Manufacturing Engineering (Fertigungstechnik) - Practice Flashcards

Comprehensive practice flashcards covering manufacturing processes, casting techniques, material properties of iron, forming methods like forging and deep drawing, and machining principles.

The 6 main groups of manufacturing processes

Primary forming (Urformen), forming (Umformen), separating (Trennen), joining (Fügen), coating (Beschichten), and changing material properties (Stoffeigenschaften ändern).

Primary forming (Urformen) examples

Casting (Gießen), injection molding (Spritzgießen), and sintering (Sintern).

Separating (Trennen) examples

Milling (Fräsen), turning (Drehen), and drilling (Bohren).

Casting (Gießen) carbon threshold

In the iron-carbon diagram, white/free carbon begins at $2.1\, \% \text{C}$, though the actual casting range usually begins at approx. $3\, \% \text{C}$ to save energy during melting.

Exogenous solidification

Solidification that occurs from the outside in, where solid parts grow from the edge toward the center.

Endogenous solidification

Solidification occurring within the melt itself, involving many nuclei within the liquid.

Ledeburit

A state created by rapid cooling where carbon atoms are trapped without forming free graphite; it is the primary component of hard, brittle white cast iron.

Tempering (Tempern)

Heating a material below its melting point for a long duration to reduce internal stresses; it changes the material from hard/brittle to tough/ductile.

Globular Gray Cast Iron (Kugelgraphit)

A highly deformable cast iron with tensile strength of $400-800\,N/mm^2$ where magnesium is added to bind carbon and reduce surface tension, preventing notches.

EN-GJL-150

A standard designation where EN = European Norm, GJ = Cast Iron, L = Lamellar graphite, and $150$ = minimum tensile strength in $N/mm^2$.

Graphite structure abbreviations (L, S, M, V, H, X)

L = Lamellar, S = Spheroidal (Kugel), M = Temper carbon, V = Vermicular, H = Graphite-free, X = Special structure.

Volumetric changes during solidification

Liquid shrinkage (Flüssige Schrumpfung), solidification shrinkage (Erstarrungsschrumpfung), and solid contraction (feste Schwindung).

Feeder (Speiser)

A reservoir in the mold that prevents shrinkage cavities (Lunker) by providing extra material and allowing air to escape.

Three main categories of casting processes

1. Lost mold/permanent model (e.g., sand casting), 2. Lost mold/lost model (e.g., investment casting), 3. Permanent mold/no model (e.g., die casting).

Investment Casting (Feingießen) properties

High dimensional tolerance, excellent surface quality, greatest design freedom, and burr-free workpieces requiring little post-processing.

Cold chamber machine (Kaltkammermaschine)

A die casting method used for Aluminum where melt is injected at high pressure ($800-1000\,bar$), producing one part every $15$ seconds.

Plastic deformation

A permanent change in shape where the volume remains constant; it occurs after the elastic limit is exceeded in the stress-strain diagram.

Crystal Anisotropy (Texture)

The alignment of grain lattice planes through plastic deformation, which changes mechanical properties depending on the direction of loading.

Recrystallization (Rekristallisation)

A process occurring at approx. $600\,^\circ\text{C}$ that removes internal stresses, allowing for easier and more extensive subsequent forming.

Backward Extrusion (Rückwärts-Fließpressen)

A forming process where the material flows in the opposite direction of the punch; commonly used to create deep-drawn-like shapes.

Impression Die Forging (Gesenkschmieden) 'narrowing'

An intentionally built-in bottleneck that forces steel into all corners of the mold, preventing it from taking the path of least resistance.

Bondering (Phosphating)

A surface treatment before deep drawing that roughens the surface and acts as a lubricant to reduce tool wear.

Fine Blanking (Feinschneiden)

A cutting process that separates material purely through flow without a fracture surface, achieved via all-sided clamping (ring indentation/ringzacke).

Roughing (Schruppen) vs. Finishing (Schlichten)

Roughing focuses on high volume removal (large depth and feed), while finishing focuses on precision, surface quality, and high cutting speed (low depth and feed).

Time-chip volume formula (Qw)

$Q_w = v_c \times f \times a_p$ (Schnittgeschwindigkeit $\times$ Vorschub $\times$ Schnitttiefe).

Turning Tool Angles (alpha, beta, gamma)

$\alpha$ (Relief angle), $\beta$ (Wedge angle), and $\gamma$ (Rake angle) always sum to $90^\circ$.

Continuous chip (Fließspan)

Forms when machining soft, ductile, homogeneous materials (like low-carbon steel or Aluminum) at high cutting speeds with large rake angles.

Built-up edge (Aufbauschneide)

A phenomenon occurring at medium cutting speeds ($v_c$) where material welds to the tool tip due to pressure and temperature; avoided by increasing speed to trigger recrystallization.

Crater wear (Kolkverschleiß)

A hollow/depression formed behind the cutting edge caused by high temperature and pressure, which eventually leads to the edge breaking off.

Chatter vibrations (Ratterschwingungen)

Excited vibrations in the tool-workpiece system caused by cutting forces and the regenerative effect; corrected by changing feed, depth of cut, or RPM.

Cutting Material Speeds (v_c)

HSS ($\sim 30\,m/min$), HM ($\sim 120-150\,m/min$), HMC/Coated ($\sim 800-950\,m/min$), and Superhard/SK ($>1000\,m/min$).