1. POLYMER MANUFACTURING PROCESSES

2. COMPRESSION MOULDING Benefits of Compression Moulding
•Cost effective tooling
•Maximized cavity count
•Economical process for medium precision
Compression moulding can be a cost effective solution in situations where:
1.The tooling already exists
2.The cross-section of the part is very large and requires a long cure time

3. INJECTION MOULDING Advantages of injection molding:
1.The complete elimination of pre-forms
•The production and need for pre-forms is a labor intensive step that can potentially affect the finished product through variability in pre-form weight and shape.
2.Elimination of operator placement of pre-forms.
•Since pre-forms are eliminated, the need for operators to place the pre-forms in a cavity (compression molding) or pot (transfer molding) is removed.
3.Injection screw pre-heats material before forcing it into cavities
•This process decreases the viscosity of the material, allowing it to flow more easily into the cavities.
•This pre-heating provides the potential for decreased cure times through
1.More rapid cavity filling due to lower viscosity
2.Material already being in the curing process through the heat added during screw charging and shear created during injection
4.Reduced cycle time
5.Flashless tooling
6.Economical process for high volumes of medium to high precision components
7.Capable of producing overmolded components
8.Minimal material waste

4. VACUUM FORMING Advantages:
•Very low tooling costs (compared to injection or blow moulding)
•Short lead time (able to move from concept to production rapidly)
Disadvantages:
•Webs form around the mould, which is due to overheating the plastic and so must be carefully monitored.
•Webbing can also occur when a mould is too large or parts of the mould are too close together.

5. ROTATIONAL MOULDING
parts assembled from several pieces can be molded as one part, eliminating high fabrication costs
consistent wall thickness and strong outside corners that are virtually stress free
reinforcing ribs can be designed into the part
The ability to add prefinished pieces to the mold alone is a large advantage. Metal threads, internal pipes and structures, and even different colored plastics can all be added to the mold prior to the addition of plastic pellets
require less tooling, they can be manufactured and put into production much more quickly than other molding processes

6. EXTRUSION Advantages Continuous High production volumes
Low cost per pound
Efficient melting
Many types of raw materials
Good mixing (compounding)
Disadvantages
Limited complexity of parts
Uniform cross-sectional shape only

7. BLOW MOULDING http://www.youtube.com/watch?v=NE4c1gwzPb4
Advantages of Blow Moulding
Well suited to low and high production rates
Outperforms metal counterparts in high speed impact tests
Many types of materials to choose from
Quick product revisions for increased flexibility
Plastic parison formed process to make hollow parts
Tooling is less expensive than Injection Moulding
Each part price is less than Rotational Moulding (faster cycle)
One piece construction (no need to connect part halves)
No cores allow for irregular shapes
Excellent ESCR (environmental stress crack resistance)
Aluminium tools are less costly
Choice between single and double walled construction
Single part replace prior several individual components
Excellent part performance under pressure
Trim and flash reusable into finished parts