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Polymer Forming Processes
Prepared byAssociate Prof. Mohamed Ahmed Awad
Cairo, 2014
Polymer Forming Processes
Raw Materials
Polymer Products
• Extrusion
• Injection
• Blow
• Compression
• Vacuum Moulding
Extrusion Animation
5
Prepared by Dr. Mohamed Ahmed Awad
Extrusion
6
Prepared by Dr. Mohamed Ahmed Awad
Injection moulding Animation
7
Prepared by Dr. Mohamed Ahmed Awad
Injection Molding
8
Prepared by Dr. Mohamed Ahmed Awad
Blow moulding Animation
9
Prepared by Dr. Mohamed Ahmed Awad
Extrusion blow-molding
10
Prepared by Dr. Mohamed Ahmed Awad
Blow moulding Steps
Extruderair injector
Part isremoved
Airblowninto
parison
Moldhalvesclose
Moltenparison isextruded
Extruderair injector
parison
Compression mouldinganimation
12
Prepared by Dr. Mohamed Ahmed Awad
Compression Molding
13
Prepared by Dr. Mohamed Ahmed Awad
14
Prepared by Dr. Mohamed Ahmed Awad
Vacuum Forming
16
Prepared by Dr. Mohamed Ahmed Awad
Review QuestionsReview Questions
Describe the polymerextrusion process Plastic granules are fed from a hopper on to a
rotating Screw. The screw forces the plastic through a heated
tube where it becomes molten before beingforced under pressure through a die.
The die contains a hole whose shapecorresponds to that of the required Article.
As it leaves the die, the 'extrusion' is cooled in awater bath or In jets of air.
Prepared by dr. Mohamed Ahmed Awad١٩
Plastic granules are fed from a hopper on to arotating Screw.
The screw forces the plastic through a heatedtube where it becomes molten before beingforced under pressure through a die.
The die contains a hole whose shapecorresponds to that of the required Article.
As it leaves the die, the 'extrusion' is cooled in awater bath or In jets of air.
Draw the Extrusion machine
Prepared by dr. Mohamed Ahmed Awad٢٠
Describe the polymer formingusing blow molding process
The required material is extruded Air is blown into a section of extruded
plastic tube, causing it to expand andtake up the shape of the mould.
The mould is opened The part is removed.
Prepared by dr. Mohamed Ahmed Awad٢١
The required material is extruded Air is blown into a section of extruded
plastic tube, causing it to expand andtake up the shape of the mould.
The mould is opened The part is removed.
Blow Molding steps
Extruderair injector
Part isremoved
Airblowninto
parison
Moldhalvesclose
Moltenparison isextruded
Extruderair injector
parison
Prepared by dr. Mohamed Ahmed Awad٢٣
Describe the polymer injectionmolding process An injection molding machine is similar to that
used for extrusion. The screw is moved backwards, as it rotates,
until a measured quantity of plastic is at positionA in the diagram.
The screw is then driven forwards by ahydraulic ram, forcing the molten plastic into themould.
The mould consists of two or more parts whichfit together forming a cavity of the requiredshape.
After a short time the mould can be opened andthe molding removed. The complete cycle canthen be repeated.
Prepared by dr. Mohamed Ahmed Awad٢٤
An injection molding machine is similar to thatused for extrusion.
The screw is moved backwards, as it rotates,until a measured quantity of plastic is at positionA in the diagram.
The screw is then driven forwards by ahydraulic ram, forcing the molten plastic into themould.
The mould consists of two or more parts whichfit together forming a cavity of the requiredshape.
After a short time the mould can be opened andthe molding removed. The complete cycle canthen be repeated.
Prepared by dr. Mohamed Ahmed Awad٢٥
Describe the Compressionmolding In compression molding, huge forces are
used to squeeze polymer into moulds.
The polymer can be in the form of apowder or 'slug'.
Compression molding is used forthermosetting plastics.
Prepared by dr. Mohamed Ahmed Awad٢٦
In compression molding, huge forces areused to squeeze polymer into moulds.
The polymer can be in the form of apowder or 'slug'.
Compression molding is used forthermosetting plastics.
Prepared by dr. Mohamed Ahmed Awad٢٧
Describe the Vacuum molding
This processes is used to make articlesfrom thermoplastic sheet.
A heater then raises the temperature ofthe sheet until it becomes soft
Finally, air is evacuated from beneaththe sheet, which allows the normal'outside' air pressure to push down onthe softened sheet, forcing it to take upthe shape of the mould.
Prepared by dr. Mohamed Ahmed Awad٢٨
This processes is used to make articlesfrom thermoplastic sheet.
A heater then raises the temperature ofthe sheet until it becomes soft
Finally, air is evacuated from beneaththe sheet, which allows the normal'outside' air pressure to push down onthe softened sheet, forcing it to take upthe shape of the mould.
Prepared by dr. Mohamed Ahmed Awad٢٩
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