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Modification Of An Existing Metal Sheet-bending Machine
CHAPTER ONE -- [Total Page(s) 4]
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CHAPTER ONE
1.0 INTRODUCTION
1.1 Importance of Sheet Metal Work and Bending Machine
What is a metal? It is a strong shinny, which conducts electricity and melts when you make it hot enough. But surely metal must be something more than this because there are other substances such as carbon,, glass and rubbers, which are, obviously not metals but can also variously claim to have strength, elasticity or electrical conductivity.
Furthermore, most of the metals will melt when heated sufficient. What then is a metal? A study of simple metallurgy will show that there is one important factor, which distinguishes metals from non-metals and that is the neat, orderly arrangement of the atoms into regular geometric molecules. Metal is a good conductor of heat and electricity and forming basic oxides.
An alloy is a fused mixture or compound of two or more pure metals. The reasons for making these mixtures are many and various. Pure metals have certain desirable properties but are often lacking in other ways. Therefore it is necessary to mix other metals with them in order to preserve and improve their basic properties. To quote a well known example: Aluminum is a light weight metal which makes it useful for aircraft construction, but it is also soft and weak so a small quantity of copper is added to it to give the necessary strength and rigidity (Courtesy, 1980).
The subsequent development of iron and steel to suit its use in various forms enables it to serve effectively wherever used. Iron and steel remains the most vastly used material for structural works, enclosures and packages.
The most popular forms of iron and steel remains the sheet form, mostly used in enclosure and vessel fabrication. The term metal sheet refers to lighter gauges of steel in rolled form ranging in thickness from approximately 0.4mm to 3.2mm. (Surenda singh, 1979).
Many engineering components are produced from flat sheets of metal which are cut to shape and then folded to form the finished article. The edges are then secured by a variety of methods such as welding, soldering and riveting. The accuracy of the size of drawing the shape on the flat sheet know as the development. Allowance is made at this stage for folding or bending, the amount varying with the radius of the bend and the metal thickness.
Quite a large of sheet metal is employed in the manufacturing industries, in building of aircrafts, automobiles and household appliances. Sheet metal to a large extent is used in the building industries for roofing, heating, prefabricated structures and air conditioning casings.
The base metal iron and bronze were appreciated for their strength especially for weapons and tools; copper, tin and lead came to be used mainly for their utility or durability- for cooking, for storage or for strengthening wooden construction of any kind.
The particular property of metals that can be mixed or alloyed in various combinations and proportions to make a better materials for particular purposes was understood in the ancient world. Copper and tin produces bronze; copper and zinc produces brass; lead and tin produces pewter. This property has been exploited with ingenuity and increasing scientific knowledge while the designation iron, copper, lead, silver and gold are still commonly used (Surenda, 1979).
All metals shares certain characteristic: a uniform smooth complexion; great strength and tenacity; but also easily worked surface; and malleability (their capacity to assume any desired shape).
All these are carried out with the help of sheet metal works, which involves fabrication of metallic objects by cutting, forming/ bending and fastening, welding etc. are referred as sheet metal works. (Oyewole and Agada, 2000).
The term bending refers to an operation in which metal is deflected from its original form to a new position generally at an angle or a curve and it remains so permanently. Bending is a common metalworking technique to process sheet metal. It is usually done by hand on a box and pan brake, or industrially on a press brake. Typical products that are made like this are boxes; such as electrical enclosures, rectangular ductwork and some firearm parts.
Usually, bending has to overcome both tensile stress as well as comprehensive stress. When bending is done the residual stresses make it spring back towards its original position, so we have to over bend the sheet metal keeping in mind the residual stresses.
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ABSRACT - [ Total Page(s): 1 ]ABSTRACT IS COMING SOON ... Continue reading---
TABLE OF CONTENTS - [ Total Page(s): 1 ]TABLE OF CONTENTFront page Certification Dedication Acknowledgment Abstract Table of content Project topic Aim Procedures Selected materials Equipment CHAPTER ONE1.0 INTRODUCTION 1.1 Importance of Sheet Metal Work and Bending Machines 1.2 Historical Review and Classification of Bending Machines. 9-121.3 Operational Characteristic of the Bending Machine CHAPTER TWO2.0 BENDING TECHNOLOY 2.1 Principles of Bending 2.2 The mechanics of Bending 2.3 Pla ... Continue reading---
SELECTED MATERIALS - [ Total Page(s): 1 ]SELECTED MATERIALSGauge Dimension• 4mm plate - 1200 x 1200mm• H Channel (8inch x 5inch) - 2.550mm• 12mm Plate (8ft x 1ft) - 2.850mm• 12mm Plate - 304 x 2550mm• 50mm Plate - 2,352 x 588mm•  40mm Shaft ... Continue reading---
AIM - [ Total Page(s): 1 ]To design and construct a mental sheet-bending machine component which is manually operated. A machine with working capacity to complete a 90o fold of a full-length plate (8ft = 2400mm) and up to 2.5mm thickness. ... Continue reading---
PROEDURES - [ Total Page(s): 1 ]These are the procedures for designing and constructing a metal sheet-bending machine.- Initial Machine Design - Materials Selection- Costing- Purchasing of the selected Materials- Equipment Used for the Construction ... Continue reading---
EQUIPMENTS - [ Total Page(s): 1 ]EQUIPMENTSï¶ Moulding flaskï¶ Hack Sawï¶ Grinding Stonesï¶ Cutting Stoneï¶ Shearing Machineï¶ Arc Welding Machineï¶ Drilling Machineï¶ Grinding Machineï¶ Lathe Machineï¶ Metal Bending Machineï¶ Shapping machine ï¶ Muilding machine ï¶ Driving machineï¶ Feed taping tool ... Continue reading---
CHAPTER TWO - [ Total Page(s): 4 ]Fig 2.6: Over bending to compensate for spring back.The nose of the bending blade is at an angle of 45° to allow for over bending when bending at 900. After the force applied is released, the material spring back and the required bend is achieved. Fig 2.6(b) shows a bend having a spring back angle i.e. distance between the over bending and the assumed position.2.6 Method of Determining Angle of Spring BackThe only practicable method to determine spring back is by experiment, others are based ... Continue reading---
CHAPTER THREE - [ Total Page(s): 5 ]A little consideration will show that when a beam is subjected to the bending moment, the metal on the upper side of the beam will be shortened due to compression and those on the lower side will be elongated due to tension. It may be seen that somewhere between the top and bottom plane, there is a surface at which the metal s neither shortened nor lengthened. Such a surface is called “Neutral surface†The intersection of the neutral surface with any normal cross-section of the beam ... Continue reading---
CHAPTER FOUR - [ Total Page(s): 1 ]CHAPTER FOURCOMPONENT DESIGN AND CONSTRUCTION Sand casting is one of the quickest and most cost effective methods adopted in the production of metal prototypes and is an excellent solution for low to medium run of pasts that do not require a specific or precise shape repeatability. The summary of making a cast material using sand casting process are as follows.1. A mold was created by placing the mixture of sand, clay and water on a pattern, and when the pattern was removed ... Continue reading---
CHAPTER FIVE - [ Total Page(s): 1 ]CHAPTER FIVE5.1 Analysis Every sector of the economy is experiencing changes. The production sector is not left out of the changes, infact it is more affected. Sheet metal today is used for doors, windows, frames, gates, etc.It’s worthy to mention, however that the road side welders have developed various ways of bending sheet metal manually, but most often, they generally have poor finishing. As a result, their output does not justify their effort or input.It could be said, that th ... Continue reading---
REFRENCES - [ Total Page(s): 1 ]REFERENCESCourtney, J.V. (1980): Workshop Processes and Materials. Van Nosh Reinhold Company Ltd Workinghan, England, Pg. 21.John, R. Walker (1976), Exploring Metal Work-Basic Fundamentals. Good Head-will Cox, South Holland, Pg. 78-80.Khurmi, R.S. and Gupta J.K. (1979). A textbook of Machine Design. Eurasia publishing house (pvt) ltd New Delhi, Pg. 15.Smith, F.J.M. (1982): Basic Fabrication, and Welding Engineering: Longman, England, Pg. 23-24Surenda, Singh (1979): Strength of material, Vikas Pu ... Continue reading---
