Contour Error Compensation based on Feed Rate Adjustment

In 3DP process, part has a large contour error due to the print machine, printing parameters, the characters of part materials and other factors. In this paper, based on the result from the Part I, the experimental method is used to study on the part contour error by placing 56 cubes in the manufacturing box in 3DP process. When the binder saturation level and the powder layer thickness are fixed, the contour error for cubes in X, Y and Z directions is obtained, and the leaking error compensation value, also means bleed compensation for the binder in different directions are achieved, and bleed compensation is used to calibrate the printer parameters. The case study also verifies the result in 3DP process, which is effectiveness in parts’ contour error compensation.

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An On-Machine Error Measurement System for Micro-Machining

ASME 2007 International Manufacturing Science and Engineering Conference ◽

10.1115/msec2007-31053 ◽

2007 ◽

Cited By ~ 2

Author(s):

Shih-Ming Wang ◽

Han-Jen Yu ◽

Yi-Hung Liu ◽

Da-Fun Chen

Keyword(s):

Machine Tool ◽

Measurement System ◽

Error Compensation ◽

Model Comparison ◽

Contour Error ◽

Machining Accuracy ◽

Error Measurement ◽

Micro Machining ◽

Machine Error ◽

Machining Errors

Technology development trends towards the ability to manufacture ever smaller parts and feature sizes with increased precision and decreased cost. Micro machining is one of the important manufacturing methods to fulfill the requirements from the industry. The objective of this paper is to develop an on-machine error measurement system that can identify the micro machining errors for error compensation so that the machining accuracy of a meso-scale machine tool (mMT) can be enhanced. Because of the difficulty in handling and repositioning the miniature workpiece, the error measurement system should be non-contact and on-machine executable. To meet this requirement, a vision-based error measurement system integrating image re-constructive technology, camera pixel correction, and model comparison algorithm error was developed in this study. The proposed measurement system consists of a CCD with CCTV lens, a precision 3-DOF platform, image re-construction sub-system, and contour error calculation sub-system. By adopting Canny Edge Detection algorithm and camera pixel calibration method, the contour of a machined workpiece can be identified and compared to the pixel-based theoretical contour model of the workpiece to determine the micro machining errors. Because the system does not have to remove the machined workpiece from the CNC machine tool, errors due to re-installing and re-positioning can be avoided. To prove the feasibility of the developed algorithm and system, measurement results obtained from the vision-based measurement system were compared with the measurements of CMM, and error compensation experiment conducted on a 3-DOF mMT was also conducted. The results have shown the good feasibility and effectiveness of the developed system.

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Iterative learning contouring controller based on trajectory generation with linearly interpolated contour error estimation and Bézier reposition trajectory for computerized numerical control machine tool feed drive systems

Advances in Mechanical Engineering ◽

10.1177/1687814019868108 ◽

2019 ◽

Vol 11 (8) ◽

pp. 168781401986810

Author(s):

Yogi Muldani Hendrawan ◽

Kenneth Renny Simba ◽

Naoki Uchiyama

Keyword(s):

Error Compensation ◽

Iterative Learning ◽

Numerical Control ◽

Contour Error ◽

Reference Trajectory ◽

Control Machine Tool ◽

Mechatronic Systems ◽

Computerized Numerical Control ◽

Mechanical Components ◽

Control Machine

In industrial applications, highly accurate mechanical components are generally required to produce advanced mechanical and mechatronic systems. In machining mechanical components, contour error represents the product shape quality directly, and therefore it must be considered in controller design. Although most existing contouring controllers are based on feedback control and estimated contour error, it is generally difficult to replace the feedback controller in commercial computerized numerical control machines. This article proposes an embedded iterative learning contouring controller by considering the linearly interpolated contour error compensation and Bézier reposition trajectory, which can be applied in computerized numerical control machines currently in use without any modification of their original feedback controllers. While the linearly interpolated contour error compensation enhances tracking performance by compensating the reference input with an actual value, the Bézier reposition trajectory enables smooth velocity transitions between discrete points in the reference trajectory. For performance analysis, the proposed controller was implemented in a commercial three-axis computerized numerical control machine and several experiments were conducted based on typical three-dimensional sharp-corner and half-circular trajectories. Experimental results showed that the proposed controller could reduce the maximum and mean contour errors by 45.11% and 54.48% on average, compared to embedded iterative learning contouring controller with estimated contour error. By comparing to embedded iterative learning contouring controller with linearly interpolated contour error compensation, the maximum and mean contour errors are reduced to 20.54% and 26.92%, respectively.

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