Machine Tool Characteristics and Operation - Assignment Example

Machine tool characteristics and operation Name Institution Date Machine tool characteristics and operation Introduction The focus of this paper is to analyze the characteristics of various machine tools and their machining operations. Specifically, the paper will elaborate characteristics of axis conventions of vertical mill, centre lathe and surface grinder. The paper has also explained the operation of types of drive and the axis control system, such as hand-wheels and servo-motors, for given machine tools and described the six degrees of freedom of a rigid body. Finally, the paper will assess the appropriateness of machine tool types for the production of specific components and geometries and plan the sequence of operations required to produce specific components. Task 1 Centre Lathe: The axis conventions on centre lather are either linear or rotary. Centre lather has three rotary axes namely, X, Y and Z. In case cutting occurs within the same plane, the cutter does not have the ability of moving within the Z vertical plane. Generally, in centre lathe, the X and Y axes can interpolate together concurrently to come up with angled lines and circular arcs (Guiral, 2012). Vertical Mill: For vertical mill, axis occurs if all the cutting takes place within all planes that are analogous to the major plane even though not essentially at equivalent depth and height. In a vertical mill, the cutter moves from the Z vertical plane to change levels, even though not concurrently with the X, Y movements (Guiral, 2012). Surface Grinder: This has 2 rotary axis movements. If the cutting occurs within equivalent plane, the cutter is not able to move vertically on the plane. Generally, the Y and X axes interpolates together simultaneously creating sloping lines as well as circular arcs (Guiral , 2012). Task 2 Tramming the Head The head of vertical milling machine can be slanted from side to side as well as from front to back. This enables the machine to be versatile, even though these adjustments can drift. It is important to seldom check and regulate the head to ensure the spindle is normal to the table’s plane. The spindle should be rotated up to 180 degrees and in case the dial indicator reads zero the spindle should be aligned front to back. In not, the head should adjusted until the dial reads half the primary reading and the whole process should be integrated until the errors returns to acceptable limits. The process should be repeated with the dial left and right (Goetsh, 2005). Squaring the Vise To ensure the parts are square and parallel, it is important to align the vice with the machine’s X travels. Ti accomplish this, the vise should be mounted on the bed and secured using T-bolts. The indicator within the machine’s spindle should also be mounted using a probe. The spindle should be lowered and the table’s beds run back. The blaze should then be set to zero. The manual cross feed should be used to operate the indicator cross. In case the vise is squared, the indicator stays at zero. In case the dial indicator does not read zero, it should be tapped lightly using a soft hammer in order to realign the vise. The T-bolts should be tightened and the alignment of the vise rechecked (Goetsh, 2005). Setting Spindle Speed The spindle speed should be set by turning the speed crank on the right side of the spindle. The spindle is supposed to be on and on rotation in order to regulate the speed. The speed dial contains two scales, one for low range and the other one for high range. The machines should be switched at the recommended ranges and in order to switch the lever, it should be ensured that the machine is not running. It is important to at times switch the lever while the spindle is not in operation while at times the spindle should be rotated slightly to ensure proper mating of gears and to allow the lever to click into gear (Goetsh, 2005) . Using Digital read-outs Mills have electronic display for precise positioning. Digital read-outs have a region for accuracy for the X and Y axis, the Z axis read off the mechanical handle. There are 2 systems of measurement that the digital read-outs supplies and they include incremental and absolute. Absolute is supposed to be utilized for the zero corner parts and shouldn’t be changed during job. On the other hand, the incremental setting can read zero as appropriate for usage between any 2 locations, features and holes (Goetsh, 2005). Task 3 Six degrees of freedom is the freedom of movement of a rigid body within a 3-dimensional space. In particular, the body has freedom to adjust and change its position as forward/backward, up/down. Left/right translation within 3 perpendicular axes, along with changes in orientation via rotation approximately 3 perpendicular axes (Krainak, Parrish & Dewald, 2008). Six degrees of freedom (6DoF) refers to the freedom of movement of a rigid body in three-dimensional space. Specifically, the body is free to change position as forward/backward (surge), up/down (heave), left/right (sway) translation in three perpendicular axes, combined with changes in orientation through rotation about three perpendicular axes, often termed pitch, yaw, and roll (Krainak, Parrish & Dewald, 2008). Normally, the design of aerial and parallel manipulator should be to position an end-effector using six degrees of freedom that include 3 in translation and 3 during orientation. This offers a direct link between actuator positions and the manipulator configuration. A good example of a six degree of freedom movement is the movement of a ship and includes the following aspects: Translation: Forward and backward movement on the X-axis Left and right movement on the Y-axis Rotation: Tilting side to side on the X-axis Tilting forward and backward on the Y-axis Turning left and right on the Z-axis Task 4 Suitability The equipment is being used as per the manufacturer’s specifications and instruction. It is located where it is used and the environment is not hazardous. The equipment usage does not pose any health risks to users in specific situations which can otherwise be safe. It is not advisable to utilise portable power tools for the equipment operations. The operation of the equipment is performed by specialist machinery with suitable guarding (Jespen, 2016) Operational plan Operations by specialist machinery and trained people Equipment should be checked before usage Mechanical faults should be reported to the supervisor The equipment should not be left unattended It should be ensured that guarding is provided to prevent unauthorized people from operating the equipment Operators should wear ear defenders and safety goggles when operating the machine to ensure there are no negative health impact on workers (Jespen, 2016) Task 5 The following features are as a result of generated material removal process In material removal process, various methods can be used. In the following feature, cutting processes was used. Cutting processes are among the most vital operations in manufacturing. This is because cutting processes are used to impart the targeted surface finish and dimensional precision to constituent (El-Hofy, 2005). Various variables significantly influence the mechanics of chip formation during cutting processes and the most common chip types are constant, segmented and built-up edge. In addition variables such as the shape of the tool, material and cutting conditions like speed and feed, traits of the machine tool greatly influence the cutting process (El-Hofy, 2005). Various cutting tool materials have different properties like hot hardness, toughness and resistance to chipping and wear. Cutting fluid is very vital in machining activities. Basically, operations that are slow and with high tool pressures necessitate a fluid with excellent lubricating attributes. On the other hand, high-speed operations with substantial increase in temperature necessitate a fluid with cooling characteristics (El-Hofy, 2005). In order to produce such shapes, the cutting processes that were involved include turning, boring and drilling as well. Formation of chip remains the same in all processes. Nonetheless, due to the 3-dimensional nature of the cut, chip movement and its control should be considered because they have a likelihood of interfering with the cutting operation. Removing the chip can cause major problem, because it can result to tool splintering. It is important to examine all processes in order to understand the relationships of design parameters like dimensional accurateness, surface finish and integrity, as well as process parameters like speed, tool material and shape, in addition to cutting fluids (El-Hofy, 2005). The following features are as a result of formed material removal process In milling, the speed and motion of the cutting tool is specified through several parameters. During the formed material process, various operations can be carried out on the work-piece to give the preferred part shape. During the formed process, various processes are used and they include: End milling: an end mill give rise to peripheral or slot cuts that are determined by the step-over distance over the work piece. The depth of the feature is machined using a pass and can be reached by making numerous passes. This feature can also be achieved through boring where the boring tool enters the work-piece axially and cuts along an internal surface giving rise to various features (El-Hofy, 2005). Broaching of a keyway Broaching refers to a machining procedure that involves pulling or pushing of a cutting tool known as broach over/through the surface undergoing machining. There are two kinds of broaching procedures, namely internal broaching and exterior broaching. In external broaching, the broaching tool is pulled or pushed over the work piece surface or the surface can move over and across the tool. On the other hand, interior broaching involves a starting hole or an opening within the wo9rk-piece to allow insertion of the tool. The tool or the work-piece is the pulled or pushed to go through the starter hole. It is possible to broach nearly all asymmetrical cross-sections provided all surfaces of the section corresponds the direction of broach travel. It is also possible to produce helical cuts through twisting of the broach tool as it goes over the work-piece surface (El-Hofy, 2005). During broaching process, there must be proper alignment of the broach, work-piece as well as ram. This is because errors in alignment can result to drifting, deflection and also even breakage. In case there is a misalignment and the keyway broach drifts and cuts a taper, it is important to try the following: Reversing the work-piece or turning broach to ensure the teeth faces towards the back of the press Allow the bushing to protrude over the work-piece to ensure that the back of the broach is supported and hence help it to maintain alignment. In case a collared bushing is utilized, it should be placed upside down under the work-piece. It should be ensured that the broach is at the center under the ram when the cut is starting. In case the broach moves out of alignment after the cut begins, it is advisable to back of the pressure on the ram and focus on aligning the broach itself. This should be repeated during successive cuts to make sure there are perfectly straight cuts (El-Hofy, 2005). Bending of a Keep plate for a toolmakers clamp Bending plates involves deflection of the plate at a 90 degree angle to the plane of the plate while being under action of external forces and moments. It is possible to determine the scope and extent of deflection by solving the differential equations of a suitable plate theory. The deflections allow calculation of the stresses and forces within the plate. After the stresses are determined, the failure theories can be utilized to establish if a plate will fail once under a particular load (El-Hofy, 2005). During the bending of a keep plate for toolmakers clamp, it is important to consider utilizing different material. Since there is a replicator 2, the printing can be done with PLA and not ABS because ABC is not appropriate for big, flat model. PLA model tends to bend even less. It is also possible to modify the model a little and various grooves within the bottom surface can be included in the model in order to offer some ‘strain relief’ and hence prevent bending (El-Hofy, 2005). In addition, adhesion can be increasing by printing the initial layer slowly and closer to the build surface, at increased temperature in order to increase adhesion. It is also advisable to raise ambient temperature; however, even though replicator 2 does not have to be a heated bed, it is important to ensure that the cooling is gradual (El-Hofy, 2005). Conclusion In conclusion, this paper has analyzed the characteristics of different machine tools and their machine operations. The paper has further discussed various characteristics such as the ability of the cutter to move on the plane, among other traits. In addition, six degree of freedom which refers to how freely a rigid body moves and changes position has been discussed as well as its application. In a nutshell, the suitability of machine tool types for producing certain components and geometries has also been discussed. Appendix 4a PLANNING SHEET                     Candidates Name: Date:27/9/2016                                           Task Description:  Plumb Bob (Body) Task No: PC/PL-BO LV2 2012                                           List of Operations         Tools and Materials  Obtain material 20mm×82mm(BDMS) Bright drawn mild steel  Mild steel  Obtain tools  Drill bit, turning tools, steelrule,scriber,chamfering tool, knurling tool  Setup lathe ( centre height ,speed, feed)  Dial clock indicator  Place material in chuck (10-20mm protruding)  Chuck key  Face off (datum)  Facing tool  Centre drill  Centre drill  drill6.8mm×19mm  Drill bit  turn19.5mm×50mm  Turning tool  Knurl material  Knurling tool  turn16mm×10mm  Turning tool  Chamfer1mm×45 Chamfering tool   Turnaround 180  Facing tool  Face off to length 80mm  Facing tool  Turn chamfer  Chamfering tool  Turn taper40  Taper turing attachment  Clean machine + work area  Turning tool  *  Cotton waste,hand brush,light oil  *    *    *    *    *                                   Safety Requirements: wear industrial boots, avoid loose clothing Estimated Time 45minutes   Instructors Sig Actual Time     Appendix 4b PLANNING SHEET                     Candidates Name: Date:10/11/216                                           Task Description:  Plumb Bob (Screw) Task No: PC/PL-SC LV2 2012                                           List of Operations         Tools and Materials  1-Obtain material 12mm×50mm(FMB/CZ121) Bright drawn mild steel  Mild steel  2-Obtain tools  Tailstock, turning tool, hacksaw, vaniercalipers  3-Setup lathe ( centre height ,speed, feed)  Tailstock, turning tool  4-Place material in chuck (10mm protruding)  Chuck key  5-Face off (datum)  Facing tool  6-Centre drill  Centre drill  7-Drill3.5mm×16mm  Centre drill, cutting fluid  8-Turn11.5mm30mm  Turing tool, live centres 9- Knurl material  Knurling tool  10-Turn8mm×12mm  Turning tool  11-Chamfer 1mm45o  Chamfering tool  12-Undercut7mm×1mm  Undercutting tool  13-Thread m8×1.25mm  Die nut m8x1.25mm  14-Undercut to half diameter  Under cutting tool  15-Turn chamfer 1mm×45o  Chamfering tool  16-Part off to length 16mm  Parting off tool  17-Clean machine + work area  Handbrush,cotton waste                                                   Safety Requirements Avoid loose clothing Wear protective clothing Estimated Time 1hr   Instructors Sig Actual Time     Appendix 4a PLANNING SHEET                     Candidates Name: Date:27/9/2016                                           Task Description:  MACHINED BLOCK Task No: PC/PL-BO LV2 2012                                           List of Operations         Tools and Materials  Obtain material 20mm×82mm(BDMS) Bright drawn mild steel  Mild steel  Obtain tools  Machine cutting tools  Setup lathe ( centre height ,speed, feed)  Tailstock, turning tool  Place material in chuck (10-20mm protruding)  Chuck key  Face off (datum)  Facing tool  Centre drill  Centre drill  drill6.8mm×19mm  Drill bit  turn19.5mm×50mm  Turning tool  Knurl material  Knurling tool  turn16mm×10mm  Turning tool  Chamfer1mm×45  Chamfering tool  Turnaround 180  Turning tool  Face off to length 80mm  Facing tool  Turn chamfer  Chamfering tool  Turn taper40  Taper turning tool  Clean machine + work area  Hand brush, cotton wool  *    *    *    *    *    *    *                               Safety Requirements No use of phones when operating machine Estimated Time :30mins   Instructors Sig Actual Time     Reference list El-Hofy H, 2005, Advanced Machining Processes: Nontraditional and Hybrid Machining Processes, London: McGraw Hill Professional. Guiral S, 2012, Engineering Mechanics, Bangalore: Laxmi Publications. Goetsh D, 2005, Technical Drawing, New York: Cengage Learning. Jespen T, 2016, Risk Assessments and Safe Machinery: Ensuring Compliance with the EU Directives, New York: Springer. Krainak D, Parrish T & Dewald J, 2008, A Method to Capture Six-Degrees-of-Freedom Mechanical Measurements of Isometric Shoulder and Elbow Torques during Event-Related fMRI, J Neurosci Methods, 161(2), pp: 314–322. Read More