An holistic implementation of lean six sigma methodology on maintenance subsystem

Purpose: One of the main problems relevant with enterprises is to be able to cope with maintenance problems in order to maintain decrease of stoppages, time and economical losses in the production area. In order to acquire an effective and profitable maintenance policy in a production company, there is high demand of methodological strategy to improve the maintenance subsystem. Purpose of this research is to be able to implement the lean six sigma methodology on maintenance subsystem as successfully and supply more effective sustainable maintenance system. Design/methodology/approach: Lean six sigma methodology purpose on eliminating defects and improve the effectiveness of a process. Research methodology is designed according to the purpose and goals of the research which is based on DMAIC tool within the phases those include quality tools relevant with lean six sigma methodology. Findings: According to the research results; it is estimated that by implementing improvements and eliminating root causes, wastes; 50% performance increase is possible in maintenance related effectiveness. Lean philosophy and six sigma methodology has high improvement potential on maintenance processes; also successful with gaining on the eliminating of defects and consequently increasing the economical outputs. Research limitations/implications: This research is limited with the experience and information from real case companies, information from relevant scientific books and theory from scientific databases. Practical implications: Lean six sigma methodology can be applied appropriately for improving the quality of the maintenance system and maintenance activities those will induce maintenance effectiveness as consequently. More effective maintenance system means decrease in the maintenance related cost, decrease in the maintenance related time due to increase in the speed and increase in the maintenance related quality. Originality/value: The originality of this research work base on implementation of advanced quality tools in DMAIC phases on maintenance subsystem and studying the quality of maintenance in multi perspective scale. © International OCSCO World Press. All rights reserved. 2015

A tribological study in the perspective of vibro-electric analysis

Purpose: In this case study, oil starvation failure that is a common problem for mechanical constructions has been studied within perspective of vibro-electric analysis. The purpose of this research is testing material properties of a ball bearing under the oil starving failure and condition of resonance for inspecting predictive maintenance approaches. Design/methodology/approach: A test setup construction designed, built and placed in a laboratory location. An electrical motor has been selected for collecting electrical and vibrational data over a bearing by making tests. Test has been implemented under the electricity frequency of 63.8 Hz that was induced the rotation of electrical motor in order to set rotational speed. Findings: Respect to results of the analysis, inspecting of oil starving failure and resonance problem has been detected more clearly and informative by vibration analysis. Research limitations/implications: This research study is limited with some experience and data from case companies, data from relevant scientific literature and theories through scientific databases. Practical implications: Implementation of condition monitoring technologies on mechanical systems brings similarities with the health systems of the human beings. Such as developments in technologies of human health management, consultation of the mechanical systems should be practised in order to prevent breakdowns which cause unplanned stoppages. Vibrational and electrical monitoring techniques can be applied at enterprises in order to ease and reach higher accuracy for detection of symptoms cause from mechanical fault initiations. Originality/value: The originality of this research receive resources from comparison of traditional condition monitoring tool vibration analysis and more recently developed electrical consumption analysis used for predictive maintenance. © International OCSCO World Press. All rights reserved. 2016

Using ahp and topsis to evaluate welding processes for manufacturing plain carbon stainless steel storage tank

Purpose: In the plain carbon stainless steel storage tank manufacturing industry, there are many types of welding processes used. When selecting the most appropriate welding process is usually done intuitively by the manufacturer depending on its own pre-experiences or common applications in similar companies. However, this approach has a shortsighted view since it generally ignores many conflicting criteria effecting the suitable welding process selection. To overcome this problem, this study aims to evaluate important criteria and alternative welding processes by using some of multi-criteria decision-making approaches to come up with better manufacturing decisions. Design/methodology/approach: This study uses a combined methodology of Analytical Hierarchy Process (AHP) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). Since both of these techniques require experts’ contributions, a group meeting is held with the experts from academia and industry. Findings: The study identified the important criteria for welding selection process in storage tank manufacturing. With the help of experts in the domain, both weights of decision criteria and ranking of alternative welding processes were determined. Research limitations/implications: Since the techniques used in the study depend on expert’s contribution, the expert knowledge on the welding process is critical. When the expert changes the resulting decision may also change. Therefore, the selection of the expert(s) must be done carefully. Practical implications: The findings of the study are valid for the specific case of the storage tank manufacturing. The study helps manufacturers to understand the framework of welding process selection and make them aware of various techniques (e.g., AHP and TOPSIS). The approach may also be welcomed by other welding applications. Originality/value: The main contribution of the study is mostly on the practical side. To the authors’ best knowledge, this paper is one of few studies investigating the selection of welding process for a plain carbon stainless steel storage tank manufacturing. It may help to increase the attention of researchers on multi-criteria decision-making applications in the welding field. © International OCSCO World Press. All rights reserved. 201

Investigations on the joint properties of the friction welding of aluminium alloy tube to tube plate using an external tool

Purpose: Aluminium and its alloys are frequently used in structural applications due to their good welding ability as well as their high strength and corrosion resistance. Several developments have been observed on the welding of aluminium in last decade. The manufacturing of heat exchangers, economizers and boilers is highly cost progress due to tube to tube plate welding’s. The purpose of this study is investigation of friction weldability of tube to tube plate aluminium alloys using an external tools (FWTPET) which is a relatively newer solid state welding process used for joining tube to tube plate. Design/methodology/approach: First, preliminary experiments were carried out to determining suitable the tool rotational speed, pressure load and temperature. An experimental setup has been designed and manufactured to keep the pressure load constant during the preliminary tests. Then, by changing the weld mouth on the plate, the gap between the tube and the plate, and the tube projection parameters, the effects of all parameters on shear strength values, micro hardness values and the formation of internal structure of the weld zone were investigated. Findings: It was founded that aluminium tubes can successfully weld to tube plates with using an external tools. Also it is seen that vertical force between tool and sample, tube protection and temperature are very important parameters which are effect of welded joint properties. Practical implications: FWTPET which is new welding method has been used in industrial field in last few years. Originality/value: In the beginnings studies concentrate on non-ferrous metals such as Al, Cu, Mg etc. So this studies on FWTPET have remarkable importance. © by International OCSCO World Press. All rights reserved

Sürtünme karıştırma kaynağı için takım tutucu tasarımı

The temperature on the stirrer tool may reaches 1000 - 1100°C during friction stir welding of high melting temperature materials such as steels. This heat occurred on tool is transfered to head of milling machine. The bearing of milling machine may be damaged due to excessive heat. The designed tool holder is including both cooling and shielding gas system. This tool holder will prevent heat transfer from tool to milling machine by means of cooling system. Furthermore, using of shielding gas system, the oxidation on the welding zone will be prevented. This study will bring some beneficial to researchers who especially study on friction stir welding

The effect of tool rotational and traverse speed on friction stir weldability of AISI 430 ferritic stainless steels

In this study, the effects of tool rotational speed and traverse speed on welding of AISI 430 (X6Cr17, material number 1.4016) ferritic stainless steels by friction stir welding method are examined. Two specimens with dimension of 3×100×200mm were joined in butt position. Tool rotational speeds were determined to be 560-1400min-1 and traverse speeds as 80-200mm/min. During the studies, tool pressure force 3.5kN and tool angle of 0° was kept constant. Hard metal carbide (WC-Co hard metal identified as K10) with equilateral triangle tip profile was used as the tool material. Determination of the tool advance speeds related to the tool rotation speeds giving the best-looking weld seals with acceptable values of mechanical properties was aimed. During welding of the specimens joined in butt position, the temperature change due to time and variation of the pressure force applied on welded specimens by the tool shoulder has been recorded. It has been observed that the best mechanical resistance values were obtained at tool rotational speed of 1120min-1 through five tool rotational speeds (560-1400). Also it has been observed that the best mechanical resistance values were obtained at traverse speed of 125mm/min through five traverse speeds (80-200) with the constant tool pressure force of 3.5kN and tool angle of 0°. © 2011 Elsevier Ltd

The effects of adherend on the strength of adhesively bonded cylindrical components

The strength of adhesively bonded cylindrical components was affected by the various factors, which are diametrical clearance, type of assembly, type of adherend, operating temperature, loading type, surface roughness, etc. In this study, the effect of three different adherend (steel, bronze and aluminium) on bonding strength was experimentally investigated and the results were discussed. The experiments were carried out for both static and dynamic loading conditions. The highest joint strength was obtained in bronze adherend while the lowest value was obtained in aluminium adherend. © 2003 Elsevier Ltd. All rights reserved

Inspection of artificially built mechanical failures through innovative condition monitoring techniques

In this study, the factors influence on root causes of failure initiation are examined with the original test implementation and condition monitoring techniques are emphasized. In working toward this goal, the laboratory test setups and tests which have been created by international research bodies are examined and in order to practise a new research work, a unique test setup system and a test plan is built. In this target of the root cause failure detection, vibration data at radial direction and electrical consumption data are collected through the analysis by comparing two different condition monitoring techniques. In this research, fault detection in modeling fault conditions and vibration, electrical consumption measurement have been let us examination in depth. During the tests, data are collected simultaneously in vibration by four-channel Data Acquisition Card (DAC) and electrical consumption by Motor Condition Monitoring (MCM) system which are integrated with an computer system. Respect to the study results; vibration analysis in detection of defects has been judged to be more successful in comparison with electric consumption analysis under the test conditions in perspective of condition based predictive maintenanceIn the study, it is mentioned that detection of failure initiations at sensitive levels and importance of consequent results

Mechanical properties and microstructure characterization of GTAW of micro-alloyed hot rolled ferritic XPF800 steel

The gas tungsten arc weldability of micro-alloyed hot-rolled ferritic XPF800 steel, which is newly produced by Tata Steel, has been studied. The weld geometry profile, mechanical properties and microstructure affected by heat input have been investigated. The micro examination of the welded joint has been characterized utilizing optical microscope and scanning electron microscope. Atomic concentrations of metallic elements in carbides have been determined by energy dispersive X-ray spectrometry. The optimum parameters for current, welding speed and heat input have been found to be 140 A, 100 mm/min and 0.62 kJ/mm in the GTAW of XPF800 plates, respectively. © 2020 Karabuk Universit

Inspection of artificially built mechanical failures through innovative condition monitoring techniques

In this study, the factors influence on root causes of failure initiation are examined with the original test implementation and condition monitoring techniques are emphasized. In working toward this goal, the laboratory test setups and tests which have been created by international research bodies are examined and in order to practise a new research work, a unique test setup system and a test plan is built. In this target of the root cause failure detection, vibration data at radial direction and electrical consumption data are collected through the analysis by comparing two different condition monitoring techniques. In this research, fault detection in modeling fault conditions and vibration, electrical consumption measurement have been let us examination in depth. During the tests, data are collected simultaneously in vibration by four-channel Data Acquisition Card (DAC) and electrical consumption by Motor Condition Monitoring (MCM) system which are integrated with an computer system. Respect to the study results; vibration analysis in detection of defects has been judged to be more successful in comparison with electric consumption analysis under the test conditions in perspective of condition based predictive maintenanceIn the study, it is mentioned that detection of failure initiations at sensitive levels and importance of consequent results