Contribution of Five-Axis Machine Geometric Errors and Workpiece Setup Errors to On-Machine Laser Scanning Measurement

2018 ◽  
Author(s):  
Soichi Ibaraki ◽  
Shunsuke Goto ◽  
Keisuke Tsuboi ◽  
Naoto Saito ◽  
Noriaki Kojima
Keyword(s):  
Measurement Error ◽  
Laser Scanning ◽  
Work Piece ◽  
Geometric Errors ◽  
Practical Application ◽  
Setup Errors ◽  
Touch Trigger Probe ◽  
Discrete Measurement ◽  
Workpiece Setup ◽  
Five Axis

On-machine scanning measurement of workpiece geometry has a strong advantage in its efficiency, compared to conventional discrete measurement using a touch-trigger probe. When a workpiece is rotated and tilted, position and orientation errors in workpiece setup with respect to the machine’s rotary axes can be a significant contributor to the measurement error. The machine’s geometric errors also influence the measurement error. To establish the traceability of on-machine laser scanning measurement with workpiece rotation, this paper kinematically formulates their contribution to measured profiles. As a practical application example, this paper studies the sensitivity of work-piece setup errors and rotary axis geometric errors on the error in laser scanning measurement of an axis-symmetric part.

Sensitivity Analysis of Geometric Errors for Five-Axis CNC Machine Tool Based on Multi-Body System Theory

2012 ◽  
Vol 271-272 ◽  
pp. 493-497
Author(s):  
Wei Qing Wang ◽  
Huan Qin Wu
Keyword(s):  
System Theory ◽  
Sensitivity Analysis ◽  
Machine Tool ◽  
Geometric Error ◽  
Machining Accuracy ◽  
Geometric Errors ◽  
Body System ◽  
Cnc Machine ◽  
Multi Body ◽  
Five Axis

Abstract: In order to determine that the effect of geometric error to the machining accuracy is an important premise for the error compensation, a sensitivity analysis method of geometric error is presented based on multi-body system theory in this paper. An accuracy model of five-axis machine tool is established based on multi-body system theory, and with 37 geometric errors obtained through experimental verification, key error sources affecting the machining accuracy are finally identified by sensitivity analysis. The analysis result shows that the presented method can identify the important geometric errors having large influence on volumetric error of machine tool and is of help to improve the accuracy of machine tool economically.

Identification and compensation of 11 position-independent geometric errors on five-axis machine tools with a tilting head

2017 ◽  
Vol 94 (1-4) ◽  
pp. 533-544 ◽  
Author(s):  
Hui Yang ◽  
Xiaodiao Huang ◽  
Shuang Ding ◽  
Chunjian Yu ◽  
Yameng Yang
Keyword(s):  
Machine Tools ◽  
Geometric Errors ◽  
Five Axis

Table-Based Volumetric Error Compensation of Large Five-Axis Machine Tools

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Jennifer Creamer ◽  
Patrick M. Sammons ◽  
Douglas A. Bristow ◽  
Robert G. Landers ◽  
Philip L. Freeman ◽  
...  
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Machine Tools ◽  
Data Gathering ◽  
Measurement Data ◽  
Geometric Error ◽  
Compensation Method ◽  
Geometric Errors ◽  
Simultaneous Generation ◽  
Five Axis

This paper presents a geometric error compensation method for large five-axis machine tools. Compared to smaller machine tools, the longer axis travels and bigger structures of a large machine tool make them more susceptible to complicated, position-dependent geometric errors. The compensation method presented in this paper uses tool tip measurements recorded throughout the axis space to construct an explicit model of a machine tool's geometric errors from which a corresponding set of compensation tables are constructed. The measurements are taken using a laser tracker, permitting rapid error data gathering at most locations in the axis space. Two position-dependent geometric error models are considered in this paper. The first model utilizes a six degree-of-freedom kinematic error description at each axis. The second model is motivated by the structure of table compensation solutions and describes geometric errors as small perturbations to the axis commands. The parameters of both models are identified from the measurement data using a maximum likelihood estimator. Compensation tables are generated by projecting the error model onto the compensation space created by the compensation tables available in the machine tool controller. The first model provides a more intuitive accounting of simple geometric errors than the second; however, it also increases the complexity of projecting the errors onto compensation tables. Experimental results on a commercial five-axis machine tool are presented and analyzed. Despite significant differences in the machine tool error descriptions, both methods produce similar results, within the repeatability of the machine tool. Reasons for this result are discussed. Analysis of the models and compensation tables reveals significant complicated, and unexpected kinematic behavior in the experimental machine tool. A particular strength of the proposed methodology is the simultaneous generation of a complete set of compensation tables that accurately captures complicated kinematic errors independent of whether they arise from expected and unexpected sources.

Diamond Turning Freeform Optics

2007 ◽  
Vol 364-366 ◽  
pp. 1-6
Author(s):  
W. Jiang ◽  
Bill Tse ◽  
Roy Louie ◽  
Frankie Chan
Keyword(s):  
Diamond Turning ◽  
Freeform Surface ◽  
Work Piece ◽  
Freeform Optics ◽  
Milling Method ◽  
Slow Tool Servo ◽  
Optics Industry ◽  
Optics Fabrication ◽  
Five Axis ◽  
Machining Parameter

Freeform optics fabrication has become one of the hottest topics in optics industry in recent years. Although it still remains a challenge, many have tried different ways of manufacturing it. Some have achieved degrees of success. By means of a Nanotech 350-FG five axis diamond turning machine, we too have successfully produced some prototype freeform optics and lens arrays with Slow Tool Servo and Milling method. The produced freeform optics are mainly for automobile LED headlamps and the lens arrays are for LED illumination. In order to produce the freeform optics, we developed our own DT Slow Tool Servo program which is capable of generating a DT program for diamond turning a universal/general 3D freeform surface. Slow Tool Servo technique and Diamond Milling technique were mainly employed to produce these freeform surfaces. The manufacturing process and machining parameter details will be given in the paper. The two main methods we used will be compared and discussed as well. In measuring the freeform surface, a 3D white light interferometer was used to scan and obtain the surface coordinates. The software made by ourselves enabled us to compare the measure results of the work piece with that of the design drawings. The deviation of our finished forms is within 5 um from that of the nominal. The surface quality Rq is about 10 nm. Measuring equipment and methodology will also be discussed in the paper.

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