Introduction to Grinding Machine PDF

 Grinding Machine 1. Types Of Grinding Machine 2 Abrasives And its Types 3  Grinding Machine Grinding is a material removal process accomplished by abrasive particles that are contained in a bonded grinding wheel rotating at very high surface speeds. The rotat...

 Grinding Machine 1. Types Of Grinding Machine 2 Abrasives And its Types 3  Grinding Machine Grinding is a material removal process accomplished by abrasive particles that are contained in a bonded grinding wheel rotating at very high surface speeds. The rotating grinding wheel consists of many cutting teeth (abrasive particles) and the work is fed relative to the rotating grinding wheel to accomplish material removal. Fig- Cutting action of abrasive grains  Types Of Grinding Machine 1. Rough Grinders a. Floor Standard Grinders b. Clench Grinders c. Portable Grinders d. Abrasive belt Grinders e. Swing Frame Grinders 2. Precision Grinders a. Cylindrical Grinders i. Centre Type Plain Grinders ii. Center Type Universal Grinders iii. Centerless Grinders b. Internal Grinders i. Chucking Type Grinders ii. Planetary Type Grinders iii. Centerless Grinders  c. Surface Grinders i. Reciprocating table-horizontal spindle ii. Rotary table-horizontal spindle iii. Reciprocating table-vertical spindle iv. Rotary table-vertical spindle d. Tool end cutter grinders e. Special Grinders Bench Type Portable type Pedestal Type Plain Center-Type Grinder Centerless Horizontal Grinder Centerless Grinding Vertical Spindle Surface Grinder  Surface Grinding Machines Surface grinding machines are used primarily to grind flat surfaces. However formed, irregular surfaces can be produced on some types of surface grinders by use of a formed wheel. Four basic types of surface grinding machines are: 1. Horizontal spindle and reciprocating table 2. Vertical spindle and reciprocating table 3. Horizontal spindle and rotary table 4. Vertical spindle and rotary table  Abrasives An abrasive is a hard and tough substance, having sharp edges. It cuts or wears away materials softer than itself. Small abrasive particles called abrasive grains are used in grinding Wheels. Important properties of abrasives are penetration hardness, fracture resistance and wear resistance. Abrasives are classified into 1. Natural Abrasives 2. Artificial Abrasives Natural abrasives- They are obtained from nature. Natural abrasives are sand stone, emery/corundum, diamond and granet. Artificial/synthetic abrasives- They are manufactured to have well defined and controlled properties of hardness, roughness and type of structure. Artificial / synthetic abrasives are Silicon carbide (SiC), Aluminium oxide (Al2O3) Bond:- The bond is an adhesive substance which cements or holds the abrasive grains together to form a grinding wheel. Depending upon the application bond imparts the qualities of hardness or softness to the grinding wheel. The choice or selection of the bond depends upon the  Accuracy  The required surface finish and  The nature of grinding operation. Grit/ Grain Size:- Size of grain grit is determined by sorting or grading the material by passing through screens with the no. of meshes per linear inch. The grain size influences stock removal rate and the generated surface finish. The selection of grain size is determined by- i. Nature of grinding operation ii. Material to be grinded iii. Material removal rate iv. Surface finish required  Bond And Various Types of Bonds In order to give an effective and continuous cutting action, it is necessary that the grains of abrasive material should be firmly together to form a series of cutting edges. Bond is an adhesive substance used to hold abrasive grains together in the grinding Wheel. The Following are the various types of bonds. a. Vitrified bond (V) b. Silicate bond (S) c. Resinoid bond (B) d. Rubber bond (R) e. Shellac bond (E) f. Oxy-chloride bond (O)  Standard Marking System The Indian standard Institution (IS 551-1954) has specified a standard system of marking the grinding wheels. According to this system the following elements are represented in a definite order. 1. Abrasive 2. Grain Size or grit 3. Grade 4. Structure 5. Bond Example of a wheel specification: “51 A 36L 5 V 40" 51 Manufacturer’s symbol indicating type of abrasive A Abrasive (aluminium oxide) 36 Grain size(medium) L Grade(medium) 5 Structure(dense) V Bond(vitrified) 40 Manufacture symbol (suffix) optional  Selection Of Grinding Wheels In selecting a grinding wheel, the following factors are considered: Constant Factors 1. Properties of the material to be ground i.e., its hardness, toughness, strength etc. 2. The amount of stock to be removed. 3. Area of contact of the wheel with the workpiece. 4. Type of grinding machine and its condition. Variable Factors 1. Wheel speed and work speed. 2. Dimensional accuracy required. 3. Type of grinding to be done. 4. Quality of surface Finish required. 5. Speed and feed of the wheel. 6. Method of grinding i.e., wet or dry  Mounting Wheels Examine for any obvious surface defects Test wheel for cracks by suspending by its centre and tapping with a light bar. It should give a clear ring sound. Examine the load bush for burrs After mounting, run the wheel for some minutes without load and without standing near.  Dressing of Grinding Wheel Remove loading and breaks away the glazed surface so that sharp abrasive particle are again presented to work  Truing of Grinding Wheels It is the process of changing the shape of the grinding wheels as it becomes worn from an original shape owing to the breaking away of the bond. "Truing is the term used to describe the removal of material from the cutting face of the wheel so that the resultant surface runs absolutely true to some other surface such as the grinding wheel shaft."  Balancing Of Grinding Wheels Grinding wheels rotate at high speeds. The weight should be evenly distributed throughout the body of the wheel. The imbalance of the wheel will develop a high unbalanced centrifugal force.  Diamond wheels These wheels are also made in almost similar shapes as of Aluminum oxide or silicon carbide wheels. They are also provided with the central hole for being mounted on a spindle. Grinding Technology Applications Grinding technology can be applied in a number of ways to improve manufacturing processes. For example, 1. It can be used to improve the surface finish of machined parts 2. To improve dimensional accuracy 3. Increase productivity 4. It can also be used to prepare surfaces for further finishing processes, such as polishing or plating. 5. In addition, grinding technology can be used to repair damaged surfaces or to create new surfaces with desired characteristics. Industrial Applications Where Grinding is Commonly Used Automotive Industry: For various applications such as grinding crankshafts, camshafts, and other engine parts. It is also used for finishing and polishing the surface of car body panels. Aerospace Industry: For producing precision parts such as turbine blades, fuel nozzles, and landing gear components. The industry requires parts with high dimensional accuracy and surface finish, which can be achieved through the grinding process. Medical Industry: For producing precision parts such as surgical instruments, dental tools, and orthopedic implants. These parts require high accuracy and surface finish, which can be achieved through grinding. Tool and Die Industry: For sharpening and shaping cutting tools, punches, and dies. The process is essential for producing high-precision components that require tight tolerances and surface finish. Construction Industry: For finishing concrete surfaces and removing excess materials such as paint, adhesives, and coatings.