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8.0 CAD module, exercise N°3The third exercise suggested is a gearwheel
drawing. For this exercise, you are going to use especially construction
straight lines as well as circular duplications.
We don’t go into details of each manipulation
already performed in previous exercises.
Click on the icon «new file» and enter in the
fields the following values :
X = 150 Y = 150 Z = 3 The grid spacing will be
at : 5 mm
Then click on the tab «drawing» and choose.
color : red. Thickness : 0.25 mm Type :
continuous Plan : plan 1.
Validate the dialogue box of the properties
with the button «OK».
Save your file as : Ex3.CAD and think of saving
it regularly.
In order to facilitate this drawing
construction, you are going to use construction straight lines that will
be deleted later. In order to be able to select them and recognize them
easily, they will be placed in the tracing «Plan 1».
Now you are going to start your drawing by the
first tooth construction of the gearwheel.
Activate the couplings «magnetic grid» and «magnetic
object» if not already activated.
Click on the icon «polyline». 
Place the pointer at position : X = 75 and Y =
75 (the grid at space 5 mm will permit you to do it with the mouse).
Validate the starting point with the left mouse
button.
Click on the icon «digital data capture» and
in the tab «relative» enter the values : X = 0 and Y = 50.
Validate with the button «OK».
Click on the left mouse button to validate the
point. Then click on the right to stop the construction.
Now, you are going to perform three rotary
duplications of this straight line.
Click on the icon «selection». 
Once the straight line is selected, click on
the right button mouse to call the contextual menu.
Click on the sub-menu «rotation».
The rotation window will appear on the screen.
In the field «angle» enter the value
«1.5°».
Tick the two boxes «show the rotation center»
and «duplication».
In the field «duplication number» enter
«1».
Validate the window with the button «OK».
Place the mouse pointer on the buttom point of
the straight line, at position X = 75 and Y = 75.
Click on the left mouse button to validate the
point position and click on the right to validate the point.
Another straight line has been created 1.5°
from the first.
The first straight line being always selected,
you are going to repeat this operation twice with 13.5° and: 15° angles.
Once these duplications done, unselect the
first straight line.
• Click on the icon «polyline»
Place the pointer at position : X = 75 and Y = 75.
Validate the starting point with the left mouse button.
Click on the icon «digital data capture» and in the tab «polar» ;
enter in the field «angle» : 97.5° and in the field «distance» : 65
mm
Validate with the button «OK».
Validate the point with the left mouse button then stop the
construction with the right button.
The
tooth construction straight lines are now finished ; you are going to
proceed to its real drawing.
Click on the icon «selection» to activate the
upper icons bar .
Unselect the last object that you have drawn (its
selection is automatically done when you clicked on the selection icon).
Click on the icon «properties». 
In the tab «drawing, choose color : black plan
: drawing (the other fields remain unchanged).
Validate the box with the button «OK».
In order to be able to draw the tooth in a
precise manner, you are going to make a «Zoom window» on the drawing
upper zone .
Click on the icon «zoom» and make a window on
the concerned drawing part (see drawing).
Now, you are going to draw a polyline that will
link the extremities of the construction straight lines.
Click on the icon «polyline»
Construct the polyline using object magnetic
couplings.
The tooth construction straight lines, being no
longer useful now, you are going to erase them.
In the menu «view» click on the sub-menu «tracing».
In the window, untick the tracing «drawing»
then validate with the button «Ok».
Now, only the plan «plan 1» is visible.
Then, reactivate the plan «drawing» in order
to view again the tooth as previously defined.
Now, you are going to create the tooth curved
lines.
Click on the icon «link» and choose «arc». 
In the window enter an arc radius of : 2 mm,
then validate with «OK».
Click on the angle peak to create the arc.
The drawing of thre tooth is now finished . You
are going to proceed to the circular duplication of it in order to get the
whole outside crown of the cogwheel.
Click on the icon «zoom page» in order to
view the whole surface. 
Select the whole tooth (mode window selection).
Click on the right mouse button to call the
contextual menu.
Select the sub -menu «rotation».
The rotation window will show on the screen
In the field «angle « enter the value
«15°»
Tick the tow boxes «show the rotation center
« and «duplication»
In the field « duplication number « enter
«23»
Validate the window with the button «ok»
Place the mouse pointer at position X = 75 and
Y = 75 (gearwheel center)
Select with the left mouse button to validate
the point, then the right mouse button to validate the drawing.
Now, you are going to draw the gearwheel shaft
hole . to do this, you will need construction straight lines, you are
going to use again the tracing «plan 1».
Unselect the still select tooth.
Click on the icon «property» 
In the tab «drawing», enter : color «red»
plan «plan 1» (the other fields remain unchanged).
Validate the function by clicking on «OK».
In order to get a reference point in the
gearwheel center, you are going to draw a cross to materialize it.
Click on the icon «polyline».
Place the pointer at X = 75 and Y = 70 then
validate by a click on the left mouse button.
Place the second point at X = 75 and Y = 80
then validated by a click on the left mouse button, then by a right click
to stop the construction.
Place the pointer at X = 70 and Y = 75 then
validate by a left click.
Place the second point at X = 80 and Y = 75
then validate by a left click, then by a right click to stop the
construction.
In order to draw the shaft hole with an exactly
manner, you are going to make a zoom window on the concerned area.
Click on the selection icon, unselect the last
drawn object, then create the zoom window.
Now you are going to draw the two construction
straight lines that will determine pin notch.
Click on the icon «polyline».
Place the pointer on the gearwheel center,
materialized by the cross.
Click on the left to validate the first point.
Click on the icon «digital data capture».
In the tab «polar», enter in the fields :
«angle» : 19.47° and in the field «distance» : 7.5 mm
Validate the window by the button «OK».
Validate the straight line by a left click of
the mouse then by a right click to stop the construction.
Repeat this operation to draw the second
straight line by entering in the field «angle» the same negative value:
- 19.47°.
Now, you are going to construct the are of the
circle delimited by the two straight lines that you have just drawn.
Click on the selection icon, then select the
last object drawn.
Click on the icon «property»
In tab «drawing», enter : color «black»
plan «drawing».
Validate by «OK»
Click on the icon «circles» then «arc».
Activate the icon «magnetic object» if not
already activated.
Construct the arc of the circle by clicking
first on the upper straight line extremity , then by clicking on the lower
straight line extremity. Then click on the gearwheel center (materialized
by the red cross).
•Validate the construction by a click on the
right mouse button.
Unselect the selected arc.
Now you are going to draw the pin notch.
Click on the polyline icon.
Hold to the lower point of the center then
validate by a left click of the mouse.
Click on the icon «digital data capture».
In the tab «relative», enter the value X =
2.5 mm (don’t enter anything in the other fields).
Validate the window «OK».
The constraint «X» being activated, you are
going to validate «Y» while maintaining the horizontal straight line (keep
the key «shift» pressed to block displacement at 15° and facilitate the
operation).
Validate the second point by a click on the
left button.
Click on the icon «copy of Y».
Click on the upper point of the circle.
The constraint «Y» being activated, you are
going to validate «X» by maintaining the vertical straight line (maintain
the key «shift» pressed to bloc the displacements at 15° and facilitate
the operation).
Validate the third point by a left click of the
mouse.
Link the fourth point by pointing on the upper
point of the circle.
Validate by a left click then a right click to
stop the construction.
Now, you are going to draw three drilling
points of the gearwheel fixing.
Click on the icon «point». 
Click on the icon «digital data capture» 
.In the tab «absolute», enter the value : X = 62.25 mm and Y = 75 mm.
Validate the window by «OK».
Validate the point by a left click.
Click on the icon «selection» , the first
drawn point is selected. 
Click on the right button to get the contextual
menu.
Select the submenu «rotation».
The window rotation appears.
In the field «angle» type the value «120°»
Tick the boxes «show the center of rotation»
and «duplication»
In the field «number of duplication» type
«2»
Validate the window by «OK».
Point on the gearwheel center (red cross) and
click on the left button to validate the position and click on the right
button to validate the three points. The three points are drawn.
Unselect the first point and click on the
button «Zoom Page» to come back to the hole drawing.
Now you are going to draw a circle concentric
to the gearwheel shaft hole, in order to specify the fixing area, that
will be machined.
Click on the icon «circle» then on «circle
by center and radius» 
Point on the gearwheel center (red cross) and
validate by a left click
Click on the icon «numerical data capture».
In the tab «polar», type the value:18mm in
the field «distance» (nothing to type in the field «Angle»)
Validate by «OK»
Validate the circle by a click on the left
moose button.
Click on the icon «selection» 
and deactivate the selected object
The last stage of the drawing will be the
construction of circles representing the lightening holes.
Click on the icon «circle» then on «circle
by center and radius».
Click on the icon «digital data capture»
.In the tab «absolute»,
enter the value : X = 109 Y= 75.
Validate with the button «OK».
Validate the point with a click on the left
mouse button.
Click on the icon «digital data capture» in
the tab «polar», enter the value : 10 mm in the field «distance» (don’t
enter anything in the field «angle»).
Validate with the button «Ok».
Validate the circle with a click on the left
mouse button.
Click on the icon «selection», he circle will
be selected.
Click on the right mouse button to call the
contextual menu.
Select the sub-menu «rotation».
The rotation window will appear on the screen.
In the field «angle» enter the value «45°»
Tick the two boxes «show the center of
rotation» and «duplication».
In the field «duplication number», enter
«7».
Validate the window with the button «Ok».
Place the pointer on the gearwheel center (red
cross) and validate with a click on the left mouse button to validate the
position and a right click for the drawing.
All circles are now drawn.
Unselect the still selected object.
The construction straight lines being no more
useless, erase them.
In the menu «view» click on the sub-menu «tracing»
In the appearing window, untick the tracing «drawing»
then validate with the button «OK».
Now only the plan «plan 1» is visible.
Select all construction straight lines of plan
1 and delete them.
Then reactivate the plane «drawing» in order
to view the drawing again.
Your drawing is now finished, you can view it in
different views by creating different windows, you can, of course, print
it.
Once these controls performed, you are going to
carry out the CAM operations by clicking on the icon «CAM». 
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