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      <title>Specify Blank Overhang</title>
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      <div class="title_topic3" id="xps10_pagetitle">Specify Blank Overhang</div>
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      <p class="para_topic">The Blank Overhang determines the maximum amount the tool will be allowed to extend beyond the face (see below). &nbsp;You enter the Blank Overhang as a percentage of the tool diameter. &nbsp;Setting the Blank Overhang so that it is smaller than the tool diameter (less than 100.0) will yield cut regions which machine less air and take less time to cut.</p>
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            <td valign="top" align="left"><img align="left" src="../graphics/note.gif" alt="Note" title="Note"></td>
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                  <p class="para_note_body">If the overhang value is set to a value less than 100% of the tool diameter, the tool may not be able to completely machine some area around the convex portions of the face for Zig or Zig-Zag cut patterns.</p>
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      <p align="center"><img align="bottom" src="graphics/blank_overhng.gif"></p>
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               <p class="para_td">Figure 1 Blank Overhang Side View</p>
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               <p class="para_td">Number</p>
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               <p class="para_td">Explanation</p>
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               <p class="para_td">1</p>
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               <p class="para_td">Cut Direction</p>
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               <p class="para_td">2</p>
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               <p class="para_td">Cast Face</p>
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               <p class="para_td">3</p>
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               <p class="para_td">Finish Face</p>
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               <p class="para_td">4</p>
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               <p class="para_td">Blank Overhang</p>
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               <p class="para_td">5</p>
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               <p class="para_td">Blank Stock</p>
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      </table><br><p class="para_topic">Figure 2, below, shows a Zig Zag cut pattern with a blank overhang of 50%. &nbsp;The tool engage is indicated by the number 1. &nbsp;Note that the tool remains in contact with the face after the last pass (number 2).</p>
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         <p align="center"><img align="bottom" src="graphics/zigzag_bo_50_no_runoff.gif"></p>
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      <div class="title_figure">Figure 2 Zig Zag Cut Type Blank Overhang = 50</div>
      <p class="para_topic">Figure 3, below, shows a Zig Zag cut pattern with a blank overhang of 100%. &nbsp;The tool engage is indicated by the number 1. &nbsp;Note that the tool remains in contact with the face after the last pass (number 2).</p>
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         <p align="center"><img align="bottom" src="graphics/zigzag_bo_100_no_runoff.gif"></p>
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      <div class="title_figure">Figure 3 Zig Zag Cut Type Blank Overhang = 100</div>
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            <td valign="top" align="left"><img align="left" src="../graphics/note.gif" alt="Note" title="Note"></td>
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                  <p class="para_note_body">Note that  <a class="links" href="javascript:void(0)" onclick="top.openFile('mfgmilling/pmill_fm_tl_run_z_zz.html');return(false);">Tool Run-Off</a> is not the same as Blank Overhang. &nbsp;With Blank Overhang, the blank is extended all around the part. &nbsp;&nbsp;Tool Run-Off occurs only when the tool completes a cutting pass.
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      <div class="title_division">Using Blank Overhang</div>
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         <li>
            <p class="para_item">In the Face Milling operation dialog, press the Cutting button. &nbsp;This will bring up the Cut Parameters dialog.</p>
         </li>
         <li>
            <p class="para_item">In the Cut Parameters dialog, specify the Blank Overhang parameters. </p>
         </li>
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      <div class="title_division">Blank Overhang Percent</div>
      <p class="para_division">Blank Overhang Percent is a cut parameter specific to Face Milling.</p>
      <p class="para_division">Use Blank Overhang Percentage when you want to merge faces to be machined. &nbsp;When there are multiple faces, which lie at the same level, Face Milling automatically attempts to merge the faces into a single region prior to machining. However, if you set the Region Sequencing option to Standard, faces are not merged to preserve the order in which you selected the faces.</p>
      <p class="para_division">The criteria used to merge the faces is dependent upon the Blank Overhang Percentage that you use:</p>
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         <li>
            <p class="para_item">If the Blank Overhang Percentage is greater than or equal to 50%, Face Milling automatically merges any faces that are within a distance of 2 * (Tool Diameter + Horizontal Clearance ).</p>
         </li>
         <li>
            <p class="para_item">If the Blank Overhang Percentage is less than 50%, Face Milling automatically merges any faces that are within a distance of 2 * Blank Overhang. This is done to ensure that once faces are merged, they are likely to remain merged after the Blank Overhang is applied.</p>
         </li>
         <li>
            <p class="para_item">It also should be noted that even when some faces get merged based on the above criteria, if there is wall geometry on the part that is not as thick as the merging criteria, the merged region may still be separated again in order to prevent the tool from gouging the wall.</p>
         </li>
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      <div class="title_division">Adjusting Blank Overhang Percent for Efficient Machining</div>
      <p class="para_division">Notice in the following figure that this part has two faces with different widths--one skinny, and one wide. &nbsp;</p>
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         <p align="center"><img align="bottom" src="graphics/fm_blk_ovrhng.gif"></p>
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      <div class="title_figure">Part To Be Face Milled</div>
      <p class="para_division">The system alerts you that the Blank Overhang Percent must be less than or equal to 100. &nbsp;However, be aware that your results vary greatly from a Blank Overhang Percent of less than 100, to that of exactly 100. &nbsp;</p>
      <p class="para_division">The following figure illustrates the result of a Blank Overhang Percent of 50.</p>
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         <p align="center"><img align="bottom" src="graphics/blnk_ovrhng_50.gif"></p>
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      <div class="title_figure">A Blank Overhang of 50 Results in Additional Passes</div>
      <p class="para_division">In the figure above, although the thin face on the left can be machined in one pass, a Blank Overhang Percent of 50 results in two passes. &nbsp;This is not efficient. &nbsp;&nbsp;Compare this to the figure below. &nbsp;This time, the Blank Overhang Percent is set to 100. &nbsp;</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/blk_ovrhng_100.gif"></p>
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      <div class="title_figure">A Blank Overhang Percent of 100 Is More Efficient</div>
      <p class="para_division">By switching the Blank Overhang Percent from 50 to 100, you eliminate one of the machining passes. &nbsp;This is more efficient because the thin face can be machined in just one pass.</p>
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