Evaluation of Plastic Waste Management in Thailand Using Material ...

Vacuum forming: A vacuum is formed between the mold cavity and the
thermoplastic sheet. The vacuum pressure (typically 14 psi) forces the
sheet to conform to the mold and form the part shape. Figure 2.7 shows
the vacuum forming method.
Figure 2.7 Vacuum forming (CUSTOMPART.NET, 2013)
Pressure forming: In addition to utilizing a vacuum underneath the
sheet, air pressure (typically 50 psi, but up to 100 psi) is applied on the
back side of the sheet to help force it onto the mold. This additional
force allows the forming of thicker sheets and creating finer details,
textures, undercuts, and sharp corners. Figure 2.8 shows the pressure
forming method.
Figure 2.8 Pressure forming (CUSTOMPART.NET, 2013)
Mechanical forming: The thermoplastic sheet is mechanically forced
into or around the mold by direct contact. Typically, a core plug will
push the sheet into the mold cavity and force it into the desired
shape. Figure 2.9 presents the mechanical forming method.
10