In this document Plastic and Polymer Composite - Fabrication Processes, there are many contents: injection molding (or compression or transfer), extrusion, thermo-forming, blow molding (injection blow molding with preforms or extrusion blow molding with parison), rotational molding (combination of 3 and 4).
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Nội dung Text: Plastic and Polymer Composite - Fabrication Processes
- Ch 6 METBD 470
Chapter 9 – Plastic and Polymer Composite
Fabrication Processes
1. Injection Molding (or compression or transfer)
2. Extrusion
3. ThermoForming
4. Blow Molding (injection blow molding with preforms or extrusion
blow molding with parison)
5. Rotational Molding (combination of 3 and 4)
- Ch 6 METBD 470
- Ch 6 METBD 470
Molding Processes for PE: Molding Processes for Nylon
(30% GF):
- Screen on batch size*
1e+008
Blow Moulding
Economic batch size
1e+007 Powder methods
Desired Injection Moulding
Batch Size
1e+006
Sheet forming
Expanded foam molding
Economic batch size (units)
1000 00
Rolling and forging
10000 Electro-discharge machining
Polymer Casting
Die Casting Sand casting
1000
Compression Lay-Up
Moulding methods
100 Rotational
Moulding
10 Resin transfer
molding (RT M)
1
T hermoforming Rapid
prototyping
Demo: the Process data-table
*Using the CES EduPack Level 2 DB © MFA and DC 2005
- Ch 6 METBD 470
You Tube Videos:
Blow Molding: http://www.youtube.com/watch?v=vSabFFQUr9E&feature=related
Extrusion: http://www.youtube.com/watch?v=kpPS6S_EB4Q
Injection:
http://www.youtube.com/watch?v=bitD1NnfjI&videos=BeAyHeQIsiY&playnext_from=TL&p
Thermoforming: http://www.youtube.com/watch?v=NPLWxxyIJcE
- Ch 6 METBD 470
• Injection Molding – most common (6070%)
– Process
Plastic pellets are heated in the injection unit and forced through a runner
system/gate(s) into a cavity in a mold.
Batch Process
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• Injection Molding
– Equipment
• Clamping Unit (Ejection System)
• Injection (Plasticating) Unit
• Frame
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• Injection Molding
–Main functions of Plasticating unit
1.Convey solid material/melt
1.Mix to produce homogeneous melt
1.Melt material
– Range of 300º F (PVC) to 740º F (Polysulphone)
1.Develop pressure for injection
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• Injection Molding
–Materials
•Both amorphous and semicrystalline are done easily
•Narrow molecular weight distribution
•With modifications to the equipment – thermoset materials and
liquid Silicone can be used
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• Injection Molding
–Parts
•Three dimensional
•Can be very complex
•Multiple cavitation is common (128 cavities)
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• Injection Molding
–Tooling Molds
•Generally steel, but some Aluminum tooling is used
•High pressure process – molds are ‘beefy’
– Plastic pressures around 30,000 psi
– Weight – LXWXH/4 (in inches)
•Tooling is expensive and can take a long time to create
- Ch 6 METBD 470
• Extrusion
–Process
Plastic pellets or powders are heated in a plasticating unit
and the melt is forced through a forming die.
Continuous Process
- Ch 6 METBD 470
• Extrusion
– Equipment
• Injection (Plasticating) Unit
• Frame
- Ch 6 METBD 470
• Extrusion
–Materials
•Both amorphous and semicrystalline are done easily
•Wide molecular weight distribution
- Ch 6 METBD 470
• Extrusion
–Parts
•Two dimensional
– Sheet
– Hoses
– Line
– Rod
– Vinyl siding
– Pipes
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• Extrusion
–Tooling Dies
•Generally steel – Aluminum is common though
•Low pressure process
– Tooling can be expensive
– Shorter lead times
- Ch 6 METBD 470
• Thermoforming
–Process
Sheet is heated and formed to the desired shape
Can be a batch or continuous process
Some consider Thermoforming to be a secondary process because the
material needs to be formed into sheet prior to being thermoformed.
- Ch 6 METBD 470
• Thermoforming
–Process
- Ch 6 METBD 470
• Thermoforming
–Process
- Ch 6 METBD 470
• Thermoforming
–Process
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