Synchronous Technology can give big benefits in modelling sheet metal to allow you to quickly design from the ground up and none more so that when some of your flanges are at an angle. I was asked recently how to have two flanges that were not at the traditional perpendicular (90°) measure the same from the base tab to the top of the flange. This is usually difficult as the flange is measured along the face and not as a perpendicular dimension. This can be done easily using Synchronous Technology and PMI (3D) dimensions. Here’s how:
Start by drawing a rectangle by centre, drawn on the x-y place and centred at the centre of the triad. Make the rectangle 250 mm by 150 mm.
Like with all ST features, you click on the region (light blue area) and the click on the steering wheel. At this stage you will be asked to enter the sheet metal thickness. Enter 1mm and project the tab downward.
To create the first tab, click on the front edge and then click on the secondary axis (upward) to start dragging off the flange:
The options bar will display all of the normal options available for a flange you would find in an ordered feature, so set the flange to measurement outside and bend outside (as these options make it easier to create closed corners if you wish).
Once the flange has been started, 2 dimension boxes are displayed, one for the height and one for the flange angle. You can set the value of the highlighted one and then use the Tab key to move to the other (if you hit the enter command, this will accept the inputs and complete the command). In this case we will make the height 60 mm and the angle 90.
Click on the right hand edge for the second flange, don’t worry about the height value (as this is measured at the angle of the flange, not the perpendicular height), but make the angle of the flange to be 120°.
Now we need to make the height equal to that of the other (upright) flange and we achieve this with a PMI dimension. Click on the smart dimension tool, select the bottom face of the tab as the first datum:
Select the top edge of the flange for the next datum:
Place the dimension off to the right and move the dimension arrow to the top and enter 60 mm (lock the dimension if you wish to fix it).
If you also create a locked dimension for the height of the perpendicular flange, you can relate one back to the other so that both are linked through the dimensions in the variable table. Name each dimension and then enter the name of one into the formula of the other. See how the dimension of the driven dimension changes to purple.
If you now wish to change the angle of the second flange, select the face of the flange and then move the steering wheel with the steering wheel origin to the bend of the flange.
Now click on the torus to change the angle of the flange. Note that any changes to the angle maintain the height.
A final option could be to close the corner between the two flanges and we can use the “2 Bend Corner” command to do this. Select each of the 2 flange bends and enter a gap to complete the operation:
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