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      <title>When to use unbend/rebend</title>
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      <div class="title_topic2" id="xps10_pagetitle">When to use unbend/rebend</div>
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      <p class="para_topic">You will want to use <b class="uiTerm">Unbend/Rebend</b> to get better results from Instancing. In NX, Sheet Metal features such as <b class="uiTerm">Hole</b>, <b class="uiTerm">Slot</b>, and <b class="uiTerm">Cutout</b> support instancing, with some limitations. When you create an Instance of a <b class="uiTerm">Hole</b>, <b class="uiTerm">Slot</b>, or <b class="uiTerm">Cutout</b> on a <b class="uiTerm">Flange</b>, the Instance direction can only be parallel to the bend tangent line. See the figure below.
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      <p align="center"><img align="bottom" src="graphics/flange3_new.gif"></p>
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            <p class="para_item">The figure above shows a 3 by 3 Instance of a Hole. If you wish to make this using <b class="uiTerm">Self&ndash;Forming Features</b>, you will have to create 3 holes and 3 instances. The reason is that when the flange forms, the web of the flange is in the ZC&ndash;YC plane. The Instance plan of creation is the XC&ndash;YC plane. When the flange forms the Instance members in the XC direction cannot project onto the formed flange and will fail. &nbsp;If you create three separate holes along the XC direction and three separate Instances along the YC direction, the flange can form and the Instance will not fail.
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            <p class="para_item">A better technique for creating the above model would be to use the <b class="uiTerm">Unbend/Rebend</b> feature. The Instance will have a time stamp before the <b class="uiTerm">Rebend</b> and thus will not fail when the <b class="uiTerm">Rebend</b> is applied. The steps to create this model are:
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                  <p class="para_item">Got to <b class="uiTerm">Preferences&rarr;Forming Method&rarr;Use Forming Operations</b>.
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                  <p class="para_item">Construct the block and flange. (Remember: The flange will be a <b class="uiTerm">Non&ndash;Forming Flange</b>.)
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                  <p class="para_item">Create an <b class="uiTerm">Unbend</b>. (This will place the model in an <b class="uiTerm">Unformed</b> state.)
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                  <p class="para_item">Create a modeling of <b class="uiTerm">Sheet Metal Hole</b> and a 3 x 3 instance of the Modeling or <b class="uiTerm">Sheet Metal Hole</b>.
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                  <p class="para_item">Create a <b class="uiTerm">Rebend</b> feature.&nbsp;(Remember: A <b class="uiTerm">Rebend</b> will only apply to an <b class="uiTerm">Unbend</b>.)
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      <p class="para_topic">The model should look like the figure above.</p>
      <p class="para_topic">An additional benefit to using the <b class="uiTerm">Unbend/Rebend</b> is that the holes and you can edit instances in their <b class="uiTerm">Non&ndash;As&ndash;Created</b> state.
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      <p class="para_topic">When the <b class="uiTerm">Unbend/Rebends</b> are created subdivides might be created. These subdivides are created where there is not a face division between the stationary face, the block, and the cylindrical face, and the bend face. There will also be a division between the web face and bend face. <b class="uiTerm">Unbend/Rebend</b> will create a sheet body and curves to create these subdivides. This geometry is hidden and is placed on the work layer.
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      <p class="para_topic">See  <a class="links" href="javascript:void(0)" onclick="top.openFile('sheetmetaldes/unbend_tips.html');return(false);">Unbend/Rebend: Tips and techniques</a> for more recommendations for using <b class="uiTerm">Unbend/Rebend</b>.
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