ME286

Define manufacturing

"made by hand" OR The transformation of RAW MATERIAL INTO USEFUL GOODS by the application of physical and chemical processes

3. How are product variety and production quantity related when comparing typical factories?

Product variety and production quantity are inversely correlated in regards to factory operations.

Define availability

Proportion uptime of the equipment of equipment reliability A = ((T-tm)/T)X100 Ex. 100 hour period, 5 for repairs, 95 left. A = 95%

List the questions to which a checker will seek answers when he reviews a set of drawings.

Questions related to shape, size, form, orientation, and location.

The formation of new strain-free grains in a metal that has been heated to an elevated temperature is called which one of the following: (a) hot hardness, (b) recrystallization, (c) strain hardening, or (d) strain softening?

Recrystallization*

State the difference between straightness and flatness. Give examples.

Straightness is a special case of flatness. Straightness applies to only one element. Flatness applies to the entire surface. For example, a side view of a corner edge of a table could be described in terms of straightness and this table's top could be described in terms of flatness.

Flatness

a surface having all elements in one plane. A flatness tolerance specifies a tolerance zone defined by two parallel planes within which the surface must lie

Straightness

an element of a surface or an axis is a straight line. A straightness tolerance specifies a tolerance zone within which the considered element must lie.

unilateral tolerances

one-sided variation from the basic size

tolerances of orientation

parallelism, angularity, perpendiculity

what dimensional entities are specified in engineering drawing besides size?

size, form, orientation, and location

tolerances of form

straightness, roundness, flatness, cylindricity

basic shaft system

system where the maximum shaft is taken as the basic size. an allowance for each mating part is then assigned and tolerances are applied on both sides of and away from this allowance

basic hole system

system where the minimum hole is taken as the basic size. allowance for each mating part is then assigned and tolerances are applied on both sides of, and away from, this allance

limits

the maximum and the minimum dimensions that are acceptable for a feature

metrology

the science of measurement

roundness

the surface of revolution where all points at the surface in a plane perpendicular to a common axis are equidistant from that axis. Consider the following roundness specification

tolerances

the total amount of variation permitted for a specific dimension. the difference b/n the upper and the lower limites

Concentricity

the variation of two cylinders from a common, or datum, axis

o Concurrent design

Goal: increase quality & reliability Includes suppliers as part of design

Typical applications of steel?

1. Construction industry 2. Railways 3. Automobile industry 4. Home appliances

c,d

10.10 Turbulence during pouring of the molten metal is undesirable for which of the following reasons (two best answers): (a) it causes discoloration of the mold surfaces, (b) it dissolves the binder used to hold together the sand mold, (c) it increases erosion of the mold surfaces, (d) it increases the formation of metallic oxides that can become entrapped during solidification, (e) it increases the mold filling time, and (f) it increases total solidification time?

a,c

10.11 Two important relationships that determine the flow of molten metal in casting are which of the following (two correct answers): (a) Bernoulli's theorem, (b) Chvorinov's rule, (c) continuity law, (d) flow curve, (e) Hooke's law, or (f) Ohm's law?

a,c

10.20 Which of the following riser types are completely enclosed within the sand mold and connected to the main cavity by a channel to feed the molten metal (two correct answers): (a) blind riser, (b) open riser, (c) side riser, and (d) top riser?

a

10.3 Sand casting is which of the following types of casting process: (a) expendable mold or (b) permanent mold?

9. What is the difference between a process layout and a product layout in a production facility?

A process layout is when you group similar activities together according to the process or function they perform. A product layout arranges activities in a line according to the sequence of operations for a particular product or service.

accuracy

Accuracy is both precision and the degree to which the measurement tallies with the original mark.

Definition of steel

All0y of iron & carbon

Which one of the following materials has the highest hardness: (a) alumina ceramic, (b) gray cast iron, (c) hardened tool steel, (d) high carbon steel, or (e) polystyrene?

Alumina ceramic

o Design for robustness

Generating parts that can counteract the effect of variation

8. Define batch production and describe why it is often used for medium-quantity production products.

Batch production is a technique where components are manufactured in groups and not in a continuous flow. In medium-quantity production the production rate of equipment is greater than the demand rate for any single product type. Thus employing batch production the same equipment could be shared among multiple products.

2. What is a capital good? Provide an example.

Capital goods are those purchased by companies to produce goods and/or provide services. Example of a capital goods is a computer.

How does cylindricity differ from circularity

Circularity is a special case of cylindricity. Circularity refers to measurements taken in one place. Cylindricity applies to circularity over the entire surface.For example, the circularity can describe a circular end of a can and the cylindricity can describe the entire body of the can

Which of the following are the three basic types of static stresses to which a material can be subjected: (a) compression, (b) hardness, (c) reduction in area, (d) shear, (e) tensile, (f) true stress, and (f) yield?

Compression, tensile, shear

Consumer vs. capital good (Give Ex.'s)

Consumer goods - purchased directly by customers (Ex. car, TV, tennis racket) Capital goods - purchased by companies to produce goods/provide services (Ex. aircraft, computer, trucks and buses)

What is a machine tool?

Cutting tool operated by power - driven machines

5. What is a "datum feature"?

Datum feature is the actual configuration of the surface of the part.

What is a "datum feature"?

Datum feature is the actual configuration of the surface of the part.

Define the term "datum".

Datum is a theoretically exact entity such as point, line, plane, or axis of a configuration. It is used as a reference for other features of a part or assembly

o Design for manufacture

Design constrained to manufacturing area

Which one of the following materials has the highest modulus of elasticity: (a) aluminum, (b) diamond, (c) steel, (d) titanium, or (e) tungsten?

Diamond

Cylindricity

a surface of revolution in which all points of the surface are equidistant from a common axis. A cylindricity tolerance specifies a tolerance zone bounded by two concentric cylinders within which the surface must lie

Circularity

a surface of revolution where all points at the surface intersected by any plane perpendicular to an axis are equidistant from that axis. In the case of a sphere all points at the surface intersected by any plane passing through a common center are equidistant from that center

Angularity

a surface or center plane or axis at a specified angle (other than 90 degree) from a datum plane or axis

Parallelism

a surface or center plane, equidistant at all points from a datum plane or an axis, equidistant along its length from one or more datum planes or a datum axis

Perpendicularity

a surface, center plane, or axis at a right angle to a datum plane or axis

nominal size

designation used for general identification of size

Hooke's Law defines which one of the following regions of the stress strain relationship for engineering materials: (a) elastic region, (b) plastic region, or (c) neither?

elastic region

2.005 | 2.000

implies that the acceptable range is from 2.000 to 2.005 limits. since, the largest limit is place at the top, this implies an external dimension

allowance

minimum clearance b/n the maximum material conditions(MMC) of mating parts. Allowance=MMC of hole-MMC of shaft

The shear strength of a metal is commonly determined in which one of the following tests: (a) bending test, (b) compression test, (c) flexure test, (d) tensile test, or (e) torsion test?

torsion test thin-walled tubular specimen is subjected to a torque. As torque is increased, the tube deflects by twisting, which is a shear strain for this geometry.

bilateral tolerances

two-sided variation from the basic size i.e. 1.000+-.005

5. Name the three basic categories of materials.

Three basic categories of materials are metals, ceramics and polymers.

4 categories of shaping operations?

1. Solidification process 2. Particulate processing 3. Deformation process 4. Material Removal process

4 types of permanent joining processes used in assembly

1. Welding 2. Brazing 3. Soldering 4. Adhesive Bonding

a

10.1 Casting is a process in which molten metal flows into a mold where it solidifies in the shape of the mold cavity; the term casting also applies to the part that is made by this process: (a) true or (b) false?

a

10.12 Total solidification time is defined as which one of the following: (a) time between pouring and complete solidification, (b) time between pouring and cooling to room temperature, (c) time between solidification and cooling to room temperature, or (d) time to give up the heat of fusion?

d

10.13 During solidification of an alloy when a mixture of solid and liquid metals is present, the solid liquid mixture is referred to as which one of the following: (a) eutectic composition, (b) ingot segregation, (c) liquidus, (d) mushy zone, or (e) solidus?

b

10.14 The empirical relationship that determines total solidification time in casting is known as which one of the following: (a) Bernoulli's theorem, (b) Chvorinov's rule, (c) continuity law, (d) flow curve, (e) Hooke's law, or (f) Ohm's law?

f

10.15 According to the empirical relationship in the previous question, total solidification time is proportional to which one of the following quantities: (a) (A/V)n, (b) Hf, (c) Tm, (d) V, (e) V/A, or (f) (V/A)2; where A = surface area of casting, Hf = heat of fusion, Tm = melting temperature, and V = volume of casting?

c

10.16 Solidification shrinkage in casting is defined as which one of the following: (a) liquid contraction during cooling prior to solidification, (b) liquid contraction during cooling and solidification, (c) contraction during the phase change from liquid to solid, or (d) thermal contraction of the solidified casting during cooling to room temperature.?

a

10.17 Metal inserts in the walls of a sand mold cavity designed to remove heat from the molten metal more rapidly than the surrounding sand are called which one of the following: (a) external chills, (b) internal chills, (c) pipes, or (d) sprues?

c,d,e

10.18 A riser in casting is described by which of the following (three correct answers): (a) an insert in the casting that inhibits buoyancy of the core, (b) gating system in which the sprue feeds directly into the cavity, (c) metal that is not part of the casting, (d) source of molten metal to feed the casting and compensate for shrinkage during solidification, and (e) waste metal that is usually recycled?

c

10.19 In a sand-casting mold, the V/A ratio of the riser should be (a) equal to, (b) greater than, or (c) smaller than the V/A ratio of the casting itself?

b

10.2 A factory that performs casting processes is called which of the following (one best answer): (a) casting plant, (b) foundry, (c) ingot-making plant, (d) metal working plant, or (e) molding plant?

a

10.4 The upper half of a sand-casting mold is called which one of the following: (a) cope, (b) drag, (c) flask, or (d) pattern?

b

10.5 In casting, a flask is which one of the following: (a) beverage bottle for workers who perform casting, (b) box which holds the cope and drag, (c) container for holding liquid metal, or (d) metal which extrudes between the mold halves?

a

10.6 The pattern that determines the geometry of the casting in expendable mold processes is usually made (a) oversized, (b) the same size, or (c) undersized relative to the dimensions of the casting?

a

10.7 In casting processes, a runner is which one of the following: (a) channel in the mold leading from the downsprue to the main mold cavity, (b) worker who moves the molten metal to the mold, or (c) vertical channel into which molten metal is poured into the mold?

a

10.8 The internal surfaces of a casting are determined during the casting process by means of which one of the following: (a) core, (b) gating system, (c) parting line, (d) pattern, or (e) sprue?

e

10.9 Heating a metal from room temperature to pouring temperature in a casting operation depends on all of the following properties except which one: (a) density, (b) heat of fusion, (c) melting temperature, (d) specific heat, or (e) thermal expansion?

What percent of the U.S. GDP is accounted for by the manufacturing industries?

12%

Which one of the following types of stress strain relationship best describes the behavior of metals at temperatures above their respective recrystallization points: (a) elastic and perfectly plastic, (b) elastic and strain hardening, (c) perfectly elastic, or (d) none of the above?

Elastic and perfectly plastic

Which one of the following types of stress strain relationship best describes the behavior of most metals at room temperature: (a) elastic and perfectly plastic, (b) elastic and strain hardening, (c) perfectly elastic, or (d) none of the above?

Elastic and strain hardening

If engineering strain and true strain were measured simultaneously during a tensile test, which would have the higher value: (a) engineering strain or (b) true strain?

Engineering strain

Name & define 2 categories of overhead costs in a manufacturing company

Factory - running operations Corporate - indirectly related operations

What are overhead costs in a manufacturing company?

Factory: maintenance, insurance, heat & light, etc. Corporate: sales, marketing, accounting, legal, etc.

The plastic region of the stress-strain curve for a metal is characterized by a proportional relationship between stress and strain: (a) true or (b) false?

False It is the elastic region that is characterized by a proportional relationship between stress and strain. The plastic region is characterized by a power function - the flow curve

Viscosity can be defined as the ease with which a fluid flows: (a) true or (b) false?

False Viscosity can be defined as the resistance with which a fluid flows:

Difference between special and general purpose production equipment?

General is flexible & adaptable, while special isn't

Explain the difference between hole-basis and shaft-basis systems

In hole-basis system the hole diameter of MMC is the reference dimension (basic sizes) or the stastive point for computation of all allowances and tolerances. In shaft-basis MMC of the shaft is that basic size

A Newtonian fluid is a fluid best defined by which one of the following: (a) its viscosity decreases as shear rate increases, (b) its viscosity decreases as temperature increases, (c) its viscosity increases as shear rate increases, (d) its viscosity increases as temperature increases, (e) its viscosity remains constant as shear rate changes, or (f) its viscosity remains constant as temperature changes?

Its viscosity remains constant as shear rate changes.

The shear strength of a metal is usually (a) greater than or (b) less than its tensile strength?

Less than it's tensile strength S=0.7(TS)

What instruments would you use to measure linear distances

Linear: distances: steel rule, vernier caliper, micrometer, diffraction grating

4. Define manufacturing capability.

Manufacturing capability refers to the technical and physical feasibility limitations of a manufacturing firm and each of its plants.

Name two manufacturing support departments

Manufacturing engineering Production planning & control

10. Name two departments that are typically classified as manufacturing support departments.

Manufacturing engineering (ii) Production planning and control

2. What is the difference between measurement and gauging

Measurement gives a numerical value of a dimension of an object whereas gauging indicates whether or not the dimension of an object conforms (pass/fail) to specifications.

4 categories of engineering materials used in manufacturing?

Metals Ceramics Polymers ___ Composites

The transverse rupture strength is a property usually associated with which one of the following material types: (a) ceramics, (b) metals, (c) plastics, or (d) rubber?

Metals*

Define batch production & describe why it is often used for medium-quantity production products

Method to manufacture a production small batches at one time to reduce costs Why? So too much change doesn't occur

Diff. btw. new shape processes & NEAR net shape processes?

NEAR net shape processes require subsequent machining

Which one of the following types of stress strain relationship best describes the behavior of brittle materials such as ceramics and thermosetting plastics: (a) elastic and perfectly plastic, (b) elastic and strain hardening, (c) perfectly elastic, or (d) none of the above?

Perfectly elastic

7. What are two subclasses of assembly processes? Provide an example process for each subclass.

Permanent joining process and mechanical fastening are two subclasses of assembly processes. Welding is considered permanent joining processes whereas threaded fasteners are mechanical assembly methods.

precision

Precision is the degree to which the instrument gives repeated measurements of the same standard (repeatability).

Differences btw. primary, secondary, and tertiary industries? Give Ex.'s of each

Primary - cultivation & extraction of natural resources (forestry, agriculture, livestock & mining) Secondary - manufacturing industry (food processing, aerospace, automotive, etc.) Tertiary - service industry (education, health & medicine, banking)

1. What are the differences among primary, secondary and tertiary industries? Give an example of each category.

Primary industries develop and use natural resources, examples are agriculture and mining. Secondary industries use yields from primary industries and convert them into consumer goods, which include automotive, stationary, etc. Tertiary industries constitute the service sector of economy such as banking, and telecommunications etc.

Diff. btw. process & product layout in a production facility?

Process - grouped by functions. flexible, material moves in any direction, move storage space on assembly line Product - arranged in line according to place of operation, efficient, moves in ONE direction, less space on assembly line

Diff. between processing operation and assembly operation?

Processing - transform material to another state Assembly - joins two parts

4. How are product variety and production quantity related when comparing typical factories?

Product variety and production quantity are inversely correlated in terms of factory operations. If a factory's product variety is high, then its production quantity is likely to be low and vice-versa.

o Design for assembly

Reduces scrap and reworking of units

How are product variety and production quantity related when company typical factories?

Relation between product variety and production quantity is inversely proportional Increase in product variety leads to decrease in production quantity

Hardness is best defined as which one of the following: (a) energy absorbed by a material when an object strikes its surface, (b) resistance to bending, (c) resistance to permanent indentation, or (d) resistance to scratching?

Resistance to permanent indentation

resolution

Resolution is the smallest difference in dimensions that the instrument can detect.

What is a ring gauge used for? What is a plug gauge? How is a snap gauge used to measure the diameter of a bar?

Ring gauge is used to gauge (inspect) shafts. Plug gauge is used to gauge(inspect) holes

6. How does a shaping process differ from a surface processing operation?

Shaping process changes the shape of the material by various methods whereas surface processing operations are performed to clean, treat, coat or deposit material onto exterior surface of the work material.

Define unit operation

Single step operation while transformation starting material into final product

Soft vs. hard product variety

Soft - (small diff., most parts common, product line almost same, diesel car & petrol car) Hard - (large diff., most parts not common, product line almost fully different, car & cement truck)

The flow curve describes the property of metals known as which one of the following: (a) ductility, (b) engineering strain, (c) fracture stress, (d) strain hardening, or (e) tensile strength?

Strain hardening

6. What is surface roughness? What measures are used to specify it in engineering drawings? How is it measured?

Surface Roughness - small, finely spaced deviations from nominal surface determined by material characteristics and process that formed the surface. It is quantified by the vertical deviations of a real surface from its ideal form and is the arithmetic average deviation of the surface valleys and peaks. Roughness is expressed in terms of its height, its width, and its distance on the surface along which it is measured. Surface profilometer, microscope (SEM) etc are used to measure surface roughness.

Define technological processing capability

The group of manufacturing processes of available in that particular firm Mainly related to type of material Indicates firm specialization and the machinery installed in the firm Indicates the ability of the firm

Which one of the following is the correct definition of ultimate tensile strength, as derived from the results of a tensile test on a metal specimen: (a) the stress encountered when the stress-strain curve transforms from elastic to plastic behavior, (b) the maximum load divided by the final area of the specimen, (c) the maximum load divided by the original area of the specimen, or (d) the stress observed when the specimen finally fails?

The maximum load divided by the original area of the specimen

Difference btw. thermoplastic and thermosetting polymer?

Thermoplastic - deform while heating, soft/weak, can remold, linear chain polymers (Ex. mugs, bags, and toys) Thermosetting - do not deform while heating, hard/brittle, can't remold, 3D structure (Ex. electrical things, telephone parts)

Most hardness tests involve pressing a hard object into the surface of a test specimen and measuring the resulting indentation or its effect: (a) true or (b) false?

True Most hardness tests involve pressing a hard object into the surface of a test specimen and measuring the resulting indentation or its effect.

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: (a) true or (b) false?

True 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.

If engineering stress and true stress were measured simultaneously during a tensile test, which would have the higher value: (a) engineering stress or (b) true stress?

True stress

o Design for environment

Using materials and processes that are environmentally friendly

The modulus of elasticity is also known as which one of the following: (a) elastic limit, (b) strain hardening exponent, (c) strength coefficient, or (d) Young's modulus?

Young's modulus

2.000 +0.005, -0.000

basic size=2.000 with a unilateral tolerance of 0.005 on the upper side. hence, the lower limit=2.000 and the upper=2.005

2.005: +0.000, -0.005

basic size=2.005 with a unilateral tolerance of 0.005 on the lower side. hence the lower limit=2.000 and the upper=2.005

What instruments would you use to measure angles?

bevel protractor, sine bar, surface plates, angle gage blocks

basic size

theorectical size or prefereable size (e.g. +-)