Wrapping Overview

The fourth axis is also used in a technique called wrapping. This is continuous rotary motion of the fourth axis during the machining process. What actually takes place is that the tool itself moves only along the top of the cylinder parallel to the axis of rotation that is defined using the options located in the Wrap section on the Verification tab of the Work Step Data dialog. The tool movements which would normally be assigned to the other axis are now translated into rotary motion of the cylinder. This causes the XY plane tool path to be "wrapped" around the part.  Therefore wrapping is very useful for machining shapes on a cylinder, or for engraving lettering on the side of a cylinder. The path curve is defined in the XY plane and then divided into points which are projected onto the cylinder as defined by the specified wrap radius. The verified toolpath (and NC code) consists of small incremental linear moves. Their accuracy is controlled by the Curve Step/Wrap Tolerance setting that specifies the distance between the projected points.

There are two ways to define the Wrapping - Radius:
 

1. Use the WORLD coordinate system as the MCS ID (Machining Coordinate System) of the wrapping Work Step and specify the wrap radius using the Surface parameter of the Z Data section on the Tool Info tab.
   
   Click here for graphic Example
    

   Z Surface = Wrap Radius

   

    

2. Create a new UCS coordinate system at the Z level of the wrapping radius and assign it as the MCS ID to the current Work Step. The Z distance between the centers of this UCS and the WORLD coordinate system specifies the wrap radius. Of course, using this approach you need to define the parts origin on the machine on the same location as the selected UCS.
   
   Click here for graphic Example
    

   The distance between the centers of the selected Machining (UCS ID) and the WORLD Coordinate System defines the wrapping radius.

    

    

   

    

Important

• When machining wrapped profiles it is important to know that by default the centerline of the tool is always aligned with the center of the rotation axis. As a result, the sidewalls of the machined profile are not aligned to the center of rotation.
  
  Click here for graphic Example
  
  If you need to have the profiles sidewalls aligned with the center of the rotation axis use the Radial Side Walls option.

   

  Tool centerline aligned with the center of rotation                Projected Machining Curve              Verified Toolpath	Resulting Pocket & Sidewall Shape              Projected Machining Curve            Machined Pocket Area            Undercut Area

   

   

• The machined profile can be wrapped around a conic cylinder by simply defining a Conic Angle.

• Do not activate automatic toolradius compensation (Cutter Comp, G41/42) since this is not supported when wrapping.  

See also:

Interactive Graphic - TOOL INFO Dialog

Interactive Graphic - VERIFICATION Dialog