shape of the removal profile is affected by the angular spindle velocity, angular feed velocity and tool path radius. A series of simulation and practical polishing experiments were conducted to verify the proposed model. The tending gene of the removal profile is defined and derived. By using the principle of maximum tending gene, the material removal profile is optimized, which is helpful to plan the process parameter properly in polishing.

Prediction of Residual Stress in Multi-Step Orthogonal Cutting

The effect of residual stresses on the fatigue behavior as well as the dimensional stability of high precision part is very important. Machining operation consists generally multi-step operations from roughing to finishing. It is therefore critical to predict residual stresses under such configuration. In this paper, an analytical algorithm is proposed to predict the final residual stresses induced by a multi-step machining operation capturing the change of stress state of the workpiece as well as material hardening behavior during the multi-step orthogonal cutting. The model predictions were compared to other work’s finite element method (FEM) predictions.