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      <title>Spiral Drive Method</title>
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      <div class="title_topic4" id="xps10_pagetitle">Spiral Drive Method</div>
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      <p class="para_topic">The Spiral Drive Method enables you to define Drive Points that spiral outward from a specified center point. The drive points are created within the plane normal to the projection vector and containing the center point. The Drive Points are then projected on to the selected part surfaces along the projection vector.</p>
      <p class="para_topic">Unlike other Drive Methods which require an abrupt change in direction to Stepover to the next cutting pass, Spiral Drive Method Stepovers are a smooth, constant transition outward. Because this drive method maintains a constant cutting speed and smooth motion, it is useful for high speed machining applications.</p>
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         <p align="center"><img align="bottom" src="graphics/surfcont_sfi05.gif"></p>
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      <div class="title_figure">Spiral Drive Method</div>
      <p class="para_topic">The Center Point defines the center of the spiral and it is where the tool begins cutting. If you do not specify a center point, the system uses 0,0,0 of the Absolute Coordinate System. If the Center Point is not on the Part Surface, it follows the defined Projection Vector to the Part Surface. The direction of the spiral (clockwise vs. counterclockwise) is controlled by the Climb or Conventional cut direction.</p>
      <p class="para_topic">The following options display in the Spiral Drive Method dialog box.</p>
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               <p class="para_th">Spiral Center Point</p>
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               <p class="para_td">Displays the Point Subfunction dialog allowing you to define the center point of the spiral drive path</p>
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               <p class="para_th">Stepover</p>
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               <p class="para_td">Specifies the distances between successive cut passes</p>
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               <p class="para_th">Max Spiral Radius</p>
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               <p class="para_td">Limits the area to be machined by speci fying a Maximum Radius</p>
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               <p class="para_th">Climb Cut / Conventional Cut</p>
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               <p class="para_td">Defines the direction the Drive Path cuts in relationship to the spindle rotation</p>
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               <p class="para_th">Projection Vector</p>
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               <p class="para_td">Determines how the Drive Points proj ect to the Part Surface</p>
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               <p class="para_th">Display Drive Path</p>
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               <p class="para_td">Creates a temporary display showing the Drive Path used to generate the Tool Path</p>
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      </table><br><div class="title_division">Spiral Center Point</div>
      <p class="para_division">Select displays the Point Subfunction dialog allowing you to define the center point of the spiral drive path.</p>
      <p class="para_division">Display highlights the center point you previously specified.</p>
      <div class="title_division">Stepover</div>
      <p class="para_division">Stepover allows you to specify the distances between successive cut passes as illustrated in the following figure.</p>
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         <p align="center"><img align="bottom" src="graphics/surfcont_sfi04.gif"></p>
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      <div class="title_figure">Stepover Distance for Spiral Drive</div>
      <p class="para_division">Spiral Drive Method Stepovers are a smooth, constant transition outward and do not require an abrupt change of direction.</p>
      <p class="para_division">Constant allows you to specify a fixed distance between successive cut passes. Key in the desired distance between subsequent cut passes. This option is similar to Constant in Planar and Cavity Milling.</p>
      <p class="para_division">Tool Diameter allows you to define the Stepover in terms of a percentage of the effective tool diameter. This option is similar to Tool Diameter option in Planar Milling.</p>
      <div class="title_division">Max Spiral Radius</div>
      <p class="para_division">Maximum Spiral Radius allows you to limit the area to be machined by specifying a Maximum Radius. This constraint reduces processing time by limiting the number of drive points created. The radius is measured in the plane normal to the Projection Vector.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/surfcont_sfi02.gif"></p>
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      <div class="title_figure">Maximum Radius Within and Exceeding Part Surface</div>
      <p class="para_division">If this specified radius is contained within the Part Surfaces, the center of the tool positions to the radius before retracting. If the specified radius exceeds the Part Surfaces, the tool continues to cut until it can no longer position to the Part Surface. The tool then retracts and engages when it can once again position to the Part Surface as illustrated below.</p>
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         <p align="center"><img align="bottom" src="graphics/surfcont_sfi02.gif"></p>
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      <div class="title_figure">Retract and Engage</div>
      <div class="title_division">Climb Cut / Conventional Cut</div>
      <p class="para_division">Climb Cut and Conventional Cut allow you to define the direction the Drive Path cuts in relationship to the spindle rotation.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/surfcont_figuressc3.gif"></p>
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      <div class="title_figure">Climb Cut and Conventional Cut</div>
      <div class="title_division">Projection Vector</div>
      <p class="para_division">Projection Vector is an option common to most Drive Methods. It enables you to determine how the Drive Points project to the Part Surface.</p>
      <div class="title_division">Display Drive Path</div>
      <p class="para_division">Display Drive Path creates a temporary display showing the Drive Path used to generate the Tool Path. The Drive Path is generated and displayed in the plane normal to the Projection Vector and containing the Center Point.</p>
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