A Method for Enhancing the Accuracy of On-Machine Inspection for Five-Axis CNC Machines

2012 ◽  
Vol 426 ◽  
pp. 351-354
Author(s):  
Sheng Bao ◽  
Xi Zhang ◽  
Ping Fa Feng
Keyword(s):  
Coordinate System ◽  
Reference Frame ◽  
Least Square Method ◽  
Practical Method ◽  
Least Square ◽  
Inspection System ◽  
Cnc Machines ◽  
Structural Parts ◽  
Five Axis ◽  
Valid Information

The efficiency of manufacturing structural parts can be improved by using on-machine inspection system. It is difficult to separate the valid information from hundreds of points and correct the errors by rotating and translating the workpiece coordinate system directly, especially for five-axis CNC machines. In this paper, a practical method is designed to correct errors easily. By using the least square method, an error reference frame is constructed, and the relation between the compensation values and coordinates of the theoretical points is derived. An example of aircraft structural parts is presented to validate the design.

A Practical Algorithm for Compensating the Whole-Error of On-Machine Measurement

2010 ◽  
Vol 431-432 ◽  
pp. 462-465
Author(s):  
Sheng Bao ◽  
Ping Fa Feng
Keyword(s):  
Reference Frame ◽  
Machine Tools ◽  
Least Square Method ◽  
Least Square ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Valid Data ◽  
Practical Algorithm ◽  
Normal Vectors ◽  
Structural Parts

The On-machine measurement is usually based on the data of points. When data come from the CNC machine tools, the information they carry may be invalid. Therefore, it is unsuitable to compensate the errors by rotating and translating all data. In this paper, a practical algorithm is proposed to compensate the errors. Firstly, the valid data are picked out and sorted according to their normal vectors. By using the least square method, an error reference frame is constructed. Then the relation between the compensation values and coordinates of the theoretical points is derived. Finally, an example of aircraft structural parts is presented to validate the design.

Turning Test and Simulation of Difficult to Cut Materials 300M in Aviation

2014 ◽  
Vol 800-801 ◽  
pp. 208-213
Author(s):  
Hui Ping Zhang ◽  
Yi Nan Lai ◽  
Chong Xun Wang ◽  
Xu Du
Keyword(s):  
Cutting Temperature ◽  
High Strength ◽  
Least Square Method ◽  
Least Square ◽  
Machining Accuracy ◽  
Linear Regression Models ◽  
Element Analysis ◽  
Cutting Velocity ◽  
Structural Parts ◽  
Materials Used

Turning process properties of difficult-to-cut materials used in aeronautics are often associated with the machining accuracy and surface quality of aerospace structural parts. This study presents the influence of cutting velocity, feed rate and back cutting depth on cutting force and cutting temperature during dry turning of ultra-high strength 300M steel, where the linear regression models of cutting forces and cutting temperature are constructed by using least square method, and the regression coefficients of these models are verified by significance tests. Meanwhile, the temperature distribution and chip in turning machining are also achieved by finite element analysis.

An Algorithm for Space Tool Compensation Used in Five-Axis Numerical Control System

2011 ◽  
Vol 141 ◽  
pp. 186-190
Author(s):  
Liang Zhao ◽  
Jing Chuan Dong ◽  
Zhi Feng Qiao ◽  
Yan Yu Ding ◽  
Zhi Yuan Tang
Keyword(s):  
Coordinate System ◽  
Local Coordinate System ◽  
Numerical Control ◽  
System Transformation ◽  
Cnc Machines ◽  
Surface Machining ◽  
New Space ◽  
Tool Compensation ◽  
And Function ◽  
Five Axis

This paper presents a new space cutter compensation algorithm used in five-axis CNC machines. Five-axis CNC machines are composed of three linear axes and two rotational axes, owing to its unique structure and function, especially it is adapted to free surface machining, and is used in mold, aviation and ship manufacture widely. This paper analyzes cutter’s feed path, creates a local coordinate system in the CC point by using transformation equation between CL point and CC point. In this local coordinate system cutter compensation is built, new CL point and new cutter angle is calculated. Through coordinate system transformation matrix, determine cutter absolute coordinate.

Inspection of Large Guide Rail Precision Based on Bistatic Measurement Method

2013 ◽  
Vol 791-793 ◽  
pp. 945-948 ◽  
Author(s):  
Yue Liu ◽  
Zhi Wei Hao ◽  
Tian Tian Ren
Keyword(s):  
Coordinate System ◽  
High Precision ◽  
Measurement Method ◽  
Least Square Method ◽  
Least Square ◽  
Guide Rail ◽  
Total Station ◽  
Measuring Tool

Use two total stations cooperating with each other to measure the straightness of the guide rail. The straightness can test the accuracy of a large rail. Put the coordinates measuring with the two total station instruments to the same user coordinate system, take a key point between some distance with the auxiliary measuring tool of high precision, measure and record the key point s coordinate values. According to them, it can calculate the straightness of guide rail by using the least square method. The straightness accuracy of bistatic measurement can reach below 0.05mm, so it can meet the accuracy requirements.

Accuracy Enhancement of Alignment for Five-Axis CNC Machine Tools through Touch Trigger Probes

2011 ◽  
Vol 381 ◽  
pp. 11-15
Author(s):  
Sheng Bao ◽  
Fu Zhang ◽  
Xi Zhang
Keyword(s):  
Reference Frame ◽  
Machine Tools ◽  
Measuring Method ◽  
Least Square ◽  
Cnc Machine Tools ◽  
Random Errors ◽  
Cnc Machine ◽  
Method Of Least Square ◽  
Touch Trigger Probe ◽  
Five Axis

The random errors exist in measuring with touch trigger probe. These errors are directly introduced into workpiece coordinate system with conventional alignment method. An enhanced measuring method is proposed in this paper to improve the accuracy of alignment for five-axis CNC machine tools. By using the method of least square, an error reference frame is constructed, and the relationship between the alignment parameters and the error reference frame is derived. An example of aircraft structural parts is presented to validate the presented method.

The tool following function-based identification approach for all geometric errors of rotary axes using ballbar

2016 ◽  
Vol 230 (19) ◽  
pp. 3509-3527
Author(s):  
Guoqiang Fu ◽  
Jianzhong Fu ◽  
Hongyao Shen ◽  
Xinhua Yao
Keyword(s):  
Least Square Method ◽  
Geometric Error ◽  
Least Square ◽  
Geometric Errors ◽  
Rotary Axes ◽  
Machining Center ◽  
Identification Approach ◽  
Error Formulas ◽  
Five Axis ◽  
Sensitive Direction

This paper proposes a tool following function-based identification approach (TFFIA) for geometric errors of two rotary axes for one five-axis machine tool. It is comprehensive to identify all geometric errors of rotary errors. Firstly, synthetic error formulas of ballbar originate from the geometric error model of machine tools in order to consider the influences of 21 errors of three translational axes. It makes the approach more reasonable and precise. Secondly, the structures of three measurement patterns of TFFIA are described. Thirdly, in each pattern, errors of rotary axes affecting the accuracy of the sensitive direction are identified. As the result, the identification equations of all 20 errors coincide with the geometric properties of errors. Moreover, the impacts of setup errors of ballbar are eliminated with least square method to improve the precise of TFFIA. According to the structures of three patterns, only three installation of workpiece ball of ballbar are needed in the whole identification of two rotary axes to obtain the required ballbar readings. It greatly shortens the measurement time. Twenty geometric errors of two rotary axes are calculated with identification equations and ballbar readings. Finally, TFFIA is applied to a SmartCNC500 five-axis vertical machining center. The corresponding comparisons are proposed to verify the effectiveness and accuracy of TFFIA.

Direct Assessment of Effective Renal Plasma Flow from Renoscintigraphy with a Gamma Camera and an On-Line Computer

1981 ◽  
Vol 20 (06) ◽  
pp. 274-278
Author(s):  
J. Liniecki ◽  
J. Bialobrzeski ◽  
Ewa Mlodkowska ◽  
M. J. Surma
Keyword(s):  
Count Rate ◽  
Renal Plasma Flow ◽  
Early Period ◽  
Least Square Method ◽  
Least Square ◽  
Uptake Coefficient ◽  
Positive Linear Correlation ◽  
On Line ◽  
Best Fit ◽  
Plasma Activity

A concept of a kidney uptake coefficient (UC) of 131I-o-hippurate was developed by analogy from the corresponding kidney clearance of blood plasma in the early period after injection of the hippurate. The UC for each kidney was defined as the count-rate over its ROI at a time shorter than the peak in the renoscintigraphic curve divided by the integral of the count-rate curve over the "blood"-ROI. A procedure for normalization of both curves against each other was also developed. The total kidney clearance of the hippurate was determined from the function of plasma activity concentration vs. time after a single injection; the determinations were made at 5, 10, 15, 20, 30, 45, 60, 75 and 90 min after intravenous administration of 131I-o-hippurate and the best-fit curve was obtained by means of the least-square method. When the UC was related to the absolute value of the clearance a positive linear correlation was found (r = 0.922, ρ > 0.99). Using this regression equation the clearance could be estimated in reverse from the uptake coefficient calculated solely on the basis of the renoscintigraphic curves without blood sampling. The errors of the estimate are compatible with the requirement of a fast appraisal of renal function for purposes of clinical diagknosis.

PENGARUH KNOWLEDGE MANAGEMENT, KOMPETENSI, MOTIVASI TERHADAP KINERJA KARYAWAN

2015 ◽  
Vol 5 (2) ◽  
pp. 1
Author(s):  
Miftahol Arifin
Keyword(s):  
Knowledge Management ◽  
Linear Regression ◽  
Significant Influence ◽  
Employee Performance ◽  
Least Square Method ◽  
Least Square ◽  
Analysis Tool ◽  
Ordinary Least Square ◽  
Competence Motivation ◽  
Performance Analyze

The purpose of this research is to analyze the influence of knowledge management on employee performance, analyze the effect of competence on employee performance, analyze the influence of motivation on employee performance). In this study, samples taken are structural employees PT.centris Kingdom Taxi Yogyakarta. The analysis tool in this study using multiple linear regression with Ordinary Least Square method (OLS). The conclusion of this study showed that the variables of knowledge management has a significant influence on employee performance, competence variables have an influence on employee performance, motivation variables have an influence on employee performance, The analysis showed that the variables of knowledge management, competence, motivation on employee performance.Keywords: knowledge management, competence, motivation, employee performance.

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