Bayesian approach to measurement scheme analysis in multistation machining systems

2003 ◽  
Vol 217 (8) ◽  
pp. 1117-1130 ◽  
Author(s):  
D Djurdjanovic ◽  
J Ni
Keyword(s):  
Bayesian Approach ◽  
Machining Process ◽  
Machining Processes ◽  
Machining Errors ◽  
Machining System ◽  
Stream Of Variation ◽  
Linear State ◽  
Dimensional Errors ◽  
Scheme Analysis

Different measurement schemes in multistation machining systems carry different amounts of information about the root causes of dimensional machining errors. The choice of a measurement strategy in a multistation machining system is therefore crucial for subsequent successful identification of the machining error root causes. Recent advances in the linear state-space modelling of dimensional errors in multistation machining processes facilitate a formal and systematic characterization of measurement schemes. In this paper, the stream-of-variation methodology is employed to characterize various measurement schemes quantitatively in multistation machining systems using the Bayesian approach in statistics. Application of these methods is demonstrated in the characterization of measurement schemes in the machining process used for machining of an automotive cylinder head.

Dimensional Errors of Fixtures, Locating and Measurement Datum Features in the Stream of Variation Modeling in Machining

2003 ◽  
Vol 125 (4) ◽  
pp. 716-730 ◽  
Author(s):  
Dragan Djurdjanovic ◽  
Jun Ni
Keyword(s):  
Space Form ◽  
Machining Process ◽  
Machining Processes ◽  
Machining Errors ◽  
Advanced Control ◽  
Stream Of Variation ◽  
Linear State ◽  
Dimensional Errors ◽  
Formal Solutions ◽  
Variation Model

Machining processes are usually multi-station processes involving a large number of operations and several locating datum changes. Machining errors are thus introduced, transformed and accumulated as the workpiece is being machined. This paper introduces procedures for expressing the influence of errors in fixtures, locating datum features and measurement datum features on dimensional errors in machining. These procedures are essential in the derivation of the Stream of Variation model of dimensional machining errors using the CAD/CAPP parameters of the machining process. The linear state space form of the Stream of Variation model allows for advanced control theory achievements to be employed in formal solutions to problems in multi-station machining. Modeling procedures presented in this paper were experimentally verified in machining of an automotive cylinder head.

Stream of Variation Based Analysis and Synthesis of Measurement Schemes in Multi-Station Machining Systems

2001 ◽  
Author(s):  
Dragan Djurdjanovic ◽  
Jun Ni
Keyword(s):  
Machining Processes ◽  
Measurement Strategy ◽  
Machining Errors ◽  
Space Modeling ◽  
Analysis And Synthesis ◽  
Stream Of Variation ◽  
Linear State ◽  
The Cost ◽  
Evaluation Measurement

Abstract The choice of a measurement strategy in multi-station machining systems is crucial for subsequent successful identification of the root causes of machining errors. The measurement strategy selection is currently not a systematic process and it involves human and expert intervention. Recent advances in the linear state-space modeling of multi-station machining processes facilitate a more formal characterization of measurements in machining and a more systematic approach in the selection of the features that need to be measured. In this paper, we employ the Stream of Variation methodology to evaluate various measurement schemes in multi-station machining systems. Based on this evaluation, measurement synthesis procedures are presented, such that the resulting measurement scheme achieves a tradeoff between measurement uncertainty and the cost of measurements.

MODELING AND CONTROL OF DIMENSIONAL QUALITY OF A SERIAL MULTI-STATION MACHINING SYSTEM

2006 ◽  
Vol 13 (05) ◽  
pp. 399-419 ◽  
Author(s):  
SHICHANG DU ◽  
LIFENG XI ◽  
ERSHUN PAN ◽  
JIANJUN SHI ◽  
C. RICHARD LIU
Keyword(s):  
State Space ◽  
State Space Model ◽  
Machining Processes ◽  
Modeling And Control ◽  
Engineering Theory ◽  
Machining Errors ◽  
Proposed Model ◽  
Machining System ◽  
Linear State ◽  
And Control

Modeling and control of dimensional quality is one of deciding factors in current manufacturing competitions, and has always presented a great challenge to both scientists and engineers since for a multi-station machining system, the final product variation is an accumulation from all stations, and the complex non-linear relationship exits between dimensional quality and machining errors. This paper develops a linear state space model using homogeneous transformation to capture the influence of machined errors on dimensional quality, and the explicit expressions for system matrices of the model are explored. The proposed model employs a linear state space form, facilitating the use of the achievements of control theory, information technology and system engineering theory to support engineers supervisory control of physical machining processes, and it also can be used as an analytical engineering tool for efficient and effective faults diagnosis, system plan and design, and optimal sensors allocation. A real machining case illustrates the proposed model.

Based on the Nc Machining System Error Aspheric Analysis and Research

2011 ◽  
Vol 383-390 ◽  
pp. 7649-7653
Author(s):  
Hong Ying Wang ◽  
Xue Me Hu
Keyword(s):  
Error Compensation ◽  
Dynamic Error ◽  
Machining Process ◽  
System Error ◽  
Machining Precision ◽  
Processing Error ◽  
Machining Errors ◽  
Machining System ◽  
Forward Process

From the machining errors and static dynamic error influence two aspects are discussed in this paper, the analysis of machining process on the processing precision influence of error, puts forward process design. Long-term since, improving precision machine tool is through the two methods: error and avoid error compensation. Avoid error is a "hard", focusing on design and processing in the error may eliminate all stages. And error compensation in existing machine, can work environment to further improve the machining precision, it is a kind of economic effectively improve the machining precision of the method. For error analysis and calculation, the ultimate goal is to eliminate and reduce processing error, the improvement of the machining errors of classification in many ways. According to the machining process of the factors causing error to occur any regularity, processing error into system error and the random error, According to the nature of the changes with time, and can be divided into static error and dynamic error.

Preliminary Design of Two Dimensional Vibration Assisted Machining System for Multi-Axis Micro-Milling Application

2020 ◽  
Vol 846 ◽  
pp. 105-109
Author(s):  
Gandjar Kiswanto ◽  
Poly ◽  
Yolanda Rudy Johan ◽  
Tae Jo Ko
Keyword(s):  
Machining Process ◽  
Micro Milling ◽  
Machining Processes ◽  
Machined Surface ◽  
Planar Surfaces ◽  
Preliminary Model ◽  
Machined Surface Quality ◽  
Machining System ◽  
Linear Vibrations ◽  
Linear Movement

Vibration assisted machining (VAM) is a method that is widely used in improving the performance of machined products. External vibrations with high frequency to ultrasonic range along with an meso-micrometer amplitude are given to the cutting tool or workpiece. This will result in a periodic separation phenomenon, hence reducing the cutting force which has positive impacts on increasing tool life and machined surface quality. Among the high-precision machining processes, micro-milling which has the ability to produce complex components with 2D and 3D features, can also be applied with the vibration assisted method, known as vibration assisted micro-milling (VAMM). Based on the direction of vibration given in the machining process, there are 1D VAMM with linear vibrations and 2D VAMM with circular or elliptical trajectory vibrations. However to date, neither developed 1D nor 2D VAMM systems are still limited to the research of planar surfaces cutting using linear movement axes, meanwhile vibration assisted in inclination cutting of micro-milling using the rotational movement axes is still very rare. Therefore the purpose of this paper is to present the preliminary model in designing a 2D VAMM system for a 5-axis micro-milling machine. The system is powered using piezoelectric actuators as the vibration-producing actuators.

Measurement Scheme Synthesis in Multi-Station Machining Systems

2004 ◽  
Vol 126 (1) ◽  
pp. 178-188 ◽  
Author(s):  
Dragan Djurdjanovic ◽  
Jun Ni
Keyword(s):  
Genetic Algorithm ◽  
Machining Process ◽  
Human Knowledge ◽  
Quantitative Characterization ◽  
Root Cause ◽  
Measurement Scheme ◽  
Machining Errors ◽  
Synthesis Procedure ◽  
Selection Of

Different sets of measurements carry different amounts of information about the root causes of quality problems in machining. The selection of measurements in multi-station machining systems is currently a slow and error-prone process based on expert human knowledge. In this paper, we propose systematic procedures for synthesizing measurement schemes that carry the most information about the root causes of dimensional machining errors. The amount of root cause information conveyed by a given set of measurements was assessed using the recently introduced formal methods for quantitative characterization of measurement schemes in multi-station machining systems. The newly proposed measurement scheme synthesis procedures were applied to devising measurement schemes in an automotive cylinder head machining process. It was observed that the measurement scheme synthesis procedure based on a genetic algorithm robustly outperformed the synthesis procedures based on the heuristics of successive measurement removal.

scholarly journals Generation and characterization of ultra-precision compound freeform surfaces

2019 ◽  
Vol 103 (1) ◽  
pp. 003685041988011
Author(s):  
Lingbao Kong ◽  
Yingao Ma ◽  
Mingjun Ren ◽  
Min Xu ◽  
Chifai Cheung
Keyword(s):  
Tool Path ◽  
Complex Geometry ◽  
Experimental Studies ◽  
Machining Process ◽  
Freeform Surface ◽  
Freeform Surfaces ◽  
Machining Errors ◽  
Hybrid Machining Process ◽  
Ultra Precision

Compound freeform surfaces are widely used in bionic and optical applications. The manufacturing and measurement of such surfaces are challenging due to the complex geometry with multi-scale features in a high precision level with sub-micrometer form accuracy and nanometer surface finish. This article presents a study of ultra-precision machining and characterization of compound freeform surfaces. A hybrid machining process by combining slow slide servo and fast tool servo is proposed to machine compound freeform surfaces. The machining process for this hybrid tool servo is explained, and tool path generation is presented. Then, a normal template-based matching and characterization method is proposed to evaluate such compound freeform surfaces. Experimental studies are undertaken to machine a compound freeform surface using the proposed method based on a four-axis ultra-precision machine tool. The machined compound freeform surface is also measured and characterized by the proposed analysis and characterization method. The experimental results are presented, and the machining errors for compound freeform surfaces are also discussed.

scholarly journals A Novel Method of Sustainability Evaluation in Machining Processes

Processes ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 275 ◽  
Author(s):  
Haiming Sun ◽  
Conghu Liu ◽  
Jianqing Chen ◽  
Mengdi Gao ◽  
Xuehong Shen
Keyword(s):  
Conversion Efficiency ◽  
Manufacturing Industry ◽  
Energy Resource ◽  
Machining Process ◽  
Utilization Rate ◽  
Sustainability Evaluation ◽  
Machining Processes ◽  
Sustainable Machining ◽  
Machining System ◽  
Improvement Method

In order to quantitatively evaluate and improve the sustainability of machining systems, this paper presents an emergy (the amount of energy consumed in direct and indirect transformations to make a product or service) based sustainability evaluation and improvement method for machining systems, contributing to the improvement of energy efficiency, resource efficiency and environmental performance, and realizing the sustainability development. First, the driver and challenge are studied, and the scope and hypothesis of the sustainable machining system are illustrated. Then, the emergy-based conversion efficiency model is proposed, which are (1) effective emergy utilization rate (EEUR), (2) emergy efficiency of unit product (EEUP) and (3) emergy conversion efficiency (ECE), to measure and evaluate the sustainable machining system from the perspectives of energy, resource and environment. Finally, the proposed model is applied to a vehicle-bridge machining process, and the results show that this paper provides the theoretical and method support for evaluating and improving the sustainable machining processes to decouple the resources and development of the manufacturing industry.

scholarly journals Chatter Suppression in Machining Processes

2021 ◽  
Author(s):  
Israr Ahmed Siddiqui
Keyword(s):  
Stability Boundary ◽  
Cutting Speed ◽  
Machining Process ◽  
Vibration Source ◽  
Skilled Workers ◽  
Machining Processes ◽  
Chatter Suppression ◽  
Excited Vibration ◽  
Machining System ◽  
Tool Chatter

The development of an untended machining system has been the subject of research for quite some time. Today, the need for such a system is greater thatn is once was because of the shortage of skilled workers, higher machining speeds, increase in precision machining, and the need to lower downtime. One aspect of machining process has been under investigation is tool chatter. Chatter is a machining instability resulting from self-excited vibration caused by interaction of the chip removal process, the cutting tool, and the structure of the machine tool. Chatter can severely reduce the material rate by putting limits to cutting speed and width of cut. This thesis describes a novel approach for active, on line suppresion of chatter in machining operations. The goal of chatter suppression is to minimize the chatter amplitude and therefore extend the chatter stability boundary. Once the presence of chatter is detected the suppression system will be activated. A neural network model is used to calculate current gradient values with respect to the parameters of the active vibratration source. This gradient information will be used by an optimization module to find the optimal set of parameters for the active vibration source. The methodology described is evaluated through simulation studies and simulation results confirmed the effectiveness of the approach.

Quality Assured Setup Planning Based on the Stream-of-Variation Model for Multi-Stage Machining Processes

2006 ◽  
Author(s):  
Jian Liu ◽  
Jianjun Shi ◽  
S. Jack Hu
Keyword(s):  
Product Quality ◽  
Cost Effective ◽  
Machining Process ◽  
Manufacturing Processes ◽  
Setup Planning ◽  
Machining Processes ◽  
Multi Stage ◽  
Variation Propagation ◽  
Stream Of Variation ◽  
The Cost

Setup planning is a set of activities to arrange manufacturing features into an appropriate sequence for processing. As such, setup planning can significantly impact the product quality in terms of dimensional variation in the Key Product Characteristics (KPC’s). Current approaches in setup planning are experience-based and tend to be conservative by selecting unnecessarily precise machines and fixtures to ensure final product quality. This is especially true in multi-stage manufacturing processes because it has been difficult to predict the variation propagation and its impact on KPC quality. In this paper, a new methodology is proposed to realize cost-effective, quality ensured setup planning for multi-stage manufacturing processes. Setup planning is formulated as an optimization problem based on quantitative evaluation with the Stream-of-Variation (SoV) models. The optimal setup plan minimizes the cost related to process precision and satisfies the quality specifications. The effectiveness of the proposed approach is demonstrated through setup planning for a multi-stage machining process.

Sign in / Sign up

Export Citation Format

Share Document