Engineering companies report significant increases in productivity when they are able to send 2D CAD drawing files to their own cutting equipment (film cutters, routers etc.) or to firms offering laser cutting services. These provide some suggestions as to the techniques that should be used to prepare CAD drawings for this purpose.

Software used by 'in house' cutting equipment

It is important to realize that it is unusual for AutoCAD or IntelliCAD to be used directly to drive cutting equipment. Many routers, laser (and flame cutters) have their own special software so your drawing needs to be converted by the software used by the particular piece of equipment. Their software will use an import facility to bring your design work into their environment. It follows then that you want to make the conversion from your CAD drawing as seamless as possible.

We recommend that you send your information to the software which controls the cutter both as a .DWG file in AutoCAD 12 format together with a DXF file. Some cutting software takes AutoCAD's DWG format, while others require DXF format.

DXF files are created using a the DXFOUT command in AutoCAD or IntelliCAD (and using other commands in  CAD software such as MicroStation and DesignCAD [note that we do not sell or support DesignCAD). Keep the number of decimal points in the DXF file to a reasonable number - 6 decimal places is the default, I use a single decimal point.

Software used by laser cutting firms

Again, many laser (and flame cutters) have their own special software so your drawing needs to be converted by the software used by laser cut firm. Their software will use an import facility to bring your design work into their environment. It follows then that you want to make the conversion as seamless as possible (see above).

The DXFOUT command

We recommend that you send your information as a .DWG file in AutoCAD 12 format together with a DXF file. DXF files are created using a the DXFOUT command in AutoCAD or IntelliCAD. Try and keep the number of decimal points in the DXF file to a reasonable number - 6 decimal places is the default, we think that this is excessive and use a single decimal point for accuracy.

What entities should be used when constructing the drawing?

Build the drawing using the simplest (an most primitive) of drawing entities. A drawing built of line segments and arcs will work well. A drawing containing polylines will be difficult to work with. For example, if you want a fold line, use a series of line segments to indicate this. Put all 'real' entities on a single layer. Create an 'annotation' layer and use it to include text notes advising the operator of any special features in your drawing. Put a small cross on this layer at 0,0 and make sure that the drawing is in the positive X and Y zone. Include at least two dimensions (horizontal and vertical) on the annotation layer so that the operator can make sure that scale is correct. The figure below shows one of our drawings prepared to the above specification. we have not yet included the horizontal dimension.

A typical CAD drawing ready to be passed to cutter software.

Nesting your drawing data

If you want to cut multiple shapes from one sheet of material, to minimize your waste, we recommend (in the absence of special nesting software), that you learn to use the BLOCK command in IntelliCAD or AutoCAD. This will enable you to move each piece around as a single entity over the sheet of material and nest it efficiently.