23 Questions
What type of extruded product is produced using a die configuration for shaping hollow sections?
Tubes and pipes
What is the cause of 'melt fracture' in extrusion, as described in the text?
Turbulent flow through the die entrance
What type of extruded product is produced using a slit-die in the extrusion process?
Sheet and film
What is the purpose of a chill-roll in extrusion for sheet and film production?
To cool and solidify the extrudate
What are the characteristic properties of a foamed polymer mentioned in the text?
Low density and high strength per unit weight
Which type of polymer foam has a matrix polymer that is a rubber?
Elastomeric foam
What are some common gases used in polymer foams?
Air, nitrogen, and carbon dioxide
How is mixing a physical blowing agent with the polymer different from mixing a liquid resin with air?
The physical blowing agent dissolves in the polymer melt under pressure
What is the function of die swell in polymer melts?
To increase viscosity
Which process involves the shape of the die orifice determining the cross-sectional shape of the extrudate?
Extrusion
In extrusion, what does the typical pressure gradient in an extruder represent?
Approximation line for computations
What is the primary function of an extruder screw inside the barrel?
Mix and transport polymer melt
At what shear rate is viscosity typically evaluated for selected polymers?
$10^3$ s$^{-1}$
Which shaping process is associated with blow molding and rotational molding?
Thermoforming
Which process involves inflating a soft polymer to conform to a blow mold?
Stretch blow molding
In thermoforming, what happens to the plastic sheet placed over a concave mold cavity?
It is vacuum drawn into the cavity
Which type of injection molding machine uses a plunger type alternative to the reciprocating screw?
Screw preplasticizer plunger type
What is the purpose of the blow pin in blow molding?
Inflating the parison
Which coating category involves coating an entire object by dipping or spraying?
Contour coating
What is the main difference between vacuum thermoforming and pressure thermoforming?
Use of vacuum
Which injection molding process involves injecting a preform molded around a blowing rod?
Injection blow molding
What does compression transfer molding entail?
Charging the pot with softened polymer and pressing it into a mold cavity.
Which material gives a porous or cellular structure to the polymer foam?
Polymer and gas mixture.
Learn about the three coating categories: wire and cable, planar, and contour coating. Also, understand the injection molding process and equipment involved in manufacturing. This quiz covers different coating methods and the stages of an injection molding cycle.
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