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The AutoFillet capability fillets
and rounds the edges of a part in only one shot. In case you need to fillet
the whole edges of the part, you just need to adjust the radius value
according to your needs and then run the capability.
In case you do not want to fillet the whole part, just select the faces to
be filleted and optionally select what we call "functional faces": these
faces identify the edges you do not want to fillet nor round.Using
Autofillet is therefore a good way of drastically reducing the time
spent on filleting.
Rounding Versus Filleting
When rounding or filleting, the application replaces sharp edges by
blending circular surfaces. The term "Rounding" applies to convex sharp
edges. Rounding removes material from the part. Conversely, the term
"filleting" is appropriate for non-convex sharp edges. Filleting adds
material to the part. This terminological distinction is to be made when
running AutoFillet since it computes fillets and rounds
altogether while complying with mechanical specifications, meaning that
very often, the rounding radius value differs from the filleting radius
value.
Scenario
This section provides a scenario showing you how to use the capability
thru a representative example of autofilleting, then discusses the
following topics:
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Click Automatic filleting
in the Advanced Dress-Up Features toolbar.
The Automatic filleting definition dialog box
appears.
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Optionally, click More to expand the dialog
box and display images helping you define your specifications.
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The Selection Type field lets you specify a
computation mode among two possible ones:
- Current solid: the whole current solid is
filleted. This is the default mode.
- Faces selection: the edges
around the faces selected are
filleted.
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Help images reflect the computation mode you select. For
the purpose of our scenario, keep Current solid.
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The Functional Surfaces field lists the faces
you do not want to fillet. Select both yellow faces as the
faces which edges you do not want to fillet. The selected faces turn
purple, indicating that they will not be filleted.
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Keep 3mm as the radius value you want to assign to
edges, whatever they are: convex or not.
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Filleting applies to sharp edges that are not convex.
This operation adds material to the part. Rounding applies to sharp
edges that are convex. This operation removes material from the part.
Because of mechanical reasons, a distinction is to be made between
filleting and rounding. The command lets you assign distinct radius
values to the different edge types.
By default, Round Radius is disabled. This
means that if you modify the radius value, the round value is
automatically modified and displays the same value as the radius value.
For the purpose of our scenario, select this option to apply a radius
value different from 3 mm to rounds. Enter 2mm. If this option is
disabled, its value is half the smallest value. For example, if the
fillet radius value is 5 and the round corner value is 4, then the value
used is 2.
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Select Show curvature less than: field to
ensure that the application displays the fillets and rounds whose radius
value is less than the smaller radius value you entered. In our example,
in case the application generates fillets or rounds whose radius value
is less than 2mm, a warning message will therefore be issued.
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Check OK to confirm. A new dialog box
appears, indicating the operation progress. In case you want to
interrupt the operation, just click Cancel. Because the
application detects fillets or rounds whose radius value is less than
2mm, a warning message is issued.
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To show the fillets and rounds, select the warning
message from the Warnings window.
The fillets and rounds are displayed in red in the
geometry area:
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Click Close to close the Warnings
window. The operation is complete. All the edges except for edges
surrounding both functional surfaces are filleted. A new feature
identified as AutoFillet.XXX is added to the specification
tree. Compared with manual filleting,
using AutoFillet is
also a way of considerably reducing the number of features in the
specification tree.
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Non-filleted Areas
For different reasons, there might be cases where the system is not able
to deal with all the edges to be modified. When this happens, the system
does not stop at the first error encountered but computes as many rounds
and fillets as possible and leaves the remaining edges untouched (see the
figure below) so that you just have to finish the job manually.
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Unchanged remaining edges: you need to
use the traditional Fillet capabilities |
The application issues a warning message to help you identify
non-filleted edges.
Slivers and Cracks
A sliver is an unwanted thin wall which should be smoothed and partially
removed by the automatic filleting operation. A thin wall that is not
rounded is not processed by the Autofillet capability unless you
select it as a sliver. For an example, see sliver A in the figure below.
A crack is an unwanted slot which should be smoothed and partially
filled by the automatic filleting operation. Similarly, a slot that is not
rounded is not processed by the automatic filleting algorithm unless you
select it as a crack. For an example, see crack C in the figure below.
If you do not select them as slivers or cracks, thin walls and thin
slots are rounded and filleted by Autofillet, as illustrated
below. The resulting height and depth of walls and slots are slightly
decreased. Furthermore, the resulting curvature radius is less than the
given round or fillet radius because of small thicknesses.
Managing Curvatures
Two capabilities are provided to help you obtain the best possible
result:
- The Preview capability provides a way of anticipating
problems.
- The Select slivers and cracks capability is available
after clicking Preview. It automatically adds the slivers and cracks to
the selection. Faces corresponding to slivers and cracks are displayed in
green.
Using Preview
The Preview capability allows you
to see the different areas where problems arise and therefore help you
select the slivers and cracks to get the best possible result. Using
Preview, you can see
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in green the areas for which the operation
will be done correctly.
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in red, the edges for which the application
cannot modify the geometry correctly (i.e. with the good curvature).
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Using Select Slivers and Cracks
Clicking on Select slivers and cracks
automatically adds the slivers and cracks which are not yet selected
and which are mandatory to run the automatic fillet correctly. Then you
just need to click Preview again to obtain the next result:
the lines are green, the problem is solved.
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Limitations
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Dedicated to casting rounds and fillets,
Autofillet has been designed for robustness purposes rather than
shape and curvature precision. Surfaces resulting from automatic
filleting may not be as precise as those obtained using the traditional
Fillet capabilities. Consequently, you should create design rounds and
fillets on the part before performing an automatic filleting.
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The bounding edges of a
smooth skin (a set of faces sharing smooth edges) are sharp.
Autofillet instantly aborts if the input body contains any sharp
edge whose bounded faces belong to the same smooth skin.
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Incorrect input |
Correct input |
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To be able to edit or update
the geometry produced by AutoFillet, a Cast and Forged Part
Optimizer license is required. Otherwise, the only solution for being
able to work on parts containing AutoFillet features is to deactivate
those features until edit or update operations can be achieved in a CATIA
session with a Cast and Forged Part Optimizer license.
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