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SOLIDCast UNIT 11: Revolved and Extruded Shapes

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In addition to basic geometric shapes and importing of three-dimensional STL files, SOLIDCast allows you to create three-dimensional shapes that are formed by revolving or extruding two-dimensional shapes (flat cross sections).

These two-dimensional shapes may be contained in FILES, or alternatively you can SKETCH shapes on the screen, using the mouse.

If you are importing two-dimensional shapes from FILES, these files can be either of two types:

1.  AFSCad files

2.  DXF files

AFSCad files are drawing files that are created by the AFSCad program, which is a 2D drawing program included with Version 4.20 of the AFS Solidification System (3D), which was the DOS forerunner of SOLIDCast. While not a Windows application, AFSCad can be run in a DOS window using a product like DOSBox.

DXF files are drawing files that can be created by almost any CAD system. To use a DXF file, you would create the 2D cross section of the casting in your CAD system and save this as a DXF file, then import the file into SOLIDCast to create a solid of revolution or extrusion. SOLIDCast will interpret DXF files that have been created using lines, circles and arcs.

Note that when you import a 2D shape, the coordinates of that 2D shape determine where it will be located in 3D space. For example, if you have a circle centered on the point (X=2.5,Y=4.0) in a 2D drawing, and then import this drawing to make an extrusion in the Z direction, the resulting shape will still be centered on the point (X=2.5,Y=4.0) in 3D space. This is how objects can be correctly located when they are imported into SOLIDCast for extrusion or revolution.

A drawing file (whether in AFSCad or DXF format) must contain ONLY ONE complete cross section for the purpose of creating a solid of revolution or extrusion. The cross section must be fully enclosed, i.e., there should be no gaps or crossovers in the cross section. If you have multiple 2D shapes that are required in order to make a complete casting model, each 2D shape must be stored in a different file.

An extrusion refers to the creation of a shape that has a constant cross section. The ends of the extrusion are parallel. In SOLIDCast, you can create an extrusion parallel to the X axis, the Y axis or the Z axis. Examples of each are shown here:

 

Solids of revolution are created by rotating a two-dimensional cross section about an axis of revolution. The axis may be parallel to the X axis, the Y axis or the Z axis, as shown here:

Creating Extruded Shapes from AFSCad and DXF Files

To create a solid of extrusion, you must have a model displayed or a blank model space showing (select Model… New Model from the main menu to create a blank model space). Then click on the icon that says “Add a shape to the model “(you can see the icon labels if you pass the mouse over the icons on the toolbar). You will see the Add Shape window appear.

Click on the “down arrow” and scroll down the list until the extruded shapes appear as follows:

If you select one of the extruded shapes, you will see the following appear:

Extruded Shape X has been selected. This indicates that a 2D shape will be extruded parallel to the X axis. The system wants to know the length of the extrusion, which is given by entering the X value at the start of the extruded shape, and the X value at the end of the extruded shape. For example, if an extrusion starts at X=1.5 and ends at X=10, then the length of the extruded shape will be 8.5.

When an Extruded Shape X is selected, the system will automatically adjust the view so that you are viewing the model in the YZ view. When selecting Extruded Shape, the view is automatically adjusted as follows:

Extruded Shape X       YZ View

Extruded Shape Y        XZ View

Extruded Shape Z        XY View

You will notice that, when you select Extruded Shape X, the toolbar at the top of the screen changes and appears as follows:

In order to indicate to the system that you will be loading a 2D file (either a DXF file or an AFSCad drawing file) click on the toolbar button labeled “dxf/adg” . You will see a window that appears as follows:

This window now allows you to select a file (DXF or AFSCad) from which to load the 2D shape. Click on the Browse button on this window. Another window will open which lets you select an AFSCad file (or a DXF file), as follows:

This window initially opens into the folder that is specified under System Parameters for Import Files. You can search through different folders using standard Windows navigating techniques. You can also search for DXF files by clicking on the “down arrow” next to the label Files of type , as shown here:

By selecting DXF Files you can then browse through any DXF files that you want to load.

After highlighting a file, click on the Open button. This will then bring you back to the preceding window, and it will appear similar to the following:

The overall dimensions of the shape (in two directions) are given on this screen. The system displays (in inches or millimeters) what it believes to be the dimensions of this shape. If the dimensions are incorrect, it may be because the shape was saved in millimeters and the system is interpreting the dimensions as inches, or vice versa. In this case, you can click on the button labeled Interpret as mm and the dimensions will be converted. When this occurs, the button label changes to Interpret as inches . Each time you click this button, it toggles back and forth between interpreting the file as inches or mm.

When you are satisfied that the correct shape file has been selected, and the dimensions are correctly interpreted, click on the OK button. The 2D shape will be displayed on the screen along with the Add Shape window as shown here:

You can now go ahead and fill in the remainder of the data for the shape. For example, if the extruded shape begins at Y=0.0 and ends at X=8.0, then fill in the Minimum Y and Maximum Y entries as follows:

Now click on the Add Shape button. This will create the extruded shape. Note that you need to click on the Close button to get rid of the Add Shape window. In this case, after creating the shape and changing the view using the Free Rotating Isometric View, this shape would appear as follows:




Creating Revolved Shapes from AFSCad and DXF Files

To create a solid of revolution, you must have a model displayed or a blank model space showing (select Model New Model from the main menu to create a blank model space). Then click on the icon that says Add a shape to the model (you can see the icon labels if you pass the mouse over the icons on the toolbar). You will see the Add Shape window appear.

Now click on the down arrow and scroll down the list until the revolved shapes appear as follows:

If you select one of the revolved shapes, you will see the following appear:

In this screen, the Revolved Shape Z has been selected. This indicates that a 2D shape will be revolved about the Z axis. This shape may be a 2D shape viewed in the XZ plane, or a 2D shape viewed in the YZ plane. The system needs to know the Starting and Ending Angles of Revolution (in degrees) and the X Axis and the Y Axis of the center of revolution. For example, a shape that is fully round will start at 0 degrees and end at 360 degrees. If the Axis of Revolution is centered on the datum point of space, then the X Axis would be 0 and the Y Axis would be 0.

When a Revolved Shape Z is selected, the system will automatically adjust the view so that you are viewing the model in the XZ view. When selecting a Revolved Shape, the system will automatically switch to one of the orthogonal views, but the tool bar at the top of the screen will be adjusted so that you can switch to one of two orthogonal views. The views that are allowed for each type of Revolved Shape are as follows:

Revolved Shape X         XZ View or XY View

Revolved Shape Y         YZ View or XY View

Revolved Shape Z         XZ View or YZ View

You will notice that, when you select Revolved Shape Z, the toolbar at the top of the screen changes and appears as follows:

You will note that this toolbar allows you ONLY to switch between the two views XZ and XY. If the 2D shape represents a section taken in the XZ view, then stay with the XZ view. If the 2D shape is a section taken in the YZ view, then switch to this view.

In order to indicate to the system that you will be loading a 2D file (either a DXF file or an AFSCad drawing file) click on the toolbar button labeled “dxf/adg” . You will see a window that appears as follows:

This window now allows you to select a file (DXF or AFSCad) from which to load the 2D shape. Click on the Browse button on this window. Another window will open which lets you select an AFSCad file (or a DXF file), as shown on the next page:

This window initially opens into the folder that is specified under System Parameters for Import Files. You can search through different folders using standard Windows navigating techniques. You can also search for DXF files by clicking on the down arrow next to the label Files of type , as shown here:

By selecting DXF Files you can then browse through any DXF files that you want to load.

After highlighting a file, click on the Open button. This will then bring you back to the preceding window, and it will appear similar to the following:

The overall dimensions of the shape (in two directions) are given on this screen. The system displays (in inches or millimeters) what it believes to be the dimensions of this shape. If the dimensions are incorrect, it may be because the shape was saved in millimeters and the system is interpreting the dimensions as inches, or vice versa. In this case, you can click on the button labeled “Interpret as mm” and the dimensions will be converted. When this occurs, the button label changes to “Interpret as inches”. Each time you click this button, it toggles back and forth between interpreting the file as inches or mm.

When you are satisfied that the correct shape file has been selected, and the dimensions are correctly interpreted, click on the OK button. The 2D shape will be displayed on the screen along with the Add Shape window as shown here:

You can now go ahead and fill in the remainder of the data for the shape. For example, the shape data may appear as follows:

Now click on the Add Shape button. This will create the revolved shape. Note that you need to click on the Close button to get rid of the Add Shape window. In this case, after creating the shape and changing the view using the Free Rotating Isometric View, this shape would appear as follows:

 Creating Solids of Extrusion and Revolution by Sketching with the Mouse

In SOLIDCast you can create a 2D shape by sketching with the mouse on the screen, and then create an extrusion or revolution with the sketched shape. You can control the mouse location more accurately if you set the Snap to Grid setting under Tools… System Parameters. For example, if you set this to 0.25 and you are working in inches, you will be able to draw to the nearest 0.25 inch on the screen.

To start the process of sketching a shape, you must first select one of the extruded or revolved solids from the Add Shape function. For example, to create an extrusion in the X direction, first click on the icon that says “Add a shape to the model” (you can see the icon labels if you pass the mouse over the icons on the toolbar). You will see the Add Shape window appear.

Now click on the down arrow and scroll down the list until the extruded shapes appear as shown following:


If you select Extruded Shape X, the screen will appear as follows:

Notice that, when an Extruded Shape X is selected, the system will automatically adjust the view so that you are viewing the model in the YZ view. When selecting Extruded Shape, the view is automatically adjusted as follows:

Extruded Shape X       YZ View

Extruded Shape Y       XZ View

Extruded Shape Z        XY View

Now you can begin drawing with the mouse, in the clear model space to the right of the Add Shape window (you can drag the Add Shape window to the side if it is in the way). Notice that the mouse coordinates (Y and Z) appear at the bottom of the screen. To begin drawing a shape, just click with the mouse.

Once you start clicking, you will notice that the toolbar at the top of the screen has changed again. While you are sketching, it appears as follows:

The icon with the “Check Mark” indicates that you are finished sketching the shape. The icon to the left of the check mark is used to delete the previous line drawn.

When sketching a shape, you are actually drawing a series of straight lines on the screen. The starting point is the first point where you click. As you click on additional points, a series of lines will be drawn. The sketching process may appear as follows:

You do NOT need to draw the last line to close the figure. When you finish sketching, click on the Check Mark icon at the top of the screen. This will close the last line drawn back to the starting point, and the screen will then appear as follows:

At this point, you need only to fill in the shape parameter data and click on the Add Shape button. This will create the 3D extruded shape in the model space.

One fairly common use for “shape sketching is to place chills on a casting model. For example, suppose we wanted to add a series of cast-to-shape curved chills around the outer perimeter of the following casting (this is a round casting that is centered on (0,0)):

We could start by changing to the XZ view and then zoom on a portion of the casting in order to see that portion in more detail:

We would then select Add Shape, and select Revolved Shape Z. Assuming that we had the Snap to Grid setting at 0.25 inches so that we could draw accurately, we could then draw a rectangular cross section of a chill as shown in the following picture:

Clicking on the Check Mark icon finishes the shape, as follows:

 

Selecting a starting angle of 5 degrees and an ending angle of 5 degrees defines a chill that extends 10 degrees around the circumference. We also select a Chill Material (say, Cast Iron) for this shape. Once these selections have been made, the chill appears as follows:

Now it is possible to Edit this one shape, perform a Ring Copy around the point (0,0) and make a copy, say, every 30 degrees around the casting. The end result of this operation would appear as follows:

We now have 12 chills equally spaced around the perimeter of the casting.

As an example of creating a casting shape using solids of revolution and extrusion, consider the following 2D figures that were created in a CAD system and saved in DXF format, which is available in virtually any 2D CAD system today:

Saved in file Y-1.DXF:

Saved in file Y-2.DXF:

Saved in file Y-3.DXF:

The process of creating a casting model from these shapes would be as follows; First, select File New Model. Then select Add a shape to the model, select Revolved Shape Z, select the DXF file called Y-1.DXF, specify a revolution of 0 to 360 degrees, leave the center of revolution at X=0, Y=0, and then click on Add Shape. The first shape will appear as follows:

Now we will add an extrusion to this shape. Select Add a shape to the model, select Extruded Shape Z, select the DXF file called Y-2.DXF, set the extrusion from 0 to 1 inch, and click on Add Shape. The second shape will appear as follows:

 

Now add the third shape as a revolved shape. To do this, select Add a shape to the model, select Revolved Shape Z, select the DXF file called Y-3.DXF, specify a revolution of 0 to 360 degrees, set the X coordinate of the center of revolution to 6.000 inches, and then click on Add Shape. The third shape will appear as shown here:

Now we can duplicate the second and third shape by a Copy operation (see the section of Editing/Copying for details). Select both the second and third shapes (by clicking the “Selection” arrow icon, holding down on Ctrl and clicking both of these shapes) then select Edit… Copy Selected Shape(s) and specify a Ring Copy about the Z axis with (0,0) at the center, with three copies at 90 degrees. This will produce the following final model for this casting:

 

 

 

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