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How to Assembly Items into Other Items (item manufacturing)

Creating Assembly Items in Total Office Manager is a two-part process. The first step is to create an assembly item. The final step is to build the assembly. The build process is how Assembly Items are placed into inventory.

An Assembly Item is similar to a Serialized Item or Inventory Part, except that it is created by using other inventory items. Users create a list of items and then assemble them into a new Item. This action, called “Build Assembly Item”, creates the Assembly Item while removing the individual items used to create it from inventory.

Imagine building a computer from a list of inventory parts, including a hard drive, memory chip, mother board, case, keyboard, monitor, and more. You could create an Assembly Item and call it “Computer”. When you build it, it is added to inventory and the items used in the assembly (hard drive, memory chip, etc.) are removed from inventory.

Note: This Help topic assumes that you are already familiar with Inventory Parts and Serialized Items. If you don’t have knowledge of these items, please read up on these topics first.

Types of Assembly Items

There are two types of Assembly Items: Inventory Part and Serialized. These Assembly Items function in the same way as standard Inventory Parts and Serialized items.


Activating The Assembly Item Feature

This is an advanced feature in the program and is hidden by default. To access this feature, it must first be turned on by your Total Office Manager Administrator.

  1. To access the Assembly Item feature, click Edit \ Preferences from the main menu. This will open your Preferences form.
  2. Click the Items tab
  3. Mark the Use Item Assemblies Feature checkbox.
  4. Click Close.

Creating an Item Assembly Item

  1. Open the Invoice Item List. Right click and select New Assembly Item.
  2. In the Assembly Type field, select either Inventory Part or Serialized.
  3. Enter an Item Number.
  4. Select an Item Category (optional).
  5. Enter a Sales Description.
  6. Click the Bill of Materials (BOM) tab and select the various items that will make up this Assembly Item.
  7. Click the Accounting tab, select the Income, COGS, and Inventory accounts you wish to use with this item.
  8. Click the Inventory tab and enter the beginning quantity for this item. This refers to the quantity on hand with which you are starting. This is typically entered when opening your company for the first time (this is optional).
  9. Click the Quantity Checking tab, and enter a pop-up message and trigger quantity (if desired).
  10. Click Save & Close

The Build Process

The Build process will create a series of Item Adjustments that match what has been selected in the BOM. These adjustments will remove inventory, as needed, and add the correct quantity of the Assembly Item.

You have the ability to create an Assembly but not actually go through Build process. This Build will be considered “Pending”. You can always go back and build it at a later date.

  • From the main menu, click Company | Assembly List.

  • Right-click and select New Assembly.

  • From the Item selection, choose the item number you wish to assemble (build).

  • Enter or select a Date (this is the date of the assembly).

  • Enter a Build Ref No (Build Reference Number) to help identify this action. This field does not automatically enter a number.

  • Enter a Memo to describe this build (optional).

  • In the Build Qty. field, enter the number of items you wish to build (or place into stock).

  • Select a Department with which to associate this assembly (optional).

  • If you wish to go through the Build process at this time, click Menu and select the Build option.

  • Click Save & Close.

Additional Information

The Maximum Number You Can Build Is label refers to the number of assembly items that may be created. This number is based on the Bill of Materials (BOM) and what is in stock. You cannot assemble into negative quantities. If you close the form without clicking the “Build” button it means that the Build is Pending; no items are removed from inventory but no items are added, either. The form includes a label that tells the user if the item is “Built” or “Pending”. If an item is “Built”, no editing is allowed except in the Memo field.

Invoice Item List

  • The Invoice Item List includes Assembly Items, and a column called ‘Assembly’ is included in the list.

  • Within the ‘Assembly’ column is a ‘Yes’ or ‘No’ option; the user must indicate which is appropriate for the item.

  • An Assembly field selection can be found in the Quick Filter and in the Filter Center. Make sure the “Assembly” column is showing when using your Quick Filter and Filter Center.

Build Assembly List

  • The Build Assembly List is where Assembly Items are created and where prior Builds can be viewed.

  • To access the Assembly List from the main menu, select Company | Assembly List.


  • Assemblies – This is a  comprehensive report that contains detailed information on each Assembly Item. To access the report from the main menu, select Reports | Company | Items | Assemblies.

  • Assembly Item Build History – This report will display how items were built and when.

  • Assembly List – This report shows a list of Pending and Built Item Assemblies with no details.

  • Invoice Item Reports – Total Office Manager includes many item related reports. Some of these reports will include information about Assembly Items.

  • Don’t Forget: You can open any list and preview or print a Quick Report. List forms may also be exported.

How is Estimated Cost Calculated

Listed below are some details on how the Estimated Cost of an Item Assembly is calculated. The Estimated Cost of an Item Assembly is the sum of all Costs for Items selected in the Bill of. This is calculated by multiplying the Cost for each Item by the Quantity entered in the Bill of Materials. The Item Cost is the Average Cost of the item when available, or the Estimated Cost when the Average Cost is not available.

It is possible for an Item Assembly’s Estimated Cost to vary over time. This is because an Item in the Bill of Materials may not have an Average Cost at the time the Item Assembly is created, therefore, the Estimated Cost of the Item is used. Anytime the Average Cost of an item is not zero it is used instead. So, as an Item’s Average Cost changes the Estimated Cost of the Item Assembly (assuming the Average Cost of the Item is not the same as the Estimated Cost of the Item) will change.

This means the Estimated Cost of an Item Assembly is always accurate to the value of the Items in the Bill of Materials. As the Item Cost changes for each item that makes up the Assembly the Item Assembly’s Estimated Cost is reflected.


  • Creating an Assembly Item is a lot like creating an Inventory Part. The Build process is how the Assembly Item is added to stock. Assembly Items do not become part of inventory until they are “Built”.

  • Assembly Items are included on the Item List under the Type “Assembly”.

  • Inventory Item Adjustments created by the Build action cannot be deleted or modified by the user.

  • You cannot delete Inventory Items (of any kind) once they have been used in an Assembly Item. The items must be removed from the Assembly Item first.

  • The cost of an Assembly Item is calculated by adding together the cost of each item on the BOM (Bill of Materials).

  • The BOM may include Inventory Parts, Non-Inventory Part, and Service items.

  • An Assembly Item cannot be deleted once used (has history).

  • You can only Build from and into the Main Warehouse; i.e.,  items used in an Assembly must always come from the Main Warehouse and be added to the Main Warehouse. No selection of warehouse is allowed.

  • If you wish to remove an Assembly Item from stock, you must use Item Adjustments and remove them from inventory.

  • Assembly Items cannot be purchased and are a not part of the Accounts Payable process. Assembly Items will not be available on Purchase Orders, Item Receipts, Bills, Checks, and Credit Card Receipts.

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