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      <div class="title_topic3" id="xps10_pagetitle">Punch tips and techniques</div>
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               <p class="para_td"> <a class="links" href="javascript:void(0)" onclick="top.openFile('sheetmetaldes/smfea_punch.html');return(false);">Punch Overview</a></p>
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               <p class="para_td"> <a class="links" href="javascript:void(0)" onclick="top.openFile('sheetmetaldes/smfea_punch_dialog.html');return(false);">Options</a></p>
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               <p class="para_td"> <a class="links" href="javascript:void(0)" onclick="top.openFile('sheetmetaldes/build_multi_parts.html');return(false);">Related Topics</a></p>
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      </table><br><div class="title_division">Distorting the punch</div>
      <p class="para_division">When you place a punch on the bend face of a flange or inset flange, the punch will be distorted when you form the flange. The punch will also distort when you place it on a general flange, bridge, or bend and form the underlying feature. This distortion is only a representation of what the metal will do when formed. There are some limitations to this capability. For example, tapers are not applied to the punch when it is in its distorted shape.</p>
      <p class="para_division">The best setting for the <b class="uiTerm">Projection Vector</b> is <b class="uiTerm">Along a Vector</b>. This will improve the response of the punch during an <b class="uiTerm">Update</b>.
      </p>
      <p class="para_division">The outline of the <b class="uiTerm">Placement Curves</b> can be open as long as the ends of the outline intersect with the periphery of the target body.
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      <p class="para_division">A sketch may be used to define the outline of a punch, but the following guideline must be followed. The placement face of the sketch cannot be the bend face of the flange, inset flange, or bend when the features are unformed, because when the feature forms this bend face becomes a cylindrical face. You may use the <b class="uiTerm">Web Face</b>, because this face is always planar face.
      </p>
      <p class="para_division">If the sketch is not constrained positionally, the Sketch might fail when the <b class="uiTerm">Self&ndash;Forming Feature</b> is <b class="uiTerm">Formed /Unformed</b>. You should not use a <b class="uiTerm">Bend Edge</b> to create a <b class="uiTerm">Positional Constraint</b> as this constraint might fail when the <b class="uiTerm">Self&ndash;Forming</b> feature is <b class="uiTerm">Formed/Unformed</b>.
      </p>
      <p class="para_division">The outline curves must project to the placement face along the user&ndash;defined <b class="uiTerm">Projection Vector</b> for the punch to construct.
      </p>
      <p class="para_division">Blends and tapers on the punch add complexity to the feature, which will make your updates take longer. If this becomes an issue make the blends and tapers as separate features and not part of the <b class="uiTerm">Punch</b> feature.
      </p>
      <p class="para_division">The punch will automatically suppress any tapers that you create with the Punch when the punch changes from its creation state to its non&ndash;creation state.</p>
      <p class="para_division">The punch will automatically create a <b class="uiTerm">Tool Center</b> point that you can add to the flat pattern if needed. If you do not want this point created deselect this option in the <b class="uiTerm">Options</b> dialog box.
      </p>
      <p class="para_division">When creating certain punches that cross two edges of the part the punch might fail. &nbsp;The figure below is an example of a punch crossing two edges that can be constructed with the <b class="uiTerm">Punch</b> feature and the curves shown.
      </p>
      <p align="center"><img align="bottom" src="graphics/image6.gif"></p>
      <p class="para_division">The punch will not create when the outline curves cross two edges that would cause the punch to split the body. The figure below is an example of such a punch. In cases such as these, it is suggested that the <b class="uiTerm">Solid Punch</b> be used.
      </p>
      <p align="center"><img align="bottom" src="graphics/punch1.gif"></p>
      <div class="title_division">Creating a lance punch</div>
      <p class="para_division">The following rules apply to the <b class="uiTerm">Lancing Curves</b> selection step:
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            <p class="para_item">You can only select the <b class="uiTerm">Lance</b> curves from the selected <b class="uiTerm">Placement Outline</b> curves.
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         <li>
            <p class="para_item">You cannot select <b class="uiTerm">All</b> of the<b class="uiTerm"> Placement Outline</b> curves as <b class="uiTerm">Lancing Curves</b>.
            </p>
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         <li>
            <p class="para_item">If all the <b class="uiTerm">Placement Outline</b> curves are G1 continuous, you &nbsp;cannot select <b class="uiTerm">Lancing Curves</b>.
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         <li>
            <p class="para_item">All curves that are G1 continuous to the <b class="uiTerm">Lancing Curve</b> will be selected automatically.
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      <div class="title_division">Punch error messages</div><pre class="indent">Unable to project the outline curves onto the placement faces.</pre><p class="para_division">The <b class="uiTerm">Punch Direction Vector</b> must point into the body from the view of the placement curves. In other words, you must be able to project the placement curves along the <b class="uiTerm">Punch Direction Vector</b> and hit the target solid.
      </p><pre class="indent">Unable to join the outline curves.</pre><p class="para_division">The placement curves must form one, continuous curve from end to end. It can be a closed or open curve.</p><pre class="indent">Hollow failure. </pre><p class="para_division">Increasing the value of any existing fillet radii in the profile or changing the taper angle may solve this problem.</p><pre class="indent">Boolean failure. </pre><p class="para_division">Increasing the punch depth may solve this problem. Make sure punch depth is greater than material thickness by at least the modeling tolerance.</p><pre class="indent">Placement blend failure. </pre><p class="para_division">Changing the die radius and/or taper angle may solve this problem. Another possibility is that the profile is too close to an edge or encompasses an existing punch.</p><pre class="indent">Punch blend failure. </pre><p class="para_division">Changing the punch radius and/or taper angle may solve this problem.</p><pre class="indent">Cannot apply offsets.</pre><p class="para_division">Flipping the punch side vector may solve this problem. &nbsp;If there are any G1 continuous faces to the selected Placement face, then the punch side vector must point towards the centroid.</p>
      <p class="para_division">For more information on <b class="uiTerm">Punch</b> usage see Appendix A:  <a class="links" href="javascript:void(0)" onclick="top.openFile('sheetmetaldes/appendix_punch_across.html');return(false);">Punch Across Edges</a>.
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