FABRICATION OF A POLYTHIENE BAG SEALING AND CUTTING MACHINE

CHAPTER ONE

1.1     INTRODUCTION
The portable sealing machine is one of the most important fabrication of engineers of 20th century, the achievements led to sweet relieve for Agriculturist, industrialist, marketers etc. for this purpose, the production of Agricultural and industrials, goods which need appropriate attention for packaging and storage has been on the increase.
Previously, the packaging system has done by the use of paper, clothing material, etc. These methods are either given way to cellophane packaging system.
Different types of packaging system emerged owing to the facts of invention of which the most commonly used is the cellophane packaging and sealing.
It has the following advantages:
Low cost of production, high resistance to acid attacks, inertness, corrosion etc.
Polyethylene is used in packaging goods like ice cream, umbrellas, exercise books, pure water, beverages, weavon, packet shirts, bread, biscuits etc. the following properties polyethylene possessed are the reasons for its varieties of purpose that is to say how cost of production, inertness, resistance to acid, and corrosion water.
The use of polythene cannot be overemphasized. Most of food packaging for hygienic. The technology of cellophane permits raw materials of textile industries to be carried with sealed polyethylene the finished products are either marketed or exported with polyethylene packaging. Most utensils are packaged with polyethylene. Special polyethylene materials have been invented of recent that have shock absorber which gives protection to the breakable material. Since this packaging came up, there had been a safer conveyance of glass and ceramics materials, especially for transportation and exportation of finished goods.
Also, it is in packaging most of electronic gadgets which includes; computers, amplifiers, calculators,  radio and T.V sets etc. for safety purposes. It will be needless talking about polyethylene. Without talking about the machines used in sealing generally. Some of the machines used in the industries include cellophane sealing machine used in sealing polyethylene materials, pneumatic, electrical sealing machine handled by electrical heater and needle point action and hand sealing. 

 

CHAPTER TWO

2.0     LITERATURE REVIEW
Based on the advancement of science and technology, there are different types and fabrication of scaling machine in use today. These include: the pneumatic sealing machine, which uses air pressure mechanism in its sealing operation. Most industries that deals on food, drinks, alcoholics and non – alcoholic, use these types of sealing machine.
Another example of sealing machines is the electrical sealing type. This machine is used for cellophane, nylons fabric, synthetic leather and other items. The operation is handled by electrical heater and needlepoint action.
The most primitive and the oldest is the hand sealing which is also the poorest method of preservation. This is done by the use of human hand to wrap or tie ropes.

2.1     MATERIALS FOR FABRICATION AND THEIR PROPERTIES
Engineering materials includes wood, metal, rubber and ceramics. Wood is one of the earliest engineering materials. It has a complex structure and is compound mainly of cellulose and lignin. Some 15% wood structures are made up of starch, resins, gums, wares, tannins and little amount of organic acid.
In fabrication, there are two types of wood: hard and soft wood. Hard woods are deciduous woods. They are dicotyledons and they have board leaves and their seeds are in enclosed structure and have widely varying properties. Examples includes Mahogany, Oak Abara, white and Black Afara and Iroko. Examples of soft wood are somidoloro fir, pines.
In comparison, the distinguishing features between hard wood and metal from other Engineering materials by considering their physical / mechanical and other properties in that metal are opaque, and can be polished to give a very string surface. Most metals are considerably heavier than other Engineering material, although some ceramics, like concrete, rock, glass factory bricks are heavier than some very light metals like magnesium. Metals are of two board groupings: ferrous and non – ferrous metals examples of ferrous metals are Iron, Alloy steel, stainless steel and tool steel, Brass, copper, zinc, etc. are examples of non – ferrous metals. Non ferrous metals are classified according to what special properties they posses and how they occur. This can be summarized as follows:
Classification                          Elements
Heavy                            Copper, Nickel, Lead, Zinc and Tin
Light                     Aluminum, Mg, Be, Lit, Ca, K.
Noble                             Gold, Silver, Platinum, Indium.
Minor                             Antimony, Cadmium, Mercury
Refractory                       Molybdenum, Tantalum, Vanadium
Rare - Earth                   Scandium, Lanthanum.
Ferro – Alloy                 Chromium, Manganese.

SELECTION OF MATERIALS
Ferrous metals are usually alloyed, and this is summarized as follows:

Types of steel       % Carbon           Application
High carbon
Galvanized steel             0.6 – 15                Structure
Spring
Medium carbon              0.3 – 0.6               Frame
Body / frame  High speed steel                      0.3 – 1.68             Files, and