1. Introduction to SolidWorks
Part 2
– Multiple extrusions and symmetric design

2. Symmetry
Make a new part consisting of 5 circles of diameters 150, 140, 80, 75 and 10 (all in mm).
Centrelines can be added after, when you are in line with the centre a blue dashed line will appear

3. Now Draw a line out from the centre, then use Smart Dimensions to show the angle between this and the centreline.
Set this angle to 10o

4. Now select this new line and click the “>>” button in the top right [pto if can’t find].
Select Mirror
Click the Mirror about: tab so it highlights red, select the centreline. ‘OK’ this.

5. Often 2-3 ways of completing the task:
Click arrow to the right of ‘SolidWorks’
Select in standard
Menu
Click the toolbar ‘underneath’ sketch

6. Now mirror both lines about the horizontal line (select both using Shift).
By Yourself repeat this for the left or right side to get the picture shown
(note dimensions have be removed for clarity).

7. Now we are going to Trim the shape into one select Trim through the “>>” button
Select Trim to closest on the left.
You should get a shape like the one shown (note: use the mouse scroll to zoom in and out)

8. Extrude the design 25mm, if you have missed cutting an edge it will show up with an error message, click the error to view its position.

9. Now lets put symmetric cuts around the outside of the ‘wheel’
Under features select Reference Geometry – axis
Select the inner cylinder (as shown)

10. Now draw two centrelines up from the axis, one vertical, one slightly off.
Use smart dimensions to set there separation angle to 5o
Draw a circle 80mm
from the radius on the
angled centreline
Click the circle, hold
‘shift’ and select the
vertical line, click
Add relation click tangent

11. Extrude cut this shape.
Now select the Extrude cut on the left panel and click Circular Pattern up the top right
On the left change the axis (the rotation symbol) to the axis created before.
Change the number of patterns from 2 to 50 [hint: calculate the corresponding number of degrees]
This should produce the shape shown on the next page.

13. But this is useless, the central shaft cannot be connected to anything.
So now create a cylindrical extrusion in the centre
Go back to the front plane and create a new sketch
Create a circle overlapping the central circle.

14. Extrude this backwards (click the reverse direction button) for 125mm, change From: sketch plane to offset of 50mm

15. Now lets do an extruded cut on a different plane.
Right click on the right plane, click insert sketch and draw the sketch shown. 40 5 6

16. Extrude Cut this shape to give the shown picture, (note that you will need to set an offset for the extrusion).
Now repeat for the top plane.

17. Your final shape should end up like the one shown.
Now you know how to create symmetric 3D objects in solid works…

18. SolidWorks Hints
You can always change a sketch or feature if you don’t like it, just right click on it on the left panel, and edit.
You can re-order your features and sketches by dragging them on the left panel (useful if adding extrusion before or after cut).
SolidWorks YouTube Channel

19. And Remember to Have Fun!
Assignment Time!
You now have enough information to complete you SolidWorks gearing assignment, so good luck!
And Remember to Have Fun!