Differences between primary, secondary, and tertiary industries? Primary industry cultivates and exploits natural resources, such as agriculture or mining. Secondary industry takes the outputs of primary industries and converts them to consumer and capital goods (industries are textiles and electronics) A tertiary industry is in the service sector of the economy (tertiary industries are banking and education)// Final Product divides in 2 classes 1. Consumer goods- products purchased directly by consumers 2. Capital Goods - those purchased by companies to produce goods and/or provide services // Annual quantities divide in 3 ranges Low production (1 to 100 units), Medium Production (100 to 10,000 u) and High Production (10,000 to millions)// Product Variety is how each product varies from one another. Soft Product variety: Small differences between products Hard Product Variety: Products differ substantially // Manufacturing Capability 3 main: 1. Technological Process Capabilities (The set of available manufacturing processes in the plant (or company), 2. Physical Product Limitations Given a plant with a certain set of processes, there are size and weight limitations on the parts or products that can be made in the plant 3. Product capacity Defined as the maximum quantity that a plant can produce in a given time period under assumed operating conditions (number of shifts per week, hours per shift, direct labor manning levels in the plant, etc.) // Relation variety-quantity quantity is inversely related to variety. Large variety = smaller quantity and inversely// three basic categories of engineering materials are metals, ceramics, and polymers. Composites, is a non-homogeneous mixture of the other types (not a basic categ.)//Shaping process vs. surface processing operation? A shaping process changes the geometry of the work material (machining or forging). Surface processing operation alters surface of the work (painting or plating). //Assembly processes? 2 subclasses: permanent joining and mechanical fastening. // Production Levels Low production: makes low quantities of specialized and customized products; Medium: 2 types Batch production: medium and hard product variety (Setups req. between batches) Cellular manufacturing Suited to soft product variety Worker cells organized to process parts without setups between different part styles; High: mass production, High demand for product.2 types: Quantity production & Flow line production// Particulate processing of metals and ceramics pressing and sintering// High-volume production of assembled products is most closely associated with product layout// Advantages of shape-casting processes Advantages: complex part geometries, some are net shape processes, very large parts are possible; applicable to any metal that can be melted; and some casting processes suited to mass production// Disadvantages of casting limitations on mechanical strength properties; porosity; poor dimensional accuracy; safety hazards due to handling of hot metals; and environmental problems//Foundry Factory that performs casting operations// Open mold vs closed mold: open mold is an open container (to atmos) in the desired shape which must be flat at the top. Closed mold has a cavity that is entirely enclosed by the mold, with a gating system leading from the outside to the cavity. Molten metal is poured into this gating system to fill the mold// 2 basic mold types expendable molds and permanent molds// Most important casting processes commercially is Sand casting// Difference between a pattern and a core in sand molding pattern determines the external shape, core determines internal geometry if the casting includes a cavity// 3 sources of contraction after pouring 1) contraction of the molten metal after pouring, 2) solidification shrinkage during transformation of state from liquid to solid, and 3) thermal contraction in the solid state// Chill is a heat sink placed to encourage rapid freezing in certain regions of the casting// The upper half of a sand-casting mold is called cope, the bottom is drag// Flask is a box which holds the cope and drag// Runner is a channel in the mold leading from the downsprue to the main mold cavity// Turbulence during pouring of the molten metal is undesirable because it increases erosion of the mold surfaces and it increases the formation of metallic oxides that can become entrapped during solidification// Total solidification time is time between pouring and complete solidification// Riser in casting is described by metal that is not part of the casting, source of molten metal to feed the casting and compensate for shrinkage during solidification, and waste metal that is usually recycled // 2 basic categories of casting processed are expendable mold processes and permanent mold processes// Split Pattern vs Match-Plate Pattern A split pattern is a pattern that consists of two pieces; a match-plate pattern consists of the two split patterns attached to opposite sides of a plate// Chaplet are metal supports of various designs used to hold the core in place in the sand mold// Properties determine the quality of a sand mold for sand casting: strength (ability to maintain shape in the face of the flowing metal) permeability - ability of the mold to allow hot air and gases to escape from the cavity; thermal stability - ability to resist cracking and buckling when in contact with the molten metal; collapsibility - ability of the mold to give way during shrinkage of the solidified casting, and; reusability - can the sand be reused to make other molds? Vacuum permanent-mold casting vs vacuum molding Vacuum permanent-mold casting is a form of low-pressure casting in which a vacuum is used to draw molten metal into the cavity. Vacuum molding is sand casting in which the sand mold is held together by vacuum pressure rather than by a chemical binder// most common metals used in die casting Common die-casting metals include zinc, tin, lead, aluminum, brass, and magnesium// Which die-casting machines usually have a higher production rate, cold-chamber or hot-chamber, and why? Hot-chamber machines are

faster because cold-chamber die casting machines require molten metal to be ladled into the chamber from an external source. Ladling takes more time than injecting the molten metal into the die as in the hot-chamber operation. // Flash is a thin portion of metal at the exterior of a casting that results from molten metal being squeezed into the spaces between the die halves of the mold at the parting line, or into the clearances around the cores and ejector pins// True centrifugal casting vs semi-centrifugal casting: true centrifugal casting, a tubular mold is used and a tubular part is produced. In Semi-centrifugal casting, the shape is solid; an example is a railway wheel. The mold is rotated so that centrifugal force is used to distribute the molten metal to the exterior of the mold so that the density of the final metal is greater at the outer sections// Cupola is a vertical cylindrical furnace equipped with a tapping spout near its base (are used for melting cast irons.)//Operations required in sand casting after the casting is removed from the mold The operations include trimming, in which the sprues, runners, risers, and flash are removed, core removal, surface cleaning, inspection, repair if needed, heat treatment, and machining//General defects in casting processes(3): misruns, in which the casting solidifies before filling the mold cavity; cold shuts, in which two portions of metal flow together but there is lack of fusion at the joint; cold shots, where solid globules of cast metal become entrapped in the casting; shrinkage cavity, which is a depression on the casting surface or an internal void in the casting caused by solidification shrinkage; microporosity, which is a network of small voids throughout the casting caused by localized solidification shrinkage; and hot tearing, which is a crack in the casting caused by a mold that does not yield to the metal during the early stages of solidification shrinkage//Composition of green sand is silica sand, clay, and water// sand casting vs investment casting Sand casting provides low production cost for a wide variety of metals, shapes and sizes. The size of the casting is unlimited. The disadvantage is the surface finish and dimensional control are not very good// Most used casting processes is sand casting// Which of the following casting processes are expendable mold operations (four correct answers): investment casting, sand casting, shell molding & vacuum molding// Shell molding is best as casting process in which the mold is a thin shell of sand bonded by a thermosetting resin// Investment casting is also known by lost-wax process//Precision-casting process (two correct answers): investment casting, plaster-mold casting// Permanent mold operations centrifugal casting, die casting and slush casting// Most important commercially casting is cast iron//Importance of bulk deformation they are capable of significant shape change when hot working is used, they have a positive effect on part strength when cold working is used, and some are net shape processes// 4 basic bulk deformation proc. The four basic bulk deformation processes are rolling, forging, extrusion, and wire and bar drawing// Rolling in BDP? is a deformation process in which the thickness of the workpiece is reduced by compressive forces exerted by two opposing rolls. The rolls rotate, thus pulling and simultaneously squeezing the workpiece between them// Rolling of steel bloom, a slab, and a billet? A bloom is a rolled steel workpiece with a square cross section of about 150 mm by 150 mm. The starting work unit for a bloom is an ingot heated in a soaking pit. A slab is rolled from an ingot or a bloom and has a rectangular cross section of about 250 mm by 40 mm. A billet is rolled from a bloom and has a square cross section of about 40 mm by 40 mm// Products produced on a rolling mill Rolled products include flat sheet and plate stock, round bar and rod stock, rails, structural shapes such as I-beams and channels// Draft is the difference between the starting thickness and the final thickness as the workpiece passes between the two opposing rolls// Force in flat rolling can be reduced Ways to reduce force in flat rolling include use hot rolling, reduce draft in each pass, and use smaller diameter rolls// Rolling Configurations Two-high – two opposing rolls Three-high – work passes through rolls in both directions Four-high – backing rolls support smaller work rolls Cluster mill – multiple backing rolls on smaller rolls Tandem rolling mill – sequence of two-high mills// Reversing mill A reversing mill is a two-high rolling mill in which the direction of rotation of the rolls can be reversed to allow the work to pass through from either side// Additional bulk forming processes that use rolls Some other processes that use rolls are ring rolling, thread rolling, gear rolling, roll piercing, and roll forging// Forging? is a deformation process in which the workpiece is compressed between two dies, using impact or gradual pressure to form the part// Forging operations basic classifications open die forging, impression die forging, and flashless forging.// Flash desirable? Because its presence constrains the metal in the die to fill the details of the die cavity// Trimming operation in impression die forging? Trimming is a shearing operation used to remove the flash on the workpiece after impression die forging// 2 basic forging equipment? The two types of forging machines are hammers, which impact the workpart, and presses, which apply a gradual pressure to the work// Extrusion? is a compression forming operation in which a workpiece is forced to flow through a die opening, thus taking the cross-sectional shape of the die opening// Direct vs indirect extrusion In direct extrusion, also known as forward extrusion, a metal billet is loaded into a container, and a ram compresses the material, forcing it to flow through a die opening at the opposite end of the container. In indirect extrusion, also known as backward extrusion, the die is incorporated into the ram, and as the ram compresses into the metal billet, the metal is forced to flow through the die opening in a direction that is opposite (backwards) of the ram motion// Products by

extrusion continuous extrusion include structural shapes (window frames, shower stalls, channels), tubes and pipes, and rods of various cross sections. Products made by discrete extrusion include toothpaste tubes, aluminum beverage cans, and battery cases// Friction a factor in determining the ram force in direct extrusion but not a factor in indirect extrusion? Friction is a factor in direct extrusion because the work billet is squeezed against the walls of the container so that friction resists the movement of the billet toward the die opening. In indirect extrusion, the billet does not move relative to the container walls, and thus there is no friction// wire drawing and bar drawing? are bulk deformation processes in which the cross section of a wire or bar is reduced by pulling (drawing) it through a die opening// compressive stresses in bar and wire drawing the process? Compressive stresses are present in wire drawing because the starting metal is compressed as it is forced through the approach of the die opening// Accessory tools for open die forging are saddles, blocks, rings, mandrels, and punches.

The starting workpiece in steel hot rolling of plate and sheet stock is slab// The maximum draft in a rolling operation depends on coefficient of friction between roll and work & roll diameter// Small diameter rolls in rolling mill types are cluster mill, four-high mill// Production of pipes and tubes associated extrusion, roll piercing & tube sinking// Operations related to open-die forging are cogging, fullering, upsetting// Flash is desirable as causes build-up of pressure inside the die, which forces the work metal to fill the die cavity// The following are classified as forging operations: coining, fullering, swaging, and upsetting// Alternative names for indirect extrusion backward extrusion & reverse extrusion// Tube and pipe cross sections can be produced by either direct or indirect extrusion// Theoretically, the maximum reduction possible in a wire drawing operation, under the assumptions of a perfectly plastic metal, no friction, and no redundant work, is 0.63// The following bulk deformation processes are involved in the production of nails for lumber construction bar and wire drawing, flashless forging, & impression die