Licom Systems Ltd.

3D Surface Creation

Training Course Notes

INDEX
OVERVIEW ........................................................................................................................ 1
WORK VOLUME ................................................................................................................. 1
WORK PLANE .................................................................................................................... 1
WORK VOLUME CREATION. .............................................................................................. 2
2D WORK PLANES ............................................................................................................. 2
RULED SURFACE ............................................................................................................. 3
SWEPT SURFACE 2 CURVES ......................................................................................... 4
SWEPT SURFACE 3 CURVES ......................................................................................... 5
SURFACE OF REVOLUTION.......................................................................................... 6
COONS PATCH 3 CURVES.............................................................................................. 7
COONS PATCH 4 CURVES.............................................................................................. 8
INTRODUCTION ............................................................................................................... 9
EXAMPLE 1 ........................................................................................................................ 9
THE TAPER ...................................................................................................................... 10
THE FLAT BOTTOM.......................................................................................................... 10
THE CURVED TOP ............................................................................................................ 10
EXAMPLE 2 ...................................................................................................................... 13
MANIPULATION OF 2D GEOMETRIES TO 3D GEOMETRIES ................................................ 14
SURFACE CREATION ........................................................................................................ 16

Work Volumes and Work Planes
Overview
The work volumes and work planes are controlled from the 3D menu. The Button Bar contains the commands to control work planes.

Work Volume
A work volume is a rectangular volume, which encloses the machining envelope of the part, or features that are to be machined.

Work Plane
A work plane is a 2 dimensional plane on which 2D geometry is drawn and machined. The post processor uses the orientation of the plane to output the correct indexing data. Work planes may be defined in several ways dependent upon the information available.
3D work volumes and Work planes are utilised for many 2½D applications.
E.G.
It is necessary to define a work volume and work plane when using a horizontal or vertical machine, which incorporates an indexing device.
It is necessary to utilise a work plane and work volumes when the data output is with respect to differing work co-ordinates, e.g. G54, G55, G56 …
It is necessary to utilise a work volume and work planes to extract 2D geometries when they are provided in 3D CAD data files.
NOTE: - The format of the NC code is controlled by the post processor configuration. It determines whether the co-ordinates are Local or Global and what indexing is allowed. In some cases several posts are used for the same machine to create the NC code for specific requirements 3D Surface Creation Notes

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Work Volumes and Work Planes
Work Volume Creation.
The work volume is created by drawing the plan view rectangle then using
3D - Set Work Volume and specifying the absolute top and bottom Z values.
The plane view rectangle must be drawing with respect to the absolute X0, Y0 position on the machine. 2D Work Planes

2D work planes are 2 dimensional sections through the work volume. They can be defined in several ways. The setting of work planes is transparent to commands.
1. As a slice through the work volume
. This is achieved by selecting a 2D line which is use to cut through the work volume. Lines selected in the ISO view will always produce a vertical slice.
. Any two geometry lines that represent the X and Y2. Using 2 lines for X and Y-axis axis can be selected. The first line selected will define the X-axis. The second line selected, which must lie in the required X, Y plane, will define the orientation of the
X, Y, Z-axes. The lines selected MUST be connected at one end.
. When geometry is created the system stores its
3. Using existing geometry orientation. When geometry is selected the plane on which is defined will become active. Having created geometries on different plane this option allows a simple method of switching between planes.
4. Parallel to the current plane
. This allows a new work plane to be specified that is parallel to the current plane by specifying an offset in the Z-axis.
5. As Current Plane, Different Origin

. This will create a new work plane in place of

the current one and a different the origin can be set on this new plane.
When using coincident work planes it is useful to name them using the work plane properties option

.

6. The By Name option allows work planes to be selected or their properties to be edited from a list of all current work planes. Work Planes that are no longer being used can also be deleted from the list.

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3D Surface Creation Notes

3D Surface Types
Ruled Surface
2 defined edges connected with straight (ruled) edges.

Z

Y
X

3D Surface Creation Notes

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3D Surface Types
Swept Surface 2 Curves
A defined edge is swept along a defined geometry path
Care is required with tight bends in the geometry path to ensure they do not cause the edge of the swept surface to turn inside out. (To travel back on it's self).

Z
Y
X

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3D Surface Creation Notes

3D Surface Types
Swept Surface 3 Curves
A defined edge (Curve1) is swept along a defined geometry path (Curve2) changing form into another defined edge (Curve 3)
Care is required with tight bends in the geometry path to ensure they do not cause the edge of the swept surface to turn inside out. (To travel back on it's self).

Z

Y
X

3D Surface Creation Notes

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3D Surface Types
Surface of Revolution
The surface generated when a Profile is revolved about an axis.

Z
Y
X

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3D Surface Creation Notes

3D Surface Types
Coons Patch 3 Curves
The surface generated from 3 defined edges. The edges MUST coincident at their ends.

Z

Y
X

3D Surface Creation Notes

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3D Surface Types
Coons Patch 4 Curves
The surface generated from 4 defined edges. The edges MUST coincident at their ends.

Z

Y
X

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3D Surface Creation Notes

3D Surface Creation
Introduction
To create the first example it is first necessary to recognise the type of surfaces required. This will depend upon the machining strategy that is to be used. For example if a surface were to be machined on the top of a block it would be practical to define the surface such that it overlapped the edges of the actual material. In some cases where the surface has to be created much bigger than the area to be machined, the machining can be restricted within a boundary. When working with work volumes and work planes, remember that the geometry manipulation commands Move, Copy, Rotate, Mirror … work differently.
When a work plane is active the manipulation commands work as normal 2D commands.
The manipulation takes place within the work plane.
When a work plane is NOT active the manipulation commands work as 3D commands. The manipulation takes place within the work volume.

Example 1

This can be made up from either 3 ruled surfaces, 3 swept surface 2 curves, or a combination of ruled and swept together with 2 fillets.
These notes will create the surfaces as ruled surfaces. from 0,0 to 140,120

Draw a rectangle

Using the rectangle set the work volume
Select 3D views

to 0 & -70

.
3D Surface Creation Notes

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3D Surface Creation
The Taper
Set up the bottom of the work volume as the current plane. Use Slice through work volume and pick the bottom line in the XZ view.

Draw a rectangle

from 20,20 to 120,100 and fillet

the corners.

Create an offset from the geometry with an offset distance Tan (5)*70. This will provide geometry, that when positioned on the top of the work volume, will allow the creation of a ruled surface forming the 5-degree taper.
Cancel the work plane

.

Select Move
For the geometry to be move select the inner rectangle. For the base point use 0,0, -70. For the new position enter 0,0,0.
Select GEOMETRY | 3D Surfaces and pick the ruled surface option. The curves, being the rectangles on the top and bottom of the work volume.

The Flat Bottom
To create the bottom ruled surface, draw two polylines one from 0,0, -70 to 0,120, -70 and the other from 140,0, -70 to 140,120, -70.
Select GEOMETRY | 3D Surfaces and pick the ruled surface option. The curves, being the polylines at the edges of the work volume.

The Curved top
Set up the front of the work volume as the current plane.
Use Slice through work volume
Create two lines
Mirror
volume.

and pick the bottom line in the XY view.

, one from 0,0 to 0,70 and the other from 20,0 to F1, 50 Angle 85

the two lines using the Mid Point (F7) at the top and bottom of the work

Draw the arc using the 2 Points and Radius option. For the First Point select the top end of the angled line on the Right. For the Second Point select the top end of the angled line on the Left. For the Radius enter 130.

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3D Surface Creation Notes

3D Surface Creation
Use the Extend command. Selecting the vertical lines at the side of the work plane for the Boundary, extend each side of the arc.
Cancel the work plane

.

Select Copy
. For the geometry to be copied select the front Arc.
For the base point use 0,0,0 and for the new position enter 0,120,0.
Select GEOMETRY | 3D Surfaces and pick the ruled surface option. The curves, being the arcs on the front and back of the work volume.
To see the results of the surface creation select Quick Shade

.

When producing a fillet between two surfaces, it is Important to remember, that the fillet is always created between the Tool Sides of the surfaces. In other words Grey side to Grey side.
From the shaded view it can be seen that the conditions are ok for the creation of the bottom fillet. Select GEOMETRY | 3D Surfaces and pick the fillet between 2 surfaces option. For the surfaces select the bottom surface in the Top Left view and the tapered surface in the Top
Right view. Set the fillet size to 8 for BOTH starting and ending radius.
To see the results of the fillet creation select Quick Shade shaded view. Then select Quick Shade

in order to turn off the

again in order to regenerate the view.

For the top fillet it is necessary to change the tool side on the top and tapered surfaces.
With the cursor positioned in the Top Left view click the right mouse button and select option from the popup menu. Pick the top and tapered surfaces the Reverse Tool Side and they should turn Red.

3D Surface Creation Notes

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3D Surface Creation
Select GEOMETRY | 3D Surfaces and pick the fillet between 2 surfaces option. For the surfaces select the curved surface in the Top Left view and the tapered surface in the Top
Right view. Set the fillet size to 8 for BOTH starting and ending radius.
To see the results of the fillet creation select Quick Shade shaded view. Then select Quick Shade

in order to turn off the

again in order to regenerate the view.

With the cursor positioned in the Top Left view click the right mouse button and select the Reverse Tool Side option from the popup menu. Pick the top and tapered surfaces and they should turn Grey.

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3D Surface Creation Notes

3D Surface Creation
Example 2

The first part of this example is normal 2D machining where by the curved shape is machined to size using the Pocketing and Rough or Finish commands.
Draw the 2D geometry as shown below. The plan section lines AA BB CC are drawn on the construction layer. The sectional views are created WITHOUT the 5mm flat, as it is NOT possible to create a surface containing a sharp edge.

Using the rectangle set the work volume
Select 3D views

to 50 & 5

.

Although the geometry may appear to be on the bottom of the work volume it is only 2D geometry and as such has no concept of Z values. In order to create the surfaces it will be necessary to manipulate the geometries into position on the correct work planes.

3D Surface Creation Notes

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3D Surface Creation
Manipulation of 2D geometries to 3D geometries
Firstly move the plan geometry onto the Z5 plane.
Select Move
. For the geometry to be move, select the plan geometry and the construction section lines, use 0,0 for the base point. Before setting the new position select
Slice through work volume and pick the bottom line in the XZ view. Now enter 0,0 and place the geometry on the work plane.
With move command still active move the section AA geometry into position.
Cancel the work plane

.

Select Move
For the geometry to be move, select the section AA.
For the base point use End Point of (F6) and pick the bottom left end of section AA. Before setting the new position select Slice through work volume and pick the plan AA section line in the XY view. Now using End Point of (F6) pick the left end of the construction AA section line in the Top Left view.

With move command still active.

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3D Surface Creation Notes

3D Surface Creation
Cancel the work plane

.

Select Move
For the geometry to be move, select the section BB.
For the base point use End Point of (F6) and pick the bottom left end of section BB. Before setting the new position select Slice through work volume and pick the plan BB section line in the XY view. Now using End Point of (F6) pick the left end of the construction BB section line in the Top Left view.

With move command still active.
Cancel the work plane

.

Select Move
For the geometry to be move, select the section CC.
For the base point use End Point of (F6) and pick the bottom right end of section CC. Before and pick the plan CC section setting the new position select Slice through work volume line in the XY view. Now using End Point of (F6) pick the right end of the construction CC section line in the Top Left view.

3D Surface Creation Notes

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3D Surface Creation
Before the surfaces can be created it is necessary to break up the plan shape into separate elements. Coons' patches can only be created where the ends of edges are coincident.
Cancel the work plane

.

Cancel the move command, press or RMB
To activate the work plane on which the plan geometry is stored select Existing Geometry

and then for the geometry select the plan profile.

Select Break using cutting geometries. For the cutting geometries select the construction section lines. Pick the profile as the geometry to be cut.
Cancel the work plane

.

Surface Creation
Now it is possible to create the first Coons' patch.
Select GEOMETRY | 3D Surfaces and pick the Coons' patch 4 curves option. The curves, being the section geometries AA and BB, which can be picked in the Top Left view and the geometries between the sections AA and BB, which can be picked in the Bottom
Right view.

Z
Y
X

The surface will be created.
In order to create the Coons' patches on the end it is necessary to break the section BB geometry. To make the picking easier turn off the surface display.
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3D Surface Creation Notes

3D Surface Creation
Select CAD | APS Layers

and turn off the surfaces layer.

To activate the work plane on which the plan geometry is stored select Existing Geometry
Select Break

and then for the geometry select the section BB geometry.

using individual points. For the break point position select the top of the or arc using either

.

Cancel the work plane

.

Now it is possible to create the ends Coons' patches.
Select GEOMETRY | 3D Surfaces and pick the Coons' patch 3 curves option. The curves being the: select section geometry CC, which can be picked in the Top Right view, the top portion of section BB geometry, which can be picked in the Bottom Left view, and the plan geometry between B & C, which can be picked in the Bottom Right view.

Z
Y
X

Select GEOMETRY | 3D Surfaces and pick the Coons' patch 3 curves option. The curves being the: select section geometry CC, which can be picked in the Top Right view, the bottom portion of section BB, which can be picked in the Bottom Left view, and the plan geometry between B & C, which can be picked in the Bottom Right view.
The surface will be created.
3D Surface Creation Notes

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3D Surface Creation
Select CAD | APS Layers

and turn on the surfaces layer.

To create the other half of the surfaces the rotate command is used. The mirror command may be used but this will result in the new surfaces having an incorrect tool side.
In order to rotate the surfaces in 3D it is necessary to draw an axis about which the rotation will take place.
To create the axis of rotation draw a polyline

from 100,75,0 to 100,75,70.

Select Rotate and pick the three surfaces in the Bottom Right view. For the axis of rotation select the polyline. Enter 180 for the angle of rotation and 2 for the number of copies. Use Quick Shade

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to see the results of the surface creation

3D Surface Creation Notes

Notes

3D Surface Creation Notes

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Notes

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3D Surface Creation Notes

Notes

3D Surface Creation Notes

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Notes

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3D Surface Creation Notes