Deformation force may be applied gradually(forging press) or as an impact load(forging
hammer) using open dies, impression dies, or flashless dies. Flashless dies prevent flow
of excess metal along parting line between two die halves this is flash, which
. Closedhookxlotrcd notes? «-
l9 lebruory 2013
Exam ll 2. Version: B _ SELECT BEST ANSWER
ALI. ANSWERS UH TI liS EXAM AND SCANTRGN
l) _ What are the primary nioteriuhi needed to produce
ferrous ritetuls? I
A, Carbon, manganese. iron.
B: . iron or
Solid Object Printing (SOP) or 3D printing Z Corp, based on a method developed @
MIT uses a wide-area inkjet to spray binding agent onto powder material(typically platter
or starch). Very cheap & fast, but limited part strength & accuracy.
An office-friendly process that employs no lasers or toxic materials.
*fabrication times: hours
*system cost: $25,000 - $150,000
*part sizes: 9-30 in, depending on model
*material cost: $100/lb.
Selective Laser Sintering (SLS) : originally DTM Corp. - mer
*Can be used to fabricate smart structures with embedded sensors.
*Many other applications: architectural design, biomedical engineering, art and sculpture,
Stereolithography(SLA) 3D Systems
The original RP process. Uses a liquid photopolymer t
*Adobe bricks are compacted dired mud, reinforced with strands of straw.
*Steel-reinforced concrete used for buildings and bridges since 19th century (adhesion not
*Plywood is a laminate of cross-grained wood veneer sheets bonded with resin.
Layout can also be done by CNC tape or wire laying machine
Reinforced plastic(often heated) can also be formed by various molding processes
compression, vacuum, or open(contact) molding e.g. hand lay-up
A family of technologies deve
Fiber materials include glass(fiberglass glass-reinforced plastic), carbon (graphite),
Kevlar, ceramics, metals.
Particles or flakes have random distributions in matrix & come in a variety of sizes. Work
by inhibiting crack propagation (crystal dislocatio
To expand and assume shape of mold cavity. Control of thickness is an important factor.
Typically a high-volume process.
Machining of molds for large parts may cost ~$100,000 (eg. Auto bumper or refrigerator
door). Hence, injection molding is only suitabl
Composites are typically composed of two heterogeneous materials, in physically district
phases, whose combination provides superior properties(stiffness, strength/weight ratio,
etc) than the individual materials.
*low strength, stiffness, melting point relative to metals; creep under steady stress; may
degrade under exposure to sunlight(UV) or atmosphere.
Plastics manufacturing developed in first half of 20th century; computer automation was
introduced in the 70s-
in England during Industrial Revolution to make lead pipes. May be performed with hot
or cold metal billet. Limited to parts of uniform cross-section, but high tolerances are
Direct extrusion: (forward extrusion): involves forcing metal billet t
drawing(forming a concave shape in a work piece held by a blank holder), and cutting by
shear action(not really a deformation process).
In deep drawing, punch and die must have suitable fillet(corner) radii & clearance to
ensure metal is deformed rather t
incomplete forging (die under-filled) or excessive forces (die over-filled). Coin
manufacture is a typical example.
Rolling: reduce part thickness(or change cross-section shape) by feeding between
counter-rotating tools called rolls on a rolling mill. Rot
Metal forming(mechanical deformation)
Forming processes involve large compressive stresses
(exceeding yield strength of metal) to change shape of work piece through plastic (nonrecoverable) deformation. Large forces are applied to work piece by a press or
Hot Working (~50-75% of Tm, Kelvin scale melting temperature).
*re-crystallation temperature internal structure of metal can re-organize.
*requires lower forces than cold-working and substantial deformation possible
*may be feasible for metals that are br
Third Angle Projections
o Front Side
Design for X
o IMPORTANT ONES: Assembly, Manufacturing
Design for Manufacturing and Assembly (DFMA)
o optimize all manuf