Unit 2 - Manufacturing groups accordin to Din 8580

Question 1

primary shaping definition

Answer 1

the production of solid bodies from a gaseous, liquid or solid state.

Question 2

primary shaping manufacturing processes

Answer 2

Creating choesion:

• from a liquid or pastry state: casting of metallic and polymeric workpieces
• from the solid, granulare or powder state of metals: extrusion or sintering
• from additive manufacturing processes: layer upon layer

Question 3

Casting technology definition

Answer 3

used to create shaped bodies by casting molten metal into suitable negative molds > mass production

Metals, ceramics and plastics

Costs of pattern and mold making are high but dividev for each unit produced

Question 4

lost molds (casting)

Answer 4

lost molds and lost patterns are made of sand, plaster o wax and they are destroyed during the casting or compoment’s demolding

Question 5

reusable molds (casting)

Answer 5

reusable molds and reusable patterns are made of metal, plastic or wood and can be reused

Question 6

sand casting (casting)

Answer 6

pattern is pressed into the sand, the mold is sealed, molten metal is poured in, wait to solidifiation, piece is extracted

Question 7

investment casting (lost wax casting)

Answer 7

precision casting process, complex components, high surface quality, minimizing the need for further processes.

Steel, aluminium, titanium, brass

Creation of wax pattern using injection molding or rapid prototyping > wax models are assembled into clusters > coated with ceramic layers > after drying and firing wa go away > you have a mold.

Question 8

sintering technology (powder metallurgy)

Answer 8

is a process to produce metallic shaped bodies from metal powders without reaching the base metal’s melting temperature

metal powder can be mixed creating pseudo-alloys

Question 9

primary shaping of plastics (5)

Answer 9

used to create shaped bodies and profiles from plastic granules.

• injection molding: molten plastic is injected into a mold, where it cools and solidifyes
• extrusion: molten plastic is pushed through a die to create continous profiles like tubes
• thermoforming: heated thermoplastics are shaped with low forming force and retain their form after cooling
• calendering: plastic sheets are rolled into thin films or panels
• blow molding: used for hollow bodies (bottles) by inflating plastic inside a mold

Question 10

layered composite materials - GLARE

Answer 10

glass laminated aluminium reeinforced epoxy

Structure: alternating aluminium sheets with glass fiber reinforced plastics
Advantages: increased mechanical strength and corrosion resistance

Question 11

fiber composite materials

Answer 11

plastic matrix (epoxy resin or thermosets) and reinforced fibers (glass or carbon)

weight reduction, cost reduction compared to metal structures

superior stiffness, vibration resistance and energy absorption

Question 12

forming technology

Answer 12

Based on the permanent plastic deformability of materials, occurs with a stress that exceeds the yield point.
Includes all processes in which metals or thermoplastics are specifically and plastically transformed into different defined geometry.

Question 13

forming processes (2 types)

Answer 13

is carried out hot or cold, depending on the material or extent of forming, most common: rolling, deep-drawing, extrusion and forging

Question 14

Hot forming

Answer 14

at higher temperatures, above the recrystallization temperature > materials are easier to form > recrystallization occurs simultaneouslu > reduction in hardening

Question 15

Cold forming

Answer 15

at room temperature > requires much higher stress than hot forming > advantage of considerable material hardening

Question 16

drop forging

Answer 16

manufacturing process in which workpieces needing to withstand the highest stress are produces by plastic deformation at high temperatures using limiting tools.

preserve the fibers in the materials > higher load capacity
forged piece is almost completely encapsed by the die
mainly used to produce safety-relevant parts
cost of a die tool usually high

Question 17

bending

Answer 17

forming process, bending moment is introduced to the base material causing a permanent plastic deformation

Question 18

stretch forming

Answer 18

is a cold forming process for large sheet metal parts. The sheets are clamped into tensioning devices and drawn over a forming die.
Eg aircraft skin

Question 19

deep drawing

Answer 19

forming process where a flat sheet of metal is transformed into a hollow shape, such as a cup open at the top

Question 20

separating

Answer 20

manufacturing process that are among the most commong globally.

Types:
-cutting: used for sheet metal
-machining: removing materials as chips
-removal: by spark erosion, electrochemical, or chemical processes

Question 21

shearing (punching)

Answer 21

punching technology, used for punching and cutting contours in this field.
Increasingly replaced with laser cutting systems

Question 22

machining

Answer 22

a manufacturing process in which materials is selectively removed from a workpiece

• geometrically defined cutters > drills, lathes, mills
• geometrically undefined cutters > grinding, honing, lapping

heavy wear on tools
tools must be harder than the material being cut
widely used in machine building, automotive, aerospace

Question 23

tool wear in machining

Answer 23

caused by high temperatures, pressure and movement
leads to dimensional errors and poor surface finish
tools need regular sharpening or replacement

Question 24

removal process

Answer 24

electrical discharge machining EDM: sparks in dielectric fluid melt and vaporize material
electrochemical machining ECM: electric current in electrolyte removes material by electrolysis
chemical removal: acids dissolve exposed areas

Question 25

joining value

Answer 25

automotive > 50% of the value aircraft > 70% of the value

Question 26

riveting

Answer 26

long-used joining method in aircraft manufacturing for metal and CFRP (Carbon fiber reinforced plastic) components. It's permanent but can be undone by drilling types: solid rivet, lock ring rivets (dynamic loads), screw rivet (hi-lock)

Question 27

riveting advantages/disadvantages

Answer 27

Advantages: -wide variety of available materials -high efficiency - usually no thermal transformation -good environmental compatibility -manual or automatic joining -high constant pre-stess Disadvantages: -less strangth than welding -surface irregolarities -difficult to rework -no or only difficult to repairs -limited applicability -possible damage to components surrondings -preliminary work necessary (punching)

Question 28

welding and problems

Answer 28

a permanent joining process that uses heat, pressure or both, with or without fillers material Problems: -rapid cooling after welding can alter material properties -may cause embrittlement or hardening -solidification shrinkage during cooling leads to residual stresses and cracks

Question 29

fusion welding

Answer 29

melting and subsequent solidification, best known and most widely used process

Question 30

heat affected zones HAZ

Answer 30

area around the weld where heat alters material properties power density decrease, size of the HAZ increase

Question 31

pressure welding

Answer 31

uses pressure and heat without melting the base material. redced risks, does not change the material properties

Question 32

friction stir welding

Answer 32

solid-state process using a rotating tool to generate heat by friction suitable for aluminium alloy skin panel

Question 33

laser beam welding

Answer 33

high.density laser melts material locally, minimal HAZ widely used in automotive, aricraft in aluminium fuselage shells is now the state of the art