PRODUCTS OF MACHINES
BY: Noor El-Din Ahmed SEC: 1 YEAR: 3
TO: ENG/Aliaa
CONTETS 1.INTRODUCTION
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1.1 Product
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1.2 Plant
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1.3 Processes
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1.4 Programs
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1.5 People
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2.TURNING
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2.1 Facing
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2.2 Parting
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2.3 Grooving
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2.4 Boring
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2.5 Drilling
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2.6 Knurling
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2.7 Reaming
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2.8 Threading
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2.9 Polygonal
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2.10 Turning products
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3. MILLING
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3.1 Milling Cutter
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3.2 Surface Finish
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3.3 Gang Milling
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3.4 Equipment
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3.5 Types and nomenclature
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3.6 Vertical Milling
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3.7 Horizontal Milling
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3.8 Milling Products
4. DRILLING
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4.1 Process
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4.2 Spot Drilling
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4.3 Center Drilling
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4.4 Deep Drilling
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4.5 Gun Drilling
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4.6 Trepanning
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4.7 Vibration Drilling 4.8 Circle interpolating 4.9 Drilling Products
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1.INTRODUCTION Production and Operations Management ("POM") is about the transformation of production and operational inputs into "outputs" that, when distributed, meet the needs of customers.
The process in the above diagram is often o ften referred to as the "Conversion Process". There are several different methods of handling the conversion or production process - Job, Batch, Flow and Group POM incorporates many tasks that are interdependent, but which can be grouped under five main headings:-
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1.1 Product Marketers in a business must ensure that a business sells products that meet customer needs and wants. The role of Production and Operations is to ensure that the business actually makes the required products in accordance with the plan. The role of PRODUCT in POM therefore concerns areas such as: -Performance -Aesthetics -Quality -Reliability -Quantity -Production
1.2 Plant To make PRODUCT, PLANT of some kind is needed. This will comprise the bulk of the fixed assets as sets of the business. In determining which PLANT to use, management must consider areas such as: - Future demand (volume, timing) - Design and layout of factory, equipment, offices - Productivity and reliability of equipment - Need for (and costs of) maintenance - Heath and safety (particularly the operation of equipment) - Environmental issues (e.g. creation of waste products)
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1.3 Processes There are many different ways of producing a product. Management must choose the best process, or series of processes. They will consider: - Available capacity - Available skills - Type of production - Layout of plant and equipment - Safety - Production costs - Maintenance requirements
1.4 Programs The production PROGRAMME concerns the dates and times of the products that are to be produced and supplied to customers. The decisions made about programme will be influenced by factors such as: - Purchasing patterns (e.g. lead time) - Cash flow - Need for / availability of storage - Transportation
1.5 People Production depends on PEOPLE, whose skills, experience and motivation vary. Key people-related decisions will consider the following areas: - Wages and salaries - Safety and training - Work conditions - Leadership and motivation - Unionisation - Communication (6)
2.TURNING Turning This operation is one of the most basic machining processes. That is, the part is rotated while a single point cutting tool is moved parallel to the axis of rotation. rotation.[1] Turning can be done on the external surface of the part as well as internally (boring). The starting material is generally a workpiece generated by other processes such as casting casting,, forging forging,, extrusion extrusion,, or or drawing drawing Tapered turning a) from the compound slide b) from taper turning attachment c) using a hydraulic copy attachment d) using a C.N.C. lathe e) using a form tool f) by the offsetting of the tailstock this method more suited for shallow tapers. Spherical generation The proper expression for making or turning a shape is to generate as in to generate a form around a fixed axis of revolution. a) using hydraulic copy attachment b) C.N.C. (computerised numerically controlled) lathe c) using a form tool (a rough and ready method) d) using bed jig (need drawing to explain). Hard turning Hard turning is a turning done on materials with a Rockwe Rockwellll C hardness greater than 45. It is typically performed after the workpiece is heat treated. treated . The process is intended to replace or limit traditional grinding operations. operations. Hard turning, when applied for purely stock removal purposes, competes favorably with rough grinding. However, when it is applied for finishing where form and dimension are critical, grinding is superior. Grinding produces higher dimensional accuracy of roundness and cylindricity. In addition, polished surface finishes of Rz=0.3-0.8z cannot be achieved with hard turning alone. Hard turning is appropriate for parts requiring roundness accuracy of 0.5-12 micrometres, and/or surface roughness of Rz 0.8 – –7.0 7.0 micrometres. It is used for gears, injection pump components, hydraulic components, among other applications.
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2.1 Facing Facing in the context of turning work involves moving the cutting tool at right angles to the axis of rotation of the rotating workpiece .[1] This can be performed by the operation of the cross-slide, if one is fitted, as distinct from the longitudinal feed (turning). It is frequently the first operation performed in the production of the workpiece, and often the last— last —hence the phrase "ending up".
2.2 Parting This process, also called parting off or or cutoff , is used to create deep grooves which will remove a completed or part-complete component from its parent stock.
2.3 Grooving
External grooving
Face grooving
Grooving is like parting, except that grooves are cut to a specific depth instead of severing a completed/part-complete component from the stock. Grooving can be performed on internal and external surfaces, as well as on the face of the part (face grooving or trepanning).
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2.4 Boring Enlarging or smoothing an existing hole created by drilling, moulding etc.i.e. the machining of internal cylindrical forms (generating) a) by mounting workpiece to the spindle via a chuck or faceplate b) by mounting workpiece onto the cross slide and placing cutting tool into the chuck. This work is suitable for castings that are too awkward to mount in the face plate. On long bed lathes large workpiece can be bolted to a fixture on the bed and a shaft passed between two lugs on the workpiece and these lugs can be bored out to size. A limited application but one that is available to the skilled turner/machinist.
2.5 Drilling is used to remove material from the inside of a workpiece. This process utilizes standard drill bits held stationary in the tail stock or tool turret of the lathe. The process can be done by separately available drilling machines.
Knurling
2.6 Knurling The cutting of a serrated pattern onto the surface of a part to use as a hand grip using a special purpose knurling tool.
2.7 Reaming The sizing operation that removes a small amount of metal from a hole already drilled .[2] It is done for making internal holes of very accurate diameters. For example, a 6mm hole is made by drilling with 5.98 mm drill bit and then reamed to accurate dimensions.
2.8 Threading Both standard and non-standard screw threads can be turned on a lathe using an appropriate cutting tool. (Usually having a 60, or 55° nose angle) Either externally, or within a bore..[4] Generally referred to as single-point threading. bore tapping of threaded nuts and holes a) using hand taps and tailstock centre b)using a tapping device with a slipping clutch to reduce risk of breakage of the tap. threading operations include a)all types of external and internal thread forms using a single point tool also taper threads, double start threads, multi start threads, worms as used in worm wheel reduction boxes, leadscrew with single or multistart threads. b) by the use of threading boxes fitted with 4 form tools, up to 2" diameter threads but it is possible to find larger boxes than this.
2.9 Polygonal turning in which non-circular forms are machined without interrupting the rotation of the raw material.
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2.10 TURNING PRODUCTS
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3.MILLING
Face milling process
Milling is a cutting process that uses a milling cutter to cutter to remove material from the surface of a workpiece. The milling cutter is a rotary cutting tool, tool, often with multiple cutting points. As opposed to drilling drilling,, where the tool is advanced along along its rotation axis, the cutter in milling is usually moved perpendicular to its axis so that cutting occurs on the circumference of the cutter. As the milling cutter enters the workpiece, the cutting edges (flutes or teeth) of the tool repeatedly cut into and exit from the material, shaving off chips (swarf) from the workpiece with each pass. The cutting action is shear deformation; the metal is pushed off the workpiece in tiny clumps that hang together to more or less extent (depending on the metal type) to form chips. This makes metal cutting a bit different (in its mechanics mechanics)) from slicing softer materials with a blade blade.. The milling process removes material by performing many separate, small cuts. This is accomplished by using a cutter with many teeth, spinning the cutter at high speed, or advancing the material through the cutter slowly; most often it is some combination of these three approaches. The speeds and feeds used are varied to suit a combination of variables. The speed at which the piece advances through the cutter is called feed rate, rate, or just feed feed;; it is most often measured in length of material per full revolution of the cutter. There are two major classes of milling process:
In face milling, milling, the cutting action occurs primarily at the end corners of the milling cutter. Face milling is used to cut flat surfaces (faces) into the workpiece, or to cut flat-bottomed cavities.
In peripheral milling, milling, the cutting action occurs primarily along the circumference of the cutter, so that the cross section of the milled surface ends up receiving the shape of the cutter. In this case the blades of the cutter can be seen as scooping out material from the work piece.
Peripheral milling is well suited to the cutting of deep slots, threads, and gear teeth.
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3.1 Milling cutters Many different types of cutting tools are used in the milling process. Milling cutters such as endmills may have cutting surfaces across their entire end surface, so that they can be drilled into the workpiece (plunging). Milling cutters may also have extended cutting surfaces on their sides to allow for peripher peripheral al milling. The cutting surfaces of a milling cutter are generally made of a hard and temperature-resistant material, so that they wear wear slowly. slowly. A low cost cutter may have surfaces made of o f high high speed steel. steel . More expensive but slower-wearing materials include cemented carbide. carbide. Thin film coatings may be applied to decrease friction or further increase hardness. They are cutting tools typically used in milling machines or machining centres to perform milling operations (and occasionally in other machine tools). They remove material by their movement within the machine (e.g., a ball nose mill) or directly from the cutter's shape
3.2 Surface finish
A diagram of revolution revolution ridges on a surface milled by the side of the cutter, showing the position of the cutter for each cutting pass and how it corresponds with the ridges (cutter rotation axis is perpendicular to image plane)
As material material passes through through the cutting area of a milling machine, machine, the the blades of the cutter take take swarfs of material at regular intervals. Surfaces cut by the side of the cutter (as in peripheral milling) therefore always contain regular ridges. The distance between ridges and the height of the ridges depend on the feed rate, number of cutting surfaces, the cutter diameter.
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The face milling process can in principle produce very flat surfaces. However, in practice the result always shows visible trochoidal marks following the motion of points on the cutter's end face. These revolution marks give marks give the characteristic finish of a face milled surface. Revolution marks can have significant roughness depending on factors such as flatness of the cutter's end face and the degree of perpendicularity between the cutter's rotation axis and feed direction. Often a final pass with a slow feed rate is used to compensate for a poor milling setup, in order to reduce the roughness of revolution marks. In a precise face milling operation, the revolution marks will only be microscopic scratches due to imperfections in the cutting edge.
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3.3 Gang milling
Heavy gang milling of milling machine tables
Gang milling refers milling refers to the use of two or more milling cutters mounted on the same arbor arbor (that (that is, ganged) in a horizontal-milling setup. All of the cutters may perform the same type of operation, or each cutter may perform a different type of operation. For example, if several workpieces need a slot, a flat surface, and an angular groove angular groove,, a good method to cut these (within a non -CNC context) would be gang milling. All the completed workpieces would be the same, and milling time per piece would be minimized. Gang milling was especially important before the CNC era, because for duplicate part production, it was a substantial efficiency improvement over manual-milling one feature at an operation, then changing machines (or changing setup of the same machine) to cut the next op. Today, CNC mills with automatic tool change and 4- or 5-axis control obviate gang-milling practice to a large exten
3.4 EQUIPMENT Milling is performed with milling cutters attached to a milling machine.
3.5 Types and nomenclature Mill orientation is the primary classification for milling machines. The two basic configurations are vertical and horizontal. However, there are alternate classifications according to method of control, size, purpose and power source.
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3.6 Vertical mill
Vertical milling Vertical milling machine. 1: milling cutter 2: spindle 3: top slide or overarm 4: column 5: table 6: Y-axis slide 7: knee 8: base
In the vertical mill the mill the spindle axis is vertically oriented. oriented. Milling cutters are held in the spindle and rotate on its axis. The spindle can generally be extended (or the table can be raised/lowered, giving the same effect), allowing plunge cuts and drilling. There are two subcategories of vertical mills: the bed mill and the turret mill.
A turret mill has mill has a stationary spindle and the table is moved both perpendicular and parallel to the spindle axis to accomplish cutting. The most common example of this type is the Bridgeport, described below. Turret mills often have a quill which allows the milling cutter to be raised and lowered in a manner similar to a drill press. This type of machine provides two methods of cutting in the vertical (Z) direction: by raising or lowering the quill, and by moving the knee.
In the bed mill, mill, however, the table moves only perpendicular to the spindle's axis, while the spindle itself moves parallel to its own axis.
Turret mills are generally considered by some to be more versatile of the two designs. However, turret mills are only practical as long as the machine remains relatively small. As machine size increases, moving the knee up and down requires considerable effort and it also becomes difficult to reach the quill feed handle (if equipped). Therefore, larger milling machines are usually of the bed type. A third type type also exists, exists, a lighter lighter machine, machine, called a mill-drill, which is is a close relative relative of the the vertical mill and quite popular with hobbyists. A mill-drill is similar in basic configuration configuration to a small drill press, but equipped with an X-Y table. They also typically use more powerful motors than a comparably sized drill press, with potentiometer-controlled speed and generally have more heavy-duty spindle bearings than a drill press to deal with the lateral loading on the spindle that is created by a milling
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operation. A mill dril also typically raises and lowers the entire head, including motor, often on a dovetailed vertical, where a drill press motor remains stationary, while the arbor raises and lowers within a driving collar. Other differences that separate a mill-drill from a drill press may be a fine tuning adjustment for the Z-axis, a more precise depth stop, the capability to lock the X, Y or Z axis, and often a system of tilting the head or the entire vertical to allow angled cutting. Aside from size and precision, the principal difference between these hobby-type machines and larger true vertical mills is that the X-Y table is at a fixed elevation; the Z-axis is controlled in basically the same fashion as drill press, where a larger vertical or knee mill has a vertically fixed milling head, and changes changes the X-Y table elevation. As well, a mill-drill often uses a standard drill press-type Jacob's chuck, rather than an internally tapered arbor that accepts collets. These are frequently of lower quality than other types of machines, but still fill the hobby role well because they tend to be benchtop machines with small footprints and modest price tags.
3.7 Horizontal mill
Horizontal milling Horizontal milling machine. 1: base 2: column 3: knee 4 & 5: table (x-axis slide is integral) 6: overarm 7: arbor (attached to spindle)
A horizontal horizontal mill has the same same sort of x of x –y – y table, table, but the cutters are mounted on a horizontal arbor (see Arbor (see Arbor milling milling)) across the table. Many horizontal mills also feature a built-in rotary table that allows milling at various angles; this feature is called a universal table. table. While endmills and the other types of tools available to a vertical mill may be used in a horizontal mill, their real advanta advantage ge lies in arbor-mounted cutters, called side and face mills, which have a cross section rather like a circular saw, but are generally wider and smaller in diameter. Because the cutters have good support from the arbor and have a larger cross-sectional area than an end mill, quite heavy cuts can be taken enabling rapid material removal rates. These are used to mill grooves and slots. Plain mills are used to shape flat surfaces. Several cutters may be ganged together on the arbor to mill a complex shape of slots and planes. Special cutters can also cut grooves, bevels, radii, or indeed any section desired. These specialty cutters tend to be expensive. Simplex mills have one spindle, and duplex mills have two. It is also easier to cut gears on a horizontal mill. Some horizontal milling machines are equipped with a power-take-off provision on the table. This allows the table feed to be synchronized to a rotary fixture, enabling the milling of spiral features such as hypoid gears.
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3.8 MILLING PRODUCTS
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4.DRILLING Drilling is a cutting process that uses a drill bit to cut or enlarge a hole of circular cross-section Drilling is circular cross-section in solid materials. The drill bit is a rotar ycutting tool, tool, often multipoint. The bit is pressed against the workpiece and rotated at rates from hundreds to thousands of revolutions per minute. minute . This forces the cutting edge against the workpiece, cutting off chips (swarf) from the hole as it is drilled.
Drilling machine
4.1 PROCESS Drilled holes are characterized by their sharp edge on the entrance side and the presence of burrs of burrs on the exit side (unless they have been removed). Also, the inside of the hole usually has helical feed marks. marks.[3] Drilling may affect the mechanical properties of the workpiece by creating low residual stresses around the hole opening and a very thin layer of highly stressed and disturbed material on the newly formed surface. This causes the workpiece to become more susceptible to corrosion at the stressed surface. A finish operation may be done to avoid the corrosion. Zinc plating or any other standard finish operation of 14 to 20 µm can be done which helps to avoid any sort of corrosion.
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4.2 Spot drilling The purpose of spot drilling is to drill a hole that will act as a guide for drilling the final hole. The hole is only drilled part way into the workpiece because it is only used to guide the beginning of the next drilling process.
4.3 Center drilling The purpose of center drilling is to drill a hole that will act as a center of rotation for possible following operations. Center drilling is typically performed using a drill with a special shape
4.4 Deep hole drilling Deep hole drilling is defined as a hole depth greater than ten times the diameter of the hole .[4] These types of holes require special equipment to maintain the straightness and tolerances. Other considerations are roundness and surface finish. Deep hole drilling is generally achievable with a few tooling methods, usually gun drilling or BTA drilling. These are differentiated due to the coolant entry method (internal or external) and chip removal method (internal or external). Using methods such as a rotating tool and counter-rotating workpiece are common techniques to achieve required straightness tolerances tolerances..[5] Secondary tooling methods include trepanning, skiving and burnishing, pull boring, or bottle boring. Finally a new kind of drilling technology is available to face this issue: the vibration drilling. This technology consists in fractionating chips by a small controlled axial vibration of the drill. Therefore the small chips are easily removed by the flutes of the drill. A high tech tech monitoring monitoring system is used to control force force,, torque torque,, vibrations vibrations,, and acoustic emission. The vibration is considered a major defect in deep hole drilling which can often cause the drill to break. Special coolant is usually used to aid i n this type of drilling.
4.5 Gun drilling Another type of drilling drilling operation operation is called called gun drilling. drilling. This method method was was originally originally developed developed to drill out gun barrels and is used commonly for drilling smaller diameter deep holes. This depth-todiameter ratio can be even more than 300:1. The key feature of gun drilling is that the bits are selfcentering; this is what allows for such deep accurate holes. The bits use a rotary motion similar to a twist drill; however, the bits are designed with bearing pads that slide along the surface of the hole keeping the drill bit on center. Gun drilling is usually done at high speeds and low feed rates.
4.6 Trepanning Trepanning is commonly used for creating larger diameter holes (up to 915 mm (36.0 in)) where a standard drill bit is not feasible or economical. Trepanning removes the desired diameter by cutting out a solid disk similar to the workings of a drafting compass. compass.
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4.7 Vibration Drilling
Titanium chips - conventional drilling vs vibration drilling
Vibration drilling of an aluminum-CFRP multi-material stack with MITIS technology
The first works on vibration drilling began in the 1950s (Pr. V.N. Poduraev, Moscow Bauman University). The main principle consists in generating axial vibrations or oscillations in addition to the feed movement of the drill so that chips could be fractionated and easily removed from the cutting zone.
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One can find two main technologies of vibration drilling: self-maintained vibrations systems and forced vibrations systems. Most vibration drilling technologies are still at a research stage. It is the case of the self-maintained vibrations drilling: the eigen frequency of the tool is used in order to make it naturally vibrate while cutting; vibrations are self-maintained by a mass-spring system included in the tool holder .[6]Other works use a piezoelectric system to generate and control the vibrations. These systems allow high vibration frequencies (up to 2 kHz) for small magnitude (about a few micrometers); they particularly fit drilling of small holes. Finally vibrations can be generated by mechanical systems systems::[7] the frequency is given by the combination of the rotation speed and the number of oscillation per rotation (a few oscillations per rotation), the magnitude is about 0.1 mm. This last technology is a fully industrial one (example: SineHoling® technology of MITIS). Vibration drilling is a favoured solution solution in order to face issues like deep hole drilling, multi-material multi-material stacks drilling (aeronautics) or dry drill ing (without lubrication). Generally it allows increasing the reliability and the control of the drilling operation.
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4.8 Circle interpolating
The orbital drilling principle
Circle interpolatin interpolating g , also known as orbital drilling , is a process for creating holes using machine cutters. Orbital drilling is based on rotating a cutting tool around its own axis and simultaneously about a centre axis which is off-set from the axis of the cutting tool. The cutting tool can then be moved simultaneously simultaneo usly in an axial direction to drill or machine a hole – hole – and/or and/or combined with an arbitrary sidewards motion to machine an opening or cavity. By adjusting the offset, a cutting tool of a specific diameter can be used to drill holes of different diameters as illustrated. This implies that the cutting tool inventory can be substantially reduced. The term orbital drilling comes from that the cutting tool ―orbits‖ around the hole center. The mechanically forced, dynamic offset in orbital drilling has several advantages compared to conventional convention al drilling that drastically increases the hole precision. The lower thrust forceresults in a burr-less hole when drilling in metals. When drilling in composite materials the problem with delamination is eliminated.
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4.9 DRILLING PRODUCTS
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