Production Technology 1 PDF

Production Technology 1 Machining Technology Dr. Sayed akl  Objectives - Knowledge of machining technology: - Basic concepts of machining process. - Methods of machining.  Basic concepts of machining process - Relative motions in machining:...

Production Technology 1 Machining Technology Dr. Sayed akl  Objectives - Knowledge of machining technology: - Basic concepts of machining process. - Methods of machining.  Basic concepts of machining process - Relative motions in machining: - Two basic motions: 1 1. Main motion. 2 2. Feed motion. & (Cutting depth) According to type of each motion and by which part is done – machining process is defined. Cutting Tool  Tool Material - It should satisfy the following properties: - Hardness: harder than work piece material. - Toughness: for shock absorption. - Wear resistant: for minimum wear. - Thermal resistant: to withstand high temperature. - Examples of tool material: - High speed steel: for high speed and temperature. - Carbon steel: for low cutting speeds. - Cemented carbides. - Ceramics. - Diamond.  Cutting Fluids - Function: - Reduce friction, noise, heat. - Washing and cleaning. - Improve surface finish. - Protection against corrosion. - Increase tool life. - Examples: - Mineral oils: for severe cutting conditions. - Soluble oils: cheap method. - Synthetic fluids: chemical solutions. - Vegetable oils: for light conditions.  Machining methods - Turning Main motion is rotary motion done by work piece. Feed motion is linear motion done by tool. Machine is called lathe.  Types of lathes - Center lath: Most widely used. - Turret lathe: Tail stock is replaced by a turret having several tools, for more than one cutting operation. - Facing lathe: No tail stock, for short components with big diameters. - Vertical lathe: Rotates about vertical axis, for big components with complicated shapes.  Examples for turning operations Turning is the oldest machining method. It represents 30-40% of machining process. It is used for external surfaces and internal surfaces. Examples: Outside diameter turning A, facing B, grooving C, Parting D, boring, threading, drilling, reaming, knurling.  Work piece clamping By different means: - Between two centers. - Universal chuck (three jaws – four jaws). - Collet chuck, a sleeve with tapered end for centering of bars. - Face plate: with orifices used for fixing clamps. - Mandrel: for hollow parts.  Work piece supporting Used for long work pieces. - Steady rest: fixed to bed. - Follow rest: fixed to carriage (feeding for whole work piece length)  Machining methods (Milling) Main motion is rotating motion done by tool. Feed motion is linear motion done by work piece. The cutting tool is multi-toothed tool and where the contact occurs intermittently, less heat generated. It is fast and fine machining used for all kinds of surfaces.  Types of milling machines A. Column and base (knee) machines. - Horizontal milling machines. - Vertical milling machines. - Universal milling machines. B. Bed – type machines. - The table is supported on a bed for more rigidity  Milling cutters Different types: - Standard / Special. - Different diameters. - Different widths. - Straight / Helical teeth. - Right hand / Left hand. - Straddle. - Staggered.  Machining methods - Grinding Machining process where the material is removed by a rotating tool (main motion) formed by a multitude bonded grits. Used for producing smooth surfaces with controlled roughness and tolerances. Used for hard surfaces and cutting tools.  Grinding machines Surface grinding (work piece is fixed on a magnet). - Horizontal spindle & reciprocating table. + - Horizontal spindle & rotating table. + - Vertical spindle & reciprocating table. - Vertical spindle & rotating table. Cylindrical grinding. + + - External: work piece is fixed between two centers. + - Internal: work piece is fixed on a head stock chuck. +  Grinding wheel characteristics 400 * 50 * 127 DIN 69 120 A 60 K 5 V 60 Dimensions Standard Abrasive material (aluminum oxide, silicon carbide) Grain size )medium, coarse, fine( Hardness )medium, soft, hard( Grain structure (dense, open) Bond type (Verified, resin, rubber Speed (m/s)  Machining methods - Drilling - Machining process where main motion (rotary) and feed motion (linear) are done by the cutting tool 1. Base 2. Pillar 3. Work table 4. Motor 5. Hand wheel 6. Quill 7. Spindle 8. Depth stop 9. Stop/Start  Types of drilling machines - Portable drill: hand operated, equipped with small motor. - Sensitive drill: Vertical spindle for holding the drill, horizontal table where the work piece is fixed, for holes 12- 16mm. - Up right drill: Vertical spindle with gear box, horizontal table with elevating screw for heavy work up to 50 mm.  Drilling operations Counter boring Counter sinking Reaming Twist drilling Subland drilling  Machining methods - Shaping Machining process where the main cutting motion is a reciprocating motion done by the tool or the machine. The feed motion is linear motion. The machine tool is similar to the turning tool but bigger. Main types of shaping machines. - Shaper: main motion is done by the tool. - Planner: main motion is done by work piece. - Slotter: vertical shaping machine for making slots. Shaping operations: Slots, keyways, splines, gears. 1. Work piece 2. Tool 3. Main Motion 4. Feed motion 5. Cutting depth