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| involves the use of a semisolid liquid or gel laden with abrasives to flow over or through a workpiece to perform edge finishing, deburring, radiusing, polishing, or minor surface machining. |
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| removes material by a focused jet of abrasives and is similar in many respects to AWC with the exception that momentum is transferred to the abrasive particles by a jet of inert gas. |
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| Abrasive waterjet cutting |
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Definition
| is where abrasives are added to the waterjet in a mixing chamber on the dowstream side of the waterjet orifice. |
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| (also sometimes referred to as etch factor) is used to describe the directionality of the cut. The _____________, A, of a material/etchant interaction in photochemical machining is defined as: A = d/U |
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| Through-etching of the workpiece. Typically performed using double-sided etching to increase production rates and minimize taper on the etched walls of the feature. |
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| simplest and oldest of the chipless machining processes. Process of removing material from a workpiece by selectively exposing it to a chemical reagent or etchant. The mechanism for metal removal is the chemical reaction between the etchant and the workpiece resulting in dissolution of the workpiece. |
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| Chemical-mechanical polishing |
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Definition
| uses the synergy of chemistry and mechanical grinding to obtain flatness on the order of 50 nm. |
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| The gross removal of material from a body by the corrosive action of an acid or an alkali that results in a substantial change of shape of the body. |
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| simplest method of applying a maskant, usually neoprene, polyvinyl chloride, or polyethylee, is appplied to the entire surface of the workpiece by dipping or spraying. Once the coating dries, it is then selectively removed in those areas where etching is desired by scribing he maskant with a knife and peeling away the unwanted portions. |
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| a chemical entity consisting of two structurally similar subunits called monomers joined by bonds that can be either strong or weak. |
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| thinning in center due to improper agitation or stacking of parts in tank |
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| the on-time as a percentage of the total cycle time (inverse of the frequency) |
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| electrical discharge machining- |
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Definition
| process removes metal by discharging electric current from a pulsating DC power supply across a thin interelectrode gap between the tool and the workpiece. |
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| electrical discharge wire cutting- |
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Definition
| in this, the electrode is a wire used for cutting through-cut features driving the workpiece with a CNC table. |
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| electrochemical deburring- |
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Definition
| a deburring process which works on the principal that electrolysis is accelerated in areas with small interelectrode gaps and prevented in areas with insulation between electrodes. |
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| Electrochemical grinding (ECG) |
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Definition
| while the product is rotated low voltage high current used to remove some of the material the rest of the affected material is oxidized the oxidized material is then ground away |
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| Electrochemical machining (EM) |
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Definition
| using high velocity stream of charged particles through a glass tube used to remove unwanted material |
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| Electrochemical micromachining |
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Definition
| Removes material by anodic dissolution with a rapid flowing electrolyte uses electrical current to bring about chemical change |
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| Electrochemical polishing |
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Definition
| low current density the charged particles are forced through a glass tube used to remove unwanted material at a slow rate fine finish |
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| A thermal process that uses a beam of high energy that vaporises the metal tat is to be removed |
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| low current density the charged particles are forced into wok piece with out a part specified had tool to remove unwanted material at a slow rate gives a fine finish |
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| using high velocity stream of charged particles through a glass tube used to drill holes usually multiple small holes at one time |
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| Something to consider in chemical machining. Etch Factor (E) describes the relationship between undercut (U) and depth of cut (d). See picture. |
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| Fine Plasma Cutting/High-definition Plasma/Precision PAC |
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Definition
| Uses a special nozzle to stabilize the plasma pressure for a more finely defined PAC beam. Reduces problems of HAZ and dross on the bottom of parts. |
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| CHM where the etchant is applied in a gel form. |
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| In PAC(plasma arc cutting), the ____________ is a negative side-effect. (Not from book, this is just an inference) This makes it unusable where the workpiece is thermally delicate/sensitive. |
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| Hydrodynamic(Waterjet) Machining |
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Definition
| uses a high-velocity fluid jet to perform a slitting operation. Water is ejected from a nozzle at very high pressure (up to 60,000 psi). |
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| Preferential etching due to ______________ can also be an issue in Chemical Machining. |
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| Nano-scale machining used to cleave wafers. Often used on defective wafers for characterization and failure analysis. |
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| Photochemical milling (689) |
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Definition
| Milling using the photoresist method of applying maskants. Named photochemical because its earliest usage was for replacing mechanical miling on large componets. It is often used to remove weight on on aircraft componets (see fig 28-4) |
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Definition
| The most common and precise method for creating maskants involves using UV light sensitive emulsions called _____ |
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| A defect due to unequal etch rates |
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| Plasma Arc Cutting (PAC) (714) |
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Definition
| Uses a superheated stream of electrically ionized gas to melt and remove material. 20,000 to 50,000 deg F.plasma is created inside a water cooled nozzle by electrially ionzing a suitable gas such as nitrogen, hydrogen, argon, or mixtures of these gases. The process can be used on almost any conductive metal. |
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| (Also called high definition plasma and fine plasma cutting) uses a special nozzle where either a high flow vortex or a magnetic field causes the plasma to spin rapidly and stabilizes the plasma pressure. The fast spinning plasma results in a finely defined beam that cuts a narrow kerf with a perpendicular edge. Precision pac also reduces the problems of HAZ and dross on the bottom parts. |
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| has recently shown the potential to improve accuracies and surface finish in tradicinal ECM. In PECM, high current densities (> 100 A/cmsq) are pulsed on for durations on the order of 1ms and pulsed off for intervals on the order of 10ms. The relaxation interval permits reaction byproducts to be removed from the interelectrode gap at low electrolyte flow rates without electrolytic desposition on the ECM tool. |
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| One of the two dfferent types of EDM based on the shape of the tool electrode used. In ____ the electrode is a die in the shape of the negative of the cavity to be produced in bulk material. By feeding the die into the workpiece, the shape of the die is machined into the workpiece |
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| A method of applying maskants is _____. It involved the use of traditional silk screening technology. The method applies the maskant through the a mask made from a fine silk mesh or stainless steel screen. Masks are typically formed by application, exposure and development of a light sensitive emulsion on top of the screen. The screen is placed on top of the workpiece and the maskant is rolled on. Good for high volume, low precision applications. |
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| Water jet Cutting (WJC) (701) |
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Definition
| uses a high- velocity fluid jet impinging on the workpiece to perform a slitting operation (Fig. 28-16), at high pressure (up to 60,000 psi) and has a jet typically 0.003in - 0.020in in diameter; AKA Waterjet machining or hydrodynamic machining |
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Definition
| uses a high- velocity fluid jet impinging on the workpiece to perform a slitting operation (Fig. 28-16), at high pressure (up to 60,000 psi) and has a jet typically 0.003in - 0.020in in diameter; AKA Waterjet cuttng or hydrodynamic machining |
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Definition
| involves the use of continuously moving conductive wire as the tool electrode. the tensioned wire of copper, brass, tungsten, or molybendum is used only once traveling from the takeoff spool to the take-up spool while being guided to produce a straigt narrow kerf in plates up to 3in thick |
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| AKA electrical discharge wire cutting; the electrode is a wire used for cutting through-cut features driving the workpiece on a CNC table; capable of producing complex 2-D patterns(Fig. 28-22) in hard to machine materials |
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| isolated high spots that can be the result of improper agitation on large parts. They can also be formed due to inadequate cleaning or inhomogeneity with the work material. |
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| Laser beam machining, LBM – |
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Definition
| has heat affected zone and recast layers that may require removal |
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Definition
| etch resistant. Covers selected areas of the work piece in CHM. |
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| Nontraditional machining – NTM |
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Definition
| these methods have been developed since WWII to address the growing list of machining requirements which cannot be handled by conventional machining alone. Can be divided into 4 groups: chemical, electrochemical, mechanical, thermal. Usually have lower feed rates and require more power consumption when compared to machining. |
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Definition
| the distance between the surface of the electrode and the surface of the workpiece. Is constrained by the minimum interelectrode distance necessary for a spark. It depends on the gap voltage plus the chip size. |
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| can result if the etchant is not properly agitated, particularly on deep cuts. |
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| PCM – the use of photoresists in chemical machining. Limited to thin material. Tooling cost low. Used in microelectronics. |
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| Shaped-tube electrolytic machining |
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Definition
| Like the electrostream process, this is also capable of gang drilling small holes in difficult- to-machine materials. Generally, this processes can't drill holes smaller than about .02in. This is capable of make shaped holes with aspect ratios as high as 300:1. The major differences between the this process and the electrostream process are the reduced voltage levels (5 to 10 V dc) and the special electrodes which are long, straight, metallic tubes coated with an insulator. |
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Definition
| also known as ram EDM, or simply EDM, uses an electrode that is a die in the shape of the negative of the cavity to be produced in a bulk material. By feeding the die into the workpiece, the shape of the die is machined into the workpiece |
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Definition
| process used in EDM by which a spark is generated in a thin interelectrode gap between a tool and a workpiece where a pulsating DC current is fed across the gap using a dielectric fluid. The dielectric fluid is ionized and a spark is created which vaporizes a tiny portion of the workpiece, leaving a void. |
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| uses two iterations of the cut and peel method of applying a maskant to etch a stepped formation into a surface |
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| when a second photon strikes the energized atom, the atom gives off 2 photons of identical wavelength moving in the same direction and with the same phase. p.712 |
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| Thermal deburring or thermal energy method |
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Definition
| developed for the removal of burrs and fins by exposing the workpiece to hot corrosive gases for a short period of time typically on the order of a few milliseconds p.715 |
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| through etching of the workpiece also called chemical blanking |
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| also called precision PAC or fine plasma cutting. Uses a special nozzle, where either a high flow vortex or a magnetic field causes the plasma to spin rapidly and stabilizes the plasma pressure. |
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Definition
| is a material-removal process that involves the interaction of abrasive grits with the work piece at high cutting speeds and shallow penetration depth. |
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| is the most widely used artificial abrasive. Also produced in an arc furnace from bauxite, iron filings, and small amounts of coke, it contains aluminum hydroxide, ferric oxide, silica, and other impurities. |
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| refers to the abrasive wear action of the grits resulting in dulled edges, grit flattening, and wheel glazing. |
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| CBN (cubic boron nitride) |
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Definition
| is not found in nature. It is produced by a combination of intensive heat and pressure in the presence of a catalyst. ______ is extremely hard, registering at 4700 on the Knoop scaled. It is the second hardest substance created by nature or manufactured and is often referred to, along with diamonds, as a superabrasive. |
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| makes it possible to grind both external and internal cylindrical surfaces without requiring the workpiece to be mounted between centers or in a chuck. This eliminates the requirement of center holes in some workpieces and the necessity for mounting the workpiece, thereby reducing the cycle time. |
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| are being used increasingly in finishing both metal and nonmetal products. These are made by gluing onto a cloth or paperbacking. |
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| (Natural ) and diamonds are other nauturally occurring abrasive materials. |
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| the work is fed very slowly past the wheel and the total downfeed or depth is accomplished in a single pass. |
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| consists of forcing a hard roll having the same contour as the part to be ground against the grinding wheel while it is revolving; a water based coolant is used to flood the dressing zone at 5 to 10 gal/min. The crushing action fractures and dislodges some of the abrasive grains. Used to employ a produce and maintain a special contour to the abrasive wheel, also called wheel profiling. |
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| is a type of grinding machine used for producing external cylindrical surfaces. |
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| the hardest of all materials. |
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| cleaning and sharpening the wheel. I f you do not ______, the wheel will not cut as well and will tend to plow and rub more. |
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| a mixture of alumina and magnetite is another natural abrasive still in use today and is used on coated paper and cloth. |
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| refers to the fracture of the grits and is the opposite of toughness. |
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| (grinding ratio) the cubic inches of stock removed divided by the cubic inches of wheel lost (from lost of grains). It is a measure of grinding production and reflects the amount of work a wheel can do during its useful life. |
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| a diamond that is a natural, off-color stone that is not suitabe for gems |
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| the bond strength which controls the fracturing of the grits. __________ is a measure of how strongly the grains are held in the wheel. It depends on the strength of the bonding materials and the amount of the bonding agent connecting the grains. |
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Definition
| process where the abrasives are bonded together into a wheel. It is the most common abrasive machining process. The performance of __________ wheels is greatly affected by the bonding material and the spatial arrangement of the particles grits. |
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Definition
| similar to grinding but materials such as sulfur, resin or wax are added to the bonding agent to modify the cutting action. |
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| an abrasive surface-finishing process where fine abrasive particles are charged (or embedded) into a soft material (called a ___). The material can range from cloth to cat iron or copper. |
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| used primarily in coated abrasives and air blasting. It is a natural abrasive that has commercial importance |
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| also called phenolic resins and cover a variety of work conditions; has replaced shellac and rubber wheels |
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| used to produce wheels that can operate at high speeds but must have a considerable degree of flexibility so as to resist side thrust. A rubber bond is composed of rubber, sulfur, and other vulcanizing agents that are mixed with the abrasive grains. |
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Definition
| wheels can be made this way by mixing the abrasive grains with shellac in a heated mixture, pressing or rolling into the desired shapes, and baking for several hours. This type of bond is used primarily for strong, thin wheels having some elasticity. |
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| this bond is formed with silicate of soda (waterglass) as the bond material. Because they are more brittle and not so strong as vitrified wheels, the abrasive grains are released more readily. |
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| made by charging an electric furnace with silica sand, petroleum coke, salt, and sawdust. By passing large amounts of current through the charge, a temperature of over 4000 F is maintained for several hours, and a solid mass of silicon carbide crystals results. |
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| a type of rough manual grinding that is done to remove fins, gates, risers, and rough spots from castings or flash from forgings, preparatory to further machining. |
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| used primarily to grind flat surfaces. The most common type of surface grinding machine has a reciprocating table and horizontal spindle. |
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| as grinding wheels lose their geometry during use, truing restores the original shape. A single-point diamond tool can be used to true the wheel while fracturing abrasive grains to expose new grains and new cutting edges on worn, glazed grains. |
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Definition
| composed of clays and other ceramic substances. ____________ are proous, strong, rigid, and unaffected by oils, water, or temperature over the ranges usually encountered in metal cutting. |
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| Band-filling Machine- 652 |
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Definition
| This machine provides continuous cutting action. Most band filing is done on contour bandsawing machines by means of a special band file that is substituted for the usual bandsaw blade. |
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Definition
| These blades are available in straight, raker, wave, or combination sets. Blade width is very important in bandsawing because it determines the minimum radius that can be cut. |
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| Used in production to finish holes, splines, and flat surfaces. Typical workpieces include small to medium sized castings, forgings, screw machine parts, and stampings. It is composed of a series of teeth, each tooth standing slightly higher then the last. |
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Definition
| It is widely used and particularly well suited for mass production because the volume can easily justify the cost of the broaching tool. It is also used for certain simple and standardized shapes, such as keyways, where inexpensive standard broaches can be used. Broaching usually produces better accuracy and finish than can be obtained by drilling, boring, or reaming. |
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Definition
| On some round broaches, ___________ are provided for finishing. These have no cutting edges but are rounded disks that are from 0.001 to 0.003 inches larger than the size of the hole. The resulting rubbing action smooths and sizes the hole. |
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Definition
| These saws necessarily differ somewhat from straight blade forms. Because they must be relatively larger in comparison with the work, only the sizes up to about 19 inches in diameter have teeth that are cut into the disk. |
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Definition
| This is another name for a circular saw that is used for cutting metal. These saws rapidly cut and produce chips like a milling cutter while producing surfaces that are comparable in smoothness and accuracy with surfaces made by slitting saws in a milling machine or by a cutoff tool in a lathe. |
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Definition
| Metal-removing action is the same as in sawing in that chips are removed by cutting teeth that are arranged in succession along same plane on the surface of a tool called a ___ ; however, there are 2 differences (1): chips are very small and therefore the cutting action is slow and easily controlled & (2) the cutting teeth are much wider so fine and accurate work can be done |
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Definition
| one of 3 basic configurations of saw blades, this blade is straight, relatively rigid, & of limited length with teeth on one side. The gage of blade thickness of nearly all hand ____ blades is 0.025 in. Saw blades for power ___ vary in thickness from .05 to .1 in |
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Definition
| From the viewpoint of strength, large teeth are desirable. Second, tooth spacing determines the space (gullet) available to contain the chip that is formed. The chip cannot drop from this space until it emergers from the slot cut in the workpiece, called _____. The _____ gullet space must be such that there is no crowding of the chip & no tendency for chips to become wedged between the teeth & not drop out when the saw emerges from the cut |
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Definition
| In this, the action is opposite to that of shaping. Among the oldest single-point machining processes, work is moved past one or more stationary single-point cutting tools and can be used to produced horizontal, vertical, or inclined flat surfaces on large workpieces (too large for shapers), as well as for producing long flat cuts like those in the way of machine tools |
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Definition
| This is used in a vertical pull-down broaching machine. The pull end of the broach is passed through the part and a key mates to the slot. The broach is pulled though the part. The broach is retracted (pulled up) out of the part. The part is transferred from the left fixture to the right fixture. One finished part is completed in every time cycle. This must be strong enough so that it will not be pulled apart. The strength of this is determined by its minimum cross section, which occurs either at the root of the first tooth or at the pull end |
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Definition
| Push broaching machines are similar to an arbor press with a guided ram; typical capacities are 5 to 50 tons. This must be strong enough so that it will not buckle. If the length-to-diameter ratio L/Dr is greater than 25, the broach must be considered a long column which can buckle if overloaded. |
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Definition
| One of the 3 classifications of metal-sawing maching. There are two types, a manual hacksaw and a power hacksaw. These machines consist of a bed, a workholding frame and a power or manual mechanism for reciprocating. |
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Definition
| the feed per tooth in broaching id the change in hieght of successive teeeth. This is called______________. The sum of this gives the depth of cut. It also determines the chip load and varies depending on the type of broaching |
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Definition
| is a basic machining proccess in which chips are produced by a succession of small cutting edges, or teeth, arranged in a narrow line on a "blade" |
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Definition
| has largely been replaced by milling and broching as a production process. In this the workpiece is fed at right angles to the cutting motion between successive strokes of the tool. |
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Definition
| in this, the the rise per tooth is typically .003in to .006in. Smaller ones are made of solid construction but larger ones are made of modular construction |
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Definition
| refers to the manner in which teeth are offset from the centerline in order to make the kerf wider than the gage(thickness of the back) of the blade |
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