Clamshell factory processing plastic box (also known as packaging) principle:
Vacuum forming

Vacuum forming is a plastic sheet thermoforming method.
pvc or pet or ps plastic sheet softened by heating an electric furnace,
A pressure by vacuum forming plastic,
Softened deformed cover attached to the vacuum forming mold,
After cooling setting demoulding
Trimming and cutting edge.

Plastic vacuum forming
It is currently the most widely used and die for the cheapest kind thermoforming process.
Just plastic injection molding mold fee of 5%
Mold sampling to cross item as long as 7-15 days

Vacuum forming principle exploded view below: