• Title/Summary/Keyword: Machining errors

Search Result 232, Processing Time 0.024 seconds

A Study of Machining Error Due to Tool Deflection in Micro Endmilling (마이크로 엔드밀링시 공구 변형이 가공오차에 미치는 영향에 관한 연구)

  • Seo, Tae-Il;Sohn, Jong-In;Lee, Hak-Yong
    • Journal of the Korean Society of Manufacturing Technology Engineers
    • /
    • v.18 no.3
    • /
    • pp.294-299
    • /
    • 2009
  • Micro end-milling has been becoming an important machining process to manufacture a number of small products such as micro-devices, bio-chips, micro-patterns and so on. Many related researches have given grand effects to micro end-milling phenomenon, for example, micro end-milling mechanism, cutting force modeling and machinability. This paper strongly concerned actual problem, micro tool deflection, which causes excessive machining errors on the workpiece. Machining error were predicted and measured through a series of test micro cutting and analysis of their SEM images and FEM analysis. Experiments are carried out to validate the approaches.

  • PDF

Development of a Geometric Error Analysis and Virtual Manufacturing System for Gantry-Type 5-Axis Machining Centers (문형 5축 머시닝센터의 기하학적 오차해석 및 가상가공 시스템 개발)

  • 윤태선;조재완;김석일;곽병만
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.15 no.10
    • /
    • pp.172-179
    • /
    • 1998
  • To quickly determine the effect of the substitute component on the machine's performance is very important in the design and manufacturing processes. And minimizing machine cost and maximizing machine quality mandate predictability of machine accuracy. In this study, in order to evaluate the effects of the component's geometric errors and dimensions on the machining accuracy of gantry-type 5-axis machining centers, a geometric error analysis and virtual manufacturing system are developed based on the mathematical model for the shape generation motion of machine tool considering the component's geometric errors and dimensions, the solid modeling techniques and so on.

  • PDF

Measuring Automation System for Analysis of Dimensional Reationships On the Machine (상관관계 해석을 고려한 온 더 머신 자동측정 시스템)

  • 정성종
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • 1996.03a
    • /
    • pp.183-187
    • /
    • 1996
  • On the machine measuring system composed of touch trigger probes, a DNC module, a CMM module, an analysis module and a man-machine interface unit was developed. Measuring accuracy is affected by working accuracy of the on the machine measuring system. The working accuracy of the system is due to geometric errors of th machine tool, servo errors of feed drives and positioning errors of probes. In order to compensate for the measuring errors due to the working accuracy, a calibration module was developed. The measuring automation system was realized with the on the machine measuring system and an IBM-PC on the machine center through a RS-232C. It turns the machining machine (CMM). The system is used for dimensional checking of machined components. initial job setup, part identification, identification of machining errors due to deflection and wear of tools. cutter run out, and calibration of machine tools. A horizontal machining center equipped with FANUC OMC wre used for verification of the system. The validity and reliability of the system. The validity and reliability of the system were confirmed through a series of experiments with gage blocks, ring gages, comparison measurement with a commercial CMM, and so on.

  • PDF

A Generalized Analysis of Volumetric Error of a Machine Tool Machining a Sculpture (자유곡면을 가공하는 공작기계 체적오차의 일반화 해석)

  • 고태조
    • Journal of the Korean Society of Manufacturing Technology Engineers
    • /
    • v.4 no.3
    • /
    • pp.39-47
    • /
    • 1995
  • This paper suggests generalize mathematica mode for the benefit of volumetric error analysis of a multi-axis machine tool machining a sculptured surfaces. The volumetric error, in this paper, is defined as a three dimensional error at the cutting point, which is caused by the geometric errors and the kinematic errors of each axis and alignment errors of the cutting tool. The actual cutting position is analyzed based on the form shaping model including a geometric error of the moving carriage, where a form shaping model is derived from the homogeneous transformation matrix. Then the volumetric error is obtained by calculating the position difference between the actual cutting position and the ideal one calculated from a Nonuniform Rational B-Spline named as NURES. The simulation study shows the effectiveness for predicting the behavior of machining error and for the method of error compensation.

  • PDF

A Study on the Compensation of the Thermal Errors for Machine Tool (공작기계 열변위 보정에 관한 연구)

  • 이인재
    • Journal of the Korean Society of Manufacturing Technology Engineers
    • /
    • v.9 no.4
    • /
    • pp.117-122
    • /
    • 2000
  • This paper presents an indirect compensation of thermal errors during machining , in which thermal error is modelled as a linear regression of temperatures measured at 4 specified positions. In this regression model, weighting coefficients of the measured temperatures were estimated by using the least square method. The grinding test with compensation , after 4 -hour warning-up operation before the test, showed that the maximum machining error of the work pieces was reduced to 12${\mu}{\textrm}{m}$ while it measured by 28${\mu}{\textrm}{m}$ without compensation . Furthermore the standard deviation of machining errors was also reduced from 8${\mu}{\textrm}{m}$ to 2${\mu}{\textrm}{m}$.

  • PDF

Compensation of Thermal Error for the CNC Machine Tools (I) - The Basic Experiment of Compensation Device - (CNC 공작기계의 열변형 오차 보정 (I) - 보정장치 기초실험 -)

  • 이재종;최대봉;곽성조;박현구
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • 2001.04a
    • /
    • pp.453-457
    • /
    • 2001
  • One of the major limitations of productivity and quality in metal cutting is the machining accuracy of machine tools. The machining accuracy is affected by geometric and thermal errors of the machine tools. In this study, the compensation device is manufactured in order to compensate thermal error of machine tools under the real-time. This paper models of the thermal errors for error analysis and develops on-the-machine measurement system by which the volumetric error are measured and compensated. The thermal error is modeled by means of angularity errors of a column and thermal drift error of the spindle unit which are measured by the touch probe unit with a star type styluses, a designed spherical ball artifact, and five gap sensors. In order to compensate thermal characteristics under several operating conditions, experiments performed with five gap sensors and manufactured compensation device on the horizontal machining center.

  • PDF

A Study on the Compensation of the Thermal Errors for Machine Tool (공작기계 열변위 보정에 관한 연구)

  • 이인재
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • 2000.04a
    • /
    • pp.673-678
    • /
    • 2000
  • This paper presents an indirect compensation of thermal errors during machining, in which thermal error is modeled as a linear regression of temperatures measured at 4 specified positions. In this regression model, weighting coefficients of the measured temperatures were estimated by using the least square method. The grinding test with compensation, after 4-hour warming-up operation before the test, showed that the maximum machining error of the work pieces was reduced to 12${\mu}{\textrm}{m}$ while it measured 28${\mu}{\textrm}{m}$ without compensation. Furthermore the standard deviation of machining errors was also reduced from 8${\mu}{\textrm}{m}$ to 2${\mu}{\textrm}{m}$.

  • PDF

Identification of guideway errors in the end milling machine using geometric adaptive control algorithm (기하학적 적응제어에 의한 엔드밀링머시인의 안내면 오차 규명)

  • 정성종;이종원
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.12 no.1
    • /
    • pp.163-172
    • /
    • 1988
  • An off-line Geometric Adaptive Control Scheme is applied to the milling machine to identify its guideway errors. In the milling process, the workpiece fixed on the bed travels along the guideway while the tool and spindle system is fixed onto the machine. The scheme is based on the exponential smoothing of post-process measurements of relative machining errors due to the tool, workpiece and bed deflections. The guideway error identification system consists of a gap sensor, a, not necessarily accurate, straightedge, and the numerical control unit. Without a priori knowledge of the variations of the cutting parameters, the time-varying parameters are also estimated by an exponentially weighted recursive least squares method. Experimental results show that the guideway error is well identified within the range of RMS values of geometric error changes between machining passes disregarding the machining conditions.

Building a Machining Knowledge Base for Intelligent Machine Tools (지능공작기계를 위한 가공 지식의 지식베이스 구성 및 운영)

  • Lee, Seung-Woo;Lee, Hwa-Ki
    • Journal of the Korea Safety Management & Science
    • /
    • v.9 no.5
    • /
    • pp.79-85
    • /
    • 2007
  • Intelligent machines respond to external environments on the basis of decisions that are made by sensing the changes in the environment and analyzing the obtained information. This study focuses on the construction of a knowledge base which enables decision making with that information. Approximately 70% of all errors that occur in machine tools are caused by thermal error. In order to proactive deal with these errors, a system which measures the temperature of each part and predicts and compensates the displacement of each axis has been developed. The system was built in an open type controller to enable machine tools to measure temperature changes and compensate the displacement. The construction of a machining knowledge base is important for the implementation of intelligent machine tools, and is expected to be applicable to the network based intelligent machine tools which look set to appear sooner or later.

A Study of Feedrate Optimization for Tolerance Error of NC Machining (NC가공에서 허용오차를 고려한 가공속도 최적화에 관한 연구)

  • Lee, Hee-Seung;Lee, Cheol-Soo;Kim, Jong-Min;Heo, Eun-Young
    • Journal of the Korean Society of Manufacturing Technology Engineers
    • /
    • v.22 no.5
    • /
    • pp.852-858
    • /
    • 2013
  • In numerical control (NC) machining, a machining error in equipment generally occurs for a variety of reasons. If there is a change in direction in the NC code, the characteristics of the automatic acceleration or deceleration function cause an overlap of each axis of the acceleration and deceleration zones, which in turn causes a shift in the actual processing path. Many studies have been conducted for error calibration of the edge as caused by automatic acceleration or deceleration in NC machining. This paper describes a geometric interpretation of the shape and processing characteristics of the operating NC device. The paper then describes a way to determine a feedrate that achieves the desired tolerance by using linear and parabolic profiles. Experiments were conducted by the validate equations using a three-axis NC machine. The results show that the machining errors were smaller than the machine resolution. The results also clearly demonstrate that the NC machine with the developed system can successfully predict machining errors induced with a change in direction.