Machine Tool Characteristics and Operation - Essay Example

Machine Tool Characterististics and Operation – 1 Insert your name Insert tutor's name here Insert Institution here Insert a date Level 4 HNC / 5 HND Engineering Unit No. 13 – Application of Machine Tools Task 1 a) I) Lathe Centre Lathe machine is designed specifically for sanding, cutting, turning, and grooving materials with relative hardness (Huang et al., 2014). They are applied in a wide range of uses due to their inherent versatility, and have the ability to machine a number of materials. The machine eliminates or gets rid of materials from a rotating work piece through the undeviating gesticulation of the different cutting tools like drill bits and tool bits. It is important to have knowledge about the depth, speed, cutting, and feeds of the cut as well as consider the usage of the tool whenever one wants to use a lathe machine. The spindle of the machine is capable of turning alongside the workpiece changing the shape of other tools for cutting and the lathe knife (Morris, 2014). Axis convention: a common operation in metal cutting is the turning. It entails rotating the workpiece about its axis with the feeding in of single-point cutting tools, and as a result, creation of desired parts and shearing away the parts that are not needed. To produce countered parts that are axially symmetrical, turning is occurring both on the internal and external surface. The x axis is perpendicular to the spindle while the z axis is along it instead of vertical along the tool axis. The intersection of these axes is the program zero. The program zeroes forms the reference point for all coordinates (Stephenson and Agapiou, 2016; Dorlin et al., 2016). The linear axes are located differently on a lathe, with the Z axis positioned horizontally along the spindle axis. The readouts are in usual adherence to conventions and marker shifting of the saddle along the Z or spindle axis. A Y axis does not really exist unless there is a third perpendicular motion, such as a milling accessory on the crosslide, and if there is a read about for it, the compound should be a U’ The diagram below shows a standard lathe coordinates system: ii) Vertical Mill Spindle axes are vertically oriented in the vertical milling machines. The milling cutters are attached by the spindle and rotated on the spindle axis. There is the possibility of extending the spindle (or lowering and raising the table producing a similar effect), to give room for drilling and plunge cuts. The spindle can be fed up and down with a quill feed lever on the head. The milling machines are generally applied in the machining of flat surfaces, though they are able to produce surfaces that are not regular. The mills are used for drilling, boring, producing slots and cutting gears. The machine removes metals by rotations of a cutter contain a number of teeth run into the workpiece that is in motion. There is a vast number of milling machines, but the most common one is the vertical milling machine (Kojovic et al., 2015). The following diagram is an image of a typical vertical mill milling machine. A milling machine is quite straight forward where the Z axis is in line with the spindle, and the X and Y axes are perpendicular to the spindle axis. At the many of the vertical mills it is the vertical Z axis movement that is controlled and in a few cases the table is moved. The work is usually mounted on the main spindle on the turning center whose axis is always parallel and horizontally located to the bed, thus moving the tool in the same direction as that of the bed and spindle extension is the Z axis motion. The X axis on the other hand is generally horizontal. There is a radical orientation of the X movement on the turning center. The Y axis is the movement in such a direction, completing a right handed Cartesian coordinate system (Le et al., 2014; Zhou et al., 2015). The diagram below shows a coordinate system for a vertical mill. iii) Surface Grinder Surface grinding machine is a tool applied to products that need a high degree of flatness and precision. Surface grinders are able to achieve very fine finishing. The wheel spins around the spindle that exists on the surface grinder. The horizontal movement is the Z axis. The grinding wheels of most surface grinding machines rotate on the horizontal axis to cut around the circumferences of the grinding wheel. The grinding wheel of the rotary surface grinding machine rotates on a vertical axis as a result of the rotation of the grinding head, thus cut on the end face of the grinding wheel as the workpiece is rotated underneath in the opposite direction by the table (Sahli et al., 2015). This motion enables the machine to grind effectively and produce a smooth finish on the flat surfaces. b) For each axis identified in the above task, provide a written explanation on how the drives are controlled, making reference to the use of manual and automated feed actions. A geared head drives powers the lathe center machine. To obtain a difference in the speed of the spindle, the gear trains are changed through the position of the levers on the head shook. There is a peed motor that runs constantly mounted on the lathe for driving of the machine. A lead screw is applied for cutting of both external and internal threats. The spindle drives the quick change gear box that connects lead screw and feed rod for cutting internal threads (Podder et al., 2014; Waskom et al., 2014). There is a computer fitted with special softwares for executing and storing commands into actions through the machine tools. The computer is known as machine control unit (MCU). It is composed of two major units: the control loop unit (CLU) and the data processing unit (DPU). The processing software consists of editing of a part program, an interpolation algorithm for achieving a smooth movement of the cutter, software for translation for converting the part program into a form that can be utilized, calculation algorithms, and system software. The data from part program is processed by the DPU that feeds it to CLU. The CLU operate the drives embedded to the machine head screws which sends back the feedback information on the actual velocity and position of each one of the axes. The head screw is connected with a DC motor or a driver. Task 2: Tool and Work Holding Devices Devices that act as the interchangeable interface between a cutting tool and a machine tool spindle so that the efficiency of either of the elements such as concentricity, gauges, balancing and holding strength are not made to look less impressive or valuable. Work holding devices are utilized to steadily keep the work for accurate drilling of holes and managing safe drilling operations. Large CNC machines and manual machines apply tool holder that is firmly grounded with a male taper that mates with the machine’s particular female taper (Mengavade and Bankar, 2016). The tool holder must be secured in a place. The pull studs are standard with the CNC machines because it gives room for easier automated tool changing (Byrne et al., 2014). Toolposts Toolholders are clenched into the toolpost that is always fastened to composite support of the lathe center machine. There are two unexceptional simple toolposts namely the multi-position quick-change and the square quick-change (Lockwood, 2014). Multi-Position Quick-Change Toolpost has a working principle like the square toolpost, however, it is possible to set the toolholders in increments of 15º around the toolpost. The square quick change toolpost can hold just one tool at a time with an easy and quick room for removal and setting of the tools. Special holders are used to grip the cutting tools. A guide which is maintained in place by a cam mechanism combines with thetoolholders on the side of the tooltpost. A height adjustment screw precisely adjusts the height of the cutting tool. All the cutting tools required for for a work is clamped in many Toolholders which are inserted and removed in quick succession. Morse taper shanks Pressing by turning the tailstock handwheel can cause the tailstock spindle to move in and out of the casting such as the quail on a drill. The spindle bore is always a touchstone for the accommodation of drill chucks, a dead center and any amount of tools for cutting like the reamers and drills. It is easy to lock the spindle using the tailstock clamp in place. Tools in the toolpost and morse taper shanks on a center lathe ER 16 holder ER 16 holder is made from alloy spring steel and hardened to HRC 44-48 and is slotted from both ends, thereby compressing from one end to the other upon tightening. The effect provides a better grip on the cutter shank as well as allowing variations usually 1 mm in shank sizes that may be used in a single couplet. The holders can handle a broad range of machining jobs and are available for drilling, milling, and high-speed applications (García-Lerma et al. 2010). Stub Arbor The arbor is much shorter than the horizontal arbor and is used to fit the vertical spindle socket, without giving support to the free end. The stub arbor enables the vertical mills to perform several functions usually only capable of being done by the horizontal mills. Autolock collet chuck This kind of chunk is a sure way of preventing any possible slip of the cutting tool. The collets are mountable on the spindle by a special R8 taper, or an international taper, or a Morse taper applicable on the Bridgeport vertical mill. There are threads on the cutters that fit Autolock chuck. Tightening the thread is accomplished by tightening the collet holding the cutter making the collet to be tightened around the endmill. Grinding wheels on a surface grinder Surface grinders are utilized to obtain irregular, angular and flat surface. The grinding wheel revolves on a spindle and that brings the work piece into contact with it. The grinding utilizes an abrasive product and is composed of abrasive grains, acting as cutting tools, clamped together in a clamp. Dressing is the action of removing the dull and glaze abrasives from the face of a grinding wheel for the purpose of cleaning and sharpening it so that it can produce a precise thread thread form on the part. There are special tools for dressing the wheels. However, the dressing is usually manually done, though some machines are capable of automatically performing the dressing (Doi et al., 2015; Ohmori and Takahashi, 2016). The wheel head is lowered until it is about to touch the truing wheel. Both the wheels are run simultaneously and the training wheel is brought closer to the wheel head by lowering it. Task 3: six degrees of freedom of a rigid body A rigid object that is not constrained has six degrees of freedom, namely three rotations and three translations (Talalay 2016). The number of the degrees of freedom of freedom of a system is defined as the number of independent coordinate variables required for a simultaneous determines the location of each particle in the dynamic system. Thus the number of degrees of freedom in a system containing n fragments in a 3D space is 3n since for specification of the center of the mass of each particle, three coordinates are required. The number of degrees of freedom will, nevertheless, be less than 3n if the all the fragments are no longer free because of rigidity applied in the system (Beitz et al., 2013; Zelik et al., 2015). Less than 3n values can be assigned to the variables of the coordinates, but there is still the need for 3n degrees for locating the center of the mass. Let the system containing n fragments in the 3d space be referred to by S3 and the number of degrees of freedom be N3. Give S3 to the treatment of a rigid body to calculate N3. There are two kinds of rigid bodies recognizable by mechanics that is, the ones formed by n mass points connected through rigid links and those formed by a continuous distribution of mass. Since 3 coordinates are used in describing the orientation and 3 for locating the center of mass, the number of degrees of freedom totals to six. For a body with mass distribution along a single line it is not possible to rotate the body through that line lowering the degrees of freedom of such a body to 5. The same concept is applicable for determining N3 when S3 is assumed to a single body and not a assemblage of particles. Thus N3=5 when n=2and N3=6 when n>2. Calculating S3 when n=3 is simple. To specify the location of center mass of the particles, nine coordinates are needed; however, because of three restraints, S3=6 (Featherstone, 2014; Hernandez et al., 2015) Read More

The following diagram is an image of a typical vertical mill milling machine. A milling machine is quite straight forward where the Z axis is in line with the spindle, and the X and Y axes are perpendicular to the spindle axis. At the many of the vertical mills it is the vertical Z axis movement that is controlled and in a few cases the table is moved. The work is usually mounted on the main spindle on the turning center whose axis is always parallel and horizontally located to the bed, thus moving the tool in the same direction as that of the bed and spindle extension is the Z axis motion.

The X axis on the other hand is generally horizontal. There is a radical orientation of the X movement on the turning center. The Y axis is the movement in such a direction, completing a right handed Cartesian coordinate system (Le et al., 2014; Zhou et al., 2015). The diagram below shows a coordinate system for a vertical mill. iii) Surface Grinder Surface grinding machine is a tool applied to products that need a high degree of flatness and precision. Surface grinders are able to achieve very fine finishing.

The wheel spins around the spindle that exists on the surface grinder. The horizontal movement is the Z axis. The grinding wheels of most surface grinding machines rotate on the horizontal axis to cut around the circumferences of the grinding wheel. The grinding wheel of the rotary surface grinding machine rotates on a vertical axis as a result of the rotation of the grinding head, thus cut on the end face of the grinding wheel as the workpiece is rotated underneath in the opposite direction by the table (Sahli et al., 2015). This motion enables the machine to grind effectively and produce a smooth finish on the flat surfaces. b) For each axis identified in the above task, provide a written explanation on how the drives are controlled, making reference to the use of manual and automated feed actions.

A geared head drives powers the lathe center machine. To obtain a difference in the speed of the spindle, the gear trains are changed through the position of the levers on the head shook. There is a peed motor that runs constantly mounted on the lathe for driving of the machine. A lead screw is applied for cutting of both external and internal threats. The spindle drives the quick change gear box that connects lead screw and feed rod for cutting internal threads (Podder et al., 2014; Waskom et al., 2014). There is a computer fitted with special softwares for executing and storing commands into actions through the machine tools.

The computer is known as machine control unit (MCU). It is composed of two major units: the control loop unit (CLU) and the data processing unit (DPU). The processing software consists of editing of a part program, an interpolation algorithm for achieving a smooth movement of the cutter, software for translation for converting the part program into a form that can be utilized, calculation algorithms, and system software. The data from part program is processed by the DPU that feeds it to CLU.

The CLU operate the drives embedded to the machine head screws which sends back the feedback information on the actual velocity and position of each one of the axes. The head screw is connected with a DC motor or a driver. Task 2: Tool and Work Holding Devices Devices that act as the interchangeable interface between a cutting tool and a machine tool spindle so that the efficiency of either of the elements such as concentricity, gauges, balancing and holding strength are not made to look less impressive or valuable.

Work holding devices are utilized to steadily keep the work for accurate drilling of holes and managing safe drilling operations. Large CNC machines and manual machines apply tool holder that is firmly grounded with a male taper that mates with the machine’s particular female taper (Mengavade and Bankar, 2016). The tool holder must be secured in a place. The pull studs are standard with the CNC machines because it gives room for easier automated tool changing (Byrne et al., 2014).

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