Sheet metal thickness - Variables - BOMs

rich_north

I work quite a lot with sheet metal and have gone down the rabbit hole of trying to get the material thickness to show up in a BOM next to the relevant parts. I often have to submit models to a supplier and check back through quotes, and it is very useful to be able to cross reference the thickness from my BOM with the quote. This works well in Solidworks as the 'sheet thickness' is a property which can be referenced directly.

My understanding is that the sheet thickness you enter when creating a sheet metal part in Onshape is not referenceable as a baked in property, and therefore not available as a property to add to a BOM.

I have seen (but not fully understood yet) solutions that use variables which can be referenced in a custom BOM using feature script I think, or a feature script that looks for the smallest value of a bounding box around a part and assumes thickness (no good on folded parts), but the issue is when you want to change the thickness of a part.

Scenario: I have a part studio with 10 sheet metal parts of varying thickness. Their thickness is derived from an imported variable table (so i don't have to type it out each time) with entries like 'SM_5' for 5mm thick etc. Often my bend radius will match/use this variable also. If I want to change all the 5mm thick parts to 4mm, I don't really want to change the variable 'SM_5' to 4mm as I have an 'SM_4' for that, and often I won't be changing all the 5mm parts to 4mm. Also I may not want to mess with a bend rad. Of course I can go through the tree/features and change the entered variable where appropriate but that's potentially a lot of hunting and rebuilding.

In my head, ideal behaviour would be to see the parts (or maybe the sheet metal models) in a table where the thickness variable could be changed, eg 'SM_5' with 'SM_4' in just the parts that required it.

Perhaps this isn't a variables problem… but it seems to be the simplest way to get a 'thickness' value in a BOM at least, which is my main focus.

Caden_Armstrong

To have the thickness show up in your native Onshape BOM, you need to have a custom property in your Onshape, and you add that property as a column.

To set the property you have two options - either use a computed property which can automatically calculate the thickness. Or you can use a "set property" featurescript. You can then configure that property the same way you configure the sheet metal thickness. This is a simple approach, but requires setup for each part.

I also sell a computed property library on fs.place that contains a computed property that will do sheet metal thickness, among many other common ones.

john_mcclary

FS: Stock Size | stockSize.fs

FS:Sheet Metal Bend Table | Bend Table Feature.pdf

You can make a copy of the two features above.

This is how sheetmetal workflow looks like for us

Frist use the BendTable to choose the thickness you want, then you can choose the tooling to define the bend raidus. This also shows what the minimum flange length for that tool is also so the designer doesn't have to reference a chart.

That creates two variables #thickness and #bendRadius now any sheetmetal feature you create after the bend table you can reference these variables. Which helps when you want all your materials to be the same thickness. It is just one place to change all the parts below.

There is an option to put a prefix there as well so you can have multiple thicknesses or bend radius, such as for a guard. That way you don't have to keep redefining between thick and thin pieces in your feature tree.

Then the stock size feature can be copied and set to your company's custom properties, which can then be referenced in a drawing or ERP export.

As you can see, the StockSize property is for the drawing callout, then all the sizes are itemized for our ERP system to check material inventory and flag to order more sheets.