Production Of Aluminium Pots

ABSTRACT

The aim of this project is to produce aluminum pots through sand casting process.  The cast process involved drawing of element to be cast, making of pattern and core boxes, moulding of pattern, and core boxes, moulding or pattern, moulds assembling, melting of a metal pouring into the mould, solidification and cooling of metal in the mould cast knockout and separation of gate runner and riser, casting surface cleaning, removal of core. This process is use to produce metallic article (alloys) of desired shape, dimension, composition and specified properties from molten metal Poured into  a mould whose internal space (impression) reproduce the configuration and dimension of the cast article, with maximum accuracy.        

TABLE OF CONTENT

Title page

Certification

Dedication

Acknowledgement

Abstract

CHAPTER ONE

Introduction

CHAPTER TWO

2.0     Literature Review

2.1     Casting

2.2     Die Casting

2.3     Sand Casting

2.4     Sand

2.5     Types of sand mould

2.6     Quality of green sand

2.7     Pattern

2.8     Mould-making or production

CHAPTER THREE

3.1     Process taken  in production of Aluminium pots

3.2     Procedure for Heating the Metal Aluminium Pot

3.3     Pouring the molten metal (Aluminium) in the mould

CHAPTER FOUR       

4.0     Cleaning, Fettling and Inspection Method, Defects

4.1     Cleaning of Casting and Assessment

4.2     Fettling of Castings

CHAPTER FIVE

5.0     Conclusion and Recommendation

5.1     Conclusion

5.2     Recommendation

Reference

CHAPTER ONE

1.0     INTRODUCTION

Aluminium pots are made from Aluminium scap. The shape of the Aluminium pots yard according to the    purpose for which they are produced.

Hence there are various shapes of Aluminium pot such as cylindrical flat bottom pots spherical bowel pots e.t.c. In some cases means of production of the pots also determine their shapes.

The pots being reported on are spherical bowel pots and circular called the mouth joined together with a narrower neck. They also possess two EAR-LIKES Handle used. For lifting when loaded. The mouth is covered with a circular lead having a handle as its center.

The cast aluminum pot serves several functions its versatility accounts   for its popularity in  many local villages, households where it serves as the primary family cooking utensil, Normally it is suspended from a tripod itself is typically constructed of 75mm diameter tree limbs about two mm  long.

Prior to the usual of an aluminum reduction plant operation in the country. Local residents used pots made of Aluminum, which came from a distant place. It did not take long for the local entrepreneur to determine that a similar pot made of aluminum was much lighter, had much better heat transfer characteristic, and provided an improved and uniform thermal dispersion into the substance being cooked. These attributes are  important economics consideration where fuel is both scarce and expensive.

It is some what ironic that the formerly discarded and displaced cast iron pots are used as the pattern for the  sand  moulds made for casting  the aluminium. Such a cast iron pot used for pattern purposes is visible, which shows the  sand mould  being prepared.

The major aspect in preparation of aluminum cooking pot include preparation of sand, melting and pouring of the molten and finally into already prepared mould and finally the removal of the solicited casting from the sand and its dressing. After the metal had been poured the end product of the foundry operation is known as casting and may vary from a fraction of a kilogram to several tones. Various materials used in the furnace for the production of .aluminum cooking pot includes the materials that `can withstand very high temperature without causing any damage by heating. This materials as called refractory material such as crucibles used in the melting of aluminum scraps. Its should posses properties such as high mechanical strength and chemical stability at elevated temperature so as to withdraw the action of metabolic  melt oxide slag and fluxes.

The major aspect of preparation of aluminum cooking pot includes preparation of sand, melting.

Fire clay has sufficient mechanical strength and chemically stable to be used as a lining materials in furnaces for melting of aluminum scraps.

Fluxes are also added during melting of metal inform and control the composition of slag with the required physical and chemical  characteristics of the slag. Parting powder is also added to separate a content of moulding flask or boxes from one another. Surface dressing powder mould against the action of the molten metal and to help to produce good surface on casting.

Surface dressing powder used in the casting of aluminum cooking pot is talc, plumb ago and  coal dust can also be used.

CHAPTER TWO

2.0     LITERATURE REVIEW

          Aluminum Cooking pots is produced by sand moulding methods.

Casting been the process of producing metallic alloys of desired shape and dimension composition and of specific properties directly from a molten metal poured into a mould. Whose internal space or impression reproduces the configuration and dimension of the required cast article with maximum accuracy.

Hence, casting is widely used in making shaped and parts ranging from small elements to very large beds and housings. In many machine e.g (internal combustion engines) compressors and metal cutting engines tools.

The quality of a casting depends on its designs as well as manufacturing process especially in foundry.

Hence an important feature of foundry is it’s ability to generate different grades of the same materials. The theory and practice of metal casting at the modern stage permit the manufacture of articles with high workings length properties.

          This  is evidence by reliable operation of casting in jet engines and nuclear power plants.

The man tendency of progress in metal castings consist in improving the quality and can be realized in various ways for this reasons the designer must know the basic cast practices and the method for obtaining high quality castings at the minimum production costs.

2.1     CASTING

          Casting is a process of producing (Making) metallic articles (alloys) of desired shape and dimensions, composition and specified properties from molten metal poured into a mould, internal shape (Impression) of which reproduces the configuration and dimension of the required cast article with maximum accuracy.

The practice of casting is quite interesting and labourers because of the various sequential and simultaneous operations involved.

The type of casting available are die casting and sand casting

2.2     DIE CASTING

          Die casting is a metal casting process that is characterized by forcing  molten metal under high pressure into a mold cavity. The mould cavity is created using two hardened tool steel dies which have been machined into shape and work similarly to an infection mould during the process most die casting are made from non-ferrous metals, specifically zinc, copper, aluminium, magnesium lead, peerter and tin-based alloyed. Depending on the type of metal being cast, a hot-or  cold- chamber  machine  is used.

         Die casting are characterized by a very good surface finish (by casting standards)  and dimensional consistency.

2.3     SAND CASTING

The traditional method of casting metals is sand moulds and has been used for so many years. Sand casting is still the most prevalent from of casting in this types of casting, intricate shapes can be produced

Basically, sand casting consist of:

–        Placing a pattern (having the shape of the desire Casting) in sand to make an    imprint

–        Incorporating a gate system

–        Removing the pattern and from the mould

–        Filling the Cavity with molten metal

–        Allowing the metals to cool until it solidifies

–        Breaking away the sand mould.

–        Removing the casting

2.4     SANDS

          Sands suitable for use in foundry practice mostly occur in nature as sedimentary rocks composed of high melting, high temperature characteristics, sand casting operation use silica (co₂) as mould material

Sand is inexpensive and is suitable as mould materials, several factors are important in the selection of sand for moulds and it involvers certain trade offs with respect to properties.

Sand having time round grains can be  packed closely and this forms smooth mould surface. Although time grain sand enhance mould strength the fine grains also lower mould permeability (Penetrating through pores)

2.5     Types of sand mould

          Sand mould are characterized by the types of sand present in them and by the methods used to produce them. There are three basis types of sand moulds.

–        Green sand

–        Cold box

–        No baked moulds.

The most common mould material is green mould sand, which is a mixture of sand clay and water. The term “Green’ refers to the fact that the sand in the mould is moisture damp. While the metal is being poured into it. Green sand Mouldings is the least expensive method of making moulds and the sand is recycled easily for subsequent re-use than the skin dried method.

In the cold-box mould process, various organic and inorganic binders are blended into the sand to bond the grains chemically for greater strength. These moulds are more accurate dimensionally than green-sand moulds but are more expensive.

In the no-bake process, a synthetic liquid resin is mixed with the sand, the mixture hardens at l00m temperature. Both the cold- box mould and no-bake mould uses cold setting process because the bonding of the mould will take place without heat. For the casting of aluminum pots in this project, green sand is a good choice, It is preferable because of the draw backs of the other methods which are as follows:

1. Distortion of the mould is greater
2. The casting are more susceptible to hot tearing because of the lower collapsibility of the mould.
3. The production rate is lower because of the considerable drying time required.

Green-sand is cheaper to obtain, its moistures content can easily be controlled. Green sand contain a high percentage of silica and its binding agent for sand grains.

2.6 Qualities of Green Sand

This is the property of retaining the moulded shape while wet and after drying completely.

(i)      Refractoriness:- This is the property of the sand to resist heat.

(ii)     Collapsibility:- This is the ability of the mould sand to collapse after       casting. It must not be so hardened that it cannot be easily broken for re-use.

(iii)    Permeability:- When molten is poured into the mould gases are generated.        The property of the mould sand which allow gases generated to pass away     rapidly is permeability.

2.7 Major Features of Sand Moulds

1. The flask (Moulding boxes) is used for making sand mould, two piece flasks consisting of a cope on top and drag on the bottom. The drag is also split         into two equal part for easy removal of the pattern.
2. A pouring basin or cup is the space opening into which the molten metal is poured.
3. A sprue is a channel through which the molten flows downward.
4. Risers which supply additional molten metal to the casting as it shinks during solidification
5. Gates are inlets into the mould cavity
6. Vent is required to permit gases escape, use a vent wire to pieces the mould over the area of the pattern to create vent holes.

The vent holes should be deep enough but must not to touch the pattern.

The making of sand mould involves processes such as mixing and milling of sand, moistening, ramming, venting and drying

2.8     PATTERN

          Pattern is a replica of the object to be cast, it is  used to prepare the cavity into which molten material will be poured during the casting process.

Pattern are used  to mould the sand mixtures into the shape of casting and it may be made of wood, plastic or metallic materials. They are designed with a variety of features to fit specific application and Economic requirement.These are:-

–        Single pattern

–        Split pattern

–        Match-plate pattern

The pattern used in this project are the aluminium pots split pattern of  sizes is 15, 20, 30 and 40.

The patterns used are basically aluminium pot pattern of different size. Split patterns are use for sizes15, 20, 30 and 40  and then are feed with sand which are packed with hand into the pot are rammed to make placed inside the drag. Then facing sand is added to make the imprint more neater.  it will not allow the pattern to stick to the mould. Then the moulding sand is fed into the moulding box whereby the cope is placed on the drag to form a complete assembling of mould before pouring.

2.9     Mould-making or production

          Sand by nature and formation are of different grain sizes, ranging from lumps to powdered ones. The lumps need       to be changed from their real forms to a uniformly finely dispered form to allow for good casting operation.

During the process of production of the pots in the workshop where the operation was carried out, the hardened large lumps of sand are crushed with should to produces a fairly uniform gram size moulding includes the following procedures.

1. The rammer is a wooden block used for stamping the sand in the flasks to make it compact. The process is know as ramming in the wokshop, they use        crude tools for the preparation of moulds, from start to finish of casting sand    is properly mixed and large lumps of sand are broken by the shovel and hoe           and is properly sieved and mixed with shovel and hoes.
2. Prickling of vents (thin passage in the mould) which allows the escape of gases forms on metal pouring into mould cavity.
3. Withdrawal of the form the mould involves lifting the either side of the pattern gently then the pattern will freely be taken out. Ashes is added by   spraying it on the mould and core mixtures to act as binder to increases the   compatibility and plasticity was first removed.
4. Finishing and assembling of the mould including the setting of the core, after     drying the mould was assembled and ready for meal pouring.