Chapters 1 & 2 Flashcards
1
Q
________ is the cornerstone of a solid
economy.
A
Manufacturing
2
Q
Countries with innovation in manufacturing are capable
A
of reducing the effects of economic crises leading to a faster return to economic stability
3
Q
Manufacturing represents a significant part of overall
A
product cost (often stated to be ca. 40%)
4
Q
Selection of suitable process(es) has big influence on
A
overall cost
5
Q
In order to select suitable manufacturing process -> engineers need to
A
be aware of available techniques and their pros & cons
6
Q
After a selection / design was made and production started,
A
a switch is often very costly
7
Q
It is important to determine the best manufacturing process
A
for given requirements
8
Q
The goals may be different:
A
- Focus on QUALITY (“cost not important”)
- Focus on COST
- Focus on SUSTAINABILITY
- Etc.
9
Q
manufacturing is a term that incorporates
A
a multitude of definitions that, even though they have different meanings; they refer to one of the aspects that leads a design to become a physical tangible product
10
Q
What is Advanced Manufacturing?
A
- The use of innovative technology to improve products or processes.
- Relevant technology can be described as “advanced”, “innovative”, or “cutting edge”, etc.
11
Q
Impacts of Advanced Manufacturing:
A
Increased level of quality
Boost productivity
Gives way to innovation
Reduced production time and cost
12
Q
One of the main advantages
of advanced manufacturing technology is
A
quality enhancement
13
Q
Advanced manufacturing
technologies help boost
A
operational productivity in various ways. …
Small batch production Rapid prototyping
14
Q
digital manufacturing helps to
A
Reduce production time and cost
15
Q
What is a manufacturing process?
A
Manufacturing as a transformation process, manufacturing does not equal production
16
Q
Multiple manufacturing processes are needed to
A
produce a product in most cases
17
Q
A simple classification of manufacturing processes into three categories:
A
Deformative
Subtractive
Additive
18
Q
Polymers manufacturing is a
A
subset of Deformative Manufacturing
19
Q
Deformative manufacturing represents processes where
A
where we transform the material from Form A to Form B without the addition or subtraction of material
20
Q
The fundamental concept of Deformative manufacturing is
A
is that the volume of materials remains unchanged throughout the process
21
Q
Forging, Rolling, Casting are examples of
A
Deformative Manufacturing
22
Q
Subtractive manufacturing represents processes where
A
we transform the material from Form A to Form B by subtraction of material
23
Q
The fundamental concept of Subtractive manufacturing is
A
that we reduce the volume of materials throughout the process
24
Q
Milling, Drilling, Turning are examples of
A
Subtractive Manufacturing
25
Additive manufacturing represents processes where
we transform the material from Form A to Form B by addition of material
26
The fundamental concept of Additive manufacturing is
is that we augment the volume of materials throughout the process
27
SLS, SLA, FFF, DED are examples of
Additive Manufacturing
28
We obtain products (and sub-products) by performing
assembly operations on individual parts
29
Mechanical joining, welding and bonding are examples of
Assembly Operations
30
Manufacturing enable a progression of materials from an
initial shape to a net shape
31
The different processes transforms the
initial shape into multiple intermediate shapes
32
Only when the shape is ‘almost’ as intended we classify it as a
near net shape
33
Final output is the
net shape or the finished part
34
Industry 1.0
18th century
35
Industry 1.0 stands for the
mechanization of production in contrast to manual processing
36
The transformation of energy sources to produce goods
highlights the first era in manufacturing evolution
37
Industry 2.0
19th century
38
Industry 2.0 stands for
the mass production of products
39
This has been particularly encouraged by the arming race between countries
Industry 2.0
40
It led mass production of airplanes, transportation vehicles in parallel to civil goods
Industry 2.0
41
Industry 3.0
’70s in the 20th century
42
Industry 3.0 stands for
the introduction of automation, robotics and computers into manufacturing
43
Computer Aided Manufacturing is one of the direct results of this era as well as the replacement of humans in hazardous working conditions by robotic arms
Industry 3.0
44
Industry 4.0
Apply information and communication
| technologies to industry
45
Industry 4.0 stands for
the integration of cyber- physical systems and the digital transformation of industries
46
integration of cognitive manufacturing
smart systems that analyze and interpret data– is offering new insights and abilities for next generation industries
47
The development of materials and man’s ability to process them is linked to
the history of man
(Stone Age (8700 BC and 2000 BC)
Copper and Bronze Age (3000 BC and 1200 BC)
Iron & Steel Age (1200 BC and 600 BC))
48
The current age is that of
plastics, composite materials, and exotic alloys
49
Alloys are
-Materials composed of two or more different elements -Major component is a metal, not a chemical compound
50
Ferrous metal alloys:
- Cast Iron > 2% Carbon
| - Steel < 2% Carbon
51
Plan carbon steel
- Low-carbon (< 0.2% C)
- Medium-carbon (0.2%~0.5% C)
- High-carbon (>0.5% C)
52
Alloy steel
- Stainless steel (low-carbon steel with 4% to 6% chromium) -Tool Steel
- Others
53
Non-Ferrous metals and alloys:
- Copper alloys
- Titanium alloys
- Aluminum alloys
- Zinc based alloys
- Etc.
54
Non-ferrous metals and alloys have properties that are not available in the ferrous metal alloy, such as:
- Easy to fabricate
- High electrical and thermal conductivity
- Light weight
- Resistance to corrosion
55
Blast Furnace ------>
includes: - Iron Ore
• Limestone, Coke • Hot Gases
goes to: Pig Iron
56
Basic Oxygen Furnace --------->
includes; -Jet of oxygen, -Usage of scrap iron
goes to: Steel/cast Iron
57
------> Molding
-Ingots
| • Continuous Casting
58
Polymers are
chains of monomers grouped together
59
We identify three categories of polymers:
Thermoplastics, Thermosets and Elastomers
60
Thermoplastics are
commercially the most important and have over 70% of the polymer market share
61
There is a wide range of
natural and synthetic polymers
62
Natural polymers
exist in flora and fauna
63
Natural polymers include
proteins, cellulose, and natural rubber
64
Synthetic polymers ______
are derived mainly from mineral oil, natural gas, and coal. They include among others nylon, polyethylene, phenolics, and epoxies.
65
General common term for a wide range of synthetic or semi-synthetic organic amorphous solid materials.
Plastic
66
```
-Light weight
Corrosion resistance
Electrical resistance
Low thermal conductivity
Variety of optical properties
Surface finish
Comparatively low cost (in material manufacturing and processes)
```
Characteristics of plastics
67
A polymer with both viscosity and elasticity and
with weak intermolecular forces
-Rubber
Elastomer
68
Thermoplastics (Thermoplastic materials)
```
-Tend to be flexible and tough
Soften with increasing temperature
Become harder and stronger when cooled
Can be cast, injected into a mold, or forced into (through) dies to produce a desired shape
Scrap can be re-melted and reused
```
69
Thermosets (Thermosetting materials)
-Significantly stronger and more rigid
Have lower ductility and poorer impact properties
Elevated temperature promotes irreversible reaction
Additional heating do not produce softening
“Set under heat and cannot be re-melted.”
70
A ceramic is
an inorganic, non-metallic solid prepared by action of heating and subsequent cooling
71
Crystalline ceramics and glass constitutes
| the
two categories of Ceramics
72
Crystalline ceramics includes
traditional ceramics such as pottery, and advanced ceramics such as tungsten carbide
73
Glass is a
non-crystalline amorphous solid with widespread usage
74
General Properties of Ceramics
```
-Hard, brittle, high melting point
Low electrical and thermal conductivity
Low thermal expansion
Good chemical and thermal stability
High elastic modulus
High compressive strength
```
75
A composite material is composed of
two or more different materials
| -These two or more different materials form a new material with enhanced properties
76
Composites consists typically of two phases:
Forming and Strengthening
77
The forming phase,
labeled as matrix/resin, provides the formability and ductility property
78
The strengthening phase,
labeled as reinforcement/fibers, provides the strength to the final part
79
Fiber/Filament
| Reinforcement:
-High Strength
High Stiffness
Low density
Carbon, Glass, Aramid, etc.
80
Matrix:
-Good shear properties
Low density
Thermoset & thermoplastic
Epoxy, Polyester, Nylon, etc.
81
Composite:
```
-High Strength
High Stiffness
Good shear properties
Low density
Anisotropic!
```
82
General properties of composites
-Two or more constituent materials
Can be stronger than steel, lighter than aluminum, and stiffer than titanium;
Low thermal conductivity, good heat resistance
Good fatigue life
Low corrosion rates
Adequate wear resistance
83
is one of the earliest manufacturing
| processes used by humans
Forging
84
is also one of the earlier manufacturing
| processes
Casting
85
Types of forging:
- Cold working (CW)
- Warm working (WW)
- Hot working (HW)
86
Shaping of material at room temperature (below recrystallization temperature)
Cold working (CW)
87
What is the Positive effect of cold working?
Work hardening (strain hardening) strengthens metal through plastic deformation (but, material becomes more brittle)
88
Shaping of material elevated above room temperature but below recrystallization temperature
Warm working (WW)
89
Trade-off between hot and cold working
Warm working (WW)
90
Shaping of material above the recrystallization temperature but below melting temperature
Hot working (HW)
91
What is the Positive effect of hot working?
Properties (e.g., toughness, ductility, elongation) improve / less force required to transform ingots
92
Shaping of material above the recrystallization temperature and melting temperature
Casting
93
Types of Recrystallization:
- Recrystallization
- Recrystallization temperature
- Energy
94
The process in which grains of a crystal structure come in a new structure or new crystal shape
Recrystallization
95
Dislocations in metal material move to grain boundaries and/or move to the material surface
Recrystallization
96
Material becomes “strain-free”
Recrystallization
97
Temperature at which 95 percent of recrystallization is complete within one hour
Recrystallization temperature
98
Different metals have different
recrystallization temperatures (e.g., Al 300°F, Fe 840°F & Ni 1,100°F)
99
Recrystallization is a function of the
total energy
100
Total energy =
strain energy + thermal energy
101
Whats the effect of energy?
the more strain energy is induced, the less thermal energy is required (the more cold working is performed, the lower recrystallization temperature)
102
Hooke’s Law (one dimensional):
σ = Ee
103
E =
Young’s modulus (stiffness of material)
104
Permanent change of shape
Plastic Deformation
105
Stress in material larger than yield strength
Plastic Deformation
106
Plastic Deformation is where ______
Where Manufacturing Happens
107
Flow stress
Stress needed to achieve a plastic deformation (strain) on a material
108
Flow stress of material is influenced by:
Strain rate, temperature, etc.
109
Metals with low yield strength and high ductility are best suited for
forging
110
Yield strength _______ with higher temperatures
decreases
111
Ductility _______ with higher temperatures
increases
112
Shape undergoing deformation have influence on the
‘next’ force needed to pursue the operation
113
The influence of shape is captured via
different experimental trials and relevant to the manufacturing process
114
Force =
Flow Stress x Area
115
In extrusion, the shape factor is trying to compare
the shape to a theoretical circular shape Cc having the same area as the extruded shape
116
In forging, we are further integrating
the coefficient of friction
117
As you further continue the forging operation,
your shape factor increase: the shape is more flat and thus D is bigger and h is smaller
118
Forging operations induce
-shape changes on the work piece
by plastic deformation
under forces applied (hammering or pressing)
by various tools and dies
119
Different classifications used for forging:
-Material: Bulk (most common) vs. Sheet
Operating temperature: Hot (vs. Warm) vs. Cold
Mode: Steady vs. non-steady state vs. mixed
Gas turbine engine (870 oC) vs internal combustion engine (Cyclic Temp.)
Type of stress: Compression vs. Tension vs. Bending, etc.
Flow: Homogeneous vs. Semi-homogeneous vs. Inhomogeneous
Succession/Operation: Primary vs. Secondary
120
Biggest forging hydraulic press in the world:
-80,000 ton closed-die hydraulic press
| Shanghai Electric Group, Shanghai, China
121
Open Die Forging is the
simplest form of (industrial) forging
122
No specialized tooling required for ____
Open Die Forging due to high flexibility
123
Work piece deformed between two flat (or simple shaped) dies
Open Die Forging
124
Process of choice when in Open Die Forging:
Work piece very large or Small batch size
125
Open Die Forging is
Often used as primary shaping process to pre- form the work piece for subsequent closed-die forging
126
Bulging of work piece is (undesired) side effect of this forging process
Open Die Forging
127
Safety issue in Open Die Forging:
flash occurs
128
Impression Die (or Closed Die) Forging is
a more complex form of (industrial) forging
129
Work piece is shaped under high pressure between two
| dies with cavity in form of desired design
Impression Die (or Closed Die) Forging
130
Enables close dimensional tolerance (e.g., for coins)
Impression Die (or Closed Die) Forging
131
____________ is expensive (Only economical for larger batch sizes)
Impression (or closed) dies
132
Flash gutter:
Small amount of material forced out of impression die cavity, forming flash
133
Process of choice when in Impression Die (or Closed Die) Forging;
Complex shape or Large batch production
134
Impression die may contain
recesses allowing work piece to transform into 3D shapes with complex surfaces
135
Upset forging describes
deformative transformation of shape by changing the diameter by compressing the length
136
Most common application of Upset forging:
Fasteners of various kind (-> thus widely used)
137
Both hot and cold ______ forging possible
upset
138
Upset forging is ______
Generally, high throughput operation
139
Applicable work pieces range from
wires with small diameter to bars with large diameters (~ 10in) (Upset forging)
140
Main rule of upset forging:
Length of to-be-deformed material restricted to max. 3x diameter (without adapted/special tooling) to prevent buckling
141
Common defects in forging:
-Incomplete die filling
Die misalignment
Forging laps
Incomplete forging penetration
(Material) Property variation (due to micro structural differences)
Pitted surface (due to oxide scales, occurring at high temperature, sticking on die(s) )
Buckling (mainly common in upset forging) (due to high compressive stress)
Surface cracking (due to temperature differential between surface and center, and/or excessive working of surface at too low temperature)
Micro-cracking (due to residual stress)
142
Design guidelines for Forging:
-Rib height to rib thickness ratio not to exceed 6:1
Part must be designed with an appropriate draft angle (standard degree: 1 +/- 0.5)
Add additional material for secondary (machining) processes and plan the parting line (where dies meet)
No sharp corners – plan with appropriate radii
Minimum (~0.2in) / maximum (~10in) wall
thickness (varies to some extent)
Consider achievable surface finish (and plan
for secondary processing if necessary)
143
Extrusion is
a deformative manufacturing process (compression forming) by which metal billet is reduced in cross-section and/or formed in different cross-sectional shape by forcing it to flow through a (or multiple) die orifice(s) under high pressure
144
Metal (hot) extrusion is mainly used to
produce cylindrical bars, hollow tubes or as intermediate shapes for drawn rod, cold extrusion or forged products
145
Most metals are hot extruded due to
required forces
146
Complex shapes can be extruded from
softer metals such as aluminum
147
Direct Extrusion:
Material is forced forward by a punch through the die orifice, producing a smaller cross-section (diameter decreases, length increases) than the initial blank
148
Direct extrusion is also known as
Forward Extrusion
149
Friction increases the
extrusion force
150
~75% area reduction is possible with using
direct extrusion
151
Indirect Extrusion:
Material is formed around the punch by being forced backward around the punch within the die, producing hollow parts with solid bottoms
152
Die is mounted on the ______
punch (also referred to as ram) (Indirect Forging)
153
For Indirect Extrusion, ________
The bottoms of the hollow parts should be thicker than the walls
154
Indirect Extrusion is also known as
Backward Extrusion
155
Area reductions of ~20-75% are possible
| with
indirect extrusion
156
Combined Extrusion:
Material is formed around the punch by being forced backward around the punch within the die and forced forward by the punch
157
Many designs in combined extrusion include:
both extrusion forms therefore, both forms are applied simultaneously to minimize production cost
158
There are a wide variety of different combinations possible depending on
the creativity of the design and manufacturing engineer
159
What is the shape factor of a circle?
1
160
Rolling is
a deformation process where shape of a (continuous) work piece is transformed using (one or multiple) pairs of rolls without changing the volume
161
Generally, rolling processes produces
constant cross-sectional shapes (exception: thread rolling)
162
Hot-Rolling (e.g., ring) and Cold-Rolling (e.g., thread) can be used ______
in rolling processes
163
Multi-stage processes are very common due to
max. deformation in one step
164
Bearings (e.g., force) and surfaces of rolls (e.g., temperature) are
highly stressed
165
Rolling is a multi-stage process that can
produce a large variety of different products
166
Succession is reflected in work piece terminology:
1. Ingots
2. Bloom (square cross-section)
3. Slab (rectangular cross section)
4. Billet (Bar w/ cross-section smaller than 6in x 6in)
167
Typical products stemming from the various rolling processes are:
- Sheet metal products (e.g., Plates, Sheets, Large diameter pipes)
- Constant cross-sectional products (e.g., Seamless pipes, Train rails, various profiles (e.g., H, T), Wires, Bars)
- Misc. products (e.g., Rings, Bolts, Train wheels)
168
Rolling Mills:
Shaping material by forcing it through two rotating rolls on both sides of the work piece
169
in Rolling mills, parts of _____
uniform cross sectional areas can be produced
170
Parts are generally longer than those produced by
extrusion and larger than those produced by wire drawing
171
Structural shapes, such as I-beams, and railroad rails are produced by
rolling
172
Thread rolling ______
deforms the material by rolling it between two threaded dies to imprint external threading on a round bar/wire material
173
The threaded dies can be
plane or round depending on the process
174
Thread rolling is a
cold forming process
175
Thread rolling produces external threads with desirable properties like
-Strong
Precise
Uniform
Smooth
176
Ring rolling is
a deformation process which increases diameters of rings by reducing the radial thickness of the work piece between a set of rollers
177
Work piece volume is maintained which leads to
diameter increase and requires rollers to adjust with work piece throughout the ring rolling process
178
Driver roll is fixed in most cases while
idle roll, rolling pins and guiding rolls adjust to the changing dimensions of the work piece
179
Two, often conical shaped rollers maintain
the upper and lower boundary of work piece (= height)
180
Ring rolling is generally a
hot working process
181
Ring rolling results in
desirable circumferential grain structure achieving better mechanical properties
182
Casting is a
prehistoric technology enabled by the fire-using technologies
183
Casting is a
primary manufacturing processes that transforms shape of a material by changing its state to allow it to fill a mold cavity and take the shape represented without changing its volume
184
Casting is applicable for
all material groups: Metals, Ceramics and Polymers
185
Polymers most famous casting processes
are Injection and Blow molding
186
Metal casting is classified based on
the mold material
187
If the mold material is a solid material (e.g., stone, metal, ceramic) and is reused in the casting process, we refer
to
permanent mold processes
188
If the mold material is sacrificed to obtain the final shape of the work piece (e.g., sand, wax) and we have to
create a new mold every time we manufacture a new part, we refer to
expendable mold processes
189
The fundamental concept of casting is by
(1) melting the material into a highly plastic (polymers) or liquid (metals) state, (2) designing a mold (and cores if applicable) to contain the molten material, (3) pouring the material into the designed mold, and, finally (4) waiting for the material to solidify/cool
190
Advantages of casting
-Suitable for mass production (selected processes)
-Ability to create complex components
-Ability to create small to large components
(such as nuclear reactor pressure heads of
60+ tons)
-Versatile process
-Ability to design both internal and external contours
-Variety of materials can be manufactures (incl. special alloys)
191
Disadvantages of casting
- Limited mechanical strength and lifecycle fatigue
- Often requires a ‘next’ process due to poor dimensional accuracy and surface finish
- Ergonomics of the process are challenging especially with respect to safety of operators
192
Main Function of a parting line
- Drag is the bottom half of the mold
- Cope is the upper half of the mold
- They are split along the parting lines - Molds have multiple internal cores
193
Main Function of cavity
- Cavity is the void in the mold
- This will be filled to create the final shape
- Often it includes cores to create internal shapes
194
Main Function of gating and runner
- Gating includes the pouring location and the downsprue
- The main function is to regulate the flow into a laminar flow so that the mold is not eroded
- The runner has the function to transfer the poured metal to the cavity
195
Main Function of riser
- Metals exhibit shrinkage during solidification
- The riser main function is to act as a reservoir to supply molten metal and fill the shrinkage voids
- A rule of thumb: Risers should never solidify, by design, before the cavity
- A common practice is to use riser solidification times of 1.2 to 1.3 the cavity solidification time
196
What is a process parameters?
Computing the amount of heat needed to pour the metal
197
A conventional pouring temperature is
100 degrees Celsius above the melting temperature
198
To facilitate the design of the mold,
following thoroughly the Design for Manufacturing and
| Assembly (DFMA) guidelines is necessary
199
Regulation of flow:
ensure a laminar flow that will not erode the walls of the mode
200
After the metal is poured into the mold cavity,
it requires a certain amount of time to
| solidify tST
201
Having a bigger contact area for the same volume enables
faster solidification
202
Chvorinov developed a rule that is dependent on:
-Mold Material
Molten Material
Volume/Area ratio of the cavity
203
The area represents the
contact area from all sides
204
Mold constant Cm and mold exponent n are
experimentally derived
205
Volume V and Area A are computed based on
the geometry
206
Design guidelines for Casting:
-Design uniform sections when possible
Include draft angle
Plan ejection pins & parting line (die casting)
Avoid sharp corners / angles and use rounded corners
Include buttresses / ribs to support material flow
Design wall thickness uniformly (uniform cross-
section)
Reflect shrinkage in casting design
Add additional material for secondary (machining) processes
207
Permanent mold casting is a process for
producing a large number of castings using a single reusable mold
208
The mold is made from
a high-temperature metallic material, such as cast iron or hot work die steel
209
Advantage of permanent mold casting:
produces metal with better dimensional tolerance, superior surface finish, and higher and more uniform mechanical properties
210
Disadvantages of permanent mold casting:
high cost of the reusable mold
211
Most common application of permanent mold casting is:
the aerospace industry for the casting of aluminium, titanium and steel ingots
212
The fundamental difference in expendable mold processes is that
the mold is sacrificed for the creation of each part
213
The great advantage of expendable mold processes is:
The creation of internal shapes
214
There are plenty of expendable mold processes:
-Sand Casting where the mold is made of Sand
Lost Wax Process where the pattern is made of
Wax
Lost Foam Process where the pattern is made of polystyrene
215
Lost wax process is primarily used in
the jewelry manufacturing industry
216
The expendable mold process is as follows:
```
-Making patterns of wax
Assembling the patterns in a tree
Placing the assembly in a plaster mold
Heating the mold with pattern to loose the wax Filling the void with molten metal
Breaking the mold
```
217
Sheetmetal deformation describes
the change of shape of a material in sheet form with no or little change in thickness
218
Generally, the sheetmetal deformation is
two-dimensional (2D)
219
In sheetmetal processing,
the modulus value of the material does not change
220
The elastic recovery of the material has to be
considered as it is usually larger than in other deformation processes
221
The sheetmetal blanking process describes
the process of remove the work piece from the blank by forcing a shaped punch through the sheet into a shaped die
222
Sheetmetal blanking is
Fast process and considered rather economical for medium and large batches
223
In sheetmetal blanking,
Different shapes are possible to be manufactured
224
The sheetmetal punching process describes
the process of removing material from the blank which remains as the desired work piece via shearing
225
The punch often passes through
a die to ensure a precision shearing of the material
226
In sheetmetal punching,
a variety of differently shaped holes can be realized
227
The sheetmetal punching process,
is very cost effective and fast on larger batches
228
Sheetmetal bending processes are
plastic deformation processes around a linear axis while not (or only slightly) changing the surface area
229
Bending processes entail
a certain elastic recovery from the combined tension and compression that needs to be accounted for
230
Parameters influencing the elastic recovery include
material type and thickness
231
Sheetmetal (deep) drawing describes
a process of forming a material through plastic deformation using a punch and die, typically creating cylindrical or rectangular containers
232
There are two common types of sheetmetal drawing processes,
deep drawing (depth > diameter) and shallow drawing (depth < diameter)
