28-08-2014, 11:53 AM
APPLICATION OF CHOKE COVER -To cover the electrical wiring in the automobiles. -To cover the electrical wiring in the tube light. CASTING PROCESS The process in which molten metal is used for producing a products is known as casting process. In this process , firstly the slab and scrap of metals are put into the furnace in which solid state of metals are converted into liquid molten state. This molten metal is poured into the mould box , which is made with the help of master piece of that product . this master piece is either of wood or metal according to the requirement. After passing some time, the molten metal becomes solidify and the same products are produced as the master piece. The casting process is subdivided into two distinct subgroups:- 1 - EXPENDABLE MOULD CASTING :- (sand, plastic, shell, and investment (lost-wax technique) mouldings.) 2 - NONEXPENDABLE MOULD CASTING :- (permanent, die, centrifugal, and continuous casting). DIE CASTING:- According to the instructions of the industrial training manager, mainly die casting method is used for making a choke cover. Die casting is the one of non expendable type mould casting method. In Industry , many types of die casting methods are used. The classification of die casting methods are given below :- CLASSIFICATION OF DIE CASTING:- (a) Gravity Die Casting (b) Pressure Die Casting According to the instructions of the industrial training manager, for making a choke cover, Pressure die casting method is used. The details of the Pressure die casting method are given below:- PRESSURE DIE CASTING:- In this casting method , various processes are performed for produced a products. These various processes of pressure die casting method are given below in sequence:- 1.) MELTING THE METAL :- In this process, a melt tower furnace is used for melting the metal. The furnace oil is used for running the furnace.The capacity of the furnace is 2 ton. This process is carried out according to the following way:- • Put the silly (solid metal block) and runner (scrap) in 50:50 ratio ie. ; one trolly silly and one trolly runner. • When the metal reaches at a holding chamber, then properly shake the metal by long iron rod. • When the metal temp. is reached at greater than 680 (°C) then add 5 – 6 kg. cover focus for separate the molten metal from dust and carbon. Cover focus is generally in white and red colours). • Shake properly the cover focus into the molten metal. • Clean the molten metal from dross (burnt particles and carbon), properly from the furnace. • Check the burner flame is in right cone (45 °). • Check the temperature of the furnace oil is in the limits (80 – 95 °C). • Check the temperature of the escaped hot air is not greater than 200 °C • When the metal temperature is reaches at 700 - 740°C, then escape the molten metal from the furnace into the ladle. The capacity of ladle is 300 kg.. • Now the molten metal is ready for D – Gassing. DESIGN OF CHOKE COVER For developing the die of choke cover , firstly make a 3D model of choke cover in the design software. The various steps that are followed, for design the choke cover in CREO 2.0 are given below:- • CREATE A NEW 3D MODEL:- For create a new 3D model in CREO 2.0 , following steps are follow:- - Select the new from the data group then the new dialogue box is open. - Select the part as type and solid as sub-type. - Give the name ‘CHOKE_COVER’ . - Now clear the check box of use default template. - Now move the cursor on ok box and click it. - Select the solid_part_mmks from template box and click ok. - By this units of part is selected as millimeter , kilogram , second and all dimensions are shown in millimeter. - By clicking ok , New graphic window is open in which three default planes front , top , and right are already shown at center of screen. • MAKE A 2D SKETCH:- For make a 2D Sketch of choke cover following steps are follow:- - Firstly Select the sketch from the datum group in the model tab of the ribbon - Select the front principal plane from screen and click on sketch. - Select the line and make a rectangle ,according to the proper dimensions. - Select the three point arc and make a sketch as follow, • MAKE A 3D MODEL:- For convert the 2D Sketch into 3D model , following steps should be follow:- - Select the extrude from the shapes group in the model tab of the ribbon and select the sketch that is already made , for convert it to 3D model. - Select the symmetric from the option tab and put the value of third parameter according to the dimension. - Now model is converted from 2D to 3D as follow, • MAKE A CIRCULAR TOP SURFACE:- For convert the top surface of 3D model , following steps are follow, - First select the sketch from datum group. - Select the front plane and click sketch. - Select the 3 point arc and make a trajectory for sweep on the centre of the part as, . - Now , Select the sweep from the shapes group in the model tab of the ribbon. - Select the trajectory , and specify the start point. - Now select the sketching and make a cross section on the start point and click ok. - This cross section moves along the trajectory. - Select the remove option to remove the material as follows, • CUT A SEMI CIRCULAR GROOVE AT TOP SURFACE:- For cut a semi circular groove at top surface of model , following steps should be follow:- - Select the extrude from the shapes group in the model tab of the ribbon and select the right plane for make sketch. Now sketching window will be open. - Make a circle according to the dimension at the top of the model as, - Now click ok. - Select the through all from the option tab and select the remove option , for make a cylindrical cut out at the top surface of the model as, • CREATE A DATUM PLANE:- For create a datum plane at some height from bottom surface of part according to the dimensions , following steps should be follow:- - Select the plane from the datum group. - Select the top plane and give dimension for create the datum plane as, • MAKE A ELLIPSE CUTS ON SIDES OF THE MODEL:- For making these cuts following steps should be follow:- - Select the blend from the shapes drop down list. - Click the section tab and define the datum plane on which sketch is made. - Now make a ellipse according to the dimensions and click ok. - Give the offset value of sketch 2 from sketch 1 and make a second ellipse according to the dimensions and click ok. - Now select remove option for make a cut at the one side of the model as follow, - Now select the blend1 from the model tree and select the mirror from the editing group. - Specify the right plane and click ok. - By this, the similar cut is generated at the other side of the model as, • GIVE DRAFT ANGLE:- Draft angle are given to all the vertical sides of the component so that it can be easily removed from the core by injector pins during pressure die casting process. The procedure of giving draft angle is given below:- - Select the draft from the engineering group. - Select the all vertical sides of component by pressing control button ,on which draft angle are to given. - Click on the references tab and select the draft hinge. - Select the bottom surface of the component. - Now give the value of draft angle and click ok. - The vertical sides of model is become tapered as, • GIVE ROUNDNESS:- Now remove , all the sharp edges of the model by follow the following steps:- - Select the round from the engineering group. - With pressing control button , Select all the sharp edges of the model which have same radius according to the drawing and give the value of radius and click ok. - Click the sets tab and select new set. - Select the rest of the sharp edges above the draft hinged surface , with pressing control button and give the value of the radius. - Now the shap edges of the model become smoothen as, • MAKE A HOLLOW COMPONENT:- Now the solid model is converted into hollow component by following procedure:- - Select the shell from the engineering group. - Select the bottom surface as removed surface. - Give the wall thickness according to the drawing as follow, • MAKE HOLES:- Holes are made on the surfaces of the component that mashed with the draft plane by following steps:- - Select extrude from the shapes group. - Select the circle from sketching group and make a circle ,according to the dimension and click ok. - Select the through all from above the option tab and select remove option for make a hole as, - Now select the Extrude1 from the model tree and select the mirror from the editing group. - Specify the right plane and click ok. - By this, the similar hole is generated at the other side of the model as, • GIVE DRAFT ANGLE TO INNER SURFACE OF HOLES:- The same above mentioned procedure of draft angle is follow, for give the taperness to the inner surfaces of the hole, so that the component can easily remove from the core during casting process. Now the solid model is ready for developing its die (core and cavity inserts).Before starting development of die , it is necessary to check the dimensions, fitment and esthetic look of the choke cover.These parameters are checked by the physical model only.For generating the physical model , RPT technology is used.