To export the flat, primary face of your part to a DXF from AutoCAD, right click on the face you’d like to export & halfway down you will see the “export face as…” option. You can then save the 2D face as a DXF.
In your export options, please be sure to select Export splines as splines. If the option is set for polylines, arcs and circles will export as segmented shapes instead of smooth curves.
After exporting, you can upload your file to our website and check the part preview to verify that the overall dimensions are correct. All files need to be at 1:1 scaling in either millimeters or inch units, with no intersecting or duplicate paths. We have more information about our design requirements here: SendCutSend Design Guidelines
For general preflight, the free, open source program QCAD is great for checking 2D files. If you end up liking it, we have guidance on reviewing designs in QCAD here: How To Preflight Your Designs Using QCAD