Layer oddities when exporting flat patterns with holes on dimples

[NateSP]

Greetings,

I am having some trouble with holes on layers in an exported dxf flat of a Sheetmetal part. Depending on where I place the hole on the sheet the feature is on a different layer on the exported dxf. I am operating in the traditional sheetmetal enviroment. To reproduce this:

1. Open a sheetmetal template.
2. Place a dimple feature in the sheetmetal part (I drew a circle of 1" diameter as the profile).
3. Place two holes that pass entirely through the sheet; one through the dimple and the other through the "base" of the sheet. I used the hole feature of diameter 0.25".
4. Make sure an up-to-date flat pattern exists for the part and the "As formed feature" selection is made in the Flat Pattern Treatments dialog.
5. Perform a "Save as Flat" on the part and choose .dxf as the exported format (I export as dxf version 14).

Open the dxf and note that the hole in the base is on the INTERIOR_LOOPS layer while the hole in the dimple is on the UP_FEATURES layer. Does anyone know a way to have both holes on the INTERIOR_LOOPS layer (without manually opening the dxf and reassigning the layer of the dimple hole?)

Thanks!

Nate

 

[NateSP]

UPDATE: After searching through the GTAC solutions database, I found a report of this issue. Apparently, it's always worked this way. This leaves one to wonder how CAM systems automatically process the holes when they are on the same layer as a formed feature...

 

[fredericmenage]

Typically, the dxf output is for 2D CAM treatment. The holes which are on your dimples would be drilled after the part is formed and this drilling operation will be performed by a different machine than the punching machine used to produce the part with the dimples. Unless the holes are punched at the same time as the dimples; in that case, they ought to be on a xx_FEATURES layer.

 

[NateSP]

Frederic,

You are correct that the hole process is separate from the forming process. This may also help explain why if you save the dxf with the "feature loops" option selected in flat pattern treatments, the hole geometry disappears from the flat entirely.

However, in our process the parts first get cut on a laser (which I have set the CAM software to ignore the xx_FEATURES layers.) Then the parts are transferred to a manual ironworker or a turret punch for forming. The punch uses another CAM software without any appreciable layer recognition.

I would like to be able to use the dxf as-exported for both machines, but there are other mutually exclusive requirements that I believe I will have to talk to the CAM software developers about.

Thanks!