Why does SolidWorks create flat patterns for sheet metal parts without bends?

[AlexLachance]

I have a weird question this morning that popped-up in my head while I was creating a design-table part that didn't require any bends or flanges.

Why does SolidWorks require a flat pattern for sheet metal parts even if they do not contain bends or flanges? The question came up after I created the design-table part with over 100 configurations and that each configuration created it's own flat pattern for it's drawing, even though the flat pattern is the same as the actual front view.

I understand some parts can be made "in context" and not be planar to one of the original planes, still I don't really understand why it is required for SolidWorks to create a flat pattern for it.

Anyone has an idea? Figured if it's not necessary, it certainly wouldn't hurt to 'remove them' and alleviate the file.

[bnemec]

I'd guess for simplicity. Why is there a cutlist when there's only one body in the file? I'd guess because of how data is stored. If I want to store an attribute for the file I have one property. If I want to store that attribute for all the configs in the file I need a LIST of properties for that one attribute. The code that supports this is much simpler to just always use a list even if there's only one item in it.

But I thought the flat view wasn't created until it is used in a drawing? We had a hell of a time with this because the detailers were making prints of sheet metal parts so they didn't check out the sldprt file. There should be no need, they're not editing the part. Weeell, apparently SW in all it's wisdom automatically creates the flat config when the view is added and since the PDM Add-in doesn't throw up a verbose flag that the user needs the .sldprt file checked out too the user goes on merrily making a trail of rework. We had A LOT of sheet metal drawings with messed up flat views. It was the most literal case of a SNAFU.

[AlexLachance]

I'd guess for simplicity. Why is there a cutlist when there's only one body in the file? I'd guess because of how data is stored. If I want to store an attribute for the file I have one property. If I want to store that attribute for all the configs in the file I need a LIST of properties for that one attribute. The code that supports this is much simpler to just always use a list even if there's only one item in it.

But I thought the flat view wasn't created until it is used in a drawing? We had a hell of a time with this because the detailers were making prints of sheet metal parts so they didn't check out the sldprt file. There should be no need, they're not editing the part. Weeell, apparently SW in all it's wisdom automatically creates the flat config when the view is added and since the PDM Add-in doesn't throw up a verbose flag that the user needs the .sldprt file checked out too the user goes on merrily making a trail of rework. We had A LOT of sheet metal drawings with messed up flat views. It was the most literal case of a SNAFU.

SNAFU, I had never heard that term but I believe it is one I will use from now on

[RonE]

I guess one reason is simplicity as bnemec mentioned. The other reason may be that SOLIDWORKS at the point of view creation of course cannot know if bends will be added later to the part. If the view is already showing the flat pattern configuration it won't be necessary to change it later.

[zxys001]

SNAFU, I had never heard that term but I believe it is one I will use from now on

https://en.wikipedia.org/wiki/SNAFU

[TTevolve]

Curious, why do you have a sheet metal part that doesn't have bends? If you going to make a flat plate, why not just do a rectangle with a single extrude? Is there some benefit to having a flat piece ad a sheet metal part?

[bnemec]

Curious, why do you have a sheet metal part that doesn't have bends? If you going to make a flat plate, why not just do a rectangle with a single extrude? Is there some benefit to having a flat piece ad a sheet metal part?

I don't know about the OP but we cut many sheet metal parts on a laser, so we need to export the dxf. We've always exported the dxf from the model, not drawing.

We also use CNC wood routers that use a dxf. To model those parts we use sheet metal environment and obviously those parts do not have bends in them. The ply wood doesn't perform well in the break press.

We had a bunch of parts modeled by college interns, that supposedly had SW training. There were a bunch of flat SM parts modeled just as you suggested. They all needed to be redone by an engineer. Which also broke the annotations in the drawings and all the mates in all the where used assemblies. Many Many hours of rework down the crapper.

Now if someone asks about a mirror part copy of a sheet metal with no bends then I'm going to

[AlexLachance]

Curious, why do you have a sheet metal part that doesn't have bends? If you going to make a flat plate, why not just do a rectangle with a single extrude? Is there some benefit to having a flat piece ad a sheet metal part?

In my case, it has to do with BOM's and exporting to our ERP and a few other things.

It makes for a "cleaner" workflow too, instead of having to convert whatever was created into a sheet metal to add the bends.

Our DXF's are generated by our drawing files, which is why I was kind of wondering about it. We have a sheet in our drawing designated for DXF generation with the desired view at 1:1 on it when a DXF is required.

[jcapriotti]

We also use CNC wood routers that use a dxf. To model those parts we use sheet metal environment and obviously those parts do not have bends in them. The ply wood doesn't perform well in the break press.

We had a bunch of parts modeled by college interns, that supposedly had SW training. There were a bunch of flat SM parts modeled just as you suggested. They all needed to be redone by an engineer. Which also broke the annotations in the drawings and all the mates in all the where used assemblies. Many Many hours of rework down the crapper.

Now if someone asks about a mirror part copy of a sheet metal with no bends then I'm going to

We model all flat plates using the the sheet metal base flange with no bends. We had a couple of potential use cases:

1. Sometimes a flat plate may add a forming tool.
2. Sometimes the design might add a hem or jog later.
3. The cutlist generated has information that we may decide to use programmatically (Bounding box, Area, Cut length, thickness, etc)
4. Cutlist information can be shown on the drawing.

Now let's talk about those mirror parts.....you don't use them?

[josh]

I don't know about the OP but we cut many sheet metal parts on a laser, so we need to export the dxf. We've always exported the dxf from the model, not drawing.

We also use CNC wood routers that use a dxf. To model those parts we use sheet metal environment and obviously those parts do not have bends in them. The ply wood doesn't perform well in the break press.

We had a bunch of parts modeled by college interns, that supposedly had SW training. There were a bunch of flat SM parts modeled just as you suggested. They all needed to be redone by an engineer. Which also broke the annotations in the drawings and all the mates in all the where used assemblies. Many Many hours of rework down the crapper.

Now if someone asks about a mirror part copy of a sheet metal with no bends then I'm going to

Sorry, I'm still not sure why you need a sheet metal flat pattern. You can pick any face of any solid model and do file->save as DXF and get a DXF of just that face. Does that not work for what you need? Not meaning in general, but specifically for that instance where you had a bunch of them.

[bnemec]

Sorry, I'm still not sure why you need a sheet metal flat pattern. You can pick any face of any solid model and do file->save as DXF and get a DXF of just that face. Does that not work for what you need? Not meaning in general, but specifically for that instance where you had a bunch of them.

We don't manually save dxfs, I wrote PDM task add-in to save out dxfs. I don't know how to handle the case of a part that needs a dxf but doesn't have a sheet metal feature.

We model all flat plates using the the sheet metal base flange with no bends. We had a couple of potential use cases:

1. Sometimes a flat plate may add a forming tool.
2. Sometimes the design might add a hem or jog later.
3. The cutlist generated has information that we may decide to use programmatically (Bounding box, Area, Cut length, thickness, etc)
4. Cutlist information can be shown on the drawing.

Now let's talk about those mirror parts.....you don't use them?

Oh yeah, use them lots. Just haven't seen a need to mirror a flat sheet metal part. If we tried,I'm sure they'd stock it as the wrong part number and inventories would always be off.

[jcapriotti]

Oh yeah, use them lots. Just haven't seen a need to mirror a flat sheet metal part. If we tried,I'm sure they'd stock it as the wrong part number and inventories would always be off.

I understand now.....yeah we don't do that either for parts, except for our automated configurable part generator. But that's because the opposite hand part has a different part number and the automation generates left and right parts at different times.....so we store DXFs for various configured sizes and options under the part number and a unique ID that maps back to the options selected.

Edit: Even for the configurable parts, the left hand part drives the flat. The mirrored Right hand part is a dumb model, it just follows whatever the left does. So if we get an order for right hand variant, the program configures the left hand always first.