Experimental study of pin surface precision on lubrication behavior of pin–bush pairs in industrial roller chains

Purpose The purpose of this paper is to study the influence of surface precision on the lubrication state of the roller chain under adequate and rare oil supply conditions, respectively. Design/methodology/approach The straightness error and roughness error of the pin generatrices were measured and the influence of surface precision on the lubrication behavior under steady state and reciprocating motion was studied through optical interference experiments. Findings The lubrication state is strongly influenced by the surface precision of the roller surface both under adequate oil supply and rare oil supply conditions. Originality/value In industrial applications, the machining errors of parts cannot be completely eliminated. Studying the influence of the surface precision on the lubrication behavior of pin–bush pairs can provide the experimental basis for the optimal design of the bush roller chains.

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.

Model establishment of surface roughness and experimental investigation on magnetorheological finishing for polishing the internal surface of titanium alloy tubes

A novel magnetorheological polishing process is devised to polish the internal surface of titanium alloy tubes. Under the magnetic field in polishing area between the internal surface of tube and polishing head, magnetorheological polishing fluid gets stiffened and acts as the polishing tool. In this process, rotation motion of tube and reciprocating linear motion of polishing head are carried out simultaneously resulting in helical motion trajectory of abrasive particles on workpiece surface. The finishing forces during magnetorheological polishing process including normal indentation force and shear force are analyzed and modeled. Based on the proposed model, final surface roughness Ra model is proposed to predict the polishing performance. Experiments are carried out to investigate the effect of polishing time and initial surface roughness Ra on polishing performance. The experimental results are compared with the model results, which are highly consistent. The results show a gradual growth of surface precision with polishing time and an augment of polishing efficiency with increasing initial surface roughness Ra.

Active shape control of an antenna reflector using piezoelectric actuators

The surface precision of an antenna reflector can be improved using the actuation of piezoelectric materials to obtain a high-performance space antenna. In this study, the active shape control of a reflector with piezoceramic (lead zirconate titanate) actuators assembled on ribs is proposed by theoretical and experimental approaches. A finite element model of the integrated reflector–actuator system is established using piezoelectric constitutive equations and the virtual work’s principle. For a desired shape, a closed-loop iterative shape control method based on the influence coefficient matrix model is developed, which resolves the issue of high-precision shape control of the antenna reflector in the presence of model errors. The shape controller based on the proposed closed-loop shape control method is implemented on a planar hexagonal reflector with 30 lead zirconate titanate actuators. Experimental results demonstrate that the closed-loop control is an effective way to improve the surface precision of the reflector considering uncertainties.

Surface quality and tool wear in micro-milling of single-crystal aluminum

Micro-milling technology is used to machine micro-components and features widely with high surface precision and processing efficiency. To identify the determinants of surface quality of single-crystal aluminum, the micro-milling mechanism of single-crystal materials was characterized based on the shear theory and the mathematical model. The slip plane (111) is the easiest to slip through analysis, so its plastic tendency is the best. A double-edged cemented micro-milling tool with diameter of 0.4 mm was used, and a response surface methodology experiment was conducted on the micro-milling of single-crystal aluminum. By the analysis of variance and range, the factors that impact surface quality were determined as feed rate, spindle speed, and milling depth. A single-crystal surface roughness prediction model was established, allowing the discussion of the influence rules of cutting parameters on the micro-milling surface and analysis of the mechanism and form of tool wear by scanning electron microscopy. These data provide the theoretical and experimental basis for the micro-milling of single-crystal materials.

Aspects of the Internal Gear Honing Process

The paper analyzes the process of internal honing of cylindrical gears, a new and modern method of finishing the gear tooth flanks. At the beginning, the kinematics of the process is being analyzed. By realizing the state of art, we were able to identify the main features of the process, its advantages in terms of surface precision and quality, the residual stresses and the wear of the flanks compared with other finishing processes. An experimental study of the geometric precision, the shape of the flanks and the roughness for honed surfaces compared to the unfinished ones, highlighted the value and the need of this process.