Inventor - Bill of materials

Did you know that Inventor has a bills of materials (BOM) function? Do you know how it works, what it's for and what it affects?

If the answer to these questions is no then it may be that you would benefit from a little update training. However, in the meantime to start you off here are a few pointers.

• The bill of materials is made up of the iProperties of all the files in your design. Changing the iProperties will change your BOM and changing a property in the BOM table will alter the iProperties. This allow your iProperties, BOM, Parts lists and title blocks all to be updated when you alter any value.
• The BOM table allows you to create custom iProperties and update the mass properties for each file in your design.
• The BOM in inventor is made up of 3 areas:
1. The Model Data tab:- this shows the files used by your model and will show each and every file in your design. This is only used within the assembly and cannot be exported or used for anything other than manipulating the properties of all your files.
2. The Structured tab:- This is the structured bills of materials as most companies require it. This tab doesn't show all the files in your design rather only the ones that are required to make up the BOM/Parts lists. Each level of this area can be placed on the drawing and as you can imagine becomes the parts lists on the sub assembly drawings.
3. The Parts Only tab:- This can be used for various things. I tend to think of this as either a spare parts list for a customer or a cutting/pick list for the factory. Assemblies dont generally appear on this list (depending on what you manufacture) however all the component parts do so it can be used also for cutting lists.

 All files in your design have a BOM structure that can be changed to one of five settings. These settings effect the behavior of the file on the structured and parts only tabs in the BOM. All the info about these settings can be found in the help file and of course we go through it with you during training, however, as a bit of a reminder for those that use them the BOM structures are:

• Normal:- By default files are set to normal. This allows a file to appear on the Structured tab and appear if its a part file on the parts only tab. Normal assemblies don't appear on the parts only tab.
• Purchased:- This allows you to set whether a file represents a bought in component. Parts from the contents centre tend to be purchased items. Purchased items can be filtered on or off on the parts lists.
• Inseparable:- This should be used for assemblies that would require a destructive force to split apart their components ie, welded or riveted assemblies. Assembly files with this setting are shown on the structured tab with their children. On the parts only tab the assembly is shown but not the children. This is where I start to think of the parts only tab as a spare parts list; for a welded component you need to manufacture individual frame members and to weld them together, so you want them all on the Structured BOM. Your customer can only buy the welded frame from you not the individual parts and so the Parts Only tab shows just the inseparable welded assembly not the parts that make it up. When you look at the Parts only tab for the BOM of the welded frame you could get the cutting list from it.
• Reference:- This is used for files that you don't want to show on your structured BOM and your parts only tabs. An example could be a table; maybe you manufacture the table and in the model show it in the context of a room so you can render it. You are not going to manufacture the room so it doesn't want to appear on the BOM and parts list. Reference also changes the line type of the file on the drawing and auto-crops the component on the drawing as well.
• Phantom:- Everyone favorite; its the hardest to understand however it is the most powerful setting. This allows you to make a file “Transparent” within the context of the BOM. What this means is that the file you make Phantom will not appear on the BOM however its children will; This is seen when using the design accelerators. An example would be a bolted connection; when you create a bolted connection your are in-fact adding a nut, bolt and washers to a sub-assembly called bolted connection. This sub-assembly doesn't want to appear on the parts list and BOM however its children do. My rule for this is if its not going to have a drawing make it phantom.

The above is only a small description of the BOM function in Inventor and certainly isnt the be all and end all of bills of materials management in the product. I hope however, this should give you a small insight into what its all about. My advice is to create a small test assembly and play with the BOM settings and see what they do for yourself.

If you have questions or want more detail about this then please get in touch or if you have support then call the support helpline.

And remember we also can help you with your full BOM management, complete with electronics, processes and documents. Symetri specialise in BOM manipulation within CAD, PDM and PLM products. For more information please get in touch.