A Machining Error Compensation Method Using on-Machine Profile Measurement in 3-Axis Aspheric Grinding

2010 ◽  
Vol 154-155 ◽  
pp. 390-395 ◽  
Author(s):  
Hao Huang ◽  
Xiang Yang Lei ◽  
Jian Wang ◽  
Qiao Xu ◽  
Liang Yu He ◽  
...  

The causes of machining errors are very complicated and apt to mutual influence in aspheric grinding, so it is difficult to improve machining accuracy by control one cause. To compensate the machining error of large aspheric grinding, an error-compensation technique using on-machine profile measurement system in three axes grinding machine are presented. To verify the effectiveness of the compensation machining and the reliability of the measurement system, experiments on high-precision grinding machine were performed. Moreover, the compensation machining with the on-machine measurement substantially decreases the machining errors and improve machining accuracy by more than 45%, compared with the non-compensation machining.

2013 ◽  
Vol 797 ◽  
pp. 103-107
Author(s):  
Xiao Long Ke ◽  
Yin Biao Guo ◽  
Chun Jin Wang

According to the demand of precision machining for optical aspheric lens, especially large scale optical aspheric lens, this paper presents an error compensation technique for precision grindging. Based on precision surface grinding machine (MGK7160), grating-type parallel grinding method is put forward to realize grinding paths planning for optical aspheric lens. In order to obtain surface metrology and evaluation after grinding, an on-machine measurement system is built. On the basis of compensation principle, machining error is separated to achieve error compensation. Grinding experiments are carried out and show that it can meet the demand of precision grinding, and the accuacy after error compensation attains 6.5μm.


Author(s):  
Shih-Ming Wang ◽  
Han-Jen Yu ◽  
Yi-Hung Liu ◽  
Da-Fun Chen

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.


2006 ◽  
Vol 304-305 ◽  
pp. 251-255
Author(s):  
L. Zheng ◽  
Yin Biao Guo ◽  
Z.Z. Wang

This paper puts forward an intelligent single-plane biaxial balance monitor system, which is used in ultra-precision grinding. It adopts the method of single-plane balance correction for the vibration of wheel and workpiece. And this system can also be used for integral balance. For ultra-precision grinding, caused by the mutual influence of the vibration of wheel and workpiece, there will be a ripple on the workpiece surface, which is mainly influenced by the frequency ratio of wheel to workpiece, the feed rate and the vibration of wheel and workpiece. This system can improve the machining accuracy, reduce the surface error of workpiece and appraise the integrated machining result, by analyzing the vibration data of wheel and workpiece and adjusting machining parameters.


Author(s):  
Xicong Zou ◽  
Xuesen Zhao ◽  
Guo Li ◽  
Zengqiang Li ◽  
Zhenjiang Hu ◽  
...  

On-machine error compensation (OMEC) is efficient at improving machining accuracy without increasing extra manufacturing cost, and involves the on-machine measurement (OMM) of machining accuracy and modification of program code based on the measurement results. As an excellent OMM technique, chromatic confocal sensing allows for the rapid development of accurate and reliable error compensation technique. The present study integrated a non-contact chromatic confocal probe into an ultra-precision machine for OMM and OMEC of machined components. First, the configuration and effectiveness of the OMM system were briefly described, and the relevant OMEC method was presented. With the OMM result, error compensation software was then developed to automatically generate a modified program code for error compensation. Finally, a series of cutting experiments were performed to verify the validity of the proposed OMEC method. The experimental results demonstrate that the proposed error compensation method is reliable and considerably improves the form error of machined components.


2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Wei Fan ◽  
Lianyu Zheng ◽  
Wei Ji ◽  
Xun Xu ◽  
Lihui Wang ◽  
...  

Abstract To guarantee the final assembly quality of the large-scale components, the assembly interfaces of large components need to be finish-machined on site. Such assembly interfaces are often in low-stiffness structure and made of difficult-to-cut materials, which makes it hard to fulfill machining tolerance. To solve this issue, a data-driven adaptive machining error analysis and compensation method is proposed based on on-machine measurement. Within this context, an initial definite plane is fitted via an improved robust iterating least-squares plane-fitting method based on the spatial statistical analysis result of machining errors of the key measurement points. Then, the parameters of the definite plane are solved by a simulated annealing-particle swarm optimization (SA-PSO) algorithm to determine the optimal definite plane; it effectively decomposes the machining error into systematic error and process error. To reduce these errors, compensation methods, tool-path adjustment method, and an optimized group of cutting parameters are proposed. The proposed method is validated by a set of cutting tests of an assembly interface of a large-scale aircraft vertical tail. The results indicate that the machining errors are successfully separated, and each type of error has been reduced by the proposed method. A 0.017 mm machining accuracy of the wall-thickness of the assembly interface has been achieved, well fulfilling the requirement of 0.05 mm tolerance.


2012 ◽  
Vol 201-202 ◽  
pp. 333-336
Author(s):  
Zheng Hua Huang ◽  
Cheng Rong Jiang

In machining, a complete machining process system consists of the machine tool, the fixture, the tool and the part together, the various errors are also inevitable. The factor analysis approach and the statistical analysis method were put forward to study the machining accuracy on the basis of the error sources analysis of the machining accuracy, and the measures were introduced to improve the machining accuracy by using the factor analysis approach. The change laws are grasped by the analysis of the machining errors, so as to take the appropriate measure to reduce the machining error and improve the machining accuracy.


1997 ◽  
Vol 119 (3) ◽  
pp. 402-409 ◽  
Author(s):  
Ee Meng Lim ◽  
Chia-Hsiang Menq

In this paper, the principle and effectiveness of the control-surface strategy in machining-error compensation for end milling processes are studied. Using this strategy, two new approaches, namely the direct compensation approach and the sensitivity function approach, are proposed. When compared to existing approaches, there are two major improvements in the proposed approaches. First, machining errors caused by tool deflection are estimated from a developed surface generation model. This eliminates the time and costs required to design and conduct the actual machining experiments and dimensional inspections. Second, the effectiveness of the proposed approaches is improved either by increasing the number of times the strategy is been used or by selecting the appropriate shifted distance based on the estimated machining-error curve. The effectiveness of the proposed error-compensation approaches is verified from simulations and experimental results for a 2D sculptured surface. By using computer aided design tool, this surface generation model can be easily applied to the problems in which the designed surfaces are complex 3D sculptured by considering more complicated chip geometry model. These proposed approaches can also be integrated into an integrated framework for machining path planning in which prediction and compensation of dimensional errors take place in the process development phase rather than in the manufacturing phase of the production cycle.


2013 ◽  
Vol 312 ◽  
pp. 710-713
Author(s):  
Jing Jun Cui

Generally speaking, the error in machining is an important indicator measuring the accuracy of finished surface. The machining error often occurs in numerical control milling. Such error will be influenced by multiple factors, such as cutter wear, thermal deformation, machine tool deformation, vibration or positioning error. Nowadays, though our science and technology develops rapidly, machining error problem in numerical control milling occurs frequently. At present, several methods can be applied to forecast machining error problems in numerical control milling, including on the basis of machining theory, experimental study, design study and artificial intelligence. The analysis and forecast of machining error problems in numerical control milling can to some extent improve the degree of machining errors so as to promote the machining accuracy in milling. The author expresses the views on machining error problems according to current situations of numerical control milling.


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