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      <title>Multiple Passes</title>
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      <div class="title_topic3" id="xps10_pagetitle">Multiple Passes</div>
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      <p class="para_topic">Contour Milling lets you define multiple passes.</p>
      <p class="para_topic">Multi-Depth Cut enables you to remove a volume of material by gradually machining toward the Part Geometry one cut level at a time. Multi-depth cuts can only be generated for operations that utilize Part Geometry (if no Part geometry is selected, only one tool path will be generated on the Drive geometry). The Tool Path in each cut level is calculated separately as an offset of the Contact Points normal to the Part Geometry and is not simply a translated copy of the first Tool Path. Because tool path contours can change shape as they diverge further away from the Part Geometry, the Tool Path in each cut level must be calculated independently. Multi-Depth Cut ignores the custom stocks (including Part Thickness) on Part Surfaces.</p>
      <p class="para_topic">The Tool Path's tolerance of the final (finish) cut level applies the user-defined Intol and Outol values specified in the Operation Parameter Dialog Box. The software calculates the Intol and Outol for each of the previous (rough) levels by multiplying the total distance from the cut level to the part surface by ten percent. This allows the Intol and Outol for rough cuts to increase in proportion to the total distance from the cut level to the Part Geometry and eliminates needless processing time.</p>
      <p class="para_topic">The traversal between levels can be minimized if the Engage option is set to Manual in Non-Cutting Moves. After finishing each level, the tool retracts to the previous level plus the Outol distance for that level, before traversing and engaging to the next level.</p>
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                  <p class="para_note_body"> NOTE: If the calculated Intol or Outol is greater than half the increment (distance between cut levels), then the software uses half the increment as the tolerance. If the calculated Intol or Outol is less than the user-specified Intol or Outol, then the soortware applies the user-specified values. These restrictions prevent the soortware from using excessively large or excessively small tolerance values.</p>
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      <p class="para_topic">In the following illustration, the user-specified Intol is .00200 and the user-specified Outol is .00100. These values are only used on the finishing pass. The Intol and Outol increase with the total distance of the cut level from the part surface.</p>
      <p align="center"><img align="bottom" src="graphics/cutlevel.gif"></p>
      <p class="para_topic">Each Tool Path is calculated independently. Intol and Outol's for rough levels are calculated in proportion to the distances from the cut level to the part surface.</p>
      <p class="para_topic">Multi-Depth Cut is a toggle button that activates or deactivates the section of the Cutting Parameters dialog box illustrated below. It works in conjunction with the Part Stock Offset described above. Multi-Depth Stock can only be used if the Part Stock Offset is greater than or equal to zero.</p>
      <div class="title_division">Step Method</div>
      <p class="para_division">The number of cut levels are specified in terms of Incremental Stock or Number of Passes. &nbsp;Incremental Stock allows you to define distance between cut levels. &nbsp;The default Increment value is the Part Stock Offset value. &nbsp;The default Passes value is One. &nbsp;If you specify a number of passes, the soortware automatically calculates the increment. &nbsp;If you specify an Increment, the soortware automatically calculates the number of passes. &nbsp;If the Increment you specify does not divide evenly into the amount of material to be removed (Part Stock offset), then the number of passes the soortware calculates rounds up to the next higher integer. &nbsp;The last Increment will be the remainder as illustrated below.</p>
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                  <p class="para_note_body"> NOTE: If the Part Stock Offset is zero, then the Increment value must be zero and only one pass will be generated. If the Part Stock Offset is zero and the Number Of Passes option is selected, any positive integer can be used and that number of passes will be generated. This is useful in smoothing the parts after finishing cuts.</p>
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      <p align="center"><img align="bottom" src="graphics/ptstck_offset.gif"></p>
      <p class="para_division">In the illustration above, the amount of material to be removed (Part Stock Offset) is .7500. An increment of .3000 has been specified. The soortware calculates three passes. The first pass cuts at a depth of .3000, the second pass cuts an additional depth of .3000, and the third pass cuts the remaining depth of .1500. The third pass is a finishing cut because the Part Stock value is specified as 0.0000.</p>
      <p class="para_division">You must also specify the type of Non-Cutting move to occur between cut levels by defining the appropriate Departure, Transfer, and Approach.</p>
      <div class="title_division">Example of Multi-Depth Cut</div>
      <p class="para_division">Here is an example of how Multi-Depth Cut works:</p>
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            <p class="para_item">Choose Cutting in the Operation Parameter dialog box.</p>
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         <li>
            <p class="para_item">Select the Multiple Passes tab.</p>
         </li>
         <li>
            <p class="para_item">Key in a value for the Part Stock Offset. For this example, key in .7500.</p>
         </li>
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            <p class="para_item">Toggle the Multi-Depth Cut button to ON.</p>
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         <li>
            <p class="para_item">Specify Passes for the Step Method.</p>
         </li>
         <li>
            <p class="para_item">Key in a value for Number of Passes. For this example, key in 2. The soortware calculates an increment of 0.3750.</p>
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      <p align="center"><img align="bottom" src="graphics/passes.gif"></p>
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                  <p class="para_note_body"> NOTE: Remember to specify the type of Non-Cutting move to occur between passes.</p>
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