GAs and BOM

General Assembly Drawings

Create your drawing by the usual process, if prompted, click OK to specify No Combined State.

Remember;

• No hidden line in views
• show axis where needed
• No part feature dimns in views, but…
• …..you can have component position dimns or assembly level feature dimns
• xsec views will give best detail of assembly interfaces
• explode states are interesting but don’t tell us how the parts fit together

What makes a good GA?

• minimum number of views to best communicate the product
• maximise the view size – use multiple sheets if needed
• minimise the BOM size
• can you see the individual parts?
• watch your balloon attachment
• DO NOT accept the software defaults

Bill of Materials – BOM

Once you have a GA drawing of your assembly file you will need to create a table which lists all the parts in that assembly and some information about them.  This is a Bill of Materials (BOM)

 

Add and define a table for the BOM

We could create a table and manually input the information describing the assembly but this would have to be updated manually and does not exploit the associativity between the assembly and the GA.  We can create an associative link between the table and the assembly using a Repeat Region (RR).

 

To create an automated BOM in Creo we need to:

• create a table
• define a simple repeat region (RR)
• enter the report symbols
• update the table
• add BOM balloons

 

 

Quick Tables

Table > Quick Table > BOM Description up/down

These are predefined tables with a RR (Repeat Region), generally a good starting point.

 

Creating a Table to contain the BOM

Use the Insert Table icon in the top toolbar and create a table with only 2 rows – the Header row and the Data row

Hover over various positions around the table to select cells, columns, rows or the whole table.

Select the table and enter its properties box (RMB menu).  Define the text justification of the columns to align in the centre of the cells.

Select the header cells individually and through the properties box (Dbl click the cell or RMB > properties) add text to define the columns.

 

Repeat Region

In the example above the ‘Matl.’ column is not automated as the models to do not have a material assigned therefore there is no parameter for that column. RMB > Properties on that cell to manually assign a material.

Create a simple RR for the information in the BOM and define the parameters to display.  This will means that the BOM table will be automatically expand (up or down) and be updated as parts are added.

To define the cells included in the repeat region;

Quick method:

• Hover your cursor at the end of a row until it highlights
• Select the row
• RMB > Add Repeat Region

Alternate method:

• Table tab > Repeat Region
• select the two cells which define the extents of the RR
• this method is useful when the RR is not a complete row or includes multiple rows – see Nested RR

 

Removing RRs

If at any time the process gets confused – commonly having multiple repeat regions in one place – then it is generally quicker to delete all the RRs and start again.

Repeat Region tool > Remove > All Regions > Yes > select the table which contain the regions

 

Assigned Report Symbols

Once the RR is created you need to assign the system parameters which will be entered into the repeated cells, this will cause the table to be automatically filled in. In the example above;

• Dbl click the first cell in the RR row and choose rpt. > index using the Report Symbol options. This will number each part in the assembly.
• Dbl click the cell below Part Name and enter asm. >mbr. > name. This will fill in the part file name
• Dbl click the cell below Qty. and enter rpt. > qty.  This will fill in the quantity of each part
• To stop multiple instances of a part being displayed separately in the table:  RR tool > Attributes > [select the Repeat Region] > no duplicates

Use the Update Table icon to update the table to show the current part information.

The Matl. column in the above example is empty at this stage as it was not included in the repeat region.  You could enter the material information manually via the cell properties.

Or you can assign a material to a part file [in the part file: File > Prepare > Model Properties > Material > Change] and then using the Report Symbol  asm.mbr.ptc_material.PTC_MATERIAL_NAME   this can be included in the repeat region.

 

Add BOM balloons to the drawing

• Create Balloons > Create Balloons – All tool
• Select a balloon and move it using the control handles
• Modify the attachment point of a balloon; select balloon > RMB menu > Edit Attachment
• It is generally clearer if the attachment is to a surface rather than an edge
• Make sure it is obvious what the balloon arrows are indicating
• Move balloon to an alternative view; select balloon > RMB menu > Move item to View
• Once Balloons have been created you enter the Table properties window to modify the Balloons 

 

 

Manually creating BOMs

Remember that if you manually create a BOM then there is no associativity to your project and you will need to update your table and balloons manually to reflect any changes in your assembly.

Create a table as above but with adequate rows for your assembly components. To add more rows – Table tab > Add Row.  Fill in the table with the appropriate component information.

Balloons will also have to be created manually: Annotations tab > Annotations drop down menu > Balloon Note

Make the Note type With Leader and probably attach to surface rather than entity for clarity.

Manual sub-assembly component numbering

Keep it logical, suggestion: