Manufacturing Homework Questions

Which one of the following is a type of machine used to perform extrusion?

press

Products purchased by companies to produce products or provide services are called which one of the following?

Capital goods

Which one of the following equipment types would usually be the least expensive to purchase and install to perform a given manufacturing process?

general purpose

Particulate processing of metals involves which two of the following steps?

pressing and sintering

Ferrous metals include which two of the following?

cast iron and steel

Which two of the following cost categories are considered to be variable costs rather than fixed costs?

direct labor and work material

Low-quantity production of large complex products is most closely associated with which one of the following layout types?

fixed-position layout

Which one of the following polymers can be subjected to multiple heating and cooling cycles without substantially altering its molecular structure?

thermoplastic polymers

Which one of the following is a property-enhancing operation?

heat treatment

Fixtures are commonly used as work-holding devices in which two of the following processes?

machining and welding

Which one of the following engineering materials is defined as a compound containing metallic (or semi-metallic) and nonmetallic elements?

ceramic

Assembly is defined as a manufacturing operation in which two or more parts are permanently joined to form a new entity (T or F)

False

Which two of the following are referred to as thin film deposition processes?

chemical vapor deposition and physical vapor deposition

A product’s total manufacturing costs typically constitute what proportion of the product’s selling price?

40%

Mining is classified as which one of the following industry categories?

primary industry

Which group includes only examples of generating the work part geometry in machining, as opposed to forming the geometry?

Contour turning, profile milling, and taper turning

A lathe can be set up to perform which group of machining operations?

Boring, drilling, and turning

Reaming is used for which group of functions

Enlarge a drilled hole, improve surface finish on a hole, and improve tolerance on hole diameter

When the drill bit in a drilling operation exits the opposite side of the work, the resulting hole is called which one of the following

A through hole

One definition of high-speed machining is the DN ratio, which means which one of the following

Bore diameter of the spindle bearing multiplied by the maximum spindle speed

A broaching operation is best described by which one of the following

A tool with multiple teeth moves linearly past a stationary work part

In its simplest definition, high-speed machining means using cutting speeds that are significantly greater than those used in conventional machining (T or F)

True

The most common type of drill bit is which one of the following

Twist drill

The three basic types of sawing, according to type of blade motion involved, are which group of the following

Bandsawing, circular sawing, and hacksawing

Spindle rotation speed N in milling is calculated using which one of the following equations, where v = cutting speed and D = diameter of the cutter

N = v/pi*D

The difference between up milling and down milling is that in down milling the direction of motion of the cutter teeth is opposite the feed direction when the teeth cut into the work (T or F)

False

A vertical milling machine is more appropriate than a horizontal milling machine for performing which group of operations

End milling, face milling, and surface contouring

In a turning operation, the change in diameter of the work part is equal to which one of the following

2 x depth of cut

A horizontal turning machine is typically used for work parts in which

The length is greater than the diameter

Which operations are classified as peripheral milling rather than face milling?

Plain milling, slab milling, and straddle milling

Compared to HSS and carbides, ceramic cutting tools are most vulnerable to

Fracture failure

The two basic types of high-speed steel are based on which alloying ingredients in steel

Molybdenum and tungsten

The two main functions of cutting fluids in machining are

Reduce friction at the tool-chip interface and remove heat

The die swell ratio for a polymer melt has a value that is never less than one (T or F)

True

A polymer melt exhibits which group of the following properties and characteristics

Becomes less resistant to flow as temperature increases, becomes less resistant to flow at high shear rates, high viscosity, and viscoelasticity

Viscoelasticity can be defined as the property of a material that determines the strain it experiences when subjected to combinations of stress and temperature over time (T or F)

True

The coefficient of shear viscosity is defined as which one of the following

Shear stress divided by shear rate

Of the following cutting conditions, which one has the greatest effect on tool wear

Cutting speed

Cast cobalt alloys typically contain which ingredients

Cobalt, chromium, and tungsten

An increase in cobalt content has which effects on WC-Co cemented carbides

Decreases strength and increases hardness

The basic Taylor tool life equation defines the relationship between which two of the following variables

Cutting speed and tool life

Which cutting fluid category provides the best lubrication

Cutting oils

Steel-cutting grades of cemented carbide typically contain

Co, TiC, and WC

Which are the most important properties of a tool material based on the three modes of tool failure

Hot hardness, toughness, and wear resistance

Polymer melts exhibit the property of viscoelasticity in the form of shape memory, which manifests itself as which one of the following in plastic extrusion

Die swell

Relative to conventional injection molding, injection pressures in structural foam molding are

Lower

Which one produces a smooth part surface

Sandwich Molding

The function of the ejection system in injection molding is

Remove the molded parts from the mold cavity after molding

Which defects are associated with injection molding

Flash, short shots, and sink marks

The parting line in injection molding is

Where mold halves open to remove the parts

Toggle-clamp units on injection-molding machines are most suited to which tonnages

Low

Which processes can produce small boat hulls

Blow molding, rotational molding, and vacuum thermoforming

In a reciprocating-screw injection molding machine, the injection of polymer melt into the mold cavity is accomplished by the rotation of the screw in the barrel (T or F)

False

Which factors will reduce shrinkage during solidification and cooling

Higher injection pressure, higher molding temperature, higher proportion of filler

Injection molding is a process in which a polymer is heated to a highly plastic state and forced to flow under high pressure into a mold cavity, where it solidifies and is then removed from the cavity (T or F)

True

In which properties do plastic parts compare favorably with metals

Impact resistance and strength-to-weight ratio

The principal components of an injection molding machine are which of the following

Clamping unit and injection unit

Injection molding can be used for elastomers, thermoplastics and thermosets (T or F)

True

The screw-preplasticizer machine is also known as

Two-stage machine

Reaction injection molding is used for which plastic type

Thermosets

Which processes are used to produce plastic sheet and film

Blown film extrusion, calendering, and chill roll extrusion

The forward movement of polymer melt in an extruder barrel is resisted by drag flow, caused by resistance to flow through the die orifice (T or F)

False

Extrusion is used for thermoplastics and elastomers but rarely for thermosets (T or F)

True

To compensate for die swell, the extrudate is often stretched to offset expansion (T or F)

True

A fiber is a long strand with length at least 100x its cross-section; a filament is continuous fiber (T or F)

True

The die characteristic indicates that flow rate through the die orifice increases as head pressure

Increases

Bambooing is a severe case of which defect

Sharkskin

Which one is not a function of the breaker plate and screen pack

Reduce the viscosity of the melt

The extruder characteristic indicates that flow rate in the extruder barrel increases as head pressure

Decreases

In dry spinning, the polymer is in solution and the solvent is removed by evaporation in a heated chamber (T or F)

True

Which sections are part of a conventional extruder barrel for thermoplastics

Compression section, feed section, and metering section

Turbulent flow through the die orifice is likely to cause which defect

Melt fracture

Extrusion is a compression process in which material is forced to flow through a die orifice to provide long continuous product whose cross-sectional shape is determined by the shape of the orifice (T or F)

True

Plastic sheet refers to stock thinner than 0.5 mm, film refers to thicker than 0.5 mm (T or F)

False

Drag flow of polymer melt in the extruder barrel increases as

Barrel diameter and screw speed increase