The details for each type of conversion are a little different because the initial file types contain different types of information. In the following sections we provide details on the specific issues related to each type of conversion process.
Conversion from .DXF Format:
Most typically, you will find yourself using the conversion from .DXF format because this is the standard 'vector' drawing format. The universal nature of the .DXF file format makes it possible for ShopBot to work with virtually every type of CAD and vector drawing format (2D or 3D). In a 2D drawing, you will be able to use different line colors to define the plunge depth for the Z Axis.
There are a couple limitations to using DXF files from a CAD program that we have already noted in the CAD section above. Briefly, the .DXF format is not intrinsically oriented to cutting or machining a part. While it will faithfully translate the exact location of all lines, your CAD software is unlikely to worry about putting the cuts in the order that you want to cut them when it generates the .DXF file. Typically, the lines are saved in the order that you draw them. Thus you will need to plan the drawing (or do a retracing of it) so that the segments are entered in the order that you want to cut them.
A second limitation of .DXF is that it knows nothing about your cutter and does not take the diameter of the bit into consideration in generating the file. You will need to plan the 'cutter compensation' into the drawing that you do – the drawing represents the center of the path of the cutter.
You will also find that some CAD objects or entities need to be 'exploded' or 'vectorized' before they can be converted to a Part File. True-Type fonts are one example. These fonts need to be exploded to their line segment components so that they can be used to generate a tool path. Curves (splines) are another type of entity that will need to be exploded. Each CAD system has a different technique for doing these explosions, but in most cases it is just a matter of selecting the entity and clicking on one function.
Because of the limitations, in most cases it is preferable to bring the .DXF file into VCarve Pro ShopBot Edition* design software where CAM functions can be used to get the tool paths just the way you want them.
But for some situations and with these above limitations in mind, the .DXF conversion process can be productive and straightforward method to get cutting. You can deal with its limitations by carefully planning the drawing and by keeping in mind that you are creating the cutter path ... not just the shape of the part. Typically, you will want to offset the cutting path to the outside of the part you want cut by one half the diameter of the cutter. For a simple drawing, this is not too difficult, and can usually be accomplished with the function for creating a parallel line that is available in most CAD programs. For example, you would draw the part you wanted to cut out, then using the parallel function you would draw a line around it that is parallel and spaced one half the diameter of the cutter. It is this second line that would be saved to the .DXF file and loaded into ShopBot. Some CAD
programs offer macros or some form of customizability that will make such cutter paths easier to draw.
Making Use of .DXF. Use your CAD or vector drawing program (such as Corel Draw) to draw
the tool path you want your ShopBot to follow. If you want to have different Z levels of plunge/cut, enter these cuts in a different color in your CAD program. The converter will prompt you for a depth for each color during the conversion process. The converter directly deals with lines, polylines, circles and arcs. Curves or splines need to be changed to a vector/segmented form in the CAD program before they are saved. Different programs call this segmenting process by different names ... typically something like 'explode' or 'convert to vector.' True-Type Fonts also need to be saved in their segmented form. After
segmenting, save this drawing as a '.DXF' file (in some CAD programs you will use 'Export' rather than save). Then start the ShopBot software and use the [FC] Command to convert the .DXF file to a Part File. It is usually most convenient if you save the file into your Part File Directory -- this way, the drawing and the converted file will be kept together.
During the Conversion. At conversion time, you will be asked if the file is 2D or 3D because
the software wants to know how to handle the Z axis. For a 3D file, the Z axis motion is obtained from the .DXF file. If you designate 2D, then the Z Axis plunges are determined by line color. So for a 2D file, your ShopBot needs to know how deep the cut is to be. When the .DXF file is being read in, you will be prompted for a depth for every color of line (or layer)
that you used in your drawing. These depths are translated into Z axis motions and put into the ShopBot .SBP file as it is being generated.
* ”VCarve Pro ShopBot Edition” was previous called “PartWorks”
If you are doing frequent DXF conversions from the same drawing program, you can speed up the conversion process by creating a set of predefined responses to the color-depth question. You do this by editing the UX_DXF.INI file. The path to this file is C:\Program Files\ShopBot\ShopBot 3\Bin\ UX_DXF.INI. You can change the values to the existing colors or you can add additional colors and depths.
TIP: Each CAD program uses different numbers for colors. You can figure out the color numbering for your CAD program by drawing some entities in different colors, then running the converter to see what color numbers are found and which is associated with which entity. The basic color numbering for AutoCAD is:
0-Black 5-Blue 1-Red 6-Magenta 2-Yellow 7-White 3-Green 8-Grey 4-Cyan 9-Light Grey
The numbering for Corel Draw (default Version 8) is: 0-Black 22-Blue
15-Red 16-Magenta 14-Yellow 10-White 13-Green 12-Cyan