ME-430 INTRODUCTION TO COMPUTER AIDED DESIGN Variable Pitch Helical Extension Spring Pro/ENGINEER Wildfire 2.0 Dr Herli Surjanhata Create a part named extension_spring and begin with three default datum planes You don’t need to change the Units since inches is the Pro/ENGINEER default units Click the Create new object icon Create a Protrusion using the Helical Sweep options From Insert pull-down menu, select Helical Sweep -> Protrusion Accept all other default Attributes (Constant > Thru Axis -> Right Handed -> Done) Select Done Pick FRONT datum plane as the sketching plane for the sweep profile – click Okay, and TOP datum plane as the Top reference Begin with sketching a vertical centerline along RIGHT datum plane Then sketch an inclined line as shown below Note: To activate the drawing tools, right-click the graphics are, then select the appropriate tool, e.g select Centerline or Line etc Or use the tool Draw this Centerline first as an axis of revolution Centerline for symmetry Note that start point of the line is on TOP datum plane, and inclined to the right Redimension and Modify the dimension of the profile as shown above To obtain diametrical dimension 2.0”, 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 [1.0] for the pitch Sketch a circle with diameter 0.25 centered on the centerlines Click this icon to continue Sketch a circle here Preview the defined elements and choose OK from the dialog box to complete the helical sweep feature The finished part in pictorial view should appear as shown below Modify the Profile of the sweep and change the value of the pitch to [0.5] Then Regenerate to see the effect Right-click the Protrusion from the Model Tree, and choose Edit Pick the trajectory Pick the trajectory Right click the mouse button, and select Edit Double click PITCH1.00, and change the value 0.5 Pick the Regenerate icon Save the model by selecting Change the spring to variable pitch and add pitch points to the profile Redefine the feature Right-click the helical protrusion from the Model Tree and select Edit Definition Left-click Attributes, press and hold Shift key and pick Swp Profile, Picth Attributes, Swp Profile and Pitch are highlighted Click Define button Select Variable -> Done Modify -> Done Select Sketch from SECTION menu Use Point icon shown in Figure below to add two sketcher points as Dimension the points as shown above When you are done with the section, Click this icon to continue Double-click Pitch from the dialog box Specify the pitch at the trajectory start and end Type [0.5] for both locations A PITCH GRAPH will appear in a sub-window Pick the two sketcher points from the profile 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 Type [0.5] and [1.0] as a pitch at each of these points as shown below The graph will automatically update as shown below Choose Done from the GRAPH menu and OK from the dialog box 10 CREATE THE TOP HOOK END OF EXTENSION SPRING Create a new datum plane offset with the TOP datum plane and pass thru the center of the wire diameter located at the top of spring Click the Datum Plane Tool icon Pick the TOP datum plane located at the bottom Enter Value – Type [12.0] for the offset translation OK – the new datum plane DTM1 is created Click the Datum Axis Tool icon In the graphics window select RIGHT datum plane as the first placement reference, Press the CTRL key and pick the FRONT datum plane As you select your references, they appear in the References collector in the Datum Axis dialog box Note: To add multiple references to your select list press the CTRL key while you select Choose OK to create the datum axis The axis A_1 is created 11 Using revolved protrusion, this end will be extended until it meets with the RIGHT datum plane The revolved angle is 30 degrees RIGHT datum plane Creating a 30-degree revolved protrusion Pick the Revolve Tool icon Click , then pick 12 Select this surface as a Sketching Plane Pick the Reference box to activate Sketch Orientation Pick the DTM1 datum plane as TOP orientation Pick the Sketch button Pick DTM1, and axis A_1 as references Pick the Close button Pick the Create an entity from an edge icon Select Loop Pick the edge of wire diameter Pick axis A_1 as axis of revolution 13 Use Edge of the wire diameter for section to be revolved Click the Check button Type in 30 for the angle Click the button Create R 0.5 Sweep From Insert pull-down menu, select Sweep -> Protrusion Select Sketch Traj Pick DTM1 as sketching plane Okay Right – Pick RIGHT datum plane Sketch and dimension the following trajectory 14 Click the Check button Free Ends -> Done Pick the Create an entity from an edge icon Select Loop Pick the edge of wire diameter 15 Click the Check button Click the OK button Creating the Top Hook End Using Sweep From Insert pull-down menu, select Sweep -> Protrusion Select Sketch Traj Pick FRONT as sketching plane Okay Top – Pick DTM1 datum plane Sketch and dimension the following trajectory 16 Start the sketching from here Click the Check button Free Ends -> Done 17 Sketch a circle as the section to be swept – see figure on the left Click the Check button Click the OK button The resulted feature is shown below 18 Creating the Bottom Hook End Using Sweep Repeat the same procedure to create the bottom See below for final extension spring Create a 90-degree revolve protrusion Create a simple sweep with a radius of R 0.5 Create the bottom hook end 19 20 ... and select Edit Double click PITCH1 .00, and change the value 0.5 Pick the Regenerate icon Save the model by selecting Change the spring to variable pitch and add pitch points to the profile Redefine... Click this icon to continue Double-click Pitch from the dialog box Specify the pitch at the trajectory start and end Type [0.5] for both locations A PITCH GRAPH will appear in a sub-window Pick... CREATE THE TOP HOOK END OF EXTENSION SPRING Create a new datum plane offset with the TOP datum plane and pass thru the center of the wire diameter located at the top of spring Click the Datum Plane