Vibration assisted machining: Modelling, simulation, optimization, control and applications

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University, 30/11/2010.Increasing demand for precision components made of hard and brittle materials such as glasses, steel alloys and advanced ceramics, is such that conventional grinding and polishing techniques can no longer meet the requirements of today's precision manufacturing engineering. Particularly, in order to undertake micro-milling of optical glasses or other hard-machining materials, vibration assisted machining techniques have been adopted. However, it is essential and much needed to undertake such processes based on a scientific approach, i.e. the process to be quantitatively controlled and optimized rather than carried out with a trial-and-error manner. In this research, theoretical modelling and instrumental implementation issues for vibration assisted micro-milling are presented and explored in depth. The modelling is focused on establishing the scientific relationship between the process variables such as vibration frequency, vibration amplitude, feedrate and spindle speed while taking into account machine dynamics effect and the outcomes such as surface roughness generated, tool wear and material removal rate in the process. The machine dynamics has been investigated including a static analysis, machine tool-loop stiffness, modal analysis, frequency response function, etc, carried out for both the machine structure and the piezo-actuator device. The instrumentation implementation mainly includes the design of the desktop vibration assisted machining system and its control system. The machining system consists of a piezo-driven XY stage, air bearing spindle, jig, workpiece holder, PI slideway, manual slideway and solid metal table to improve the system stability. The control system is developed using LabVIEW 7.1 programming. The control algorithms are developed based on theoretical models developed by the author. The process optimisation of vibration assisted micro-milling has been studied by using design and analysis of experiment (DOE) approach. Regression analysis, analysis of variance (ANOVA), Taguchi method and Response Surface Methodology (RSM) have been chosen to perform this study. The effects of cutting parameters are evaluated and the optimal cutting conditions are determined. The interaction of cutting parameters is established to illustrate the intrinsic relationship between cutting parameters and surface roughness, tool wear and material removal rate. The predicted results are confirmed by validation experimental cutting trials. This research project has led to the following contribution to knowledge: (1) Development of a prototype desktop vibration assisted micro-milling machine. (2) Development of theoretical models that can predict the surface finish, tool wear and material removal rate quantitatively. (3) Establishing in depth knowledge on the use of vibration assisted machining principles. (4) Optimisation of cutting process parameters and conditions through simulations and machining trials for through investigation of vibration assisted machining.Financial support was obtained from Brunel University

The adoption of software process improvement (SPI) program in the construction industry

Integrating the design process and automating the construction process are called for in the Industrialised Building System (IBS) Roadmap 2003-2010 and the Construction Industry Master Plan (CIMP) 2006-2015. Hence, the industry needs to improve the construction delivery process by having as many processes utilizing advanced IT/ICT technologies. With a goal of producing zero product failure and meeting the users’ requirement satisfaction, this is an initial study into automating the construction tasks by studying a systematic process management commonly used for software implementation. We present a feasibility study on the use of a Software Process Improvement (SPI) Program in an IT organization—assuming that the construction organization will become an implementer of computer-integrated procedures in the future. Based on a case study conducted at a local IT software company, it documents the implementation of a SPI program to improve the internal software process development. The study uses the Capability Maturity Model Integration (CMMI) from Software Engineering Institute as SPI framework and IDEAL model-SPI life cycle model for executing and managing SPI program. Results show that the SPI Program model is successful in terms of the IT organization increasing its work productivity, high end-user product satisfaction and reduction of software defects. The paper concludes with discussions on how we can bridge computer science approach into the construction industry, thereby contributing to the development of future theoretical and application methodologies towards applying IT/ICT initiatives in the local construction industry

Design and Investigate of Flushing System for Electrical Discharge Machining (EDM) Application

Electrical Discharge Machining (EDM) is high precision machining process in which no actual contact between the workpiece and electrode during sparking. Dielectric fluid play a role as flushing medium and semiconductor between workpiece and electrode to stabilization and controlled spark gap ionization condition. In real condition, nozzle flushing system in EDM machine not able to complete remove debris formed during machining and affect the machining performance. Improper flushing due to lack of guideline at setup position of nozzle and inlet pressure caused low material removal rate, irregular tool and higher cost on raw material. To overcome this problem, the design and investigate of flushing system in EDM application is required. The design and investigation undergo by simulation of ANSYS Computational Fluid Dynamics (CFD) with a virtual experiment to accurate prediction of flushing performance. The influence of nozzle size and inlet pressure supplied on flushing efficiency were analyzed to avoid improper flushing on die-sinking EDM process. The simulation and experiments clarified that the higher inlet pressure, P=0.20 bar and larger nozzle diameter, D=6mm resulting in higher total pressure which is 2647.16 Pa. Furthermore, the streamline of velocity and eddy viscosity contour in the work tank using to analyze the turbulence zone by nozzle flushing obtained by the CFD analysis. The condition in case 5 (D=5mm, P=0.15 bar) is more efficiency on debris removal rate based on the result of high total pressure on machining zone and eddy viscosity contour showed the turbulence zone only formed area near to outlet of system. The model results have been shown good agreement with experiment and co-relation data

Integration the 6th category business excellence framework, the 8th clause ISO 9001:2015 and the 6th category KPKU Indonesia framework

KPKU (Kriteria Penilaian Kinerja Unggul) Indonesia framework 2015 adopted Business Excellence Framework 2013-2014, that is a framework used by the “Ministry of State-Owned Enterprises” of the Republic of Indonesia to assess the performance of SOEs in Indonesia. One of the KPKU criteria is the operation, that is the most dominant criteria in company performance. They are proven by the score in Baldrige Excellence Framework (110 point is the highest score) for product and process results which are influenced by operational criteria in the 6th category of BEF. Currently, Indonesia does not have yet business excellence framework based on companies in Indonesia and does not have yet Indonesia operational excellence model, either in Indonesia or based on previous research. Currently, there is no model that integrates (Baldrige Excellence Framework, ISO 9001: 2015, and KPKU). This research will develop the Indonesia operational excellence model based on the Baldrige Excellence Framework, ISO 9001:2015, and KPKU Indonesia framework. Stage of the research is the literature survey, identifying the 6th Category Baldrige Excellence Framework; KPKU and the 8th Clause ISO 9001:2015, and integration the 6th KPKU framework and the 8th Clause ISO 9001:2015 to the 6th Category Baldrige Excellence framework. The results of the study are the Indonesian operational excellence framework that consists of 5 criteria and 14 sub-criteria, namely Product and Process Design, Process Management, Process Efficiency and Effectiveness, Process Improvement, and Safety and Emergency Preparedness. This model is appropriate for company performance measurement, especially operational performance

A performance of 2 dimensional ultrasonic vibration assisted milling in cutting force reduction, on aluminium AL6061

This paper were investigate a performance of 2 Dimensional Ultrasonic Vibration assisted Milling (UVAM) toward Aluminium Al 6061. The focus is to find the performance of reduction of cutting force compared to the conventional machining in the industries shop floor. Due to the major effect of cutting force of production in industries, the excessive cutting force problem must be investigated deeply as it will cause shortens tool life and reduces the production rate. A scientific approach has been found in order to reduce the cutting force during machining which is integrating the ultrasonic concept into workpiece. The modelling of vibration cutting ratio has been simulated to find the time force contact and non-contact. Thus, less cutting force could be found. The ultrasonic vibration platform that generated by XY25XS from Cedrat Technologies is travelled in X direction as a feed movement. Thus, the X and Y axis vibration actuate along the workpiece for the machining process. The performance of UVAM in cutting force reduction found the superior benefits of UVAM is come from the alternating cycle’s between tool and workpiece. The comparison between UVAM and conventional machining in reduction of cutting force is 32%. The potential of the UVAM tool wear and tool life will be discussed deeply in finding and next in the conclusion section

Design and Develop of Open Architecture CNC Movement Control System for Analysing Precision Motion of EDM Machine

Since the third Industry Revolution (IR3.0), automation become a key technology in industry especially CNC machine. An EDM machine is CNC based that able to reduce the process time, increase the productivity of manufacturing process, and duel with complex task. Therefore, it was one of the best choice to become the education element in manufacturing field. However, high in cost and complexity in structure were the weaknesses and limitations of EDM machine. An open architecture CNC movement control system was studied in order to create a high flexibility, affordable, and simple movement control system for EDM machine. LabVIEW was chosen as the main controller software and NI MyRIO as the main processor in this movement control system. The hardware was built by using open architecture components which reusable and low in cost. This system was able to control the movement of X, Y, and Z axis of the EDM machine in term of distance travel. The time counter in LabVIEW program was used as the feedback system due to absent of encoder as the position feedback element. The relationship between traveled time and distance traveled was determined for the adjustment and programs for single direction, dual direction, specific distance movement, multi axis movement and stop when sensor triggered were developed. The desired value was compared with the actual distance travel in order to calculate the percentage of error of the control system. The percentage of error for X, Y, Z and the gap created was 0.37%, 0.38%, 0.49% and 2.9% respectively. This experimental study will fulfill three objectives. First is to design an open architecture CNC movement control system in X, Y, and Z axis for EDM application. Second is to integrate and analyze the CNC movement control system with the machine hardware. Lastly is to analyze the performance of the developed movement control system with respect to the CNC movement system

Human machine interface design analysis of defect detection prototype by wonderware intouch software

Human Machine Interface (HMI) serves as a bridge for operators to understand the processes that occur on the machine. Without HMI, operators will have difficulty in monitoring and controlling the machine. HMI used in this study using Wonderware InTouch software. The HMI design that is used, displays the home button, as the start screen. There are two options in the home menu, which is the option to login as an identification and classification operator. To start operation and enter the monitoring window, any operator that uses this HMI must login using a username and password. The function of HMI in this research is as a connector between operators with machine. In this paper we have presented the human machine interface design of defect detection prototype by wonderware intouch software. Based on the tested results can be concluded that the designed is successfully

Integration the 6th category Business Excellence Framework, the 8th clause ISO 9001:2015 and the 6th category KPKU Indonesia Framework

Abstract: KPKU (Kriteria Penilaian Kinerja Unggul) Indonesia framework 2015 adopted Business Excellence Framework 2013-2014, that is a framework used by the “Ministry of State-Owned Enterprises†of the Republic of Indonesia to assess the performance of SOEs in Indonesia. One of the KPKU criteria is the operation, that is the most dominant criteria in company performance. They are proven by the score in Baldrige Excellence Framework (110 point is the highest score) for product and process results which are influenced by operational criteria in the 6th category of BEF. Currently, Indonesia does not have yet business excellence framework based on companies in Indonesia and does not have yet Indonesia operational excellence model, either in Indonesia or based on previous research. Currently, there is no model that integrates (Baldrige Excellence Framework, ISO 9001: 2015, and KPKU). This research will develop the Indonesia operational excellence model based on the Baldrige Excellence Framework, ISO 9001:2015, and KPKU Indonesia framework. Stage of the research is the literature survey, identifying the 6th Category Baldrige Excellence Framework; KPKU and the 8th Clause ISO 9001:2015, and integration the 6th KPKU framework and the 8th Clause ISO 9001:2015 to the 6th Category Baldrige Excellence framework. The results of the study are the Indonesian operational excellence framework that consists of 5 criteria and 14 sub-criteria, namely Product and Process Design, Process Management, Process Efficiency and Effectiveness, Process Improvement, and Safety and Emergency Preparedness. This model is appropriate for company performance measurement, especially operational performance.   Keywords: Integration, Baldrige Excellence Framework, ISO 9001:2015, KPKU, operational excellence

The Influence of Graphitization Catalyst Electrode in Electrical Discharge Machining of Polycrystalline Diamond-Finish-ing Condition

Electrical Discharge Machining (EDM) is a non-contact machining process that becomes famous in machining of Polycrystalline Diamond (PCD). The material is typically used as the cutting tools for aerospace and automotive industries. However, low electrical conductivity and high melting temperature of PCD has caused slower EDM process. This investigation purposely designed to investigate the influence of different types of electrode which are Copper (ordinary electrode) and Copper-Nickel (newly proposed graphitization catalyst electrode) on EDM performance of MRR and Ra. Interestingly the newly proposed electrode gave positive impact to the investigated performance indication. Cu-Ni electrode recorded 35% better in MRR than the Cu electrode, though with higher short-circuiting rate. Cu-Ni also provided the lowest Ra value with 10% better than the best Ra produced by Cu electrode. This phenomenon occurred as due to the high interaction between the catalyst materials of nickel and diamond which supported by the qualification data provided in this investigation

Analysis of worker performances using statistical process control in fish paste otak-otak food industries

This research focuses on the improvement of Small and Medium Enterprises through the used of Process Statistical Control (SPC). An industry that focuses on the fish paste (known as “otak-otak”) production was taken as the case study in this research and the problems analysed are based on the real industrial experiences. The data collection for control charts were recorded for two weeks consisting of working time for each operator. The data were collected in subgroup of 16 with sample size of 5. The collection of data for weight of product was recorded randomly for the whole production line, while data collection of working time of operation was taken randomly from each operator every 30 minutes of the working hour. From this study, there are several problems had been detected in the process that been categories in six element that is people, method, measurement, machine, environment and materials. There were lack of motivation, lack of skill, lack of supervision, manual operation, lack of standard of procedure, waiting time in process, weight-based operator, lack of quality check, not using weight scale, conveyer that sometimes got stuck, spoon for tools, no automation, poor layout arrangement, talking while working, small working space, lack of hygiene, waiting time for material and easily spoiled. The findings can be used as the guideline to the industries for future production improvement. The industries would focus on elimination or reduction of the problems through their innovative solution