AutoCAD Mechanical: Bill of Materials – Part 1

This skill builder demonstrates how the bill of materials (BOM) works in AutoCAD Mechanical (September 2008).

In AutoCAD Mechanical, you are required to define the component properties for the parts and assemblies to populate the properties to the BOM.

You start with the following:

• Understand the Part References
• Create part references to populate information in the BOM
• Create a parts list
• Create balloons
• Edit BOM

Part Reference

In AutoCAD Mechanical, a part reference is an object that stores information about a part and assemblies using component properties. Component Properties are like attributes placed in blocks. When placed, component properties prompt for information such as part number, description, and material.

A part reference is represented by an object as shown in the following image.

(1) Part Reference object used for standard parts

Note: This part reference is attached to the standard part and appears with a solid center. As a result the part reference will move if you relocate the standard part.

Note: This part reference helps in positioning the balloon point to the standard part.

(2) Part Reference object used for user-defined or non-standard parts

Note: This part reference has no solid center. As a result, you must select the part reference if you move the part to position the balloon on this part.

Note: In AutoCAD Mechanical, the part reference is created when placing standard parts including screws, bearings, sprockets, and steel shapes. It automatically populates the component properties in the BOM.

To change the component properties after you insert a part reference, double-click the part reference object to display the Part Reference dialog box.

The following image shows the component properties for the part definitions in the Part Reference dialog box associates to the BOM. When you edit these component properties in the part reference dialog box, the changes are displayed in the BOM automatically. Likewise, any changes made manually in the BOM update the component properties in the part reference dialog box.

To begin, download and open wheel_sub_assembly_2009.zip below:

wheel_sub_assembly_2009.zip (zip - 178Kb)

Expected completion time for the skill builder is 7 – 10 minutes

Create Part References to populate information in BOM

For the non-standard parts, you create part references to populate information for the bill of material. Here, you create part references for the wheel base and the wheel.

Type AMPARTREF at the command line
Select point or [Block/Copy/Reference]: Locate a point on the wheel base.

The Part Reference dialog box is displayed. Enter the following information for each field in the Component properties list.

Name: Wheel Base
Description: Wheel Base
Material: mild steel

Click OK. This information is stored in the part reference and automatically populates the BOM. Next, create a part reference for the wheel in the assembly using the same command AMPARTREF.

Type AMBOM at the command line
Current BOM = Main
Specific BOM to create or set current [Main/?] : Press Enter
BOM dialog box displays.
Notice the component properties – Wheel base and wheel are populated in the BOM.

Create a Parts List

Next, you use the AMPARTLIST command to create and place the parts list in a drawing.

Type AMPARTLIST at the command line
Select border/annotation view or specify BOM to create/use [Main/?] : Press Enter. The Parts List ISO – Main dialog box is displayed.
Click OK and place the parts list on the drawing as shown in the following image.

To insert a parts list into a layout and have its contents based on a different BOM, first start the AMBOM command to open the BOM dialog box. After the BOM dialog box is displayed, activate the BOM you want a parts list, and then click the Insert Parts List button.

Create balloons

After the part references are created, you use balloons to itemize parts in an assembly to identify the parts and subassemblies in communicating the design to others. With the parts list item number in the balloon and the balloon leader line pointing to the part. You can identify which part it is in the drawing and its location in the assembly when you review the information in the parts list.

Type AMBALLOON at the command line
Current BOM = Main

Select part/assembly or
[auTo/autoAll/set Bom/Collect/arrow
Inset/Manual/One/Renumber/rEorganize/annotation View]: Type T for auto to create balloons automatically for some selected parts in the assembly. Use a selection window to select the part reference nodes.

Align [Angle/Standalone/Horizontal/Vertical] : Type H to locate the balloons horizontally. To position the balloons vertically, type V at the command prompt. Click a location to place the balloons. The balloons are created.

Edit BOM

When a BOM exists in the drawing, it continues to associate the part references, balloons and parts Lists. Any changes made on the part references and parts lists automatically update the balloons and BOM. You can also manually edit in the BOM to update the balloons and parts list.

Add a base plate on the wheel sub assembly using the AMRECTANG command at a full base - of 350 mm and a full height – of 12 mm.

Create a part reference for the base plate.

Notice the information automatically populates on the parts list and BOM. Likewise, if you removed the part reference, the information is removed. It prevents mistake made in quantity calculation for the manufacture and standard parts in the design.

Keep in mind all material lists and information in the BOM are populated from the part references. You can have a part reference for a part, a subassembly, or assemblies but ensuring that the information is correct for an accurate BOM.

For more information on the BOM, see the Help in AutoCAD Mechanical.