MFGE 2332 Exam 2 review Mark SUMMERS

Polarity DC (-)

"Direct Current" Reverse polarity, electrode is positive, workpiece is negative, wide shallow welds

Polarity DC (+)

"Direct Current" straight polarity, electrode is negative (DCEN), workpiece is positive, narrow deep welds

CAPILLARY

(BLANK) action helps pull the filler material into the gaps between the parts during a furnace brazing operation.

Threading

(BLANK) is a cold working process that creates grooved features on cylindrical features.

Malleable

(BLANK) material is easily formed under compressive loading.

ductile

(BLANK) material is easily formed under tensile loading.

WAVE

(BLANK) soldering is a high output process that bonds electronic components to a PCB

Slotting

- A punching operation that forms rectangular holes in the sheet. Sometimes described as piercing despite the different shape.

Lancing

- Creating a partial cut in the sheet, so that no material is removed. The material is left attached to be bent and form a shape, such as a tab, vent, or louver

Gas Metal-Arc

- General purpose welds

Open-die Forging

- The simplest forging operation (also called upsetting or flat-die) • A metal workpiece is placed between two flat dies, then reduced in height by compressing

-OFW or "Torch"

- low temperature process/ requires two handed skilled workers

PUNCHING

- material is removed from a larger piece of stock, the removed part is scrap

Extrusion process

1) Extrusion is continuous production process. 2) Mechanical screw rotates continuously, and it pushes the molten material through the die. 3) This die has a required shape such as circular for pipes. 4) The extruded material is then cooled in the water bath and cut in the required length. Extrusion is useful for uniform sections.

Constituent Materials

1) Reinforcement (in the form of Particles or, Fibers) •Major load carrying component (Gives strength, stiffness, and other mechanical properties). •Dominates properties such as CTE and thermal conductivity. 2) Matrix or Binder •Gives shape to the part (Provides lateral support) •Support the fibers in place and transfers loads/stresses to the fibers •Provides barrier against physical damage and environment •Protects the surface from abrasion and slow the propagation of cracks in the composite.

Blanking

A desired part is removed from a larger piece of stock.

Polarity AC

Alternating Current, ideal for welding thick sections

100

As a good rule of thumb, (BLANK) Dc amps are required to weld two pieces of 1/16" thick steel together.

DECREASE

Creating a highly polished surface on the mating surface of two mating parts that are being adhesively bonded will (BLANK) the bonding strength of the joint.

Slitting

Cutting straight lines in the sheet, no scrap material is produced

PRESSURE OR FORCE , CURRENT

During a resistance welding operation, first a(n) (BLANK) is applied to hold the parts together, and then a(n) (BLANK) is passed through the parts to be joined.

Shielded Metal-Arc

Field welds on large steel pipes

Oxidation or Contaminants

Flux and inert gas reduce (BLANK) in welded joints.

thicker

Gas Metal-Arc Welding uses a consumable bare wire and is more suitable for joining (BLANK) sheets of material

Non-consumable Electrode

Gas Tungsten arc Welding Process (GTAW) Plasma-Arc Welding (PAW)

Resistance welding

Good for automated welds

Billet

Has comparable width, height, and length dimensions

Pressure Gas Welding

Heat two sides "faces" and press them together

Laser-Beam Welding

High power laser beams as heat source Welds deep and narrow joints No vacuum

Gas Tungsten-Arc

High quality weld requiring skilled welder

HEAT EFFECT ZONE

In a fusion weld the (BLANK) is the area of the base part that experiences reduced material strength.

K-factor

In a sheet metal part, the (BLANK) is a function of several different parameters, including material type/thickness, bend radius, and tonnage.

FILLER, BASE

In brazing and soldering operations, the (BLANK) metal is melted but the (BLANK) metal is not melted

Rotary Swaging

In this process, a solid rod or tube is subjected to radial impact forces by a set of reciprocating dies of the machine.

Coining

It is closed die forging method used in minting coins, medallions, and jewelry. LUBRICANTS SHOULD NOT BE USED

Electron-Beam Welding

Kinetic energy converted to heat Requires special equipment for the vacuum condition High quality welds, deep and narrow No shielding gas or flux

equations for problem 9

Lt=A+B-BD BA=Pi(R+KT)A/180 ossb=(tana/2)(T+R) BA=(2xOSSB)-BD Lt1=A+B-BD Lt2=A+B+C-(2*BD)

Thermite Welding

Mix of Metal Powder (Aluminum) and a metal oxide (Iron oxide, rust) High Temp ignition source, 2,000 degrees F/ 4,500 degrees F Railroads

- Mercury - Lead - Cadmium - Chromium

Name (4) hazardous materials banned by the European Union in the 2000's

3 Types of flames

Neutral- A%=O% Oxidizing- A%<O% Carburizing- A%>O%

Perforating

Punching a close arrangement of many holes in a single operation.

Nibbling

Punching a series of small overlapping slits or holes along a path to cutout a larger contoured shape. This eliminates the need for a custom punch and die but will require secondary operations to improve the accuracy and finish of the feature

Trimming

Punching away excess material from the perimeter of a part, such as trimming the flange from a drawn cup.

ROHS-

Restriction of Hazardous Substances

Parting

Separating apart from the remaining sheet, by punching away the material between parts.

Cutoff

Separating apart from the remaining sheet, without producing any scrap. The punch will produce a cut line that may be straight, angled, or curved

Shearing

Separating material into two parts

Consumable Electrode

Shielded Metal Arc-Welding (SMAW) "Stick" Gas Metal-Arc Welding (GMAW) "MIG" Submerged-Arc Welding (SAW) Flux-Cored Arc Welding (FCAW) Electrogas Welding (EGW) Electroslag Welding (ESW)

INNER, OUTER

The (BLANK) bend radius is specified on a drawing as opposed to the (BLANK) bend radius.

70

The Tensile strength of an E7013 electrode is (BLANK) ksi

INCREASE

The flat pattern length will (BLANK) if the k-factor is increased.

Resistance brazing

The parts to be joined are pressed between electrodes and a current is passed through. The heating of the joint is primarily by conduction from the hot electrodes.

Furnace brazing

The process is carried out in a furnace with controlled atmosphere or vacuum, brazing jigs or fixtures must be used.

Piercing

The typical punching operation, in which a cylindrical punch pierces a hole into the sheet

Plate

Thicker than 6mm

Thermite

Use extensively by railroad workers

GTAW or "TIG"

Uses a Non- Consumable electrode and usually AC current / uses DC current and used for thicker materials

GMAW or "MIG"

Uses a consumable electrode and gas lines for flux/ Uses DC current and used for thinner materials

BA, BD

When calculating flat pattern length, the (BLANK) is computed first, and then used to compute the (BLANK).

At the tip of the inner cone

Where is the hottest part of the flame in an OFW welding operation?

Resistance welding

Work pieces are welded due to a combination of a pressure applied to them and a localized heat generated by a high electric current flowing through the contact area of the weld

Friction welding

a Solid-State Welding process, in which two cylindrical parts are brought in contact by a friction and pressure when one of them rotates. Friction between the parts results in heating their ends. Forge pressure is then applied to the pieces providing formation of the joint.

Bending

a metal forming process in which a force is applied to a piece of sheet metal, causing it to bend at an angle and form the desired shape. (Deformation along one axis)

Capillary action

a phenomenon where liquid spontaneously rises in a narrow space such as a thin tube.

sheet-metal forming

a piece of sheet metal is plastically deformed into a three-dimensional shape, often without significant changes in sheet thickness or surface characteristic.

ring rolling

a thick ring is expanded into a large-diameter thinner one. The ring is placed between two rolls (one is driven and other idle). Its thickness is reduced by bringing rolls closer. As thickness reduces diameter increases (volume remaining constant).

3 different zones in a weld,

base metal, Heat affected zone, weld metal

Electrode Coating

claylike materials that include silicate binders and powdered materials, such as oxides, carbonates, fluorides, metal alloys, cotton cellulose, and wood flour.

Spring back

elastic recovery

Deep drawing

forcing it into a die cavity in the shape of the desired part.

Flux

generates a shield gas around the weld zone and Retard oxidation of the metals being welded

Forged part

has increased surface/volume ratio

• Solid state welding involves one or more of the follow parameters.

heat and pressure

Reflow soldering

in this method, a solder paste (a mix of solder and flux particles) is applied onto the surface of the parts to be joined and then are heated to a temperature above the melting point of the solder. The process is conducted in a continuous furnace.

Resistance spot welding(RSW)

in which two or more overlapped metal sheets are joined by spot welds.

ROHS

indicates a substance that restricts the use of six specific hazardous materials in electrical and electronic products.

Thread rolling

is a cold forming process by which threads are formed. The threads are formed on the rod with each stroke of pair of flat reciprocating dies or, rotary dies

Brazing

is a joining process in which filler metal (typically brass) is placed between the faying (mating) surfaces to be joined and temperature is raised to melt the filler metal, but the base metals are not melted.

Roll forming

is a metal forming process in which sheet metal is progressively shaped through a series of bending operations. As the sheet is forced through the roller dies in each roll station, it plastically deforms and bends. (lubricant used)

Hot working

is defined as the plastic deformation of metals above their recrystallization temperature

Hot forging

is done at a high temperature, which makes metal easier to shape and less likely to fracture.

Warm forging

is done at intermediate temperature between room temperature and hot forging temperatures.

Cold forging

is done at room temperature or near room temperature.

Heading

is performed on the end of a rod or wire to increase cross-section. Ex) Nails, bolt heads, screws, rivets

Cold working

is the plastic deformation of metals below the recrystallization temperature. In most cases of manufacturing, such cold forming is done at room temperature.

Extrusion

is the process by which a block of material is reduced in cross section by forcing it through a die orifice under high pressure. IS A HOT WORKING PROCESS?

Rolling

is the process of reducing the thickness or changing cross-section of long workpiece by compressive forces applied through a set of rolls

Forging

is the term for shaping metal by using localized compressive forces.

Spinning-Spin forming

is used to form cylindrical parts by rotating a piece of sheet metal while forces are applied to one side.

Composite material

o -Two or more different materials combined on macroscopic scale o -Reinforcement + Matrix

Metal-forming processes are usually classified according to two broad categories

o Bulk, or massive forming operations o Sheet-metal forming operations (sheet metal)

Brazing fluxes act to

o Dissolving oxides formed prior to heating. o Preventing the formation of new oxides during heating. o Lowering the surface tension between the molten brazing metal and the surfaces to be joined.

Thermosetting polymers

o Polymers become permanently hard when heat is applied and do not soften upon subsequent heating. o During initial heat treatment, covalent crosslinks are formed between adjacent molecular chains. o They are generally harder, stronger, and more brittle than thermoplastics, and have better dimensional stability. e.g., Epoxies, Phenol Formaldehyde (Bakelite), Polyesters

Thermoplastic polymers

o Polymers soften when heated (and eventually liquefy), and harden when cooled. o This process of liquefying and solidifying is reversible and repeatable. e.g., Polyethylene(PE), polypropylene(PP), polycarbonate(PC), polymethylmethacrylate (PMMA) .........

Soldering

operation where the filler metal has a melting temperature below 450ºC (840ºF). It is typically used for joining thin metals, connecting electronic components, joining metals while avoiding exposure to high elevated temperature, and filling surface flaws and defects.

Torch-brazing

oxy-acetylene (carburizing flame), oxyhydrogen, or other gas flame combination can be used as heat source.

Electrical current

provides the heat required for an Arc-welding process

Notching

punching the edge of a sheet, forming a notch in the shape of a portion of the punch

Lubrication

reduces the friction and suppress tool wear

Stretch forming

stretched and bent simultaneously over a die to form large contoured parts.

dip brazing

the assemblies are immersed in a bath of molten brazing metal, the bath provides the heat and the metal for the joint

bulk forming

the input material is in billet, rod, or slab form, and the surface to-volume ratio in the formed part increases considerably under the action of largely compressive loading.

Wave soldering

the method uses a tank filled with a molten solder. The solder is pumped, and its flow forms a wave of a predetermined height. The printed circuit boards (PCB) pass over the wave touching it with their lower sides. Components are adhesively bonded to PCB. Board is inverted and passed through wave of solder. Solder will not stick to polymer surfaces. High velocity hot air jet removes excess solder away.

Oxyfuel-Gas

thin materials requiring low skilled welder

Sheet

thinner than 6mm

SMAW or "Stick"

uses a consumable electrode with coating for flux/ base metal is not melted

Induction brazing

uses induction heating by high frequency AC current as a heating source. Parts are preloaded with filler metal and are placed near the induction coils for rapid heating.

Iron soldering

utilizes a heat generated by a soldering iron

Torch soldering

utilizes a heat of the flame from a torch. The torch mixes a fuel gas with oxygen or air in the proper ratio and flow rate, providing combustion process at a required temperature.

Impression-die (closed-die) Forging

• The workpiece takes the shape of the die cavity while being forged between two shaped dies. • This process is usually carried out at elevated temperatures, to lower the forging forces and develop enhanced ductility of the workpiece. • Some of the material flows outward and forms a flash