Mr. Education

Firstly I am gonna tell you what is the basic difference between heat and thermodynamics. Heat  ⇒  Energy moves due to the temperature difference untill thermal equilibrium. Thermodynamics  ⇒  heat along a cycle (without rate). Heat Transfer  ⇒  rate of energy transfer (at any time). Non-equilibrium phenomena  Help you in Cost reduction . Different Modes of Heat Transfer There are three modes of heat transfer which are discussed ahead: Conduction  ⇒  By molecular vibration (if fixed pattern solids → conduction rate high called conductors). Convection  ⇒  Conduction + Advection (bulk fluid motion). Radiation  ⇒  Heat transfer in vacuum. Ques: Why Diamond (non-metal, 2300 W/m.K) has high thermal conductivity than metals (copper = 430 W/m.K)? Ans: Diamond's arrangement of atoms is more perfect than copper, that's why diamond has higher thermal conductivity. 1. Conduction It is defined as, " a mode of heat transfer due to the...

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...