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ME-430 INTRODUCTION TO COMPUTER AIDED DESIGN Variable Pitch Conical Spring Pro/ENGINEER Wildfire 2.0 Dr. Herli Surjanhata START CREATING A NEW PART Create a part named con_spring and begin with three default datum planes. It is not necessary to change the Units since inches is the Pro/ENGINEER default units. Click the Create new object icon. CREATE A SPRING USING HELICAL SWEEP Create a Protrusion using Helical Sweep options. From Insert pull down menu, select Helical Sweep -> Protrusion Done Pick FRONT datum plane as the sketching plane, and TOP as the Top reference. Select Top and Right as Specify Refs planes. Begin with sketching a vertical centerline along RIGHT using the Select icon. icon to sketch an inclined line as shown below. Click to dimension the sketch as shown below. Make sure the bottom point of the inclined line has diametrical dimension with respect to the center line. Click icon to modify the dimensions. Note that start point of the line is on TOP/DTM2, and inclined to the left. Re-dimension and modify the dimension of the profile as shown above. To obtain diametrical dimension 7.5”, do the following: Left-click end point of line at the bottom -> left-click center line -> Left-click end point of line at the bottom again -> middle-click to accept the position of the dimension. Click this icon to continue. Enter [1] for the pitch. Sketch a circle with diameter 0.5 centered on the centerlines. Click the icon to continue. Preview the defined elements and choose OK from the dialog box to complete the helical sweep feature. The finished part in standard orientation view should appear as shown below. Click the icon to save the spring. OK. Right click the helical sweep protrusion in the model tree, then select Edit. Pick the trajectory inclined line. Right click, and select Edit. Pick PITCH1.00 and change the value of the pitch to [1.5]. Select the to Regenerate to see the effect. MODIFY THE SPRING – VARIABLE PITCH To change the pitch at specific locations along the sweep, right click the Protrusion in the model tree, and select Edit Definition. Pick the Attributes first, then press and hold Ctrlkey, pick Swp Profile and Pitch elements followed by click Define. Choose Variable and Done from the ATTRIBUTES menu. Now Modify -> Done from the SECTIONS menu. Select Sketch from SECTION menu. Click Sketch from SKETCHER icon to Use the Point add three sketcher points as shown in Figure. Dimension the points as shown. Click the icon to continue. When you are done with the section enter [0.75] as the pitch at the start and end of the profile. A PITCH GRAPH will appear in a sub-window. Pick the three points in the main window, select the lower point first, and the system will prompt for the pitch at each added point and move up to the next point until all points are added. Pitch at those points as shown below. The graph will automatically update. Choose Done from the GRAPH menu and OK from the dialog box. CREATE A REVOLVED PROTRUSION AT THE BOTTOM PART OF SPRING Click the Revolve Tool icon Click the Revolve Tool icon Pick Select this surface as Sketch Plane , then click . . Pick the white are of Reference option to activate it. For the Reference of Sketch Orientation, pick the TOP datum plane. Pick the Sketch button. Pick TOP and RIGHT datum planes as references. Click the Close button. Pick the Create an entity from an edge icon. Select Single option.