CUTTING LIFE IMPROVEMENT OF MACHINE TOOLS

Machining without the use of any cutting fluid (dry machining) is becoming increasingly more popular due to concern regarding the safety of the environment. Because of this demands for increasing tool life without use of coolants are arising. This paper is an attempt to review the different techniques employed to improve the tool life. The paper begins with reviewing tool wear, different methods to measure wear, and different approaches employed to improve tool life such as tool geometry, machining parameters, edge honing, and thin film coatin

STUDY ON THE PERFORMANCE PARAMETERS OF TWO STAGE EVAPORATIVE COOLING SYSTEM

The Evaporative cooling systems are continuously going modifications for increased efficiency and reduced energy consumption. It is the demand of time to develop energy efficient technology as far as environmental aspects and economic dependency on unconventional sources is concerned. Due to this, the evaporative cooling systems are used for commercial cooling and humidification control of buildings, cold storages, green houses, etc. Two stage indirect/direct evaporative air cooler can provide summer comfort conditions as an environmentally clean, fresh supply air and energy efficient cooling system for the regions where direct system alone is not suitable. In this paper, the performance parameters of Indirect/Direct evaporative cooling system are studied. Effects of various operational and geometrical parameters on cooling performance of this cooling system also have been studied. Results show that indirect/direct cooling systems can provide comfort conditions, which use only water as cooling media and consume much less energy in comparison with conventional vapour compression systems. Additionaly, in certain localities having high humidity the use of evaporative cooling is having limited use. In these situations when evaporative cooling systems are used in conjuction with mechanical vapour compression systems for the precooling of the air, these systems can also have potential to save considerable amount of energy and there by the cost of operation of the equipment

EXPERIMENATAL INVESTIGATION OF THERMAL CHARACTERISTICS ONCROSS FLOW TUBULAR HEATEXCHANGER FOR INDIRECT EVAPORATIVE COOLING

The demandfor cooling system increases worldwide. Indirect Evaporative cooling can be used to cool air from the surface of heat exchanger without change in humidity. As there is no contact between water and air due to cross flow heat exchanger. Primary air stream is cooled by secondary air stream after evaporation of water in wetted surface of cross flow tubular heat exchanger made of PVC pipe and tested it in summer condition. By measuring humidity and DBT thermal characteristic such as cooling capacity, heat transferred per unit time, wet bulb effectiveness, COP, Dew point effectivenessis calculated.Temperature difference between inlet temperature (from atmosphere) and outlet temperature (to room) up to 8 to 10 ºCis achievedwith constant Humidity

OVERVIEW ON MICRO MACHINING

In recent years, advanced materials with distinctive metallurgic properties like super alloys, composites and ceramics has been developed to satisfy the strain of maximum applications. whereas these materials square measure more durable, tougher, less heat sensitive and bit more resistant to corrosion and fatigue, they're additionally troublesome to machine.Micro systems can be used in wide applications in biomedical electronics, optics, micro-mechanics, microfluidics, dies, moulds etc. element components employed in these systems have feature dimensions in micrometers and part volumes less than 1 mm3. Manufacture of these parts with high accuracy could be a challenge

RECONFIGURABLE MACHINE TOOLS

The uniqueness of Reconfigurable Manufacturing Systems (RMSs) is that the structure of the system as well as of its machines and controls can be rapidly changed in response to market changes (demand and products). A major component of RMSs is the reconfigurable machine tool (RMT). By contrast to conventional CNCs that are general–purpose machines, RMTs are designed for a specific, customized range of operation requirements and may be cost–effectively converted when the requirements change. In this paper, systematic design tools that have been recently developed for RMTs are reviewed, and three examples are provided to compare RMTs to traditional types of machine tool

COMPUTATIONAL ANALYSIS OF HEAT TRANSFER ENHANCEMENT IN A CIRCULAR TUBE USING SEMICIRCULAR NOTCHED ROTARY TWISTED TAPE INSERTS

Heat transfer enhancement of air flow using twisted tape inserts in a circular copper tube have been investigated under turbulent flow regime. A simulation technique is employed to simulate the swirling flow of twisted tape insert with and without semi-circularnotch with three different pitch ratios (P/w = 3,4 and 5). The Reynolds number is varied in the range of 25000 to 35000. The heat transfer enhancement represented by a Nusselt number (Nu) in turbulent flow regime is investigated by using CFD (Ansys 16.0 FLUENT) to investigate the physical behaviourof the thermal and fluid flows under uniform heat-flux condition.Results shows that the semi-circularnotch twisted tape inserts develops a strong turbulence flow within fluid flow which increases heat transfer rate. The use of semi-circularnotch twisted tape lead to a considerable increase in heat transfer and pressure drop in comparison with the plane tube. The heat transfer rate increases with increase in Reynolds number and decrease in pitch ratio

Reconfigurable Machine Tools

The uniqueness of Reconfigurable Manufacturing Systems (RMSs) is that the structure of the system as well as of its machines and controls can be rapidly changed in response to market changes (demand and products). A major component of RMSs is the reconfigurable machine tool (RMT). By contrast to conventional CNCs that are general–purpose machines, RMTs are designed for a specific, customized range of operation requirements and may be cost–effectively converted when the requirements change. In this paper, systematic design tools that have been recently developed for RMTs are reviewed, and three examples are provided to compare RMTs to traditional types of machine tool

Experimenatal Investigation of Thermal Characteristics Oncross Flow Tubular Heatexchanger for Indirect Evaporative Cooling

The demandfor cooling system increases worldwide. Indirect Evaporative cooling can be used to cool air from the surface of heat exchanger without change in humidity. As there is no contact between water and air due to cross flow heat exchanger. Primary air stream is cooled by secondary air stream after evaporation of water in wetted surface of cross flow tubular heat exchanger made of PVC pipe and tested it in summer condition. By measuring humidity and DBT thermal characteristic such as cooling capacity, heat transferred per unit time, wet bulb effectiveness, COP, Dew point effectivenessis calculated.Temperature difference between inlet temperature (from atmosphere) and outlet temperature (to room) up to 8 to 10 ºCis achievedwith constant Humidity