Rotational Molding

Rotational molding, also known as rotomolding or centrifugal casting, involves filling a mold cavity, generally with powder, and rotating th...

Blow Molding

Blow molding is a technique for forming nearly hollow articles and is very commonly practiced in the formation of PET soft-drink bottles. It...

Thermoforming

Thermoforming is the heating of a thermoplastic sheet until it is soft and stretchable and then forcing the hot sheet against the contours o...

Two-Shot Injection Molding

Two-shot or overmolding refers to a process whereby either different colors or different materials are molded into one part. In this process...

Coinjection Molding

Coinjection molding refers to a process whereby two materials are injected into the same cavity. The first material is injected into the cav...

Gas-Assisted Injection Molding

In gas-assisted injection molding the mold is partially filled with polymer, followed by a gas, which presses the polymer out to the surface...

Lost-Core Process

Products that are hollow or contain complex undercuts can be fabricated using the lost-core process as illustrated in Fig. 1.24. Core materi...

Injection/Compression Molding

Injection/compression molding refers to the process wherein the cavity is not completely filled during injection of the resin. In this proce...

Injection Molding

Injection molding is a widely used process to produce parts with variable dimensions. An injection molding machine consists of the following...

Extrusion

In extrusion operations, a solid thermoplastic material is melted, forced through an orifice (die) of the desired cross section, and cooled....

Processing of Thermoplastics

Processing involves the conversion of the solid polymer into a desirable size and shape. There are a number of methods to shape the polymer,...

Rheological Properties

Viscosity is the resistance to flow. As shown in Table 1.5, polymer melts have viscosities of 100 to 1,000,000 Pa-s, whereas water has a vis...

Effect of Fillers

The term fillers refers to solid additives, which are incorporated into the plastic matrix.7 They are generally inorganic materials and can ...

Failure Behavior

The design of plastic parts requires the avoidance of failure without overdesign of the part, leading to increased part weight. The type of ...

Viscoelasticity

Polymer properties exhibit time-dependent behavior, meaning that the measured properties are dependent on the test conditions and polymer ty...

Mechanical Properties

The mechanical behavior of polymers is dependent on many factors, including polymer type, molecular weight, and test procedure. Modulus valu...

Crystallization and Melting Behavior (Tm)

In its solid form, a polymer can exhibit different morphologies, depending on the structure of the polymer chain as well as the processing c...