Jianfu Zhang

Evaluation systems and methods of enterprise informatization and its application

An efficient evaluation index system and evaluation method for enterprise informatization is critically important for guiding the implementation and development tasks of enterprise information systems. This paper, based on pre-research for a group of typical enterprises and item, factor and reliability analysis of acquired samples, presents a comprehensive evaluation index system which includes three key first-level indicator sets (consisting of the current status of enterprise informatization, the production management characteristics and the system functional requirements), 16 second-level indicators and 80 third-level indicators. According to the characteristics of the designed objectives in the evaluation index system, we propose to use the grey relative correlation analysis method to evaluate the influencing factors of the enterprise informatization, employ the grey comprehensive correlation analysis method to determine the production management characteristics of the enterprise and adopt the grey clustering assessment technology to assess the information system functional requirements based on Grey System Theory. Moreover, case studies for enterprise informatization that mainly focus on the process enterprises in southwest China were illustrated. The research results show that the proposed evaluation system and evaluation method is reliable, practical, and able to better reflect the level of enterprise information and demand characteristics.

Investigations on the critical feed rate guaranteeing the effectiveness of rotary ultrasonic machining.

HighlightsA critical feed rate guaranteeing the effectiveness of RUM was first reported.When the feed rate exceeds its critical value, the cutting force increases abruptly.A model for the critical feed rate was developed.Methods for improving the critical feed rate were proposed. &NA; Rotary ultrasonic machining (RUM) is a well‐known and efficient method for manufacturing holes in brittle materials. RUM is characterized by improved material removal rates, reduced cutting forces and reduced edge chipping sizes at the hole exit. The aim of this study is to investigate the critical feed rate to guarantee the effectiveness of RUM. Experimental results on quartz glass and sapphire specimens show that when the feed rate exceeds a critical value, the cutting force increases abruptly, accompanied by a significant decrease of ultrasonic amplitude. An analytical model for the prediction of critical feed rates is presented, based on indentation fracture mechanic and the theory of impact of vibrating systems. This model establishes the theoretical relationships between the critical feed rate, idling resonant ultrasonic amplitude and spindle speed. The results predicted by the analytical model were in good agreement with the experimental results.

An identification method for key geometric errors of machine tool based on matrix differential and experimental test

This paper presents a key geometric errors identification method for machine tools based on matrix differential and experimental test. An error model for a machine tool was established by regarding the three-axis machining center as a multi-body system. The sensitivity coefficients of the machining error with respect to the geometric errors were determined using the matrix differential method, and the degree of influence of the geometric errors on the machining accuracy under ideal conditions was discussed. Using the 12-line method, 21 geometric errors of the machine tool were identified, allowing the three-dimensional volumetric error distributions of the machine tool to be mapped. Experimental results allow the degree of influence of the geometric errors on the machining accuracy under actual conditions to be confirmed. Finally, the key geometric errors affecting the machining accuracy were identified by a combination of matrix differential and experimental test. This paper provides guidance for the machine tool configuration design, machining technology determination, and geometric error compensation.

An improved production planning method for process industries

An effective production planning method plays a key role in the production management system for the process manufacturing industries. It is particularly important to develop ways to solve the problems under demand uncertainty, planning inadequacy and capability unbalance. In this article, we present a process industries oriented production planning optimisation method that focuses on minimising inventory costs, and optimising production load rate and balance load rate. By analysing the demand forecasts model and minimum inventory costs control model, we propose how to achieve total production demand amounts in correlation with production orders. We also discuss the Weibull distribution-obeyed equipment repair model to maximise the equipment utilisation rate. The equipment repair time is also considered when specifying the production lead time. The production planning system optimisation objectives function is given, in the condition of the equipment production capacity model and the smallest economic batch requirement. To validate the proposed methods, real production and sales data are sampled from a pharmaceutical plant. The case study shows that the improved production planning models are more targeted and effective for Chinese process industries.

Investigations on the edge-chipping reduction in rotary ultrasonic machining using a conical drill

The edge chipping of holes, which is induced by mechanical machining, restricts the applications of brittle materials. Rotary ultrasonic machining is considered a suitable approach to machine holes in brittle materials with a smaller edge-chipping size. However, obvious edge chipping at the hole exit in rotary ultrasonic machining remains observable. In this study, conical diamond core drills with various characteristic angles (θ) were designed to further reduce the edge-chipping size for rotary ultrasonic machining. Machining tests on quartz glass were conducted to evaluate the effectiveness of this new type of drill. Experimental results show that the conical drill can obviously reduce the edge-chipping size only when certain conditions are satisfied. The mechanism of edge-chipping reduction using a conical drill was revealed by the theoretical analysis and detailed observation of the thrust force and obtained cylinder. To guarantee the feasibility of the conical drill, its characteristic angle should exceed a critical value at a certain feed rate. A higher feed rate requires a higher critical characteristic angle. The other advantage of the conical drill is its ability to suppress the bad effects of increasing the feed rate on the stability of ultrasonic vibration.

A Simulation Study on the Effect of Micro-Textured Tools during Orthogonal Cutting of Titanium Alloy Ti-6Al-4V

The cutting force, cutting temperature and mechanisms are studied by Finite Element Method during the orthogonal metal cutting of Ti-6Al-4V with micro-textured cutting tools. The relation between the texture’s antifriction effect and the parameter of the textures is analyzed. The Derivative-Cutting phenomenon is found when cutting Ti-6Al-4V using textured tools. The mechanisms about how the micro-textured tools change the frictional behavior in the chip-tool interface are explained using Derivative-Cutting characteristic. The antifriction performance of micro-textured cutting tools in the metal cutting process is discussed. The cutting force and cutting temperature is decreased effectively in the cutting simulation with the micro-textured tools manufactured in reasonable parameters.

Investigation into the rotary ultrasonic face milling of K9 glass with mechanism study of material removal

Rotary ultrasonic face milling (RUFM) process is introduced into flat surface machining of K9 glass in this study. The model of material removal for RUFM is developed. The cutting force, tool wear and subsurface damage of RUFM and diamond milling of K9 glass are compared. The results present that the relationship between cutting depth and ultrasonic amplitude has remarkable effects on cutting force, and suggest that cutting depth should be smaller than ultrasonic amplitude with RUFM process to obtain better processing performance. The experiments conducted as cutting depth is smaller than ultrasonic amplitude show that RUFM process can significantly reduce the cutting force, tool wear on the end face, and subsurface damage depth. Brittle deformation, materials removal and sub-surface damage features of K9 glass in RUFM and diamond milling are observed by scanning electron microscopy. The study indicates that the established material removal model for RUFM is reliable.

Experimental investigation on the effects of thermomechanical loading on the vibrational stability during rotary ultrasonic machining

ABSTRACT Ultrasonic vibration is assumed to be stable or unchangeable during the process of rotary ultrasonic machining (RUM) on brittle materials, neglecting the effects of different processing parameters. However, no experimental evidence has been reported to validate this assumption. In this study, the effect of thermomechanical load on the stability of ultrasonic amplitude during RUM was investigated by theoretical analysis and experimental procedures on quartz glass and sapphire. It was shown that the instability of ultrasonic amplitude during the machining process is mainly attributed to variation of resonant frequency under the implementation of thermomechanical load. The thermal effects of ultrasonic vibration decrease the resonant frequency of the ultrasonic machine, while mechanical loading during the machining process increases the resonant frequency. Furthermore, a higher feed rate or a harder material leads to a higher resonant frequency change. The variation of ultrasonic power can be used to review the validity of difference-neglected assumption when different values of processing variables, materials, or even machine tools are used during modeling. The results of this study should be well considered for future references when designing an ultrasonic machine.

Theoretical and Experimental Research on the Features of Cutting Force in Rotary Ultrasonic Face Milling of K9 Glass

This study introduces rotary ultrasonic face milling (RUFM) process into flat surface machining of K9 glass. The effective cutting velocity, and cutting length of single diamond particle were presented in RUFM. The model of material removal for RUFM was developed through examining indentation fracture mechanics theory and material removal characteristics of brittle materials, and analyzing kinematics properties of diamond grits in RUFM. With a view of comparative researches, the cutting force of RUFM and diamond milling of K9 glass are compared. The experimental results tell that the relationship between the cutting depth (dc) and the ultrasonic amplitude (A) of the cutter has remarkable effects on cutting force, which was also discussed in the kinematic characteristics analysis section. The results also show that RUFM process can significantly reduce cutting force and the effects of process variable changes on cutting force in RUFM are weaker as dc is smaller than A. However, the reduction trends of the cutting forces in RUFM are very small and even increased in some process conditions, as dc is larger than A. It suggests that the cutting depth should be smaller than the ultrasonic amplitude of the cutter with RUFM process to obtain better processing performance.

ACTIVITY BASED CIM MODELING AND TRANSFORMATION FOR BUSINESS PROCESS SYSTEMS

Computation-Independent Model (CIM) to capture domain requirements and the transformation from CIM to the Platform-Independent Model (PIM) are two crucial parts of the Model-Driven Architecture (MDA). This paper presents an ontology-activity-based CIM modeling approach to achieve a semi-automatic transformation from CIM to PIM. It proposes that the key elements in business process modeling are activities and these should therefore form the basis in constructing the domain ontology. Aiming to provide the key description capability for the process model, it discusses the hierarchy of the model by adding an activity dimension between the object and process tiers. It also proposes a model-relevance-calculation-based method for extracting ontology activities from the process meta-models. Based on the presented model acquisition method, a decomposition approach is proposed to simplify the complexity of the transformation relationships between the CIM and PIM by introducing the concepts of ontology activities. A general framework surrounding the transformation from CIM to PIM is discussed. It uses the Web Ontology Language (OWL) to describe the ontology activity and considers the Unified Modeling Language (UML) to be the PIM.