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Question 2

What are the Principle methods used to produce metallic powders?

Answer 2

Atomization - Converts molten metal into a spray of droplets that solidify into powders. Chemical - Includes a variety of chemical reactions by which metallic compounds are reduced to elemental metal Powders.Electrolyte - An electrolyte cell is set up in which the source of the desired metal is the anoded

Question 3

Describe what happens to the individual particles during compaction.

Answer 3

The applied pressure in compaction results initially in repacking of the powders into a more efficient arrangement, eliminating bridges formed during filling, reducing pore space, and increasing the number of contacting points between particles. As pressure increases the particles are plastically deformed, causing inter particle contact area to increase and additional particles are made to contact.

Question 4

What is the difference between deep drawing and bar drawing?

Answer 4

Deep drawing - Refers to taking flat sheet metal and forming it into a hollow or concave shape, such as a cup, by stretching the metal.

Question 5

In rolling of steel, what are the differences between a bloom, a slab, and a billet?

Answer 5

Bloom - has a square cross section 150 mm x 150 mm (6 in x 6 in) or larger. Slab - is rolled from an ingot or a bloom and has a rectangular cross section of width 250 mm (10 in) and thickness 40 mm (1.5 in) or more.Billet - Is rolled from a bloom and is square with dimensions 40 mm (1.5 in) on a side or larger.

Question 6

Why is flash desirable in impression die forging?

Answer 6

As the flash begins to form in the die gap, friction resists continued flow of metal into the gap, thus constraining the bulk of the work material to remain in the die cavity.

Question 7

In blanking of a circular sheet-metal part, is the clearance applied to the punch diameter or the die diameter?

Answer 7

It is applied to the Punch Diameter.

Question 8

For what is the bend allowance intended to compensate?

Answer 8

Compensates for stretching while bending. The problem is to determine the length of the neutral axis before bending to account for stretching of the final bent section.

Question 9

Identify a major technical problem in tube bending.

Answer 9

Tubes tend to collapse and fold when attempts are made to bend it.

Question 10

What are the 3 basic categories of material removal processes?

Answer 10

Conventional machining - A sharp cutting tool is used to mechanically cut the material to achieve the desired geometry. Abrasive Processes - mechanically remove material by the action of hard, abrasive particles. Nontraditional Processes - use various energy forms other than a sharp cutting tool or abrasive particles to remove material.

Question 11

What are the two basic categories of cutting tools in machining? Give two examples of machining operations that use each of the tooling types.

Answer 11

The two categories are (1) single-point tools, used in operations such as turning andboring; and (2) multiple-edge cutting tools, used in operations such as milling and drilling

Question 12

What is the relationship between the coefficient of friction and the friction angle in the orthogonalcutting model?

Answer 12

The relationship is that the coefficient of friction is the tangent of the friction angle

Question 13

Name the three modes of tool failure in machining.

Answer 13

The three tool failure modes are (1) fracture failure, (2) temperature failure, and (3)gradual wear

Question 14

What are the two principal locations on a cutting tool where tool wear occurs?

Answer 14

Wear occurs on the top face of the cutting tool as crater wear and on the side or flank of the tool, called flank wear. Portions of flank wear are often identified separately as notch wear, corresponding to the surface of the work; and nose radius wear, corresponding to the tool point.

Question 15

Give two examples of machining operations in which generating and forming are combined to create workpart geometry.

Answer 15

The two examples given in the text are thread cutting on a lathe and slot milling

Question 16

How does a boring operation differ from a turning operation?

Answer 16

Boring produces an internal cylindrical shape from an existing hole, while turning produces an external cylindrical shape.

Question 17

Name the various ways in which a workpart can be held in a lathe.

Answer 17

Methods of holding the work in a lathe include: (1) between centers, (2) chuck, (3) collet,and (4) face plate

Question 18

Describe the difference between up milling and down milling?

Answer 18

In up milling, the cutter speed direction is opposite the feed direction; in down milling, the direction of cutter rotation is the same as the feed direction.

Question 19

How do shaping and planing differ?

Answer 19

In shaping, the work is stationary during the cut, and the speed motion is performed by the cutting tool; while in planing, the cutting tool is stationary, and the workpart is moved past the tool in the speed motion.

Question 20

Define machinability.

Answer 20

Machinability can be defined as the relative ease with which a material can be machinedusing an appropriate cutting tool under appropriate cutting conditions.

Question 21

Which cutting speed is always lower for a given machining operation, cutting speed for minimumcost or cutting speed for maximum production rate? Why?

Answer 21

Cutting speed for minimum cost is always lower because of the fourth term in the unit costequation, which deals with the actual cost of the cutting edge. This term tends to push the U-shapedfunction toward a lower value in the case of cutting speed for minimum cost.

Question 22

What are some of the principal abrasive materials used in grinding wheels?

Answer 22

The principal abrasive grit materials include (1) aluminum oxide, (2) silicon carbide, (3)cubic boron nitride, and (4) diamond.

Question 23

Name some of the principal bonding materials used in grinding wheels.

Answer 23

The bonding materials in grinding wheels are (1) vitrified bond - clay and ceramics, (2)silicate, (3) rubber, (4) resinoid, (5) shellac, and (6) metallic.

Question 24

Define the term manufacturing system.

Answer 24

The text defines manufacturing system as a collection of integrated equipment andhuman resources that performs one or more processing and/or assembly operations on a startingwork material, part, or set of parts. The integrated equipment consists of production machines,material handling and positioning devices, and computer systems.

Question 25

What is the difference between fixed automation and programmable automation?

Answer 25

In fixed automation, the processing or assembly steps and their sequence are fixed bythe equipment configuration. The program of instructions is determined by the equipment designand cannot be easily changed. In programmable automation, the equipment is designed with thecapability to change the program of instructions to allow production of different parts or products

Question 26

What is an actuator in an automated system?

Answer 26

In automated systems, an actuator is a device that converts a control signal into a physical action, which usually refers to a change in a process input parameter. The action is typically mechanical, such as a change in position of a worktable or rotational speed of a motor.

Question 27

What is the difference between absolute positioning and incremental positioning?

Answer 27

In absolute positioning, the locations are defined relative to the origin of the axis system. In incremental positioning, each succeeding location is defined relative to the previous location.

Question 28

Identify some of the non-machine tool applications of numerical control.

Answer 28

The applications include (1) arc welding and resistance welding, (2) electronic component insertion, (3) electrical wire wrap machines, (4) drafting, (5) tape laying for fiber reinforced polymer composites, and (6) coordinate measuring machines.

Question 29

There are four categories of nontraditional machining processes, based on principal energy form. Name the four categories.

Answer 29

The four categories are (1) mechanical, but not including conventional machining; (2)electrical; (3) thermal; and (4) chemical

Question 30

What is rapid prototyping? Provide a definition of the term.

Answer 30

Rapid prototyping consists of a family of fabrication processes developed to make engineering prototypes in minimum possible lead times based on a computer-aided design (CAD)model of the item.