<!DOCTYPE html
  PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<!--
Copyright (c) 2006 UGS Corp.

All Rights Reserved.

This software and related documentation are proprietary to UGS Corp.
-->
<html>
   <head>
      <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
      <title>Cavity Milling Islands &mdash; cut depth options</title>
      <script language="javaScript">
        abridged="false";
        displayConditions=new Array();
      </script>
      <link type="text/css" href="../css/main_styles.css" rel="stylesheet">
   </head>
   <body class="bodydocs" onload="top.pageLoader()" bgcolor="#FFFFFF">
      <div class="title_topic2" id="xps10_pagetitle">Cavity Milling Islands &mdash; cut depth options</div>
      <hr noshade="true">
      <p class="para_topic">NX regards areas enclosed by Part Boundaries with material retained inside as islands. This means that some areas not conventionally thought of as islands are regarded as islands by NX. It is important to keep this definition in mind when using Cut Depth options such as Floor &amp; Island Tops, Levels at Island Tops, and Top Off Islands to understand the behavior.</p>
      <p class="para_topic">The following figure illustrates how all areas defined by Part Boundaries with material retained inside are regarded as islands by NX.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/pcmill_islands_bdry.gif"></p>
      </div>
      <div class="title_figure">Islands Defined by Part Boundaries, Material Retained Inside</div>
      <p class="para_topic">In the above figure, only island A fits the conventional definition of an island. NX, however, regards the bottom of pocket B and all of the steps (such as C and D) as islands because these areas are defined by Part Boundaries with material retained inside.</p>
      <p class="para_topic">Pockets are defined by two boundaries: one with material retained inside and the other with material retained outside as illustrated below. The upper boundary is defined with material retained outside, allowing the tool to drop down inside the pocket. The lower boundary is defined with material retained inside, effectively defining the floor of the pocket.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/pcmill_islands_pt_bdry.gif"></p>
      </div>
      <div class="title_figure">Islands Defined by Part Boundaries</div>
      <p class="para_topic">If Cut Depths are specified as Floor &amp; Island Tops, for example, tool paths are created within each area NX regards as an island as well as at the floor as illustrated below.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/pcmill_cut_depths.gif"></p>
      </div>
      <div class="title_figure">Cut Depths Defined at Floor and Island Tops</div>
      <p class="para_topic">In Cavity Milling, Part , Blank and Check, geometry are defined by boundaries, faces, curves, and bodies. When you choose curves, the system creates a face that extends from that curve to the lowest cut level along the taper angle. These faces are confined to the edges that define them and cannot be projected beyond those edges. The difference between the Part and Blank geometry define the volume of material to be removed.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/pcmill_blank_pt.gif"></p>
      </div>
      <div class="title_figure">Blank and Part Geometry in Cavity Milling</div>
      <p class="para_topic">Blank geometry can represent raw stock material as illustrated above or it can represent a forging or casting by defining a uniform offset from the selected Part boundaries, faces, curves, or bodies.</p>
      <p class="para_topic">It is not always necessary to specify Blank geometry in Cavity Milling. The Part geometry alone may enclose and define the entire cut volume.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/pcmill_entire_cut_vol.gif"></p>
      </div>
      <div class="title_figure">Part Geometry Defining Entire Cut Volume</div>
      <p class="para_topic">Blank geometry can also be used to isolate and cut specific areas. You can create Blank geometry so that the resulting boundary will surround only an isolated area of the Part and the material to be cut away. The system will then cut from the Blank to the Part.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/pcmill_intfi09.gif"></p>
      </div>
      <div class="title_figure">Boundary Isolating a Small Cut Volume</div>
      <table border="0">
         <tr>
            <td valign="top" align="left"><img align="left" src="../graphics/note.gif" alt="Note" title="Note"></td>
            <td valign="bottom" align="left" width="100%">
               <div class="para_note">
                  <p class="para_note_body">Island Cleanup should be turned on when using the follow periphery cut pattern. This assures that excess material will not be left along the wall of islands, which could leave too much material for the tool at the next cut level.</p>
               </div>
            </td>
         </tr>
      </table>
   </body>
</html>