best practice, output to 2D machining ops (waterjet, laser, plasma...)

[potrero]

Could anyone please give some pointers (preferably walk thru the workflow) for a "best practice" method to create files suitable for 2D manufacturing processes, such as water jet, laser, or plasma cutters?

For instance, if one starts with a flat part with some holes in it, what would you do?

What's the best way to output DXF's of 2D parts?

Often times, shops require input in inches, not mm, ... what's the best way to prepare metric parts for inch 2D output?

 

[hudson888]

What we do is to carry a view of the flat pattern on the drawing. If it is a folded sheet metal part then we have the bend lines shown there as well, and the view becomes an important to the design for that information. We don't generally dimension much else on drawings that can be made from a flat pattern, but a couple of overall sizes are useful for material ordering.

We draw in millimetres, and the drawing states as much. It carries a note stating that all undimensioned elements derive from CAD and that a DXF file may be provided for the flat pattern shown.

For folded flat patterns I use the Sheet Metal Forming Flattening module to output curves on a layer designated for flat patterns to the geometry is easily isolated. If the part is just a flat body then I still prefer to be sending curves to the DXF file so I perform a projection based on the flat face again on the designated layer.

In giving the DXF we run a macro to reposition a copy of the flat pattern onto an empty layer where it is oriented conveniently on the XY plane with 0,0 at the bottom left. The macro also outputs the DXF file before deleting the copy of the flat pattern. By working with layers by convention the macro can at any point select all of type curves and grab the required geometry. I've written in user pauses where one needs to interact with it.

Lastly I don't provide DXF in non native units I send the supplier a PDF of the drawing with the flat pattern and require them to meet out requirements. They can and do find ways to manipulate anything that they require of the data for themselves. Many times they need to add lead in and out cutting moves etc so they have some tools to work with the geometry and provided the requirement is clear we have had no problems whatsoever to date.

Cheers

Hudson