• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.17 no.4
• /
• pp.133-139
• /
• 2008

With the increasing demand for higher production quality and growing competition in the global market, coordinate measuring machine(CMM) has been widely used in industry to improve the efficiency and effectiveness of measurement. In this paper the performance evaluation of coordinate measuring machine is proposed using design of experiments. A factorial design is applied to carry out the performance test proposed by ISO 10360 with a length bar and to investigate CMM measurement errors associated to orientation and length in the work volume. The determination of the significance of effects in an experiment is made through the analysis of variance(ANOVA). The results show that the proposed method is suitable to analyze the factors which affect the CMM measurement performance.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.11
• /
• pp.99-109
• /
• 2004

This paper proposes precision evaluation method for the positioning error of three-DOF translational parallel mechanism. The proposed method uses conventional CMM as metrology equipment to measure the position of end-effector. In order to obtain accurate measurement data from CMM, the transform relationship between the coordinate system of the parallel mechanism and the CMM coordinate system must be identified. For this purpose, a new coordinate referencing (or coordinate system identification) technique is presented. By using this technique accurate coordinate transformation relationships are efficiently established. According to these coordinate transformation relationships, an equation to calculate error components at any arbitrary position of the end-effector is derived. In addition, mathematical fitting models to represent the position error components in the two-dimensional workspace of the parallel mechanism are also constructed based on response surface methodology. The proposed error evaluation method proves its effectiveness through the experimental results and its application to real three-DOF parallel mechanism.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.15 no.1
• /
• pp.1-7
• /
• 2006

A method of the volumetric error measurement and calibration of NC machine tools is studied using an artifact method. In this study, a hole-pate is designed and machined using stainless steel. We tested and applied the hole-plate artifact in a commercial CMM(Coordinate Measuring Machine), after calibration of the hole-plate using a precise CMM. It has been shown that not only the measurement of geometric error components but also the 2D length error calculation in a working volume is available using the hole-pate artifact method. The results of study can also be used in NC machine with touch probe as the same method in CMM.

• Journal of the Korean Society for Precision Engineering
• /
• v.26 no.3
• /
• pp.47-54
• /
• 2009

In the manufacturing industry, there has been a significant increase in the use of coordinate measuring machines(CMM). In this paper, the sources of CMM measurement performance are discussed. The effects of workpiece position, length and orientation are analyzed by using the design of experiments. Both a fractional factorial design and a factorial design are employed to conduct the experimental study. The analysis of variance is performed to determine the significance of factors in the experiment and regression analysis is applied to make the measurement approximate model. The results show that position along the Z axis, length and orientation affect the CMM measurement performance.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.11a
• /
• pp.838-841
• /
• 2000

To improve the accuracy of products and improve the product quality, we need to enhance the machining accuracy of the machine tools. To this point of view, measurement and inspection of finished part as well as error analysis of machine tools has been studied for last several decades. OMM(On the Machine Measurement) has been issued to alternate with CMM, pointing out disadvantages of high expenses and lots of setting time in CMM. In this paper, we study 1) the spherical surface manufacturing by volumetric error compensation of machine tool, 2) the system development of OMM without detaching work piece from a bed of machine tool after working. 3) the generation of the finished part profile by On the machine measurement. Furthermore, the output of OMM is compared with that of CMM, and verified the feasibility of the measurement system.

• International Journal of Reliability and Applications
• /
• v.9 no.1
• /
• pp.7-15
• /
• 2008

The dimensional measurement equipment, such as Coordinate Measurement Machine (CMM), Optical Coordinate Measurement Machine (OCMM), and Checking Fixture (CF), take multiple dimensional measurements for each part in an automobile industry. Measurements are also recorded under different measurement systems to see if the responses differ significantly over these systems. Each measurement system (CMM, OCMM, and CF) will be considered as different treatments. This set-up provides massive amounts of process data which are multivariate in nature. Therefore, the multivariate statistical analysis is required to analyze data that are dependent on each other. This research provides step by step methodology for the evaluation procedure of the compatibility of measurement systems and clarify a systematic analyzation among the different measurement system's compatibility followed by number of case studies for each methodologies provided.

• Journal of the Korean Society for Precision Engineering
• /
• v.26 no.4
• /
• pp.91-99
• /
• 2009

Because of both precise measurement and efficient quality control, coordinate measuring machines(CMMs) have been widely used in the industry. The purpose of this paper is to present a method to estimate the CMM measurement uncertainty using design of experiments. A factorial design is applied to carry out the performance test proposed by ISO 10360 and to investigate CMM measurement errors associated to orientation and length of the length bar. In order to assess the measurement uncertainty for the performance test, an analysis of the uncertainty components that make up the uncertainty budget has been carried out. The procedure for evaluating the uncertainty of it follows GUM ("Guide to the expression of uncertainty in measurement"). The results show that the proposed method is suitable to investigate CMM performance and determine the contribution of machine variables to measurement uncertainty.

• IE interfaces
• /
• v.12 no.2
• /
• pp.180-192
• /
• 1999

A coordinate measuring machine (CMM) is a computer-controlled measuring device that uses a probe to obtain measurements on a manufactured part's surface. CMM's have been very popular over traditional hard gauges due to their flexibility, accuracy, and ease of automated inspection. This paper considers the use of a CMM for the inspection of gears. We compare the inspection capability of a CMM and that of a gear-specific measuring machine. The result of this paper may benefit gear manufacturing companies in their dimensional quality assurance activities, especially for special type gears and for large-scale gears which are not measurable by gear-specific measuring machines.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2001.04a
• /
• pp.143-148
• /
• 2001

Volumetric error measurement and calibration of a coordinate measuring machine are studied by using a Ball-Bar artifact. Examples of the Ball-Bar design are shown using inbar materials and precision steel balls. Also, for the uncertainty error using the Ball-Bar is discussed. Method of Ball-Bar artifact and the analysis of the error vectors are proposed. Using the Ball-Bar data, we studied the method of volumetric errors ana]ysis of a coordinate measuring machine.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.28 no.7
• /
• pp.986-991
• /
• 2004

For volumetric error measurement and calibration for machine tools, manufacturing machine or coordinate measuring machine (CMM), are studied using a Ball-bar artifact. A design of the Ball-bar is suggested manufactured by Invar, which is a low thermal expansion material, and precision steel balls. The uncertainty for the artifact method is discussed. A method of the Ball-bar artifact for obtaining 3-D position errors in CMM is proposed. The method of error vector measurement is shown using the Ball-bar artifact. Finally, the volumetric error is calculated from the error vectors and it can be used for Pitch error compensation in conventional NC machine and 3-D position Error map for calibration of NC machine tools.