A Micro Cutter Auto-Alignment System with On-Machine Positioning Error Measurement and Compensation Methods

Shih-Ming Wang,Ji-Jun Lin,Zhe-Zhi Ye,Shambaljamts Tsooj,Chun-Chieh Wang 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

To perform an accurate micro machining process, accurate alignment of the micro cutter with respect to the local coordinate frame for machining is essential. Due to the fragility of the micro tool, traditional cutter alignment method used in industry is no longer proper for micro machining. Utilizing machine vision technology with 2 CCDs, a micro tool positioning error measurement and auto-compensation method and system were proposed. In the measurement method, Power Law Method was first used to enhance the image taken by a CCD. Canny Edge Method and image projection method were then used to identify the contours of the cutter and the workpiece from the image. Finally, the position errors of the cutter were determined through calculating the number of pixels between the cutter and the workpiece. The proposed error compensation system can automatically generate NC codes which will accurately re-locate the cutter based on the measured position errors . Experiments were conducted on a micro machine tool, and the results have shown that the y-dir. positioning error of the cutter was significantly improved from -0.025 mm to 0.001 mm, and the total machining error was reduced from -0.02 mm to -0.001 mm.

A New Synchronous Error Control Method for CNC Machine Tools with Dual-Driving Systems

Shih-Ming Wang,Ren-Jeng Wang,Shambaljamts Tsooj 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.

Driving an object along one axis with two driving systems is a common method for obtaining high acceleration and high trust force for a large CNC machine tool. However, if large synchronous movement error exists between the two driving systems, the machine will not be able to achieve high acceleration. Moreover, it may also cause serious structure deformation and damage to the machine. To solve this problem, a new control method integrating the model reference adaptive control and variable structure control was developed and verified in this study. The proposed method can determine and compensate on-line the synchronous movement errors between two driving systems so that the master driving unit and the slave driving unit of a dual-driving system can synchronously move with no large drag force and reach the desired acceleration. Experiments were performed on a gantry-type two-axis platform with a sliding 5-Kg metal block attached on the X-axis. The experimental results showed that the maximum and the average synchronous movement errors were reduced from 0.061 mm to 0.040 mm and from 0.032 mm to 0.013 mm, respectively.

An On-Machine and Vision-Based Depth-Error Measurement Method for Micro Machine Tools

Shih-Ming Wang,Han-Jen Yu,Shih-His Liu,Da-Fan Chen 한국정밀공학회 2011 International Journal of Precision Engineering and Vol. No.

The error measurement method is an essential for further enhancing the machining accuracy of a micro machine tool. An on-machine vision-based measurement method that can measure 2-D contouring-/tracking errors of a micro machining process had been previously developed. An on-machine depth-error measurement method was proposed in this study to fulfill the complete 3-D machining errors measurement. The method adopts image re-constructive technology and camera pixel correction to provide non-contact measurement capability. To improve the measurement limits due to the pixel resolution and the filler of view of a CCD, a 2-step measurement method with use of a depth model was developed. Because of the capability of eliminating the shadow effects caused by the tilting light source, the proposed method provides more accurate and reliable measurement results. Sensitivity analysis was conducted to assess the influence of the CCD setup errors on the measurement accuracy for implementation. Experiment was conducted and the results have shown the effectiveness and feasibility of the measurement method.

On-machine Volumetric-error Measurement and Compensation Methods for Micro Machine Tools

Shih-Ming Wang,Ji-Jun Lin 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.

The CNC micro machine tool is an essential of the micro machining process for manufacturing miniature high-tech products. A software-based error compensation method based on measured volumetric errors that can pre-compensate cutting path can further enhance a machine’s accuracy without increasing its manufacturing cost. Considering the limited workspace of a micro machine tool and the instrument cost, an on-machine and vision-based measurement method integrating machine vision method with use of 3 COMs and homogeneous transformation method was proposed in this study. Sensitivity analysis was conducted to analyze the influence of the CMOS pixel error to the measurement accuracy. To improve the machining accuracy, the measured errors were directly compensated to the machining trajectory with use of an error compensation method that consists of an element-free error interpolation scheme and a recursive software error compensation scheme. Experiments on a toggletype micro machine tool were conducted to verify the effectiveness of the proposed methods. The results have shown that the feasibility and effectiveness of the proposed methods. The tracking errors of the machine was further improved from (x = 7.9 μm, y = 4.1 μm) to (x = 5 μm, y = 3.7 μm).

Practice of Smart Manufacturing Implementation on Traditional Manufacturing Industry

Shih-Ming Wang 한국생산제조학회 2022 한국생산제조시스템학회 학술발표대회 논문집 Vol.2022 No.5

Study of an Efficient Real-Time Monitoring and Control System for BUE and Cutter Breakage for CNC Machine Tools

Shih-Ming Wang,Chien-Da Ho,Po-Cheng Tsai,Chuntai Yen 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

If machining abnormalities, such as build-up-edge and cutter breakage, occur during machining, serious damage on the workpiecesurface and deterioration of production efficiency will happen, and cause additional energy consumption for rework and increase themanufacturing cost. To minimize the effects, an on-line diagnosis method with use of Fast Fourier Transform and algorithm of shorttimesignal variation analysis was developed to analyze the vibration signals to quickly detect the two abnormalities in this study. Inaddition, the real-time machining information from CNC controller was extracted through a bi-lateral communication module toprevent misdiagnosis. The control commands were automatically generated by the proposed system and directly sent to the CNCcontroller to stop the machine for cutter replacement. Without complex computation, the system can detect the occurrence of BUEor cutter breakage within 1 second and complete machine control within 3 seconds. The system can instantly transmit and save thereal machining information and diagnosis/control results to the remote central monitoring platform for further process improvement. With use of TCP/IP communication protocol the central monitoring platform can remote log into the on-site monitoring computer todirectly operate the diagnosis/control system. Experimental results showed the feasibility and effectiveness of the proposed system.

On-line Error-matching Measurement and Compensation Method for a Precision Machining Production Line

Shih-Ming Wang,Chun-Yi Lee,Hariyanto Gunawan,Chin-Cheng Yeh 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.2

When producing a matching part for good mating with its counterpart (assembly part), good matching accuracy between the matching part and assembly part is highly required. The matching errors are influenced by not only the errors of the matching part but also the errors of the assembly part. Because the errors of an assembly part could be different from others, it is very difficult to have very good mating accuracy, if the manufacturing of a matching part does not take the actual errors of the assembly into account. Furthermore, it will need additional off -line assembly mating tests to find a good mating pair. This study proposes an error-matching compensation method to solve the not-good-mating problem for manufacturing assembly modules with good matching accuracy. In this method, the actual errors of an assembly part are directly in-line measured and used to compensate the machining process of a matching part so that a dedicated part with the good mating condition can be on-line made for the error-measured assembly part. In addition to having better matching accuracy, this method also provides advantages of high production efficiency and cost saving, because it will not need the off -line mating test to find good mating pairs. This method also includes a function of in-line auto-generation of error compensation NC programs to support continuous production. In this study, error analysis of two mating types (planar mating and triangle mating) were explored and discussed. The Human–Machine Interface was built with the use of C# language. Finally, machining experiments with in-line measurements were conducted to verify the proposed method. The experimental results have shown the feasibility and effectiveness of the proposed method.

Hypoglycemia Revisited in the Acute Care Setting

Shih-Hung Tsai,Der-Ming Chu,Yen-Yue Lin,Chin-Wang Hsu,Chien-Sheng Cheng 연세대학교의과대학 2011 Yonsei medical journal Vol.52 No.6

Hypoglycemia is a common finding in both daily clinical practice and acute care settings. The causes of severe hypoglycemia (SH) are multi-factorial and the major etiologies are iatrogenic, infectious diseases with sepsis and tumor or autoimmune diseases. With the advent of aggressive lowering of HbA1c values to achieve optimal glycemic control, patients are at increased risk of hypoglycemic episodes. Iatrogenic hypoglycemia can cause recurrent morbidity, sometime irreversible neurologic complications and even death, and further preclude maintenance of euglycemia over a lifetime of diabetes. Recent studies have shown that hypoglycemia is associated with adverse outcomes in many acute illnesses. In addition, hypoglycemia is associated with increased mortality among elderly and non-diabetic hospitalized patients. Clinicians should have high clinical suspicion of subtle symptoms of hypoglycemia and provide prompt treatment. Clinicians should know that hypoglycemia is associated with considerable adverse outcomes in many acute critical illnesses. In order to reduce hypoglycemia-associated morbidity and mortality, timely health education programs and close monitoring should be applied to those diabetic patients presenting to the Emergency Department with SH. ED disposition strategies should be further validated and justified to achieve balance between the benefits of euglycemia and the risks of SH. We discuss relevant issues regarding hypoglycemia in emergency and critical care settings.

Distributed Quasi-Orthogonal Space-Time Block Code for Four Transmit Antennas with Information Exchange Error Mitigation

( Shu-ming Tseng ),( Shih-han Wang ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.10

In this paper, we extend the case of information exchange error mitigation for the distributed orthogonal space-time block code (DOSTBC) for two transmit antennas to distributed quasi-orthogonal space-time block code (DQOSTBC) for four transmit antennas. A rate 1 full-diversity DQOSTBC for four transmit antennas is designed. The code matrix changes according to different information exchange error cases, so full diversity is maintained even if not all information exchange is correct. We also perform analysis of the pairwise error probability. The performance analysis indicates that the proposed rate 1 DQOSTBC outperforms rate 1/2 DOSTBC for four transmit antennas at the same transmission rate, which is confirmed by the simulation results.

The Effects of Consumers’ Perceived Value and Satisfaction on the Purchase Behavior Towards Biotechnology-Derived Health Products

Hsien-Ming, Shih,Feng Lin,Wen-Tsann Lin,Ching-Hsin Wang,Meng-Hua Li 대한산업공학회 2015 대한산업공학회 추계학술대회논문집 Vol.2015 No.11

In this study, consumers’ perceived value of branded products is regarded as their overall evaluation of the brand according to currently available information. When consumers develop favorable perceived value for a brand, their satisfaction with the brand’s product increases accordingly, thus prompting purchase behavior. This study adopted a reliability and path analysis to test the research hypotheses. The findings of this study indicate that perceived value positively influences customer satisfaction, and customer satisfaction positively influences purchase behavior. However, perceived value does not significantly influence purchase behavior.