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      <title>Remove Edge Traces</title>
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      <div class="title_topic3" id="xps10_pagetitle">Remove Edge Traces</div>
      <hr noshade="true">
      <p class="para_topic">Remove Edge Traces is a cut parameter specific to Contour Milling and Zlevel.</p>
      <p class="para_topic">Edge tracing (edge roll) is generally an undesirable condition that can occur when the Drive Path extends beyond the edge of the Part Surface. The tool rolls over the edge of the Part Surface potentially gouging the part. Remove Edge Traces allows you to control whether or not edge tracing occurs.</p>
      <p class="para_topic">The Remove Edge Traces button toggles ON (in) and OFF (out). When toggled OFF, edge tracing is allowed to occur as illustrated below.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/surfcont_cfi10.gif"></p>
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      <div class="title_figure">Remove Edge Traces - Off</div>
      <p class="para_topic">In the above figure, Edge Tracing occurs because the boundary extends beyond the Part surface. The tool attempts to reach the boundary while remaining in contact with the Part Surface, thus rolling over the edge.</p>
      <p class="para_topic">Edge Tracing will only occur under the following conditions:</p>
      <ul>
         <li>
            <p class="para_item">When the Drive Path extends beyond the edge of the Part Surface.</p>
         </li>
         <li>
            <p class="para_item">When the Tool Axis is independent of the Part Surface normal, as in Fixed Axis operations</p>
         </li>
      </ul>
      <p class="para_topic">Edge Tracing will never occur in Variable Axis operations that utilize Normal To Part, Relative To Part, 4-Axis Norm To Part, 4-Axis Rel To Part, or Dual 4-Axis Relative To Part Tool Axis definitions.</p>
      <p class="para_topic">When toggled ON, Edge Tracing is not allowed to occur as illustrated below.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/surfcont_cfi09.gif"></p>
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      <div class="title_figure">Remove Edge Traces - On</div>
      <p class="para_topic">When Edge Tracing is removed, the transitional tool movements are Non-Cutting. If for example, if a Clearance Plane is defined for Reposition Engages and Retracts as illustrated below, the tool will retract to the Clearance Plane between the Zig and Zag movements.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/surfcont_cfi08.gif"></p>
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      <div class="title_figure">Non-Cutting Transitional Movements</div>
      <p class="para_topic">The following is a discussion of special cases where Edge Traces occur. In some cases you can remove Edge Traces while in others you cannot. As a rule, Edge Traces can only be removed from edges where the system applies Engages and Retracts.</p>
      <div class="title_division">Gaps</div>
      <p class="para_division">Gaps in the Part Surface (or surfaces) that cross the cut direction cause Edge Traces to occur. As the tool cuts along the Part Surface, it encounters the gap and falls off the edge. It then traverses the gap, climbs up onto the next edge and continues cutting.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/surfcont_cfi07.gif"></p>
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      <div class="title_figure">Gap Greater Than or Equal to Tool Diameter</div>
      <p class="para_division">If the gap is less than the tool diameter as illustrated below, the tool remains in constant contact with a Part Surface. The system sees this as a continuous cutting move and does not apply Retract or Engage. In this case, Edge Traces cannot be removed.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/surfcont_figures192.gif"></p>
      </div>
      <div class="title_figure">Gap Less Than Tool Diameter</div>
      <p class="para_division">If the gap is greater than or equal to the tool diameter, then the system must apply a Retract and Engage to jump the gap. In this case, Edge Traces can be removed as illustrated below.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/surfcont_figures193.gif"></p>
      </div>
      <div class="title_figure">Gap Greater Than or Equal to Tool Diameter</div>
      <div class="title_division">Large Boundary</div>
      <p class="para_division">For Zig-Zag cut types, Edge Traces always occur when the drive path extends beyond the Part Surface a distance less than the tool radius. As the tool rolls over the edge of the Part surface, it reaches the projected boundary and stops before falling off. The tool then steps over to the next pass while still in contact with the Part Surface and begins cutting in the opposite direction. Because this is a continuous cutting move and does not require a retract and engage, Edge Traces cannot be removed. This case only applies to Zig-Zag cut types.</p>
      <p class="para_division">To remove the Edge Traces, you must first modify the boundary so that it either corresponds to the edge of the Part Surface or extends beyond the edge of the Part Surface a large enough distance to require the tool to engage and retract.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/surfcont_figures194.gif"></p>
      </div>
      <div class="title_figure">Boundary Extending Just Beyond Part Surface</div>
      <div class="title_division">Vertical Steps</div>
      <p class="para_division">Edge Traces always occur where a vertical step crosses the cut direction causing the tool to drop down to or climb onto another Part Surface. Edge Traces cannot be removed for vertical steps.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/surfcont_figures195.gif"></p>
      </div>
      <div class="title_figure">Edge Traces for Vertical Step</div>
      <div class="title_division">Compliant Edge Traces</div>
      <p class="para_division">Compliant Edge Traces occur when the tool rolls over an edge parallel to the cut direction while continuing to contact that edge as illustrated below.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/surfcont_figures196.gif"></p>
      </div>
      <div class="title_figure">Compliant Edge Traces</div>
      <p class="para_division">It is generally undesirable to remove compliant edge traces because they are needed to cut off material near the edges. Compliant Edge Traces therefore cannot be removed.</p>
      <div class="title_division">Cusp Edge</div>
      <p class="para_division">Edge Traces always occur when the cut direction crosses over a cusp edge (a peak formed by an acute angle between adjacent Part Surfaces). Edge tracing can be avoided by using Extend at Convex Corner.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/surfcont_figures197.gif"></p>
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      <div class="title_figure">Cusp Edge Trace</div>
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