Chapter 13
A three-plate mold offers which of the following advantages when compared to a two-plate mold (two best answers)
automatic separation of parts from runners, gating is usually at the base of the part to reduce weld lines
The term encapsulation refers to which one of the following plastics shaping processes
casting
The principal components of an injection molding machine are which two of the following
clamping unit, injection unit
Which of the following are sections of a conventional extruder barrel for thermoplastics (three best answers)
compression section, feed section, metering section
In rotational molding, centrifugal force is used to force the polymer melt against the surfaces of themold cavity where solidification occurs
false
The forward movement of polymer melt in an extruder barrel is resisted by drag flow, which iscaused by the resistance to flow through the die orifice
false
Which of the following defects or problems is associated with injection molding (three correct answers)
flash, short shots, sink marks
The two most common polymer foams are which of the following
polystyrene, polyurethane
The function of the ejection system is which one of the following
separate the part from the cavity after molding
The parting line in injection molding is which one of the following
where the two mold halves come together
Which of the following processes are associated with the production of plastic sheet and film (three correct answers)
blown-film extrusion process, calendering, chill-roll extrusion
A thermoforming mold with a convex form is called which one of the following
a positive mold
Use of a parison is associated with which one of the following plastic shaping processes
blow molding
Which of the following processes would be applicable to produce hulls for small boats (three best answers)
blow molding, rotational molding, vacuum thermoforming
