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Uncover the world of lathe operations like turning, facing, and drilling. Dive into turning parameters, forces, and material removal rates. Enhance your knowledge of lathe components and attachments for efficient machining. Design tips ensure smooth operations and high-quality results.
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ManufacturingRounded Shapes Manufacturing Processes
Outline • Types of Processes • Turning Parameters • Geometry • Material Removal Rate • Forces • Lathe Components • Lathe Attachments • Design Considerations • Types of Lathes
Types of Processes • Turning • Facing • Form Tools • Boring • Drilling • Parting • Threading • Knurling
Turning Parameters • Geometry • side rake angle • back rake angle • relief angles • cutting-edge angles • nose radius • Forces in Turning • cutting force • thrust force These forces cannot be calculated accurately; they are determined by experiments • Material Removal Rate
Lathe Feedand Speed V = πDN/12 V = cutting speed in ft/min; Velocity at which the tool head moves along the workpiece surface D = diameter of the rotating tool or rotating workpiece N = RPM of the rotating tool or rotating workpiece Feeds for a lathe are listed as in/rev or m/rev. Multiply these by the RPM to obtain the feed in in/min or m/min.
Lathe Feedand Speed Example: Work Material: Aluminum Tool Material: High Speed Steel Workpiece Diameter: 3.375 in Recommended Cutting Speed: 600 ft/min N = 12V/πD N=12*600/(π*3.375) =679.2 RPM The closest available speed on the lathe, without exceeding this value, is 630 RPM so this value should be used. Recommended Feed for HSS/aluminum = .01-.02 in/rev f = (.01-.02)*630 RPM = 6.3-12.4 in/min
Material Removal Rate Material Removal Rate (MRR) is the volume of workpiece material removed per unit time MRR = πDavgdf N Davg = average diameter =(Doriginal + Dfinal)/2 = (Doriginal - d) d = depth of cut f = feed, in/rev or mm/rev N = RPM
Material Removal Rate Example: Original Diameter = 3.375 in RPM = 630 RPM Feed = .01 in/rev Depth of cut = .02 in MRR = πDavgdfN Davg = 3.375 - .02 = 3.355 in MRR = π*3.355*.02*.01*630 = 1.33 in3/min
Lathe Components • Bed • Carriage • Headstock • Tailstock • dead center • live center • Feed Rod and Lead Screw
Lathe Attachments • Chucks • Collets • Face Plates • Mandrels • Accessories
Design Considerations Design parts so they can be fixtured or clamped easily Design the part so that tolerances of the dimensions and finishes are as large as possible Avoid tapers, sharp corners, and large variations in the dimensions of the part Produce blanks as close to the final design as possible Design the workpiece so that the cutting tools can move across it without obstructions Standard cutting tools should be able to machine the design Select materials that can be machined properly
Types of Lathes • Tracer Lathes • Automatic Lathes • Automatic Bar Machines • Turret Lathes • Computerized Lathes
Summary Various processes are available to create different shapes and surface effects Several different fixtures exist to hold a workpiece in a lathe A workable design must be considered in order to allow efficient machining
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