fabrication of plastics

Fabrication of plastics: Injection Moulding, Blow Moulding:

Presented by, Praveen.M BTE-09-043 Fabrication of plastics: Injection Moulding, Blow Moulding

CONTENTS :

Plastics Types of plastics Fabrication of plastics Moulding Injection Moulding Blow Moulding CONTENTS

PLASTICS:

Plastics are synthetic organic materials which can be moulded into any desired shape when subjected to heat and pressure. Plastics are compounds of carbon with other elements such as oxygen, hydrogen and nitrogen. The carbon combines with itself and other elements and forms more complicate compounds. PLASTICS

TYPES OF PLASTIC:

Plastics are broadly classified into Thermoplastics Thermosetting plastics Thermoplastics: Plastics which can be remoulded are called thermoplastics. E.g. Polyethylene, Polystyrene Thermosetting plastics: Plastics which cannot be remoulded are called thermosetting plastics. E.g. Polyester TYPES OF PLASTIC

FABRICATION OF PLASTICS:

1) The process of making various products of plastics is known as fabrication of plastics . 2) Methods used in the fabrication of plastics 1 . Moulding 2. Calendaring 3. Casting and 4. Laminating FABRICATION OF PLASTICS

INJECTION MOULDING:

INJECTION MOULDING

INJECTION MOULDING:

Injection moulding is a manufacturing process for producing parts from both thermoplastic and thermosetting plastic materials . Injection moulding is the most common method of part manufacturing . It is ideal for producing high volumes of the same object . It is a fast process and is used to produce large numbers of identical items from high precision engineering components to disposable consumer goods. INJECTION MOULDING

PROCESS OF INJECTION MOULDING:

Material is introduced into the injection moulding machine via a Hopper. The injection moulding machine consists of a heated barrel equipped with a reciprocating screw, which feeds the molten polymer into a temperature controlled split mould via a channel system of gates and runners. The screw melts the polymer, and also acts as a ram during the injection phase. PROCESS OF INJECTION MOULDING

PROCESS OF INJECTION MOULDING:

The screw action also provides additional heating by virtue of the shearing action on the polymer. The polymer is injected into a mould tool that defines the shape of the moulded part. The pressure of injection is high, dependant on the material being processed; it can be up to one thousand atmospheres. PROCESS OF INJECTION MOULDING

TYPES OF INJECTION MOULDING:

TYPES OF INJECTION MOULDING Co-injection (sandwich) moulding Fusible (lost, soluble) core injection moulding Gas-assisted injection moulding In-mould decoration and in mould lamination Injection-compression moulding Insert and outsert moulding Lamellar (micro layer) injection moulding Low-pressure injection moulding Metal injection moulding Microinjection moulding

BLOW MOULDING:

BLOW MOULDING

BLOW MOULDING:

Blow moulding, also known as blow forming, is a manufacturing process by which hollow plastic parts are formed . It is a process used to produce hollow objects from thermoplastic . In general, there are three main types of blow moulding: extrusion blow moulding, injection blow moulding, and stretch blow moulding . BLOW MOULDING

TYPES OF BLOW MOULDING:

Extrusion blow Moulding Injection blow Moulding Stretch blow Moulding TYPES OF BLOW MOULDING

EXTRUSION BLOW MOULDING:

In this type of blow moulding the molten plastic is moulded by squeezing it out by applying pressure. The molten polymer is led through a right angle and through a die to emerge as a hollow (usually circular) pipe section called a parison . When the parison has reached a sufficient length a hollow mould is closed around it . EXTRUSION BLOW MOULDING

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The mould mates closely at its bottom edge thus forming a seal . The parison is cut at the top by a knife prior to the mould being moved sideways to a second position where air is blown into the parison to inflate it to the shape of the mould . After a cooling period the mould is opened and the final article is ejected.

INJECTION BLOW MOULDING:

Injection blow moulding is used for the Production of hollow objects in large quantities . The Injection blow moulding process produces bottles of superior visual and dimensional quality compared to    extrusion blow moulding . The process is ideal for both narrow and wide-mouthed containers and produces them fully finished with no flash. INJECTION BLOW MOULDING

PROCESS:

The injection blow moulding process is divided into three parts. They are Injection Blowing Ejection PROCESS

STRETCH BLOW MOULDING:

Stretch blow moulding is the method of producing a plastic container from a preform or parison that is stretched in both the directions when the preform is blown into its desired container shape . Stretch blow moulding is possible for various thermoplastic materials. With the commercial introduction of containers, stretch blow moulding became a common term in the blow moulding industry. STRETCH BLOW MOULDING

PROCESS:

Injection: Molten polymer flows into the injection cavity via the hot runner block, to produce the desired shape of the PREFORM with a mandrel (the core pin) producing the inner diameter and the injection cavity the outer. After a set time the injection moulds and core pins part and the preform held in a neck carrier is rotated 90º . Stretching & Blowing: Once conditioned to the correct temperature the preform is ready for STRETCHING and BLOWING to the finished shape . PROCESS

PROCESS:

Once the preform is within the BLOWMOULD area the moulds close, a stretch rod is introduced to stretch the preform longitudinally and using two levels of air pressure, the preform is blown circumferentially. Discharge: After a set time for cooling the moulds open and the preform is removed via drop chutes or robotics. In practice the four stages are carried out concurrently using a revolving carousel of moulds. PROCESS

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