Published on February 11, 2009
Manufacturing Processes : Manufacturing Processes By:- Akash Goyel Vinit Garg Gears : Gears Applications 1.Automobiles 2.Gear Boxes 3.Machine Tools 4.Indutrial and agricultural machinery : Requirements 1.Robust construction 2.Reliable performance 3. High efficiency 4.Economy 5. Long life Factors for selection of Materials : Factors for selection of Materials 1.Type of service 2.Peripheral speed 3.Deegre of accuracy 4.Manufacturing process 5.Dimensions and weight 6.Allowable stress 7.Shock resistance 8.Wear resistance : Manufacturing Processes of Gears : Roll forming Gear blank mounted on shaft Pressed against hardened steel Accurate and does not require finishing Stronger in tension and fatigue Used for spur and helical gears : Stamping Made in punch press from sheet Shaved for finish and accuracy Suitable for large production Used in toys, watches and clocks. : Powder Metallurgy Metal powder is pressed into dies Sintering is done The product is coined to increase density and surface finish Used in toys, instruments and motor drivers. : Features of Hobbing : Features of Hobbing Process of generating teeth by means of hob Continuous indexing process Hob and gear moves at relative speed Arial – spur and helical gears Radial and Tangential – Worm and worm wheel Gear Shaping : Gear Shaping Rack type cutter Pinion type cutter : Rack type Cutter has form of basic rack for which gear is to be generated Cutter reciprocates and removes metal during cutting stroke When cutter and blank have completed distance equal to one pitch of blank, motion of blank is arrested, the cutter is withdrawn to give relief to cutting edges and cutter is returned to starting position Pinion type : Pinion type Pinion is used to generate a tooth profile Cutter is fed radically into blank equal to depth of tooth required Cutter may be reciprocated in horizontal or vertical axis. Features of Gear Shaping : Features of Gear Shaping Very high accuracy Both internal and external gears can be cut Low production rate as compared to hobbing Return stroke is wasted Worm & worm wheels can not be produced Milling : Milling Disc type cutter End mill cutter Disc type : Disc type Gear blank is mounted on arbor Cutter is aligned vertically with indexing head spindle Table of machine is moved upwards by an amount equal to full depth of gear tooth Longitudinal feed of table is engaged Blank is then indexed to next position Gear Planning : Gear Planning The Sunderland Process The Maag Process : The work is mounted with axis horizontal (Sunderland) or vertical (Maag) & the cutter is carried on a saddle position that moves vertically downwards as cutting proceeds Gear Finishing : Gear Finishing Shaving Lapping Grinding Shot Blasting Phosphate coating : Thank You Slide 22: Forging Steel bar is forged into cups, cones, wear rings, and automotive rings in hot forging. Steel bar is fed through an induction heater system until it reaches a temperature near melting. This temperature offers maximum formability for hot forging. The heated bar is sheared into slugs once it reaches the forging press. Then the slug is upset, partially formed, and pierced. The main forging press produces about 8 parts per minute. Smaller forgings are rolled into larger rings in open die ring rolling where the part is worked between a king wheel and mandrel. Ring rolling imparts directionality to the grain structure that goes with the shape of the part. This increases the application strength and fatigue life of the part. After ring rolling, the part is further sized on diameter to bring it closer to near net shape. The forging then is placed on the draw line which offers several options for cooling: air, controlled temperature, etc.