2012-03-18 18:35:45 (CET)

Program Page, DXF and HPGL import





USBCNC uses a build in CAD/CAM library for these advanced import functions. You can load a file and then perform one of these operations:

   Loads a DXF or HPGL file
   Select engraving, this is milling over the lines from the drawing.
   Select profiling, this is for milling out objects and taking the tool diameter into account.
   This is for pocketing, to mill out the complete object.
   Drilling, draw points in the DXF file to use this.



After loading a DXF file, all layers will be visible. You can unselect layers at the right side, such that you see only the part that you want to use. You also can change the origin of the drawing by pressing the appropriate button under the layer selection list box. The positions of the buttons give the positions of the origin. So e.g. when you press the upper right button, then the most upper right position of the drawing will become x=0, y=0 when milling.




The DXF import supports:

  • Lines
  • Arcs
  • Circles Poly lines with arcs
  • Points for drilling


 The workflow of using these features is:


1) Load drawing

2) Select the correct layers

3) Apply origin offset if wanted

4) Set correct parameters

5) Calculate tool path

6) Save tool path and optionally immediately load it for milling.




Parameters involved:


When moving from one region to another, the machine goes to this height.


Z value where the tool touches the material to be machined.


Z value specifying the milling depth lowest Z value. Final Z must be lower than Start Z.

Z Increment

This specifies the step size when machining in passes.

Feed rate

Milling feed (F) in mm/min.

Plunge rate

Feed (F) that the Z moves down into the material also mm/min.

Spindle speed

S value for spindle.


Spindle direction (M3/M4).

Tool number

This is only used for the M6 tool change command.

Tool Diameter

Diameter of the tool for the offset and pocketing calculations.


Outside/inside/clockwise/counterclockwise operation.

Finish allowance

Material that is left for the finishing pass when pocketing. This finishing pass is at full depth for getting a clean edge.


Step size

Step oversize for pocketing, this value should be lower than the tool diameter.

Laser mode

For profiling, when switched on, the tool will be switched off when moving from one region to another.

Make bridges

Leave small pieces of material, that prevent you object from falling out (and get damaged) when profiling.

Bridge distance

Approx distance, the exact distance is calculated such that all bridges have equal distance.


Bridge FinalZ

Lowest Z value for bridge, this value should be between startZ and final Z.

Bridge Width

 The width of a bridge.



  When the parameters are set, press calculate tool path, it will be visualized on the screen.


Here an example of profiling with bridges:




Note: The offset and pocket calculation might not always work, this is usually because of small errors in the drawing like lines over each other or not connecting lines. Experimenting with the Calculation Accuracy might help. Also check/correction of your drawing may help.

The engraving function is robust and will always work.