Suggested Technique for Modeling a Chain Assembly in Pro/ENGINERR Wildfire 3.0
by Romeo Ridel

Follow the simple steps below to model a chain assembly (similar to a bicycle chain):

• Create a new assembly named chain.asm
  
  
• In this assembly, create a sketch of the path that the chain should follow. Make sure that the length of the curve is a value that can be evenly divided by the length of each link. If you are using the example files given at the bottom of this article, then the dimensions in Figure 1 can be used.
  
  
• Click and when the Sketch dialog box opens, select ASM_FRONT as the Sketch Plane and accept the default values for the Sketch Orientation.
  
  
• Click Sketch and sketch two horizontal lines of length five each and two Tangent End arcs of radius 1.59155 each.
  
  
• After completing the sketch and exiting Sketcher mode, to determine the length of the curve, click Analysis > Measure > Length.
  
  
• Select the edges of curve while pressing CTRL and make sure that the entire curve is highlighted in red. The curve length will be shown in the Results box. In Figure 1, the curve length is 20.
  
  
• The two parts show in Figure 2 and Figure 3 are included in the example files. In this example the distance is 0.5 between the pins/holes of each link. One link has the shafts; the other link has the holes. The datum points in each part are crucial—this is where the parts will link together.
  
  
• Create two datum points on the previously created curve such that their location on the curve is governed by a length ratio. The first point has a length ratio of 0.0, and the second point has a length ratio of 0.025. The length ratio can be computed by dividing the link length by the overall length of the chain. In this example, the length ratio = 0.5 / 20 = 0.025.
  
  
• Click then select the entire datum curve as a reference. Keep clicking the right mouse button until the entire curve highlights, then click on the curve to select it.
  
  
• In the Offset box, type 0.0 and leave Ratio selected. Before clicking OK, select New Point in the Placement tab and repeat the previous procedure but this time type 0.025 for the ratio value.
  
  
• Finally, select OK to end the datum point creation. This creates the datum points together as a single feature to facilitate the points being patterned together. (Figure 4)
  
  
• Pattern these two points around the curve by selecting the datum point feature first then selecting Pattern from the right-click menu. Select the Dimension tab and select the 0.00 dimension as the dimension to vary in the first direction.
  
  
• In the Increment box type 0.05 for the curve length ratio increment. The curve length ratio increment is equal to the length ratio multiplied by two.
  
  
• Select an additional dimension for the first direction by pressing CTRL and select the 0.025 dimension from the second point. Type 0.05 again for the curve length ratio increment. Type 20 for the number of pattern members in the first direction. The total number of instances should be half of the total number of links because these points will represent the link_seg1.prt. The number of links is equal to the datum curve length divided by the link length, or in this example 40 links. Therefore, the total number of instances for this first pattern should be 40 / 2 = 20.
  
  
• Apply the changes and close the Dashboard to finish the feature. This will create 40 total points around the datum curve. (Figure 5)
  
  
• Assemble link_seg1.prt by aligning PNT0 and PNT1 to APNT0 and APNT1, respectively. (Figure 6)
  
  
• Select the component link_seg1.prt and then pattern it by selecting Pattern from the right-click menu, then accept the default pattern type Reference.
  
  
• Apply and save changes to finish the feature. This will pattern the link_seg1.prt around the datum curve with a space between each link for the link_seg2.prt. (Figure 7)
  
  
• Create two more datum points (as before) that are offset by one length ratio, so the first point's length ratio should be 0.025 (0.00 + 0.025) and the second point's length ratio should be 0.05 (0.025 + 0.025). These points will lie on top of APNT1 and APNT2 from the first pattern of points. (Figure 8)
  
  
• Pattern these points (APNT40 and APNT41)
  
  
• Assemble link_seg2.prt by aligning PNT0 and PNT1 to APNT40 and APNT41, respectively. (Figure 9)
  
  
• Select the component link_seg1.prt then pattern it by selecting Pattern from the right-click menu. Accept the default pattern type Reference and then apply and save the changes to finish the feature. This will pattern link_seg2.prt around the datum curve, completing the chain assembly. (Figure 10)