<p>The high-speed motorized spindle is the core component of the machine tool, and its assembly accuracy directly determines the quality of the processing product and the service life of the spindle itself. As a typical revolving components assembly, it is critical to ensure that the radial and axial runout performance of the assembly is extremely excellent to satisfy the requirements of high precision and rigidity.&nbsp;Meanwhile, geometric deviations are inevitably observable on manufactured components of spindle, especially the form deviations of revolving part have huge influences on the quality and function of spindle. However, geometric deviations are reduced to dimensional and orientation defects without considering form deviations in most previous models of deviation analysis. Skin Model Shape of a workpiece is a discrete geometry representation of the physical interface between the workpiece and its environment, which is based on a representation of non-ideal workpieces employing discrete geometry representation schemes, such as point clouds and surface meshes. This paper presents a deviation analysis method for high-speed motorized spindle assembly using Skin Model Shapes, concerning all kinds of geometric deviations of the components. The high-speed spindle is usually composed of the shaft, the frameless motor, the bearings, the spindle shell and the locating bushes. Deviations of the components are represented by the Skin Model Shapes, which is a point cloud-based discrete representative that is able to model the actual toleranced surfaces instead of the ideal or associated ones in an assembly. Traditional assembly simulation based on skin model shapes mainly uses Constraint Registration or Difference Surface method to compute the relative position between different parts. This paper solves the constrained objective function by means of the ideas of sequential quadratically constrained quadratic programming (SQCQP) method, which can solve problems with high degree of non-linearity and also has relatively small amount of calculation. The beginning of this paper reviews mainstream assembly three-dimensional deviation analysis methods and the current status of research on assembly deviation analysis of high-speed motorized spindle. Following is the basic conceptions about Skin Model Shapes and sequential quadratically constrained quadratic programming (SQCQP) method. In the theory development part, the main calculation process of the Skin Model Shapes based deviation analysis model is deduced. A case study in high-speed motorized spindle assembly process is used to show the performance of the proposed method. Precision of the method is verified by comparing the computed results with experiment results of five spindle assembly samples. The assembly of the high speed motorized spindle is investigated intensively by the proposed method. The procedures outlined in the paper are quite general and can be used for tolerance analysis of any assembly process.</p><p>Key words: High-speed motorized spindle; Skin model; Assembly deviation analysis; SQPCP</p>

Three-Dimensional Deviation Analysis of High-Speed Spindle Assembly Based on Skin Model Shapes

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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