A workpiece registration and localization adjustment method with contact inspection under multi-tolerance conditions

2018 ◽  
Vol 233 (6) ◽  
pp. 1653-1662 ◽  
Author(s):  
Lei Jiang ◽  
Yong Li ◽  
Lei Han ◽  
Yisheng Zou ◽  
Guofu Ding ◽  
...  
Keyword(s):  
Machine Tool ◽  
Surface Characteristic ◽  
Experimental Results ◽  
Coordinate Systems ◽  
Adjustment Method ◽  
Current Process ◽  
Workpiece Localization ◽  
Position And Orientation ◽  
Iterative Registration

The workpiece contour errors from previous process affect current process. In order to improve workpiece allowance distribution, this article presents a workpiece registration and localization adjustment method with contact inspection. According to the analysis of machining deviation, the rotational and translational registration matrixes from multi-tolerance surfaces to workpiece are obtained by surface characteristic and translational vectors. The workpiece localization (position and orientation) adjustment can be realized by transforming coordinate systems of 5-axis machine tool. Through adaptive and iterative registration and adjustment, the optimized workpiece localization for current process is obtained. The experimental results show that the method can improve allowance uniformity effectively.

scholarly journals A Noncontact Method for Calibrating the Angle and Position of the Composite Module Array

2020 ◽  
Vol 10 (12) ◽  
pp. 4358
Author(s):  
Xinghua Li ◽  
Jue Li ◽  
Xuan Wei ◽  
Xiaohuan Yang ◽  
Zhikun Su ◽  
...  
Keyword(s):  
Machine Tool ◽  
Error Detection ◽  
Experimental Results ◽  
Freeform Surface ◽  
Angle Sensor ◽  
Noncontact Method ◽  
Wide Range ◽  
Array Calibration ◽  
The Mathematical Model ◽  
Composite Module

Freeform surface is one of the research focuses in the measurement field. A composite module is composed of a plane and rotating paraboloid. The composite module array can identify 21 geometric errors of the machine tool in a wide range, which is composed of several composite modules. Eliminating the error of the array itself is of great significance for improving measurement accuracy. For this reason, this paper proposed a noncontact method for calibrating the angle and position of the composite module array. This paper used a self-developed angle sensor to access corresponding information and established the mathematical model according to the freeform surface’s geometric characteristics to achieve calibration. In addition, the influence of array placement error on calibration was analyzed. The experimental results showed that the angle repeatability was within 0.4″ around the X-axis and within 0.3″ around the Y-axis, and the position repeatability was within 0.4 µm in the X direction and within 0.7 µm in the Y direction. The measurement comparison experiments with high-precision laser interferometer and uncalibrated array verified the correctness of the experimental results. This method provides an important reference for practical application and freeform surface array calibration, and creates conditions for the implementation of machine tool error detection.

Experimental Research Regarding the Influence of Hydraulic Resistances on the Hydrostatic Guideways Stiffness

2014 ◽  
Vol 657 ◽  
pp. 475-479
Author(s):  
Marius Pascu ◽  
Gheorghe Stan
Keyword(s):  
Machine Tool ◽  
Hydraulic Resistance ◽  
Experimental Research ◽  
Machine Tools ◽  
Dynamic Stiffness ◽  
Experimental Results ◽  
Graphical Form ◽  
Experimental Setup ◽  
Experimental Database ◽  
Supply Circuit

A very important factor for the hydrostatic guideways is given by the presence of the restrictor on the supply circuit, whose hydraulic resistance may have important effects on the lubricant film behaviour and implicitly, on the static and dynamic stiffness of the system. This paper presents a new method of experimental research regarding the hydrostatic guideway stiffness, depending on the hydraulic resistances values which supply each pocket. During the experiments which approach the influence of the hydraulic resistances values of the restrictors on the hydrostatic guideway stiffness, a centered constant loads of 20, 50 and 100 [daN] was used. The experiments were carried out on an experimental setup composed of an open hydrostatic guideway, having the pocket dimensions of 150x88 [m, supplied with liquid under pressure through means of a pack of adjustable restrictors. The obtained experimental results are presented in both tabular and graphical form and constitute an experimental database which can be used by the machine tools designers and manufacturers. The paper contains recommendations regarding the usage of hydraulic resistances values depending on the machine tool type and size. Also, from the obtained results, recommendations can be made with regard to the type of restrictors to be used, so that the lubricant filtration grade is comprised between admissible values.

The Effect of Flatness of Joint Faces upon the Static Stiffness of Machine Tool Joints

1967 ◽  
Vol 182 (1) ◽  
pp. 463-476 ◽  
Author(s):  
R. H. Thornley ◽  
R. Connolly ◽  
F. Koenigsberger
Keyword(s):  
Plastic Deformation ◽  
Machine Tool ◽  
Empirical Relation ◽  
Experimental Results ◽  
Static Stiffness ◽  
Interface Pressure ◽  
Surface Deflection ◽  
Machining Operations

This paper looks into the types of flatness errors produced in typical machining operations. The effect of these flatness errors on the pressure/deflection curves of the surfaces is reported. An empirical relation, based on the experimental results, between surface deflection and mean interface pressure is suggested. The effect of bonding joints is shown to eliminate plastic deformation of the surfaces and produces a joint having linear characteristics.

A New Automatic Backlash Adjustment Method for Lapping of Spiral Bevel Gear

2012 ◽  
Vol 565 ◽  
pp. 307-311
Author(s):  
Jian Wu Yu ◽  
Yi Jian Deng ◽  
Wen Yi Zou ◽  
Gong Fa Zhang
Keyword(s):  
Control Method ◽  
Experimental Results ◽  
Surface Finishing ◽  
Line Detection ◽  
Spiral Bevel Gear ◽  
Hypoid Gears ◽  
Adjustment Method ◽  
Bevel Gears ◽  
On Line ◽  
Spiral Bevel

Based on the lapping principle of spiral bevel gears and hypoid gears, this paper focuses on a new automatic backlash adjustment method for lapping process, which includes on-line detection and measurement of backlash, automatic backlash control and software etc. The experimental results shows that this on-line automatic backlash control method is efficiency and stable in lapping process, and it can improve gear surface finishing and reduce transmission noise apparently.

Thermo-Mechanical Behavior of a Micromirror for Laser-to-Fiber Active Alignment Using Bimorphs With Breakable Tethers

2006 ◽  
Author(s):  
Hajime Kitagawa ◽  
David J. Boteler ◽  
Yung-Cheng Lee
Keyword(s):  
Mechanical Behavior ◽  
Joule Heating ◽  
Room Temperature ◽  
Beam Steering ◽  
Experimental Results ◽  
Position And Orientation ◽  
Optimum Alignment

We will present a novel micromirror design in which tethered bimorph strips are used for mirror active alignment including beam steering and position fixing. A micromirror is attached to bimorphs that are pre-stressed at room temperature. A series of tethers link the bimorphs to the substrate to restrain their deformation. Breaking a tether by Joule heating allows the deformation of the bimorph to increase, changing the mirror position and orientation for precision alignment. With a large number of tethers, an optimum alignment can be achieved after breaking a selected group of tethers. We also report the experimental results of devices fabricated.

An improved thermo-mechanical model for spindle transient preload analysis

2019 ◽  
Vol 233 (11) ◽  
pp. 1698-1711
Author(s):  
Jiandong Li ◽  
Yongsheng Zhu ◽  
Ke Yan ◽  
Jun Hong ◽  
Xiaoyun Yan
Keyword(s):  
Machine Tool ◽  
Centrifugal Force ◽  
Mechanical Model ◽  
Operating Conditions ◽  
Experimental Results ◽  
Discrete Approach ◽  
Network Method ◽  
Transient Feature ◽  
Transient Network ◽  
Improved Model

Preload has a significant effect on the precision of machine tool spindle, and it changes transiently in different operating conditions. In this paper, the transient feature of spindle preload under multi-factor coupled effect was discussed theoretically and experimentally. By adopting the transient network method and the time-discrete approach, the integrated thermo-mechanical model of a spindle was established. The axial and radial deformations of spindle system, induced by centrifugal force, thermal, and assembly stresses, were all discussed. The effects of the various factors on the transient preload were analyzed, and results show that speed and temperature contribute the most to the transient preload, followed by the bearing deflection. Finally, experimental results indicate the correctness of the improved model.

Error modeling and sensitivity analysis of a novel 5-degree-of-freedom parallel kinematic machine tool

2018 ◽  
Vol 233 (6) ◽  
pp. 1637-1652 ◽  
Author(s):  
Xuan Luo ◽  
Fugui Xie ◽  
Xin-Jun Liu ◽  
Jie Li
Keyword(s):  
Sensitivity Analysis ◽  
Machine Tool ◽  
Jacobian Matrix ◽  
Error Modeling ◽  
Degree Of Freedom ◽  
Geometric Errors ◽  
Parallel Kinematic Machine ◽  
Parallel Kinematic ◽  
Position And Orientation ◽  
Five Axis

5-Degree-of-freedom parallel kinematic machine tools are always attractive in manufacturing industry due to the ability of five-axis machining with high stiffness/mass ratio and flexibility. In this article, error modeling and sensitivity analysis of a novel 5-degree-of-freedom parallel kinematic machine tool are discussed for its accuracy issues. An error modeling method based on screw theory is applied to each limb, and then the error model of the parallel kinematic machine tool is established and the error mapping Jacobian matrix of 53 geometric errors is derived. Considering that geometric errors exert both impacts on value and direction of the end-effector’s pose error, a set of sensitivity indices and an easy routine for sensitivity analysis are proposed according to the error mapping Jacobian matrix. On this basis, 10 vital errors and 10 trivial errors are identified over the prescribed workspace. To validate the effects of sensitivity analysis, several numerical simulations of accuracy design are conducted, and three-dimensional model assemblies with relevant geometric errors are established as well. The simulations exhibit maximal −0.10% and 0.34% improvements of the position and orientation errors, respectively, after modifying 10 trivial errors, while minimal 65.56% and 55.17% improvements of the position and orientation errors, respectively, after modifying 10 vital errors. Besides the assembly reveals an output pose error of (0.0134 mm, 0.0020 rad) with only trivial errors, while (2.0338 mm, 0.0048 rad) with only vital errors. In consequence, both results of simulations and assemblies validate the correctness of the sensitivity analysis. Moreover, this procedure can be extended to any other parallel kinematic mechanisms easily.

A Kind of Sub-Pixel Grid Characters Thickness Adjustment Method

2010 ◽  
Vol 174 ◽  
pp. 118-122
Author(s):  
Shu Hua Liu ◽  
Ping Li Li ◽  
Meng You Yuan ◽  
Hong Zhi Zhang
Keyword(s):  
Experimental Results ◽  
Adjustment Method ◽  
Raster Image ◽  
Image Layer ◽  
Printing Quality ◽  
Text Content ◽  
Background Image

In order to ensure printing quality of text content in raster image, we usually need to adjust the thickness of characters in the pre-press. This paper presents a sub-pixel adjustment method, based on analysis of characters’ neighborhood pixel information, so that we can control the scope and direction of the adjustment. In our method, Image is considered as a combined result of a foreground character layer and a background image layer. By performing the steps of separating characters from background, calculating ink density of each pixel of characters, adjusting each pixel’s ink density by analysis of neighborhood stroke shape, we achieve a result so fine that could simulate the effects performed by vector methods. The method can be adapted to global or any certain direction (e.g. vertical, horizontal, diagonal, etc) thickness adjustment. Experimental results show that the method can achieve excellent results and is proved to be very practical.

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