ABSTRACT

          A mould can generally be defined as a pattern constructed for the production of the same shape and size.  The constructional material differs from one operation to another.  When one considers the money at hand, he decides whether to start from the primary production level or secondary production level.  Referring to the project, the aim is for the establishment of small-scale production.  This would employ the use of the manual soap cutters, which is either used to cut the soap produced into bars or tablets depending on specification.

          In the construction works flat hard woods of 20m thickness were cut and assembled by nailing.  The constructed woulds have the following dimensions : 15cm long, 38cm wide and 15cm high.

The moulds are rectangular in shape.  Handles was incorporated in the mould to make it convenient to be carried about during soap production.

          Finally, the five moulds produced were capable of presenting relatively resistance to impact and bending forces as a result of the hard wood that was used.  With this the moulds can carry a reasonable volume of soap Surry without collapsing.

TABLE OF CONTENTS

CHAPTER ONE

INTRODUCTION

TYPES OF MOULDS

MOULDS FOR THERMOSETTING POLYMERS

MOULDS FOR THERMOPLASTICS

USES OF MOULDS IN INDUSTRIES

IMPORTANCE OF MOULD INDUSTRIES

CHAPTER TWO

LITERATURE REVIEW

TYPES OF MOULDING

NOULDING OF PLASTICS AND ELASTOMERS

CHAPTER THREE

MATERIAL SELECTION

PLASTICS AS CONSTRUCTION MATERIAL

PROPERTIES OF ENGR MATERIALS

WOOD AS A CONSTRUCTION MATERIAL

FACTORS TO CONSIDER IN SELECTION OF MATERIALS

CHAPTER FOUR

FABRICATION PROCEDURE

TOOLS FOR CONSTRUCTING MOULDS, TABLE AND CUTTERS

CONSTRUCTION METHOD

SAFETY PRECAUTONIS

CONSTRUCTION OF CUTTERS AND TABLE

CHAPTER FIVE

DISCUSSION

CHAPTER SIX

COST EVALUATION

CHAPTER SEVEN

CONCLUSION

CHAPTER EIGHT

RECOMMENDATION

REFERENCES

CHAPTER ONE

INTRODUCTION

          The equipment mostly used or applied in the industries and manufacturing setups requiring the production of definite patterns, shapes and different designs, embossments and others, are usually moulds.

The moulds used for the numerous types of plastic and the several types of moulding methods in commercial use constitute a controlling factor in the molding industry.  The most advantageous utilization of both plastic and molding equipment requiring a properly designed and constructed mould.

The application of moulds depends on its ability to withstand pressure, corrosion and distortion.

          Mould can be defined as a pattern constructed for the manufacture of the same protype.  The material of construction of moulds varies from one operation to another.  The need for the designing and development of moulds of different materials, composition, texture, shape, resistance arises as a result of the diverse application of moulds in manufacturing industries.

Early moulds were used by blacksmiths in construction and designing materials of different shapes and sizes.  Moulds basically consists of a cavity and a plunger, or force.  Most moulds also include an ejection mechanism for removing the moulded article.

TYPES OF MOULDS

          Moulds can be divided into four general group or classes: prototype, hand, semiautomatic and automatic moulds.  The best type to be used depends on the product design, moulding material, equipment available, production requirement and economic factors.

1.      PROTOTYPE MOULDS

They are used when a limited number of items is to be produced, as for example, for the evaluation of a new product.  These moulds are made from easily machined metals or from casting materials, and the molds details are assembled into supporting frames.

2.      HAND MOULDS

Are the oldest type of moulds, and can be constructed in either simple or sophisticated designs.  They must be removed from the press for loading and unloading are used for short production runs or for designs requiring many inserts and complicated coring geometly.  Use of hand moulds results in higher labour cost, lower production rates, and thus high unit cost than those for the used of semiautomatic and automatic molds.

3.      SEMIAUTOMATIC MOULD

They are mounted into a press for the duration of a production run.  The moulded part is automatically ejected from the cavity as the press opens, but an operator is required to load the moulding material, actuate press control for the moulding sequence, and remove the piece from the mould this method is widely used for all types of moulding.

AUTOMATIC MOLDS:   This include additional mechanical component such that, when the mould is mounted in press, the complete operation sequence from the time the material is loaded until the completed parts are discharged from the mould is carried out automatically.

Automatic moulds offer the most economical approach to long production runs, because labour cost are kept to a minimum and all moulding approach or operations are accurately controlled.  The thermoplastics can be moulded at rate up to 700 cycles/hr and thermosetting polymers at up to 450 cycles/hr tooling must be of the highest quality to meet the exacting demands of high speed production.

MOULDS FOR THERMOSETTING POLYMERS

          Thermosetting polymers are commonly moulded by either compression or transfer moulding.  In compression moulding, moulding material of a specified weight or volume, as either powder or perform, is placed in a displacement cavity; single or multiple cavity moulds may be used.  The press has a stationary platen and a moving platen actuate to close the mould and to maintain pressure and heat on the moulding material for the time necessary to form and cure the part.  Excess materials flows out of the cavity at the parting line of the mould to form flash, which must be removed by auxiliary operation.

In transfer moulding, the moulding material is preformed to a particular size and then into a chamber to tube from which it is moved through a runner and gate system into a closed cavity and lunger sections of the mould.  This method makes it possible the mould of foagile and delivate designs, inserts, and deep holes of small diameters.

Single or multiple cavity may be employed.  Ordinarily, parts made in this process have little or not flash at the parting lines.  Cycling is more efficient, tool life is long (except in areas where high wears is caused by abrasion through runner and gates), and fewer auxiliary operations for hole forming are required than is compression moulding.  In most cases a degating operation.

          Generally, the material required for a given number of parts is greater than for compression moulding owing to the transfer runner system.  However, in most cases, this is offset by greater moulding efficiencies; in other cases, the product design could be realized except by this method because of the high cost of operations that would be required if compression were used.  Ordinarily, values of physical properties furnished by suppliers are those of compression moulded specimens, these values are often lower for transfer mouldings, materials suppliers’ recommendation should be consulted on this point in designing equipment.

TRANSFER MOULDS

          Transfer mould are usually of the flash type since no extra loading space is required.  Two basic mould arrangements are utilized for transfer moulding, with modifications to suit a particular moulding or equipment.  The older of the two is integral, or pot-type, transfer.  The mould cavities and plungers are similar to those of a flash mould, but includes gates, runners, and transfer chamber.  The transfer chamber is above the cavity the area of the transfer chamber normally must exceed the total cavity area (including the sprues and runners) by at least 25% to ensure that the mould does not open during the moulding cycle.

MOULDS FOR THERMOPLASTICS

Thermoplastic material are commonly moulded by injection moulding, material is fed froma hopper into a heating chamber where a double acting plunger forces the material from the cylinder through a nozzle and a system of runners and gates into the cavity.  Single cavity moulds eliminate the runner system.

The first stage of two stage plunger injection is similar to single stage plunger injection except that instead of flowing directly into the mould, the material flow into a second stage chamber, normally for transfer moulding.

Equipment available for transfer moulding includes (a) Heat transfer (b) Integral floating pot transfer.  In this method conventional single movement presses may be used with the mould designed for transfer moulding.   (c) plunger, or top-ran transfer.  This moulding equipment has a main cylinder to actuate the mould opening and closing, and an independent cylinder for forward and return strokes of the transfer plunger to move the moulding material from the transfer chamber through the runner and gating system into the mould cavity.

There are many variations of this equipment in which the plunger cylinder may be mounted at the top or bottom of the press in some cases horizontal plunger cylinders may be employed for special application.

Compression Moulds

There are several basic types of moulds designed in use for compression mould.  In flash mould a charge of predetermined weight or volume is placed directly into the mould cavity and the moulding formed under pressure and heat.  Excess materials flows horizontally away from the closed cavity into clearance area between the stationary and moving halves of the mould.  The excess material or flash, requires finishing operations to remove it from the moulded part.  Single or multiple cavity mould may be used.  This design may be used for all general types of mould materials of larger capacity, from which a double acting plunger transfers the material into the mould.  This system improves plasticizing of the material, improves control of metered weight, and makes possible a machine of large capacity.

The  reciprocating screw system employs a screw to mix and melt material in a cylinder.  After the material is melted it builds up in front of the screw tip, forcing screw to retract; the revolving motion stops and the screw becomes the plunger with a forward motion which moves the material into the mold.

Hand, semiautomatic, or automatic moulds may be used in injection moulding.

USES OF MOULDS IN THE PRODUCTION INDUSTIRES

1.           The metallurigical industries uses mould patterns for different casting operation and application for the production of metal blocks, building blocks etc.   It is also sued in production of both industrial and household plastics ware moulds are used.

2.           The food industries uses moulds processes for their production.  Production of brick, cake and other confflectionary products is usually a mould patterns process.

3.           Mechanical Engineers uses mould set ups for the production of different parts of machines with intricate shapes that cannot be conveniently manufacture on a lathe.

4.           Mould is also used in candle making industries.  This has resulted increase in candle production activities.

5.           In building technology, mould is used in the production of blocks and bricks needed for building construction.

6.           In pharmaceuticals industries, ninety percent (90%) of the tablets drugs of different shape and texture are made using mould system process.

7.           Lastly, moulds are highly needed in soap making industries for the production of both bar and tablets soaps.

IMPORTANCE OF MOULD MANUFACTURING INDUSTRIES

          Setting up of moulds manufacturing industries in any country has a lot of economic benefits attached to it.

1.           The high foreign exchange cost spent in the importation of moulds and different machines could be saved and used for other developmental projects.

2.           Establishing mould manufacturing industries will go a long way in providing job opportunities for the increasing number of unemployed citizens thereby reducing the high crime rate associated with unemployment.

3.           This will encourage proper harnessing of abundant metallic ores deposited in different part of the nation.

4.           This will serve as source of income for the nation.  Thus turning her from an importer of moulds to exporter of moulds.

5.           These mould industries will help in manufacture of high texture and corrosive resistance mould that would serve efficiently in accordance with climate condition of the nation.

6.           This will encourage the production of different spare parts of machines previously abandoned in many industries due to the lack of spare parts or high cost of their importation.

7.           Lastly, setting up mould producing industries will have a positive effect on all facts of projects associated with lack of spare parts and accessories.

TABLE

A table is one of products of furniture makers.  The general term furniture has wide meanings but from the standpoint of the cabinet makers, furniture was classified into four classes as follows:

Supporting unit, which include tables, desks, writing fitments.

Seating units, like chairs, stools, settees etc

Reclinding units: like Beds, Divans etc

Storage units: like cabinets, side boards, wood robles and bookcases.

The normal height of any working top in the seated position is between 28½ in (720m) to 29 in (73.5cm) with chair seats 10½ in (27cm) to 11½ (29cm) lower.

TYPES OF TABLES

(1)      Refectory tables:   They have long narrow trestle type table with fixed tops used in dimming room in the middle ages.

(2)      Extending tables:  They incorporate same form of lengthening top for additional sitters, of which the type is the draw leaf extension table dating from the 15th century and still one of the most popular form. Examples are boardroom and conference tables.

(3)      Pedestal tables:              They are usually circular or D – end and are supported by a central podium or pillar terminating in three or four legs.

(4)      Sofa tables: They are rectangular tables with draws or the long side and small flaps at the end supported by brackets.

(5)      Coffee tables:        This is originally small and circular tables with tray type logs, but now embracing a wide a range of low occasional tables.

(6)      This will encourage the production of different spare parts of machines previously abandoned in many industries due to the lack of spare parts or high cost of their importation.

(7)      Lastly, setting up mould producing industries will have a positive effect on all facts of projects associated lack of spare parts and accessories.

This material content is developed to serve as a GUIDE for students to conduct academic research