Manufacturing Processes Exam 2 Quizzes

We can decrease the amount of shrinkage in injection molding by
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We can decrease the amount of shrinkage in injection molding by
increasing the molding pressure

increasing the molding temperature

design a thinner wall
As we increase the shear rate applied to a polymer, we would expect the viscosity to
decrease
Suppose that we would like to produce plastic bottles for your favorite beverage. Which of the following processes would we most likely use to produce the bottles?
blow molding
The property of a polymer melt to "remember its shape" and that causes die swell is known as
viscoelasticity
If we were trying to produce a contoured, plastic skylight, the most likely shaping process that we would use is
thermoforming
Suppose now that we would like to produce those individual little keys on the keyboard of your computer. The process we would most likely use to produce these parts is
injection molding
The tool used to produce the cross-sectional shape of a plastic extrusion is the
die
Suppose that we would like to produce plastic gutters (uniform cross-section) using a thermoplastic. Which of the following plastic shaping processes would best be suited to produce this shape?
extrusion
A very important polymer shaping technique that is based on die casting in metals is
extrusion
Suppose that we would like to coat copper wire with a thin, insulating plastic coating. Which of the following processes would we most likely select to coat the wire?
extrusion
The following type of polymer tends to be very strong, but brittle and burns when heatedthermosetting polymerOne method that can be used to fabricate plastic trash bags isblown-film extrusionThis type of polymer melts when it is heated, and can therefore be shaped into a part by melting the polymer and molding it into the desired shape or by extruding the polymer through a set of diesthermoplasticIncreasing the temperature of a polymer melt tends to have what effect on its viscosity?decreases viscosityIf we wanted to produce a thermosetting polymer dinner plates (yellow of course), which of the following processes would we most likely usecompression moldingWe would expect the best surface finish to be obtained with which of the following types of mechanical deformation?cold workingMetal deformation processes which are performed on workpieces with small area-to-volume ratios are known collectively asbulk deformation processesWe can achieve the greatest dimensional accuracy with which of the following metal deformation processes?cold workingWe can achieve the greatest amount of mechanical deformation with which of the following types of metal forming?hot workingDeep drawing is an example of what classification of metal deformation processes?sheet metalworking processesSome metals deform easily, and it is therefore not necessary to heat the forming tools to the same temperature as the workpiece during hot working to achieve effective metal deformation. Such hot working processes in which the tools are not heated are known as isothermal forming processes.FalseHot working is defined as the mechanical working of a metal above0.5 TmWe would expect to see no increase in strength with which of the following types of metal deformation?hot workingWe would expect the forces required to work a metal to be lowest withhot workingWe would expect to see greater strain rate sensitivity in metals athigher temperaturesWe would expect to see the highest coefficient of friction with which of the following metal forming processes?hot workingMetal deformation processes which are performed on workpieces with large area-to-volume ratios are known collectively assheet metalworking processesForging and rolling are examples of what classification of metal deformation processes?bulk deformation processesWhich of the following metals is better suited to strengthening by cold working (strain hardening)?metal with a strain hardening coefficient, n, = 0.5An increase in flow stress associated with an increase in strain rate is known as which of the following properties in metals?strain rate sensitivityThe instantaneous value of stress required to continue deforming a material is known as theflow stressThe primary reason for barreling in open die forging is due tofrictionA forging machine which uses impact forces to compress the workpiece is known as aforging hammerWhat advantages do bulk deformation processes such as rolling and forming provide?There is little to no material waste. The material may be made stronger and the grain structure may become preferentially aligned in the forming process Large changes in shape are possible.In this type of forging, the force required to forge a part is reduced by reducing the area of contact between the upper die and the workpiece.orbital forgingThe type of forging which uses flash to increase the pressure within the die, allowing the work metal to fill the intricate details of the die, is known asimpression die forgingSteel slabs (or ingots) are placed in furnaces for many hours so their composition and temperature will be uniform before rolling. What are the furnaces used to do this called?soaking pitsWhich of the following processes is utilized to form the heads of nails?upset forging or headingWhich of the following types of forging operations might be performed to redistribute metal before forming a shape with impression die forging?edgingIn impression-die forging, the area of which of the following parts of an impression die is used to control the pressure within the dies?landThis piece of equipment is typically placed next to an impression-die forging machinetrimming pressA metal deformation process characterized by the deformation of a piece of metal between two dies in compression is known asforgingDoes silicon processing (production of electronic grade silicon, ingots, and wafers) have to be performed in a clean room?YesWhat is the difference between p and n regions?n regions have additional electrons, p regions have an excess of holesWhich of the following statements is true for transistors?Can act as a switch (can be turned on and off) Can amplify signals Are often used for guitar pedalsAnisotropy is ________not behaving the same in all directionsWhen preforming doping, how do we increase the conductivity of a semiconductor?Add impuritiesAt what temperature range does thermal oxidation take place?900°C-1200°CDoes polycrystalline silicon conduct electricity?yesDuring metallization, why is aluminum traditionally used?It is the easiest to depositWhy do we machine a flat into the silicon ingots?To have a reference point since the ingot is a cylinderWhat is the thickness range for a silicon wafer?0.4 - 0.7 mmSilicon ingots are produced using the single crystal Czochralski process. What does this mean?The melted silicon forms around the silicon crystal and is then pulled upwardHow are electrical signals are carried one side of a circuit board to the other?With via holes.How are tracks made on a printed circuit board?Photolithography is used to mask off areas of resist to form the tracks.What are the benefits of using surface mount components as opposed to through-hole mounted components?Greater circuit densities are possible .Components can be mounted on both sides of a board. Smaller components can be usedThe connection between a ribbon cable and its connector is an example of what type of connection?Insulation displacementWhat is the purpose of a printed circuit board?Provides electrical connections between electronic components mounted on the board. Provides structural support for the components it contains.