Research on Stress and Strain in Isometric Polygonal Profile Connection Based on FEM

Because of the problem of key joint or spline joint, the isometric polygonal profile connection was put forward, and the mathematical model of isometric polygonal curve was analyzed in this paper. Based on the periodicity characteristics of equivalent effective stress and total displacement in the whole structure through preliminary analysis, 1/3 structure of isometric polygonal profile shaft and hub was adopted during geometry model being established. The shearing strength in isometric polygonal profile hub and shaft, the main stress in hub and the total strain in shaft were calculated and analyzed based FEM.

Research on Grinding Technology of Isometric Polygonal Profile

On the basis of analyzing the structure characteristics of the Isometric Polygonal Profile (IPP) hole, equations of the track for grinding wheel center and the formula of calculating node coordinates according to equal-error linear approximation method are established and the determination method of grinding technology parameters value and problems to be attention at grinding process are discussed. Grinding experiments show that both processing precision and surface roughness can reach with the fit requirements of IPP connection according to these principles. It is available for reference that grinding complex non-circular column surface is ground by CNC machine tools.

Research on NC Grinding Accessories of Isometric Polygonal Profile

In order to study the grinding technology of Isometric Polygonal Profile (IPP), NC grinding accessory of IPP is developed, which is driven by Program Logic Controller (PLC) and step-motors. On the basis of the principle of coordinate conversion and envelope curve, formative motions of IPP are discussed in detail. Because the relationship between the rotation of parts and synchronization motion in both x and y axes of coordinates frame is of the proportional transmission, and the synchronization motion is harmonic motion in both x and y axes of coordinates frame, the relationship of them is of the proportional transmission too, but the frequency of the synchronization motion is low and the displacement is small, so the eccentric mechanism is used in the grinding accessory. The grinding process of three axes linkage of IPP can be translated into process of two axes linkage between three coordinates on machine tools by means of combination of PLC and the eccentric mechanism. It has been found by grinding experiment that the NC grinding accessory is available used for grinding IPP and other polygonal profile.

Theoretical Optimum of Implant Positional Index Design

Rotational freedom of the implant-abutment connection influences its screw joint stability; for optimization, influential factors need to be evaluated based on a previously developed closed formula. The underlying hypothesis is that the manufacturing tolerances, geometric pattern, and dimensions of the index do not influence positional stability. We used the dimensions of 5 commonly used implant systems with a clearance of 20 μm to calculate the extent of rotational freedom; a 3D simulation (SolidWorks) validated the analytical findings. Polygonal positional indices showed the highest degrees of rotational freedom. The polygonal profile displayed higher positional stability than the polygons, but less positional accuracy than the cam-groove connection. Features of a maximal rotation-safe positional index were determined. The analytical calculation of rotational freedom of implant positional indices is possible. Rotational freedom is dependent on the geometric design of the index and may be decreased by incorporating specific aspects into the positional index design.

Time Series Model Study on the NC Grinding Process of Isometric Polygonal Profile

This paper studies the NC grinding process for Isometric Polygonal Profiles (IPP) with self-made machine tools accessories, and establishes the time series model of the grinding process by means of measuring and analyzing the vibratory signal in the grinding process. The grinding experiment indicates that the surface formative motions of IPP can be achieved with the step-motor-driven accessories and it is reasonable to design the grinding machine for IPP according to the principle. This method solves the technical problems in IPP NC processing and can act as an important elicitation and illustration for NC processing other polygonal profiles.