Producing paper-like thin plastic articles (e.g., trays, cups, shells): which forming process is typically used on heated thermoplastic sheets?

Introduction / Context:
Thin-wall, paper-like plastic articles such as disposable trays, clam shells, and cups are produced by shaping heated sheets over moulds. Selecting the right process is key for economics and wall-thickness control.

Given Data / Assumptions:

• Articles are thin, shallow, and made from sheets (PS, PET, PVC, PP, etc.).
• High production rates and low tooling cost are desirable.

Concept / Approach:
Vacuum thermoforming heats a thermoplastic sheet to its softening range and draws it onto a mould using vacuum. It is ideal for producing large numbers of thin, lightweight parts with modest draw ratios. Blow moulding forms hollow bottles from parisons, not shallow sheet parts. Injection moulding fills closed moulds with melt—excellent for complex 3D parts but less economical for broad, thin shells when sheet stock is practical.

Step-by-Step Solution:
Identify geometry: thin, open, tray-like.Match to sheet-based process: vacuum thermoforming.Exclude blow and injection moulding due to mismatched part geometry and economics.

Verification / Alternative check:
Packaging lines for cups and trays predominantly use thermoforming machines fed with extruded sheets.

Why Other Options Are Wrong:
Blow moulding: for hollow containers.Injection moulding: viable but often less efficient for broad, thin shells vs thermoforming.

Common Pitfalls:
Assuming all high-volume thin parts are injection moulded; sheet forming dominates for trays and cups.

Final Answer:
Vacuum thermoforming