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      <title>Motion Output</title>
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      <div class="title_topic3" id="xps10_pagetitle">Motion Output</div>
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      <p class="para_topic">Many machine controllers allow you to move the tool along a true circular path or along a rational B-spline curve (NURBS). Motion Output allows you to choose whether potential circular tool motions or NURBS will be included in your tool path. When you use this option, the system will convert a series of linear moves to a single circular move or convert linear/circular moves to a rational B-spline curve if enough of the GOTO points lie on the same arc.</p>
      <p class="para_topic">Circle records output to the CLSF are generated from either selected geometry or the processor. If the radius of the circle is outside the range of .0001 - 999.9999 inches or .001 - 9999.999 millimeters, then the current postprocessor will output a warning indicating that the radius is out of range. This, however, does not indicate an error since the postprocessor will automatically convert the arc into one or more linear segments.</p>
      <p class="para_topic">Milling operations allow you to choose one of the following options for Machine Control&gt;Motion Output.</p>
      <div class="title_division">Linear Only</div>
      <p class="para_division">Linear Only allows you to prevent any circular moves from being generated. When you choose this option no circle records will be generated in the tool path and CLSF. Any circular tool paths (like those that follow the inside of a fillet) will be converted to a series of linear GOTO moves.</p>
      <div class="title_division">Circular - Perp to TA</div>
      <p class="para_division">Circular - Perp to TA will have the system generate all of the possible circular tool motions that lie in planes that are normal to the tool axis.</p>
      <div class="title_division">Circular - Perp/par TA</div>
      <p class="para_division">Circular - Perp/par to TA will have the system generate all of the possible circular tool motions that lie in planes that are normal or parallel to the tool axis.</p>
      <div class="title_division">Nurbs</div>
      <p class="para_division">Nurbs causes the tool to drive along Non-Uniform Rational B-Spline curves (up to order 4 [degree 3] cubic splines) rather than along approximate line/arc segments. This option should be used for fixed axis machining, when the tool axis is aligned with the ZM axis, to perform high speed operations requiring a very smooth and accurate surface cut (particularly on contoured surfaces) and when your Fanuc, Seimens, Heidenhain, or Fidia UNC control supports Nurbs input. The finished part should not deviate from the design geometry more than the specified Intol/Outtol if the defined Fitting Control Tolerance is within the Intol/Outtol band. If a smoother tool path is desired, you can specify a tighter Fitting Control Tolerance. When using this option, the tool displays only at the beginning and end of each cutting pass regardless of the specified Display Frequency. This option is available only for fixed axis machining methods (Fixed Axis Surface Contouring, Planar Milling, Cavity Milling).</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/com_motionfi05.gif"></p>
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      <div class="title_figure">Tool Path using Nurbs for High Speed Machining</div>
      <p class="para_division">The MDF (Machine Data File) must be modified to output splines. If you use the GPM postprocessor, in MDFG select Machine Tool Motion Control&gt;Spline Interpolation Motion Parameters, and Machine Tool Motion Control&gt;Motion G Codes&gt;Normal Motion G Codes&gt;Spline Interpolation G Code.</p>
      <p class="para_division">Refer to Appendix D for the Standard B-Spline Format.</p>
      <p class="para_division">Selecting Nurbs enables you control the surface finish by determining how accurately the tool path follows the Nurbs.</p>
      <div class="title_division">Join Segments</div>
      <p class="para_division">Join Segments determines whether or not the separate curve segments join together into one curve to form a single Nurbs for each cutting pass.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/com_motionfi04.gif"></p>
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      <div class="title_figure">Join Segments</div>
      <div class="title_division">Angle Tolerance</div>
      <p class="para_division">Angle Tolerance is available when Join Segments is toggled ON. This option enables you to determine which angles formed between the joined curves forming the Nurbs will be smoothed out. Angles smaller than or equal to the specified Angle Tolerance will be smoothed. Angles greater than the specified Angle Tolerance will not be smoothed. To obtain reliable results, you should use an Angle Tolerance of 5_ or less.</p>
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         <p align="center"><img align="bottom" src="graphics/com_motionfi03.gif"></p>
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      <div class="title_figure">Angles Smaller than the Specified Angle Tolerance are Smoothed</div>
      <p class="para_division">Fitting Control Tolerance (described below) works in conjunction with Angle Tolerance. The specified Fitting Control Tolerance determines the degree of smoothness applied to the angle. The larger the Fitting Control Tolerance, the smoother the blend between the curves.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/com_motionfi02.gif"></p>
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      <div class="title_figure">Larger Fitting Control Tolerance Creates a Smoother Blend</div>
      <div class="title_division">Fitting Control Tolerance</div>
      <p class="para_division">In addition to determining the degree of smoothness applied to angles (as described above), Fitting Control Tolerance also determines how accurately the tool path follows the Nurbs. A tighter tolerance (defined by a smaller value) causes the tool path to follow the Nurbs more accurately.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/com_motionfi01.gif"></p>
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      <div class="title_figure">Loose vs. Tight Fitting Control Tolerance</div>
      <p class="para_division">The Fitting Control Tolerance may be specified by either keying in a value or by moving the slider bar.</p>
      <p class="para_division">The above two options can be used together to achieve the desired &quot;hand polished&quot; finished surface by not only smoothing the surface, but also avoiding sharp turns and jerky movements. By using a tight Fitting Control Tolerance and an Angle Tolerance of less than five degrees, you fit accurately to a smooth single Nurbs tool path.</p>
      <p class="para_division">Lathe operations allow you to choose one of the following options for Machine Control&gt; Motion Output.</p>
      <ul>
         <li>
            <p class="para_item">Linear Only</p>
         </li>
         <li>
            <p class="para_item">Circular</p>
         </li>
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      <div class="title_division">Linear Only</div>
      <p class="para_division">Linear Only works the same as it does for milling operations. See the discussion above.</p>
      <div class="title_division">Circular</div>
      <p class="para_division">Circular generates all possible circular tool motions.</p>
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