Mr. Education

Standardization It is defined as, " producing maximum variety of products from the minimum variety of materials, tools, parts and processes " . Establishing standards of measure  ↔  by extent, quality, quantity, value, performance, etc. Aims & Purpose of Standardization: Design and production norms.  Reduce variation in types and grades. Achieve quality characteristics in raw material, semi-finished and finished product. Benefits of Standardization: Better quality Loner life service  Easy availability or replacement or maintenance of parts Less time and effort required to manufacture. Principles of Standardization: Consensus   ↔  general agreement  Involvement of all stake holders   ↔  for the preparation of any standard Openness to the public   ↔  standard open to public  State of the Art   ↔  Time based technical capability on the relevant consolidated findings of science, technology and experience. Coherence of...

Surface It is the one touches when holding an object, such as manufactured part. Nominal Surfaces   ↣  intended surface contour of part (defined by engineering lines). Strength increases  ↣  adhesively bonded or joints + rough surfaces . Surfaces are important for a number of reasons: Aesthetic Reasons   ↣  smooth and fire of scratches to give favorable impression to customer. Surfaces affect safety. Friction and wear depend on surface characteristics. Assembly of parts is affected by their surfaces. Smooth surfaces make better electrical contacts. Mechanical and physical properties. Surface technology is concerned with: Surface Characteristics  Surface Texture Surface Integrity Relationship between manufacturing process and characteristics of resulting surface. 1. Surface Characteristics  Surface characteristics are defined as: Substrate   ↣  main core (bulk of part) of material. Grain size depend on metal processing (casting, molding...

Tolerance It is defined as, "the magnitude of permissible variation of a dimension or other measured value from the specified value". Purpose   ↠  permit dimensional variations of components, performance, specification and design . As the permissive tolerance goes on decreasing , the manufacturing cost to achieve it goes on increasing exponentially . Classification of Tolerance: Unilateral tolerance   ↠  If tolerance distribution is only one side of the basic size. Bilateral tolerance   ↠  When tolerance distribution lies on either side of the basic size. Compound tolerance   ↠  When tolerance is determined by established tolerances on more than one dimensions. Geometric tolerance   ↠  Used to indicate the relationship of one part of an object with another. Classification of Geometric Tolerance: Form tolerance   ↠  group of geometric tolerance applied to individual features ( includes straightness, circularity, flatness, cylin...

Machining It is defined as, " a manufacturing process which creates desired shape by removing unwanted material from a larger piece material " . Conventional Machining   ↔  Machining in which there is a direct contact between material and tool. Non-conventional Machining   ↔  No direct contact between material and tool. Non-Conventional Machining Following are the types of non-conventional machining. 1. Electric Discharge Machining (Spark Erosion or Thermal Erosion or Electro-Erosion or Spark Machining Process or EDM) Technique which uses thermo-electric process to erode undesired material from workpiece is called Electric Discharge Machining . Tool is negative terminal whereas workpiece is positive terminal. Spark Gap   ↔  distance between work and tool and is filled by dielectric fluid. Application: Drilling of very small holes. Milling of machine complex shapes. 2. Wire Cut EDM Wire of about (0.02 - 0.03) mm in diameter is used which is made of brass, ...

Turning Turning is defined as, " machining of cylindrical 2D components (length, diameter) " . For turning, following equations are applied: Milling Milling is defined as,  " machining of prismatic 3D components (length, breadth height) " . Drilling Drilling is defined as,  " cutting process that uses drill bit to cut a hole of circular cross-section in solid materials " . Note: Milling Machine References: Material from Class Lectures + Book named Fundamentals of Modern Manufacturing Materials, Processes and Systems by Groover + My knowledge.  Photoshoped pics  are developed.  Some pics and GIF from Google.   Videos from YouTube ( Engineering Sights ).

Gear Generation by Machining  Tooth profile is provided by much simpler form cutting tool through hobbing, gear shaping. It involves the following methods: Gear Hobbing Gear Shaping 1. Gear Hobbing  It is defined as, " a machining process in which gear teeth are progressively generated by a series of cuts with a helical cutting tool " . Most accurate machining process. Used for gears production because it has excellent surface finish. Continuous Indexing Process   ↠  in which both cutting tool and workpiece rotate in constant relationship while hob is being fed into work. Feed Directions   The direction of feed during hobbing operation depends upon the type of gear to be cut. Following are the types of feed directions: Axial Feeding   ↠  cutting spur and helical gears (Hob axis is parallel to Blank axis). Radial Feeding   ↠  for bevel gears (Hob axis is perpendicular to Blank axis). Tangential Feeding   ↠  for worm, straight, spiral...

Gear Forming by Machining Formation of gear through machining consists of following methods: Form Milling by Disc Cutter Form Milling by End Mill Cutter Shaper, Planner and Slotter Broaching 1. Form Milling by Disc Cutter It is defined as, " Tooth is cut one by one by plunging the rotating cutter into the blank " .  Each gear needs a separate cutter. 8 - 10 standard cutters are available for producing 12 - 120 teeth gears. Used for big spur gears of large pitch. 2. Form Milling by End Mill Cutter It includes the cutting of tooth at a time and then indexed for the next tooth space for cutting. For a small volume production of low precision gears. Set of 10 cutters   ↠  12 - 120 teeth gears . Used for teeth of large gears/module. To reduce cost, same cutter is often used for multiple sized gears resulting in profile errors . Characteristics: Use of Hardened stainless steels (HSS) form milling cutters. Use of Ordinary milling machines. Low production rate (need of indexing...

Gear Finishing For an effective and noiseless operation at high speed, teeth profile is accurate, smooth and without irregularities. Finishing operation is done to: Eliminate after effect of heat treatment.  Correct error of profile and pitch. Ensure proper concentricity of pitch circle and center hole. Types of Gear Finishing Process Following are the types of gear finishing process: 1. Gear Shaving It is defined as, " a finishing process in which gear tooth is running at high rpm in mesh with a gear shaving tool " . Serrations  ↠  serves as cutting edges (scrapping operation). It involves simultaneous rotation of workpiece and cutter as a pair of gears with crossed axes. Soft materials  ↠  Aluminum alloy, brass, bronze, cast iron and unhardened steels are finished by shaving process. Limitations The lack of chance to remove the distortion caused by heat treatment. 2. Gear Rolling / Roll Finishing / Gear Burnishing It involves revolving of gear between two hard...

Gears It is defined as, " machine element used to transmit power " . To meet device conditions , you need to design a: Robust Construction Reliable Performance  High Efficiency Economy Long Life Factors which decrease the wear and tear of a gear are: Noise produced during working High load carrying capacity Constant velocity ratio Manufacturing of Gears Several processing operations are done for the manufacturing gears, which are as: Performing of Blank (with or without)  ↠  important part of gears. Annealing of Blank (Forged or Cast steel) Machining of Gear Blank Producing Teeth or Machining of Teeth Finishing of Teeth (by shearing, grinding)  ↠  if required Full or Surface Hardening of Machined Gear  ↠  case hardening  Inspection and Testing of Finished Gears Manufacturing process involves following categories: Forming   ↠  shaping of plastic deformation in which volume remains constant (approx.) before and after the process. E.g. : D...

Manufacturing Processes It is defined as, " a process which converts unfinished materials to finished products using machine or machine tools " . It is classified as: Casting, foundry or molding process Forming or Metalworking processes Machining Process  Joining Assembly Surface Treatment (Finishing) Heat Treatment  Rapid Prototyping Cutting It is defined as, " process of removing material from work piece to obtain require shape and size " . It is classified as: Non-Cutting Process   →  Shape is obtained under the action of force and heating. E.g.: forging, drawing, spinning, rolling, extrusion. Cutting Process   →  Shape obtained by removing unwanted metal from work piece. E.g.: turning, drilling, boring, milling. Factors Affecting Cutting Process Factors which affects the cutting process is described below: Cutting Speed, depth of cut, feed, cutting fluids Tool angles   →  influence on chip flow direction, resistance to tool chipping. Chip Form...