Manufacturing Technology 1 (MEC 112) - Turning - Benha University - PDF

08/10/2024 Benha University Faculty of Engineering (Shoubra) Mechanical Engineering Department (1st year) Manufacturing Technology 1 (MEC 112) Turning 1 Introduction  The main function of a turnin...

08/10/2024 Benha University Faculty of Engineering (Shoubra) Mechanical Engineering Department (1st year) Manufacturing Technology 1 (MEC 112) Turning 1 Introduction  The main function of a turning operation is to remove metal from a job to give it the required shape and size. The job is securely and rigidly held in the chuck or in between centers on the lathe machine and then turn it against a single point cutting tool which will remove metal from the job in the form of chips. 2 2 1  08/10/2024 Working principal of lathe machine 3 3 TYPES OF LATHES  Lathes are manufactured in a variety of types and sizes, from very small bench lathes used for precision work to huge lathes used for turning large steel shafts. But the principle of operation and function of all types of lathes is same. The different types of lathes are:  1 - Speed Lathe Speed lathe is the simplest of all types of lathes in construction and operation. The important parts of speed lathe are; (1) Bed, (2) Headstock, (3) Tailstock, and (4) Tool post mounted on an adjustable slide. It has no feed box, leadscrew or conventional type of carriage. The tool is mounted on the adjustable slide and is fed into the work by hand control. The speed lathe finds applications where cutting force is least such as in wood working, centering, polishing etc. This lathe has been so named because of the very high speed of the headstock spindle. 4 4 2  08/10/2024 Woodworking lathe 5 5 Woodworking Tools 6 6 3  08/10/2024 2 - Center Lathe or Engine Lathe The term “engine” is associated with this lathe since in the very early days of its development it was driven by steam engine. This lathe is the important member of the lathe family and is the most widely used. Like the speed lathe, the engine lathe has all the basic parts, e.g., bed, headstock, and tailstock. But its headstock is much more robust in construction and contains additional mechanism for driving the lathe spindle at multiple speeds. Unlike the speed lathe, the engine lathe can feed the cutting tool both in cross and longitudinal direction with reference to the lathe axis with the help of a carriage, feed rod and lead screw. 7 7 Principal components of a center lathe 8 8 4  08/10/2024 3 - Bench Lathe This is a small lathe usually mounted on a bench. It has practically all the parts of an engine lathe or speed lathe and it performs almost all the operations. This is used for small and precision work. 4 - Tool Room Lathe This lathe has features like an engine lathe, but it is much more accurately built. It has a wide range of spindle speeds ranging from a very low to a quite high speed up to 2500 rpm. This lathe is mainly used for precision work on tools, dies, gauges and in machining work where accuracy is needed. 9 9 5 - Capstan and Turret Lathe The development of these lathes results from the technological advancement of the engine lathe, and these are vastly used for mass production work. The distinguishing feature of this type of lathe is that the tailstock of an engine lathe is replaced by a hexagonal turret, on the face of which multiple tools may be fitted and fed into the work in proper sequence. Due to this arrangement, several different types of operations can be done on a job without re-setting of work or tools, and several identical parts can be produced in the minimum time. 10 10 5  08/10/2024 Essential components and operating principles of 11 capstan and turret lathes 11  Main features of turret and capstan lathes:  A square turret is mounted on the cross slide in place of the usual compound rest in engine lathe. Sometimes a fixed tool holder is also mounted on the back end of the cross slide.  Considerable skill is required to set and adjust the tools on such machines properly. But once the machines are set, they can be operated by semiskilled operators.  Eliminating the tool changing time and the setup time between operations reduces the production time 12 considerably. 12 6  08/10/2024  6 - Facing lathes  These are used to machine work of large diameter and short length. These machines are generally used for turning external, internal, and taper surfaces, facing, boring, and so on. Facing lathes have relatively small length and large diameter of faceplates (up to 4 m). Sometimes, they are equipped with a tailstock.  It consists of the base plate (1), headstock (4) with faceplate (5), bed (2), carriage (3), and tailstock (6). The work is clamped on the faceplate using jaws, or clamps, and T-slot bolts. It may be additionally supported by the tailstock center. The feed gear train is powered from a separate motor to provide the longitudinal and transverse feeds. 13 13 Facing Lathe 14 14 7  08/10/2024  7 -Vertical turning and boring machines  These machines are employed in machining heavy pieces of large diameters and relatively small lengths. They are used for turning and boring of cylindrical and tapered surfaces, facing, drilling, countersinking, counterboring, and reaming. The heavy work can be mounted on rotating tables more conveniently and safely as compared to facing lathes.  The horizontal surface of the worktable excludes completely the overhanging load on the spindle of the facing lathes. This facilitates the application of high-velocity machining and, at the same 15 time, enables high accuracy to be attained. 15 16 Facing on a vertical boring machine 16 8  08/10/2024 8 - Special Purpose Lathes These lathes are constructed for special purposes and for jobs, which cannot be accommodated or conveniently machined on a standard lathe. 9 - Automatic Lathes These lathes are so designed that all the working and job handling movements of the complete manufacturing process for a job are done automatically. These are high speed, heavy duty, mass production lathes with complete automatic control. 17 17 CONSTRUCTION OF LATHE  A simple lathe comprises of a bed made of grey cast iron on which headstock, tailstock, carriage and other components of lathe are mounted.  The major parts of lathe machine are given as:  1. Bed  2. Head stock  3.Tailstock  4. Carriage  5. Feed mechanism  6.Thread cutting mechanism 18 18 9  08/10/2024 19 19 Different parts of engine lathe 20 20 10  08/10/2024 21 21  Bed  The bed of a lathe machine is the base on which all other parts of lathe are mounted. It is massive and rigid single piece casting made to support other active parts of lathe. On left end of the bed, headstock of lathe machine is located while on right side tailstock is located. The carriage of the machine rests over the bed and slides on it. On the top of the bed there are two sets of guideways-inner ways and outer ways. The inner ways provide sliding surfaces for the tailstock and the outer ways for the carriage. Generally, cast iron alloyed with nickel and chromium material is used for manufacturing of the lathe bed.  Head Stock  The main function of headstock is to transmit power to the different parts of a lathe. It comprises of the headstock casting to accommodate all the parts within it including gear train arrangement. 22 22 11  08/10/2024 Tail Stock The tail stock is commonly used for giving an outer bearing and support the circular workpiece being turned on centers. Tail stock can be easily set or adjusted for alignment or non- alignment with respect to the spindle centre. 23 23  Carriage  Carriage is mounted on the outer guide ways of lathe bed, and it can move in a direction parallel to the spindle axis. It comprises of important parts such as apron, cross-slide, saddle, compound rest, and tool post. The lower part of the carriage is termed the apron in which there are gears to constitute apron mechanism for adjusting the direction of the feed. The cross-slide is basically mounted on the carriage, which generally travels at right angles to the spindle axis. On the cross-slide, a saddle is mounted in which the compound rest is adjusted which can rotate and fix to any desired angle. The tool post is an important part of carriage. 24 24 12  08/10/2024  Feed Mechanism  Feed mechanism is the combination of different units through which motion of headstock spindle is transmitted to the carriage of lathe machine.  Thread Cutting Mechanism  The half nut or split nut is used for thread cutting in a lathe. It engages or disengages the carriage with the lead screw so that the rotation of the leadscrew is used to traverse the tool along the workpiece to cut screw threads. The direction in which the carriage moves depends upon the position of the feed reverse lever on the headstock. 25 25 Split nut Mechanism 26 26 13  08/10/2024 LATHE ACCESSORIES There are many lathe accessories provided by the lathe manufacturer along with the lathe, which support the lathe operations. The important lathe accessories include centers, catch plates and carriers, chucks, collets, face plates, angle plates, mandrels, and rests. These are used either for holding and supporting the work or for holding the tool. 27 27 Lathe centers The most common method of holding the job in a lathe is between the two centers generally known as live centre and dead centre. They are made of very hard materials to resist deflection and wear, and they are used to hold and support the cylindrical jobs. 28 28 14  08/10/2024 Carriers or driving dog and catch plates These are used to drive a job when it is held between two centers. Carriers or driving dogs are attached to the end of the job by a setscrew. A projecting pin from the catch plate or carrier fits into the slot provided in either of them. This imparts a positive drive between the lathe spindle and job. 29 29 Face plates Face plates are employed for holding jobs, which cannot be conveniently held between centers or by chucks. A face plate possesses the radial, plain and T slots for holding jobs or work-pieces by bolts and clamps. Face plates consist of a circular disc bored out and threaded to fit the nose of the lathe spindle. They are heavily constructed and have strong thick ribs on the back. They have slots cut into them; therefore nuts, bolts, clamps and angles are used to hold the jobs on the face plate. They are accurately machined and ground. 30 30 15  08/10/2024 Chucks Chuck is one of the most important devices for holding and rotating a job in a lathe. It is basically attached to the headstock spindle of the lathe. The internal threads in the chuck fit on to the external threads on the spindle nose. Short, cylindrical, hollow objects or those of irregular shapes, which cannot be conveniently mounted between centers, are easily and rigidly held in a chuck. Jobs of short length and large diameter or of irregular shape, which cannot be conveniently mounted between centers, are held quickly and rigidly in a chuck. There are several types of lathe chucks, e.g.  (1) Three jaws or universal  (2) Four jaws independent chuck  (3) Magnetic chuck  (4) Collet chuck 31 31 Three jaws chuck Four jaws chuck 32 32 16  08/10/2024 Collet chuck Magnetic chuck 33 33  Mandrels A mandrel is a device used for holding and rotating a hollow job that has been previously drilled or bored. The job revolves with the mandrel, which is mounted between two centers. It is rotated by the lathe dog and the catch plate, and it drives the work by friction. 34 34 17  08/10/2024  The WP to be machined is tightly fitted on a conical mandrel, provided with center holes to be clamped between centers using a dog plate and a lathe dog (a).  The expanding mandrel (b) consists of a conical rod (1), a split sleeve (2), and nuts (3 and 4).  The work is held by expansion of a sleeve (2), as the latter is displaced along the conical rod (1) by nut (3).  Nut (4) removes the work from the mandrel. There is a flat (5) on the left of the conical rod used for the setscrew of the driving lathe dog. 35 35  Rests A rest is a lathe device, which supports a long slender job, when it is turned between centers or by a chuck, at some intermediate point to prevent bending of the job due to its own weight and vibration set up due to the cutting force that acts on it. The two types of rests commonly used for supporting a long job in an engine lathe are the steady or centre rest and the follower rest. 36 36 18  08/10/2024 Lathe Tools Parting tool Lathe Tools 37 37 Boring bar 38 38 19  08/10/2024 39 High Speed Steel (HSS) Tools 39 Turning tool holder 40 40 20  08/10/2024 Lathe tool holders 41 41 Lathe operations 42 42 21  08/10/2024 43 43 44 44 22  08/10/2024 Boring operation Boring operation for Boring bar attachment for 45 big size tube large machine 45 TAPERS AND TAPER TURNING A taper is defined as a uniform increase or decrease in diameter of a piece of work measured along its length. In a lathe machine, taper turning means to produce a conical surface by gradual reduction in diameter from a cylindrical job. Taper in the Metric System is expressed in taper per mm. Taper per mm = (D – d) /l Where, D = is the diameter of the large end of cylindrical job, d = is the diameter of the small end of cylindrical job, and l = is the length of the taper of cylindrical job, all expressed in mm, A taper is generally turned in a lathe by feeding the tool at an angle to the axis of rotation of the workpiece. The angle formed by the path of the tool with the axis of the workpiece should correspond to the half taper angle. 46 46 23  08/10/2024 47 47 A taper can be turned by anyone of the following methods: 1. Swiveling the compound rest, 2. Setting over the tailstock centre, 3. Using a broad nose form tool, 4. By a taper turning attachment, 5. By combining longitudinal and cross feed in a special lathe and 6. By using a numerically controlled lathe 48 48 24  08/10/2024 Taper Turning by Swiveling the Compound Rest The compound rest can easily be swiveled or rotated and clamped at any desired angle. Once the compound rest is set at the desired half taper angle, rotation of the compound slide handle manually will cause the tool to be fed at that angle and generate a corresponding taper. This method is limited to turn a short but steep taper because of the limited movement of the cross-slide. 49 49 Taper Turning by Swiveling the Compound Rest 50 50 25  08/10/2024 Taper Turning Attachment Method In this method, the taper turning attachment has guide bar which may be set at any desired angle or taper. The cross slide (1) is disengaged from the cross-feed screw and is linked through the tie (2) to the slide (3). The merit of this method is that the lathe centers are kept in alignment. 51 51 Taper Turning with Tailstock set over Method  This method is basically employed for turning small tapers on longer jobs, the angle of taper α should not exceed 8°. It is confined to external tapers only. 52 52 26  08/10/2024 Form Tool Method In this method a taper form is used to obtain tapers. It is limited to short external tapers. The tool edge must be exactly straight for accurate work. 53 53 Taper Turning with Double Feeds In certain lathes both longitudinal and cross feeds may be engaged simultaneously causing the tool to follow a diagonal point which is the resultant of the magnitude of the two feeds. The direction of resultant feed may be changed by varying the rate of feeds. 54 54 27  08/10/2024 SPECIFICATION OF LATHE The size of a lathe is generally specified by the following means: (A) Bed length, which may include head stock length also. (B) Maximum length of the job that can be held between head stock and tail stock centers (Maximum distance between centers). (C) Swing or maximum diameter that can be rotated over the bed ways. (D) Maximum diameter of work accommodated over the carriage. (d) Maximum diameter of the bar that can pass through spindle or collet chuck of the lathe 55 55 56 56 28  08/10/2024 In addition to these dimensions, other important specifications are: Number of spindle speeds and speed range Number of feeds and feed range Motor power 57 Overall dimensions and net weight 57 Machining time  Standard Time The standard time per piece, required to machine a single workpiece in a definite operation, consists of different elements, among them the machining time, which is the time required for the chip removal operation. Thus; the machining time can be defined as the time during which the chip is being cut from the workpiece without the direct participation of the operator. 58 58 29  08/10/2024 Machining time for Turning The machining time 𝑻𝒎 consumed in turning a bar with the tool travelled in the direction of feed motion in longitudinal turning can be obtained as follows; 𝑳 𝑻𝒎 = 𝒎𝒊𝒏 𝒔𝑵 𝑾𝒉𝒆𝒓𝒆; 𝑳 = 𝑻𝒓𝒂𝒗𝒆𝒍 𝒐𝒇 𝒕𝒉𝒆 𝒕𝒐𝒐𝒍 𝒊𝒏 𝒕𝒉𝒆 𝒅𝒊𝒓𝒆𝒄𝒕𝒊𝒐𝒏 𝒐𝒇 𝒕𝒉𝒆 𝒇𝒆𝒆𝒅 𝒎𝒐𝒕𝒊𝒐𝒏, 𝒎𝒎 𝑵 = 𝑺𝒑𝒊𝒏𝒅𝒍𝒆 𝒔𝒑𝒆𝒆𝒅 𝒐𝒓 𝒓𝒐𝒕𝒂𝒕𝒊𝒐𝒏𝒂𝒍 𝒔𝒑𝒆𝒆𝒅 𝒐𝒇 𝒕𝒉𝒆 𝒘𝒐𝒓𝒌𝒑𝒊𝒆𝒄𝒆, 𝒓𝒑𝒎 𝒔 = 𝑭𝒆𝒆𝒅, 𝒎𝒎/𝒓𝒆𝒗 59 59 60 60 30  08/10/2024 In longitudinal turning, the tool travel L is made up of: 𝑳 = 𝒍 + 𝒚 + ∆ (𝒎𝒎) 𝑾𝒉𝒆𝒓𝒆; 𝒍 = 𝑳𝒆𝒏𝒈𝒕𝒉 𝒐𝒇 𝒕𝒉𝒆 𝒎𝒂𝒄𝒉𝒊𝒏𝒆𝒅 𝒔𝒖𝒓𝒇𝒂𝒄𝒆 𝒊𝒏 𝒕𝒉𝒆 𝒅𝒊𝒓𝒆𝒄𝒕𝒊𝒐𝒏 𝒐𝒇 𝒕𝒉𝒆 𝒇𝒆𝒆𝒅 𝒎𝒐𝒕𝒊𝒐𝒏, 𝒎𝒎 𝒚 = 𝑻𝒐𝒐𝒍 𝒂𝒑𝒑𝒓𝒐𝒂𝒄𝒉, = 𝒂 𝒄𝒐𝒕𝝋 𝒎𝒎 𝝋 = Plan approach angle ∆ = 𝑻𝒐𝒐𝒍 𝒐𝒗𝒆𝒓𝒕𝒓𝒂𝒗𝒆𝒍 = 𝒂𝒃𝒐𝒖𝒕 𝟐 𝒎𝒎 61 61 In facing the end of a shaft: 𝑫 𝑳= +𝒚+∆ 𝒎𝒎 𝟐 In facing the end of a pipe: 𝑫 𝒅 𝑳=𝒍+𝒚+∆= +𝒚+∆ 𝒎𝒎 𝟐 As in longitudinal turning, the approach and overtravel in facing with a bent shank tool are; 𝒚 = 𝒂 𝒄𝒐𝒕𝝋 𝒎𝒎 𝒂𝒏𝒅 ∆ = 𝒂𝒃𝒐𝒖𝒕 𝟐 (𝒎𝒎) 62 62 31  08/10/2024 63 63 In cutting off (parting) a shaft with a cut- off tool having its cutting edge parallel to the work axis: 𝑫 𝟐 + If the cut-off tool has an inclined cutting edge then; 64 64 32  08/10/2024 65 65 In cutting off a pipe with a tool having its edge parallel to the axis: While if the tool has an inclined cutting edge, then; 66 66 33  08/10/2024 If several passes are required to do a job and the speed and feed remain constant for all the passes, the machining time will be; 𝑳 𝑻𝒎 = 𝒊 𝒎𝒊𝒏 𝒔𝑵 𝑾𝒉𝒆𝒓𝒆; 𝒉 𝒊 = 𝒏𝒖𝒎𝒃𝒆𝒓 𝒐𝒇 𝒑𝒂𝒔𝒔𝒆𝒔 = 𝒂 𝒉 = 𝒎𝒂𝒄𝒉𝒊𝒏𝒊𝒏𝒈 𝒂𝒍𝒍𝒐𝒘𝒂𝒏𝒄𝒆 𝒐𝒏 𝒆𝒂𝒄𝒉 𝒔𝒊𝒅𝒆 𝒐𝒇 𝒕𝒉𝒆 𝒘𝒐𝒓𝒌 (𝒎𝒎) 𝒂 = 𝒅𝒆𝒑𝒕𝒉 𝒐𝒇 𝒄𝒖𝒕 (𝒎𝒎) 67 67 Metal Removal Rate (MRR) The metal removal rate (MRR) is the product of the cutting speed and the cross sectional area of the uncut chip. For cylindrical turning operation, the cutting speed calculated at the machined surface, is different than that calculated at the work surface, that is why the metal removal rate should be calculated using the average cutting speed based on the mean diameter between the two surfaces, so that; 𝑴𝑹𝑹(𝒄𝒚𝒍𝒊𝒏𝒅𝒓𝒊𝒄𝒂𝒍 𝒕𝒖𝒓𝒏𝒊𝒏𝒈) = 𝒂. 𝒔. 𝒗𝒂𝒗 𝒄𝒎𝟑 ⁄𝒎𝒊𝒏 68 68 34  08/10/2024 𝑾𝒉𝒆𝒓𝒆; 𝒂 = 𝑫𝒆𝒑𝒕𝒉 𝒐𝒇 𝒄𝒖𝒕 (𝒎𝒎) 𝒔 = 𝑭𝒆𝒆𝒅 𝒎𝒎⁄𝒓𝒆𝒗 (𝒂. 𝒔) = 𝑼𝒏𝒄𝒖𝒕 𝒄𝒉𝒊𝒑 𝒂𝒓𝒆𝒂 (𝒎𝒎𝟐 ) 𝝅𝑫𝒂𝒗 𝑵 𝒗𝒂𝒗 = 𝒎⁄𝒎𝒊𝒏 𝟏𝟎𝟎𝟎 𝒅𝒘 + 𝒅𝒎 𝑫𝒂𝒗 = 𝒎𝒎 𝟐 𝒅𝒘 = 𝑾𝒐𝒓𝒌 𝒔𝒖𝒓𝒇𝒂𝒄𝒆 𝒅𝒊𝒂𝒎𝒆𝒕𝒆𝒓 𝒎𝒎 𝒅𝒎 = 𝑴𝒂𝒄𝒉𝒊𝒏𝒆𝒅 𝒔𝒖𝒓𝒇𝒂𝒄𝒆 𝒅𝒊𝒂𝒎𝒆𝒕𝒆𝒓 𝒎𝒎 69 69 70 70 35  08/10/2024 Power consumed in machining operations For a given work material machined under given condition, the energy required to remove a unit volume of material (specific cutting pressure), 𝒌𝒔 (𝑵⁄𝒎𝒎𝟐 ) can be obtained. This factor is mainly dependent on the work material and become constant at high values of cutting speed, feed, and depth of cut, and if its value is known, the power 𝑷𝒎 (𝒌𝑾) required to perform any machining operation can be obtained from; 𝒌𝒔 𝑴𝑹𝑹 𝑷𝒎 = (𝒌𝑾) 𝟔𝟎𝟎𝟎𝟎 𝒇𝒄 𝑾𝒉𝒆𝒓𝒆; 𝒌𝒔 = 𝑵⁄𝒎𝒎𝟐 , 𝒇𝒄 is the main cutting force component (𝑵) 𝒂.𝒔 71 71 𝒌𝒔 𝒄𝒂𝒏 𝒃𝒆 𝒐𝒃𝒕𝒂𝒊𝒏𝒆𝒅 𝒂𝒔 𝒇𝒐𝒍𝒍𝒐𝒘𝒔; 𝑻𝒉𝒆 𝒓𝒂𝒕𝒆 𝒐𝒇 𝒆𝒏𝒆𝒓𝒈𝒚 𝒄𝒐𝒏𝒔𝒖𝒎𝒑𝒕𝒊𝒐𝒏 𝒅𝒖𝒓𝒊𝒏𝒈 𝒎𝒂𝒄𝒉𝒊𝒏𝒊𝒏𝒈 (𝑷𝒐𝒘𝒆𝒓) 𝑴𝒆𝒕𝒂𝒍 𝑹𝒆𝒎𝒐𝒗𝒂𝒍 𝑹𝒂𝒕𝒆 = 𝑻𝒉𝒆 𝒆𝒏𝒆𝒓𝒈𝒚 𝒄𝒐𝒏𝒔𝒖𝒎𝒆𝒅 𝒑𝒆𝒓 𝒖𝒏𝒊𝒕 𝒗𝒐𝒍𝒖𝒎𝒆 𝒐𝒇 𝒎𝒆𝒕𝒂𝒍 𝒓𝒆𝒎𝒐𝒗𝒆𝒅 𝒌𝒔 𝒇𝒄 𝒗 𝒇𝒄 = = 𝒌𝒔 (𝑺𝒑𝒆𝒄𝒊𝒇𝒊𝒄 𝒄𝒖𝒕𝒕𝒊𝒏𝒈 𝒆𝒏𝒆𝒓𝒈𝒚 𝒐𝒓 𝑺𝒑𝒆𝒄𝒊𝒇𝒊𝒄 𝒄𝒖𝒕𝒕𝒊𝒏𝒈 𝒑𝒓𝒆𝒔𝒔𝒖𝒓𝒆), 𝒂 𝒔 𝒗 𝒂 𝒔 𝒘𝒉𝒊𝒄𝒉 𝒊𝒔 𝒂 𝒑𝒂𝒓𝒂𝒎𝒆𝒕𝒆𝒓 𝒓𝒆𝒑𝒓𝒆𝒔𝒆𝒏𝒕𝒔 𝒕𝒉𝒆 𝒆𝒇𝒇𝒊𝒄𝒊𝒆𝒏𝒄𝒚 𝒐𝒇 𝒕𝒉𝒆 𝒄𝒖𝒕𝒕𝒊𝒏𝒈 𝒐𝒑𝒆𝒓𝒂𝒕𝒊𝒐𝒏 72 72 36  08/10/2024 𝑷𝒎 = 𝒌𝒔. 𝑴𝑹𝑹 𝑵 𝒄𝒎𝟑 𝟏𝟎𝟔 𝑵𝒎 𝑷𝒎 = 𝒙 𝒙 = 𝒎𝒎𝟐 𝒎𝒊𝒏 𝟏𝟎𝟔 𝒎𝒊𝒏 𝑵𝒎 𝟏 𝑱𝒐𝒖𝒍𝒆 𝑷𝒎 = 𝒙 = 𝒎𝒊𝒏 𝟔𝟎 𝒔𝒆𝒄 𝑱𝒐𝒖𝒍𝒆 𝑷𝒎 = = 𝑾𝒂𝒕𝒕 𝒙 𝟏𝟎 𝟑 = 𝒌𝑾 𝒔𝒆𝒄 𝒌𝒔. 𝑴𝑹𝑹 𝑷𝒎 = (𝒌𝑾) 𝟔𝟎𝟎𝟎𝟎 73 73 , if the overall efficiency of the machine tool motor and drive systems is denoted by the electrical power 𝒆 consumed by the machine tool is given by; 𝒎 𝒆 74 74 37  08/10/2024 End of Lecture 75 75 38