iParts - The Basics
Creating a basic iPart (Inventor R2008)
Estimated Time Required to Complete: 25 minutes
|This is the first in a two-part Skill Builder series which explore iParts. A subsequent Skill Builder will address table-driven feature suppression, and using Microsoft Excel to edit the table.|
In This Exercise
In this Skill Builder, you create and edit a standard iPart. In this exercise you learn how to:
- Create a table-driven part.
- Distinguish the difference between standard and custom iParts.
- Use the tabs in the iPart Author dialog box.
- Use keys to simplify use in an assembly.
- Download the file simple_handle_iPart.zip
- Extract the file simple_handle_iPart.ipt
- Have Inventor R2008 or R2009 installed.
- Understand how to open, create and save part files in your active project.
- Download (and unzip) the zip file containing the source file to use during this exercise.
The zip file contains an Autodesk Inventor 2008 part file named simple_handle_iPart.ipt.
The part file contains two sketches to create the iPart.
Most designers have parts that may differ by size, material, or other variables, but the same design works in many models. You can create these designs as iParts, and then use one or more of the variations. Since each table entry creates a unique part, you can use different configurations of the same iPart in an assembly.
You use the iPart Author to create part families that contain a table. For standard iParts, each iPart variation is an iPart member, which is defined by a row in the table. When placing the part in an assembly, select the row (member) needed.
iParts can also be used to represent assemblies by constructing a simplified table-driven part such as the caster in the following image. It has multiple wheel sizes and mounting configurations. By using feature suppression one mounting configuration can use holes, while another can use slots.
Another important aspect of creating iParts is creating sketches that behave predictably. It requires fully constrained geometry with dimensions, dimensions driven by parameters and geometric constraints.
If dimensions are given parameter names or you create User Parameters, Inventor automatically adds them to the table when you create an iPart. If the dimensions are left in their “natural” state as model dimensions (d0, d1, d2 and so on) you must manually add them to the table.
Standard vs. Custom iParts
When you create an iPart factory, you determine if parameter values are to be selected from a list, or can be specified when the iPart is placed in an assembly. To create a custom parameter, right-click when editing the iPart table and select the Custom Parameter Column. You can specify the value for that column each time the part is used in an assembly. For example, an 8-inch steel channel has a custom parameter column that defines length. Each time the iPart is used a new part file is created with a unique length. A Custom Parameter Column appears blue in the table.
The following images show the dialog box presented when Standard and Custom iParts are placed in an assembly. The Standard iPart dialog box contains a selectable list of parameter values. The Custom iPart dialog box has a selectable list on the left and an area on the right where you enter custom values. The Custom iPart dialog box also contains a Browse button to specify the file save location for the generated iPart. By default, Custom iParts are saved in the same folder as the iPart factory. When a Standard iPart factory member is generated it is saved to a subfolder under the parent part location with the same name as the parent iPart.
Another key difference is noted when you open the generated iPart on disk. If you open a Custom iPart factory member, the Part Features menu is active. If you open a Standard iPart factory member, the Part Features menu is not available.
Note: When you create an iPart from a normal part file it becomes a table-driven part. Deleting the table converts an iPart back to a normal part. The active row values are used to determine feature sizes and location when the table is deleted.
Open the Source
- Open the simple_handle_ipart.ipt file included in the downloaded zip file. The part contains two sketches. The sketches have been named to indicate their use.
- Click Tools> fx Parameters to open the Parameters dialog box. Notice that all dimensions have assigned names. When the iPart is created, these names will appear as table column headers. Also note that the value of the parameter Handle_Rad is an equation (Major_Rad *2).
- After you examine the Parameters, close the dialog box without making any changes.
- In order to show the sketch dimensions as expressions, with nothing selected right-click in the graphic screen and select Dimension Display > Expression from the context menu. Notice that the sketch dimensions match the names in the parameters dialog box.
- Open the iProperties and choose the Project tab. Note that a part number was assigned that differs from the file name. The part number will appear in the iPart table and will be appended with a dash number (10-100-01) when you create the iPart. The dash number will increment with each new row.
Create the handle
- From the Part Features menu, select Sweep.
- If the profile (ellipse) is not automatically selected, choose the profile. Once the profile is highlighted, the path button is enabled. Select the open profile for the sweep path to create the handle.
- Next, add some mounting holes to the handle. Start a new sketch on the flat surface of one of the ellipses. Use the Project Geometry command to copy both ellipses to the sketch plane, and then exit the sketch.
- From the Part Features menu, select the Hole command.
Set these parameters:
- Placement = From Sketch
- Termination= Distance
- Hole depth value = 6mm
- Tapped Hole, Thread Type = ISO Metric profile
- Full Depth, Size 5mm
- Designation = M5x0.8, Class = 6H
- Direction = Right Hand
Make sure the Select arrow is active, and then select the ellipse center points in the sketch to create the holes.
|Note: Use the Flip Direction button if the holes are going away from the body.|
- To control the hole depth for the iPart, click Tools> fx Parameters to open the Parameters dialog box. Locate the dimension with a value of 6mm. Change the name of the model parameter to Thread_Depth. (No spaces are allowed in the parameter names.)
|Note: You can use un-named dimension variables in the table, but you must add them to the table manually. It is also difficult for other users to know what they control. For these reasons, it’s a good idea to name the variables you want to control in the table.|
Create the iPart
- Click Tools > Create iPart. The iPart Author dialog box is displayed.
- Notice that columns were created for all named parameters. Columns in an iPart are typically used for values that change. Since the parameter Handle_Rad is controlled by the value of Major_Rad, do not include this variable as a column. To remove it, highlight Handle_Rad in the Name list and click the << symbol. You can also highlight the column name, right-click and select Delete Column from the context menu to remove the column.
- To allow for different mounting hole sizes, add the mounting hole information to the table. Navigate to the Threads tab and add the Designation (M5x0.8) column by highlighting it, and then clicking the >> button to add it to the table.
- Right-click the first row in the iPart table and select Insert Row from the context menu. Repeat to add a third row.
|Notice that Inventor incremented each Member name and Part Number with a new dash number. Use the Options button to control the increment. We will now configure the iPart rows.|
- Fill in the following table values:
|94 mm||10 mm||6.25 mm||40.5 mm||6 mm||M5x0.8|
|132 mm||12.5 mm||8 mm||50 mm||8 mm||M6x1|
|179 mm||14.5 mm||9 mm||58 mm||10 mm||M8x1.25|
The highlighting on the first row indicates it is the default row. You can set a different row as the default. Highlight it, right-click and select Set As Default Row. This action also builds the part to the active row values when you exit.
Before you finish, select the Verify button to check the table for errors. Any cells with errors are shaded yellow. Correct any errors, then click OK to save the table and exit.
Navigate to the Model browser and expand the Table. Notice the check mark next to -01. It indicates the active (default) row. To activate a different row, double-click it in the browser. Activate each row to build the part to the values in the row and check for errors in your iPart. If a row has errors in it, Inventor will display a message indicating a build failure. When you double-click a table row to activate it, you are also designating that row as the default value. Make sure that -01 is checked as the default before moving on.
The last step is to make it easy for the designer to choose the correct member when inserting the iPart into an assembly. Create one or more Keys to simplify the process.
If no parameters are designated as keys, the user is presented with all the variables contained in the table when they place the part in an assembly. This can make it difficult to navigate to the correct row. A key filters the parameter list to present only the variables designated as keys to the user when the part is placed in an assembly. The keys are presented in ascending order (1, 2, 3 and so on).
Create the Key
In this example, the handle is specified in the manufacturers catalog by selecting the mounting hole size and an “outside to outside” overall length dimension. We currently do not have a parameter in our table to indicate this number, so we will create a custom parameter and then use it as the Key.
- Navigate to the Model browser, select the table, right-click and select Edit Table.
- Navigate to the Other tab and select Click here to add value. Type in Catalog Description for the name. Notice that unlike the Parameters area, spaces are allowed in the iPart table.
- After you create the custom parameter name, it appears in the following table. A gray key also appears next to the value in the name column. If you click the key symbol it changes to a solid blue color with a number next to it. If it is the first key selected it will be designated number one. You can also right-click the key symbol and assign a key value. Use one of these methods to designate Catalog Description as Key 1.
- Fill in the Catalog Description values. In the column under Catalog Description fill in the following values and then choose OK.
- For the M5x0.8 hole use M5x106.5
- For the M6x1 hole use M6x148
- For the M8x1.25 hole use M8x197
Make sure the first row is the default, and then save the file.
Start a new assembly. Use Place Component to place simple_ipart_handle_iPart.ipt in the assembly. In the Place Standard iPart dialog box, notice that the Key tab is active and shows only the single key you designated. Also, the value presented in the dialog box is the row designated as the default. Click in the assembly window to place the first size. You can flip back and forth between the display of key names and member names in the browser by using the “List by member name” and “List by keys” context menus in the iPart table.
Use the Place Component command to place a copy of each of the remaining two handle sizes. To see the entire list, click in the Value column and choose All Values. Once you highlight the size you want, click in the assembly window to generate the part. Multiple clicks place multiple copies of the same iPart.
Congratulations! You just created, saved and used your first iPart.
Let’s review your accomplishments…
In this Skill Builder you:
- Used a supplied part to create a table-driven iPart file that contained three definitions – each a specific size.
- Reviewed the sketch in the supplied part to understand the importance of dimensions, constraints and parameters in the creation of well-behaved iParts.
- Learned the location of the Create iPart tool (under the Tools main menu).
- Learned how to name the dimension variables that will become columns in the iPart.
- Learned how to add and remove columns from the iPart table.
- Learned how to create a custom parameter in the Other tab.
- Learned how to create a Key to simplify selecting the correct table value when you place the iPart in an assembly.
- Learned how to insert different versions of the iPart in an assembly.
In the next Skill Builder, you will learn how to create and use multiple keys, build an iPart using selective feature suppression, and learn how to use Excel to edit the iPart.