B --> B1[Injection Moulding]
B --> B2[Blow Moulding]
B --> B3[Extrusion]
C --> C1[Machining]
C --> C2[Welding]
C --> C3[Assembly]
C --> C4[Surface Finishing]
style A fill:#f9f,stroke:#333,stroke-width:2px
style B fill:#bbf,stroke:#333,stroke-width:2px
style C fill:#bbf,stroke:#333,stroke-width:2px
graph TD
A[Plastic Processing Methods] --> B[Primary Processes]
A --> C[Secondary Processes]