Non-Traditional Machining Methods (AMP 1-3 PDF)

# Types of Non Traditional Machining ## Unit. classify ### Types of Non-Traditional Machining - Thermal - Electric discharge machining (EDM) - Wire cut Electric Discharge machining - Laser Beam Machining (LBM) - Ion Beam Machining (IBM) - Electron Beam Machining (EBM) - El...

# Types of Non Traditional Machining ## Unit. classify ### Types of Non-Traditional Machining - Thermal - Electric discharge machining (EDM) - Wire cut Electric Discharge machining - Laser Beam Machining (LBM) - Ion Beam Machining (IBM) - Electron Beam Machining (EBM) - Electric Discharge Grinding (EDG) - Plasma Arc Machining (PAM) - Mechanical - Abrasive jet Machining (AJM) - Water jet machining (WJM) - Ultrasonic Machining (USM) - Electro-chemical - Electro-chemical machining (ECM) - Electro-chemical Grinding (ECG) - Chemical machining (CHM) ### Required characteristics of tool material (EDM) 1. It must be a good conductor of electricity 2. It must have high thermal conductivity 3. It must have low wear rate 4. It must have low electric resistance 5. It must have high melting point 6. It must be cheap and readily available ## Laser Beam Machining (LBM) - Laser beam machining uses the principle of conversion of electrical energy by flash lamp into heat energy. - This heat energy is used to remove the metal from the work piece. - The laser beam is then focused by a lens to give high energy in a concentrated form and helps to melt and vaporize the material from the workpiece. ### Main components 1. Laser generation unit 2. Cooling arrangement 3. Collimating lens 4. Workpiece table ### Applications - Stereolithography - Laser welding - Laser drilling - Laser cutting ### Disadvantages 1. Low material removal rate 2. Limited life of fragile route 3. Overall efficiency 10 - 15% ### Advantages 1. No burrs or chips 2. Less effect on work-piece formations ## Plasma Arc machining (PAM) ### Applications 1. For stack cutting, plate cutting 2. It can cut hot extrusions to desired length ## WEDM ### Applications 1. Gauges, templates, coin discs 2. Small series of spare parts ## USM ### Applications 1. To cut diamond in desired shape 2. Machining of hard and brittle material like ceramic, glass ## EDM ### Process in parameters 1. Spark gap 2. Current 3. Resistance and capacitance 4. Voltage (DC) 5. Pulse 6. Dielectric fluid pressure ### Advantages 1. Material removal rate is moderate 2. No thermal distortions on the workpiece 3. Less operator skill is required 4. Machining time is less ### Disadvantages 1. High tool wear rate 2. Energy consumption is more 3. High machining cost ## State need and importance of Non-traditional machining 1. For complex surface machining 2. For high accuracy and surface finish 3. For technology advancement 4. When the shape of the part is too complex ### Advantages 1. Any complicated shapes can be produced 2. Very fine holes can be drilled 3. Parts produced are burr free 4. Drilling of tapered holes is possible 5. High accuracy can be achieved ### Define non-conventional machining processes Non-conventional machining processes are a group of processes that cut material by using chemical energy, mechanical energy or electrical energy but do not use a sharp and hard cutting tool as required in conventional machining processes. ## Explain working principle of USM with sketch - Ultrasound transducers use ultrasonic waves to remove material from the workpiece - These ultrasonic waves cause high frequency vibration and create slurry.  ## Explain the principle of ultrasonic welding - Ultrasonic welding uses high frequency force and low amplitude to produce heat - This high frequency force acts as a driving force for abrasives - Ultrasonic machines generate high frequency vibrations and create waves of about 20,000 - 30,000 Hz ### Advantages 1. Produces less 2. Suitable for machining hard and brittle materials 3. Threading hard materials ### Disadvantages 1. Metal removal rate is slow. 2. High wear rate of the tool 3. Tool cost is high 4. High power consumption ### Applications 1. Die sinking operations 2. Drilling of jet engine turbine blade 3. Multiple hole drilling 4. Machining steam turbine blades with close tolerances ### Advantages of ECM 1. The metal removal rate is high 2. No tool wear, so tool life is high 3. Generates burr free surface 4. Used for profiling and contouring of complex shapes ## Disadvantages of ECM 1. Initial investment is high. 2. High power consumption. 3. Cannot produce sharp corners and edges. 4. Require more floor space. ## Plasma Arc machining (PAM) - It works on the principle of electro-thermal machining process - Ionized gas is used in the form of a flame to remove material - When a flowing gas is heated at high temperature of 16,500°C it becomes partially ionized (plasma) - Plasma is a mixture of free electrons, positively charged ions and neutral atoms. ### Advantages 1. Rate of cutting is high 2. It can cut any material irrespective of its hardness 3. It can cut carbon steel 3 times faster than oxy-fuel cutting ### Disadvantages 1. Initial cost is high 2. Large HAZ compared to laser cutting 3. Expensive equipment 4. Consumes much energy ## difference between dielectric fluid and electrolyte | DIELECTRIC FLUID | ELECTROLYTE | |-----------------------|----------------| | It is used in EDM process | It is used in ECM as a conducting medium| | Conductor as well as insulator medium for electrical supply | Conducting medium | | Tool wear in the dielectric fluid is not corrosive in nature. | Tool wear in electrolyte is corrosive in nature. | | May or may not be corrosive in nature | Non-corrosive in nature | ## AJM ### Application 1. Drilling holes 2. Cutting slots 3. Machining of semi conductors ## WED: ### Application 1. For the production of any prototype 2. Small series of spare parts ## WJM ### Application 1. To cut thin non-metallic sheets 2. Used in food industry ## WJM set up diagram  ## Advantages of EDM 1. It is a fast process 2. Automatically cleans the surface of the work piece 3. Does not produce hazardous gas 4. This process is eco-friendly. ## Disadvantages of EDM 1. Initial investment is high. 2. High maintenance requirement 3. Only soft materials can be machined. ## Diff between EDM and ECM | Parameter | EDM | ECM | |----------------|---|---| | Heat generation | It is generated during the process. | No heat is generated during the process. | | Tool wear | More tool wear during machining | No tool wear. | | Material removal rate | Low material removal rate. | High material removal rate. | | Power Supply | High voltage, low current DC | Low voltage, high current DC | | Power Consumption |Less power consumption | More power consumption | | Example | 2 kW/cm³/min | 7 kW/cm³/min | ## Chapter 2: Milling- Sketches ### Up milling and down milling sketches  ### Up Milling - Cutter is rotated in a direction against the direction in which workpiece travels. - The thickness of chip is minimum at the beginning of the cut and it reaches maximum at the end of the cut. - It is difficult to pour coolant at the contact of cutter with the workpiece. ### Down Milling - Cutter is rotated in the same direction which the workpiece travels. - The chips are disposed off easily and do not interfere during cutting. - Coolant can be poured directly at the cuting zone easily. - It gives a better surface finish. ## Explain the cutting parameters in milling. How is the machining time calculated on a milling machine. ### Cutting Parameters 1. **Cutting speed:** It is the peripheral linear speed of the milling cutter resulting from rotation. - Cutting speed (V)= Π × d × N/1000 m/min - V= Π × d × N/60 m/min 2. **Feed:** It’s the rate at which the workpiece advances under the cutter, measured in the following ways: - Feed per tooth (f) - Feed per revolution - Feed per minute 3. **Depth of cut:** It’s the thickness of material removed in one pass of the cutter, measured perpendicularly between the original and final surface of the work-piece. ### Plain milling machine - The cutter is parallel to the axis of rotation of the spindle. - It is the simplest type of milling machine. ## Dividing head - To produce multiple gear teeth, the gear periphery needs to be divided into an equal number of parts with the help of a dividing head. - It is a special attachment used to divide the periphery of the work piece or gear blank into any number of equal parts. ### Types of dividing heads / index heads 1. Plain or Simple Dividing head 2. Universal dividing head 3. Helical dividing head 4. Optical dividing head ### Explain universal indexing Universal indexing allows for all types of indexing to be executed. ### Explain plain indexing Plain indexing is used for work pieces that require a smaller number of divisions on the periphery. ## Classification of gears according to the position of shaft axis - Parallel shaft - Spur gears - Helical gears - Rack and pinion - Intersecting shaft - Bevel gears - Straight bevel gears - Spiral bevel gears - Hypoid bevel gears - Non-parallel and non-intersecting - Spiral gears - Worm and worm wheel ### Spur gears These gears are used when the axis of two shafts are parallel to each other. They have teeth parallel to the axis of the shaft. ### Helical gears These gears are used when the axis of two shafts are parallel to each other. They have teeth at an angle which is called the helix angle, with respect to the axis of the shaft. ### Rack and pinion gears One gear is having infinite diameter called “Rack” as shown in the figure. It is used to convert rotary motion into linear, or vise versa. The tooth can be spur or helical. ### Bevel gears These gears are used when one shaft needs to transmit power to another shaft, which is intersecting with the first. The most common angle between the shafts is 90**. ### Types of bevel gears a. Straight bevel gears b. Spiral bevel gears c. Hypoid bevel gears ## Gear materials - Metallic materials - Ferrous metals - Cast iron - Cast steel - Medium and high carbon steel - Alloy steel - Non-ferrous metals - Aluminium - Bronze - Non-metallic materials - Wood - Plastic - Fibre ## Different methods of gear manufacturing - Casting - Stamping - Rolling - Powder metallurgy - Extrusion - Plastic machining ### Casting - Cheapest method of producing gears. - Heavy gears are manufactured by this process. - It is used for slow speeds (used in automotive and machinery applications) ### Stamping - It is used for mass production of small gears. - This method is used for metal sheets up to 3mm thick. - It uses punch and die. - It produces high accuracy. - It is used in toys, machines and clocks. ### Rolling - Hot and cold rolling processes are used to manufacture these gears. - In hot rolling, gear blank is rolled against a master gear. - The teeth are finished by machining. ### Powder Metallurgy - It is used to produce spur, bevel and spiral gears. - It doesn't require finishing. ### Extrusion - It is used to produce small gears from materials like Al, brass, bronze. - The gear blank is pressed through a die. - The gear needs finishing. ### Plastic molding - Used to produce gears from plastic materials. - Injection molding and compression molding are used. - These are for light duty gears. ### Machining - This is the most accurate and widely used method for manufacturing gears. - It is used for all types of gears. ### Explain gear hobbing process with a neat sketch - It uses a tool known as a hob to machine the gear. - The hob looks like a worm. - The hob and the gear have a rotating motion, and the gear also moves radially towards the hob. - The hob rotates through one pitch distance for each revolution of the gear. - The shaping and finishing processes are done simultaneously. - The process is continuous and fast.  ### Advantages of gear hobbing 1. It is a fast and continuous process 2. High rate of production 3. Quick to set up, economical 4. High accuracy can be obtained 5. Many gears of the same size can be cut simulataneously. 6. It can cut spur, helical, worm gear, sprockets, splines. 7. It can be used for both long shafts and splines. 8. It is accurate and efficient. ### Disadvantages of gear hobbing 1. Can not generate internal gears. 2. Can not cut gears which are having shoulders and flanges. 3. Can not produce unsymmetrical shapes. ### Types of gear hobbing machine 1. Horizontal gear hobbing machine 2. Vertical gear hobbing machine ### Gear shaping It is the process of generating the tooth profile for a gear using a rack cutter or pinion cutter. ### Gear shaping set-up / construction - It consists of a work table, arbor to hold the gear blank, and a cutter (usually rack or pinion) mounted on a head. - The cutter reciprocates up and down and rotates. - The gear blank rotates. ### Gear shaping using a rack cutter - The cutter is shaped like a rack. - It is used to shape the gear blank by moving the rack cutter across the gear until the desired depth is achieved. - The cutter and gear blank are driven by a motor. - The cutter reciprocates vertically and rotates at the same time. ### Gear shaping using a pinion cutter - The cutter is shaped like a pinion. - It is used to shape the gear blank by moving the pinion cutter, which rotates, across the gear until the desired depth is achieved. - The cutter and the gear blank rotate uniformly about their respective axes. - It is more efficient than gear shaping with a rack cutter because the process is continuous. ### Advantages of gear shaping 1. Only one cutter is required to cut all gears of any number of teeth of the same pitch. 2. It is much faster. 3. The rate of production is higher because the cutting action is continuous. ## Types of gear finishing - Gear shaving - Gear grinding - Gear burnishing - Gear lapping - Gear honing - Roll finishing ### Gear shaving - It is a finishing process for gears that have already been cut. - It uses a tool that has teeth that are slightly offset from the teeth of the gear. - The tool is moved across the gear, removing material and producing a more accurate tooth profile. ### Gear grinding - Removes material with a grinding wheel. - It is used to create very high surface finish. - More efficient than gear shaving. ### Gear burnishing - It is a finishing process used to improve the surface finish of gears. - It uses a tool that is hardened and polished. - This tool is pressed against the surface of the gear, which compresses the metal and creates a more smooth and accurate surface. ### Gear lapping - It is a finishing process used to create a very accurate surface finish on the gear. - It uses a tool with a fine abrasive material. - This tool is moved across the gear, which removes material and creates a smooth and accurate surface. ### Gear honing - It is a finishing process used to correct errors and imperfections in the tooth profile of a gear. - It uses a tool with a fine abrasive material. - The tool is rotated and moved across the gear, which removes material and produces a more accurate tooth profile. ### Roll finishing It is a finishing process that creates a smooth and accurate surface finish on the gear. It uses hardened, polished rollers to press the gear and create a more polished surface. ## Explain working & importance of re-circulating ball screws used in CNC machine - Re-circulating ball screws are used in movement transmission to convert rotary motion into translation motion in CNC machines. - Steel balls are inserted between the threaded shaft and the nut to transform sliding friction into rolling friction. - Re-circulating ball screws are important for CNC machine functionality and performance. ### Importance: - It provides high efficiency and durability. - It improves wear resistance. - It reduces friction between parts. - It reduces backlash. - It is mostly used in X-Y recorders and power actuators of CNC machines. ## Gear finishing methods For smooth running, good performance, and long service life, gears need finishing. This requires the following: - Accurate dimensions and form - High surface finish - Hard and wear resistive at their tooth flanks ### Commonly used gear finishing methods 1. Gear shaving 2. Gear grinding 3. Gear burnishing 4. Gear lapping 5. Gear honing 6. Roll finishing ## Gear grinding Gear grinding is a finishing process for gears that uses a grinding wheel to remove material and produce a more accurate tooth profile. It is used to correct any errors or imperfections that may have been introduced during the manufacturing process. It is particularly important for gears that are subject to high loads or operate at high speeds. ### Compare gear burnishing with gear grinding Gear burnishing and gear grinding both improve the surface finish of gear teeth. However, there are some key differences between the two processes. - Gear grinding is used for creating a smooth and accurate surface finish. It can also be used to correct errors or imperfections in the tooth profile, but it does not achieve the same level of accuracy and surface finish as gear shaving. - Gear burnishing, on the other hand, uses the principle of plastic deformation to create a smoother and harder surface. This process is typically used to improve the surface finish of gears that have already been ground. ### Gear burnishing process Gear burnishing is a finishing process that is used to improve the surface finish and hardness of gears. It uses a hardened and polished tool to press against the teeth, which compresses the metal and creates a smoother and harder surface. This process is typically used to improve the surface finish of gears that have already been ground, but it can also be used to correct minor imperfections in the tooth profile. ### Advantages of gear burnishing - It produces a smoother and more accurate tooth profile. - It increases the hardness of the gear by achieving a work hardening effect. - It is a more cost-effective process than other finishing methods. ### Disadvantages of gear burnishing - It cannot be used to correct significant errors or imperfections in the tooth profile. - It is not as effective at removing material as other finishing methods. ### Applications of gear burnishing Gear burnishing is commonly used for finishing gears that are subject to high loads, such as those used in automotive transmissions and industrial machinery. It is also used to improve the surface finish of gears that are used in high-precision applications. ## Rack Shaving Rack shaving is a gear finishing process that uses a rack-shaped tool to shave off material from the gear teeth, resulting in a more accurate and smooth profile. The process is typically used on spur and helical gears, and it is especially suitable for gears that are subject to high loads or require high accuracy. ### Advantages of rack shaving - It produces a more accurate and smooth tooth profile. - It improves the load-carrying capacity of the gear. - It reduces the wear and tear on the gear mesh. - It is a relatively fast and efficient process. ###Disadvantages of rack shaving - It cannot be used to correct significant errors or imperfections in the tooth profile. - It is not as effective at removing material as other finishing methods. ###Applications of rack shaving Rack shaving is commonly used for finishing gears that are subject to high loads, such as those used in automotive transmissions and industrial machinery. It is also used to improve the surface finish of gears that require high accuracy, such as aerospace gears.