ITEC 240 - Test 3
milling
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pull broach
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push broach
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sawing
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shaping
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Reaming
An operation used to make an existing hole dimensionally more accurate than can be obtained by drilling alone and to improve its surface finish.
Boring Mill
Boring operations on relatively small workpieces can be carried out on a lathe, boring mills are used for large work pieces. These machines are either vertical or horizontal, and are capable of performing operations such as turning, facing, grooving, and chamfering. A vertical boring machine is similar to a lathe but has a vertical axis of workpiece rotation.
Chuck
Chucks can be power actuated or actuated manually, using a chuck wrench and are usually equipped with three or four jaws. In a lathe, one end of the workpiece is clamped to the spindle by a chuck, collet, or faceplate, or mandrel
Coated tools
Coatings for cutting tools and dies should have these characteristics: high hardness, chemical stability, inertness, low thermal conductivity, good bonding, little or no porosity
Chips
Cutting processes remove material from the surface of a workpiece by producing chips (turning, cutting-off, slab-milling, end-milling)
Ceramics
compounds of metallic and nonmetallic elements. The term ceramics refers to both the material and the ceramic product itself.
discontinuous chip
consist of segments that may be firmly or loosely attached to each other. Because of the discontinuous nature of chip formation, forces continually vary during cutting. If the chip is not stiff enough, the machine tool may begin to vibrate and chatter therefore may affect the surface finish and dimensional accuracy of the machined component, and may damage the cutting tool or cause excessive wear
Turning
means that the part is rotating while it is being machined the starting material is usually a workpiece that has been made by other processes, such as casting, forging, extrusion, or drawing. Turning processes are very versatile. Turning, to produce straight, conical, curved, or grooved workpieces such as shafts, spindles, and pins. Turning and facing operations on all types of materials uses single point or form tools, requires skilled labor, low production rate, but medium to high with turret lathes and automatic machines requiring less skilled labor.
Cutting Fluids
oils, emulsions, semi synthetics, synthetics
Tool Life Curves
plots of experimental data obtained by performing cutting tests on various material under different conditions and with varying process parameters, such as cutting speed, feed, depth of cut, tool material, and geometry, and cutting fluids.
face milling
the cutter is mounted on a spindle having an axis of rotation perpendicular to the workpiece surface. The cutter rotates at a rotational speed and the workpiece moves along a straight path at a linear speed. When the utter rotates there operation is climb milling; when it rotates in the opposite direction, the operation is conventional milling. the cutting tools are mounted on the cutter body.
Drill Life
the life of drills is usually measured by the number of holes drilled before they become dull
Drill Press
the most common type of drilling machine is the drill press
Die sinking
the production of cavities in small forging dies
lapping
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Drilling
Drilling can be performed on a lathe by mounting the drill bit in a drill chuck into the tail stock quill (a tubular shaft). The workpiece is placed in a work holder on the headstock, and the quill is advanced by rotating the hand wheel. Holes drilled in the manner may not be concentric because of the tendency for the drill to drift radially . The concentrically of the hole is improved by subsequently boring the drilled hole.
Automatic Bar Machine
Formerly called automatic screw machines, thse machines are designed for high-production-rate machining of screws and similar threaded parts. Because they are capable of producing various other components, they are now called automatic bar machines. All operations on these machines are performed automatically, with tools attached to a special turret. After each screw or part is machined to finished dimensions, the bar stock is fed forward automatically then cut off. These machines may be equipped with single of multiple spindles.
Finishing cuts
In machining, the usual procedure is to perform one or more roughing cuts at high feed rates and large depths of cut and follow it with a finishing cut at a lower feed and depth of cut for a good surface finish.
Roughing Cuts
In machining, the usual procedure is to preform one or more roughing cuts at high feed rates and large depths of cut and to follow it with a finishing cut at a lower feed and depth of cut for a good surface finish
Surface finish
In order to obtain finer surface finish and closer tolerances, additional finishing operation , better control of processing parameter, and the use of higher quality equipment may be required
Chip Management
Involves collecting chips from their source in the machine tool in an efficient manner and removing them from the work area.
Mist
Mist cooling supplies fluid to inaccessible areas and provides better viability of the workpiece being machined. it is particularly effective with water-based fluids and in grinding operations. Mist cooling requires venting to prevent the inhalation of fluid particles by the machine operator and others and has limited cooling capacity
Collet
a longitudinally-split tapered bushing. In a lathe, one end of the workpiece is clamped to the spindle by a chuck, collet, or faceplate, or mandrel
Engine lathe
Powered with overhead pulleys and belts from nearby engines originally but are now powered with individual electric motors.
Whisker- reinforced tools
Recent developments include the use of whiskers as reinforcing fibers in composite cutting-tool materials. Examples of whisker-reinforced materials include silicon-nitride base tools reinforced with silicon-carbide whiskers, and aluminum oxide-based tools reinforced with silicon carbide whiskers, sometimes with the addition of zirconium oxide. However, the high reactivity of silicon carbide with ferrous metals makes SiC- reinforced tools unsuitable for machining irons and steels.
Bed
The bed supports all major components of the lathe. Beds have larger mass and are rigidly built, usually from gray or nodular cast iron. The top portion of the bed has two ways, with various cross-sections, that are hardened and machined for wear resistance and dimensional accuracy during use
Carriage
The carriage, or carriage assembly, slides along the ways and consists of an assembly of the cross-slide, tool post, and apron. The cutting tool is mounted on the tool post, usually with a compound rest that swivels for tool positioning and adjustment. The cross-slide moves radially in and out, controlling the radial position of the cutting tool in operations such as facing. The apron is equipped with mechanisms for both manual and mechanized movement of the carriage and cross-slide by means of the lead screw.
Head Stock
The headstock is fixed to the bed and is equipped with motors, pulleys, and V-belts that supply power to the spindle at various rotational speeds. The speeds can be set through manually-controlled selectors. Most head stocks are equipped with a set of gears, and some have various drives to provide a continuously variable speed range to the spindle. Head-stocks have a hollow spindle to which work holding devices, such as chucks and collets, are attached, and long bars or tubing can be fed through for various turning operations.
Twist Drill
The most common drill is the conventional standard-point twist drill, the main features of which are the paint angle, lip-relief angle, chisel-edge angle, and helix angle. The geometry of the drill tip is such that the normal rake angle and velocity of the cutting edge vary with the distance from the center of the drill.
Flooding or Flood Cooling
The most common method of cutting fluid application, used to wash away chips
Inserts
The need for better tool changing operations has led to the development of inserts. Inserts are individual cutting tools with several cutting points. A square insert has 8 cutting points, a triangular insert has 6
Tail Stock
The tail stock, which can slide along the ways and be clamped at any position, supports the other end of the workpiece. It is equipped with a center that may be fixed or may be free to rotate with the workpiece. Drills and reamers can be mounted on the tail stock quill (a hollow cylindrical part with a tapered hole) to drill axial holes in the workpiece.
Boring
To enlarge a hole or cylindrical cavity made by a previous process or to produce circular internal grooves. Carried out on a lathe, boring produces a circular internal profile in hollow workpieces or on a hole made by drilling or another process. Boring is done with cutting tools that are similar to those used in turning. Because the boring bar has to reach the full length of the bore, tool deflection and maintenance of dimensional accuracy and be a sig. problem.
Tapping
Turning operations are capable of producing threads on round bar stock. When threads are produced externally or internally by cutting with a lathe-type tool, the process is called thread cutting or threading. When cut internally with a special threaded tool (tap), the process is called tapping. External threads may also be cut with a die or by milling. Although it adds considerably to the cost, threads may be grounded for improved dimensional accuracy and surface finish.
Reamer
a multiple-cutting-edge tool with straight or vertically fluted edges; that removes very little material.
friction sawing
a process in which a mild-steel blade, or disk, rubs. The frictional energy is converted into heat, which rapidly softens a narrow zone in the workpiece. the action of the blade or disk, which is sometimes provided with teeth or notches, pulls and ejects the softened metal from the cutting zone.
Broaching
a production process and can produce parts with very good surface finish and dimensional accuracy. It competes favorably with other processes, such as boring, milling, shaping, and reaming, to produce similar shapes. Although broaches can be expensive, the cost is justified with high- quantity production runs.
feed marks
a spiral profile, The higher the feed the smaller the tool nose radius and the more prominent the marks
coolants
also called cutting fluids and lubricants, they are used extensively in machining as well as abrasive machining processes to achieve the following results: reduce friction and wear therefore improving tool life and surface finish, reduce forces and energy consumption, cool the cutting zone, wash away the chips, protect the machined surfaces from environmental corrosion
Cubic boron nitride
cBN, is the hardest material presently available, it provides cutting edge strength
Turret Lathe
capable of performing multiple cutting operations, such as turning, boring, drilling, thread cutting, and facing, on the same workpiece. Several cutting tools are mounted on the hexagonal main turret, which is rotated for each specific cutting operation.
built-up edge
consisting of layers of material from the workpiece that are gradually deposited on the tool, may form at the tip of the tool during cutting. The built-up edge is commonly observed in practice and is one of the factors that most adversely affects surface finish in cutting.
end milling
flat surfaces as well as various profiles can be produced by end milling. The cutter end milling has either straight or tapered shanks for smaller and larger cutter sizes. The cutter usually rotates on an axis perpendicular to the workpiece, although it can be tilted to machine-tapered surfaces.
filing
involves the small-scale removal of material from a surface, corner, or hole, including the removal of burrs.
kerf
the width of cut in sawing
Threading
to produce external or internal threads
honing
tool that is plastic gear impregnated with fine abrasive particles. The process is faster than grinding and is used to improve surface finish.. To further improve the surface finish, ground gear teeth are lapped using abrasive compounds with either a gear-shapped lapping tool of a pair of mating gears that are run together. Production rates are lower and costs are higher and produces high quality gears with long life and quiet operation
Bur
used for special applications such as removing material in die making, deburring, scale and removal from surfaces, and producing chamfers on parts.
Continuous chips
usually formed with ductile materials at high cutting speeds and/or high rake angles. the deformation of the material takes place along a narrow shear zone
chip breakers
when chips become tangled around the tool holder, the fixture, and the workpiece, as well as the chip-disposal systems, and the operation has to stop to clear away the chips and this problem is alleviated with chip breakers
