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      <title>5-Axis</title>
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      <div class="title_topic4" id="xps10_pagetitle">5-Axis</div>
      <hr noshade="true">
      <p class="para_topic">5-axis displays the following options for describing a 5-axis tool control:</p>
      <p align="center"><img align="bottom" src="graphics/seqmill_figuressmpg33.gif"></p>
      <p class="para_topic">Normal To Ps (or Ds) causes the tool axis to remain perpendicular to the specified surface. This generally involves keeping the center of the bottom of the tool (through which the tool axis runs) in contact with the surface.</p>
      <p class="para_topic">You can contact the surface at another point on the tool bottom while maintaining the tool axis normal to the surface if you use a flat or bull end cutter and a Tip Angle = 0.</p>
      <p class="para_topic">If that is the case, you must enter the (positive) Distance Between Tool End And Contact Point, and then, using the Vector Subfunction, the Contact Direction (a non- zero vector that must never be parallel to the tool axis). The &quot;new&quot; tool contact point is determined by moving the specified distance perpendicular to the tool axis in the direction of the vector (Contact Direction).</p>
      <p class="para_topic">If the distance is too large, then the radius of the tool at the bottom is used.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/seqmill_enat11.gif"></p>
      </div>
      <div class="title_figure">5-Axis, Normal to Part (or Drive) Surface - Offset</div>
      <p class="para_topic">Parallel to Ps (or Ds) causes the side of the tool to be kept parallel to the surface rulings at the contact points whenever that surface is a cylinder, cone, tabulated cylinder, or ruled surface. Otherwise, the tool axis is kept parallel to the surface parameter curves at the contact points. Furthermore, a ring on the tool must be specified to indicate where the side of the tool must touch the controlling surface, so the Tool Ring option menu is activated as soon as you choose this option.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/seqmill_figuressm13.gif"></p>
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      <div class="title_figure">5-Axis, Parallel to Drive Surface</div>
      <p class="para_topic">Tangent to Ps (or Ds) causes the side of the tool to be tangent to the specified surface while the tool axis stays perpendicular to the current direction of motion. After choosing this option, the Tool Ring option menu is activated so that you can specify where the side of the tool is to touch the controlling surface.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/seqmill_figuressm14.gif"></p>
      </div>
      <div class="title_figure">5-Axis, Tangent to Drive Surface</div>
      <p class="para_topic">At Angle to Ps (or Ds) causes the tool axis to maintain a fixed angle (Tilt) with the surface normal and a fixed angle with the current direction of motion (a Lead or Lag angle).</p>
      <p class="para_topic">Tilt - is the angle that the tool axis makes with the specified surface normal. The set of all vectors making a given angle with the controlling surface normal forms a cone. The set of all vectors making a fixed angle with the current direction of motion forms a plane or another cone (to be described). In general, there are two possible intersections between the two geometric objects, so there are two possible tool axes. The sign of the tilt angle is used to distinguish between the two candidates. A positive angle is measured from the Part (or Drive) Surface normal toward the other surface normal. A negative angle is measured away from the other surface normal.</p>
      <p class="para_topic">In the following figure, positive Tilt Angle &quot;a&quot; represents a rotation from the Part Surface normal towards the Drive Surface normal.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/seqmill_figuressm15.gif"></p>
      </div>
      <div class="title_figure">5-Axis, at Angle to Part Surface - Tilt Angle=a, Lead/Lag=0</div>
      <p class="para_topic">The tool axis lies in the plane perpendicular to the direction of tool movement unless you specify a Lead or Lag Angle. In the above figure, the tool is cutting through the plane of this paper, which is perpendicular to the direction of tool movement. There are only two positions where the cone of possible tool axes intersect this plane, and the sign of the tilt angle determines which is used.</p>
      <p class="para_topic">Lead/Lag - is the angle that the tool axis makes with a plane that is perpendicular to the current direction of motion. A positive angle corresponds to a Lead angle (i.e., the angle between the tool axis and the direction of motion is acute), while negative angle corresponds to a Lag angle (i.e., the angle between the tool axis and the direction of motion is obtuse).</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/seqmill_figuressm16.gif"></p>
      </div>
      <div class="title_figure">Lead and Lag Angles</div>
      <p class="para_topic">When using a Lead or Lag angle, the tool axis is determined by the intersection of two cones. In the following figure, you can see that the tool axis is further tipped above (Lead) or below (Lag) the plane of the paper.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/seqmill_enat06.gif"></p>
      </div>
      <div class="title_figure">5-Axis, at Angle to Part Surface</div>
      <p class="para_topic">Both Tilt and Lead/Lag are measured in degrees and must fall in the range from -90 degrees to +90 degrees. If the Tilt angle falls outside this range, the error message Absolute Value Of Tilt Angle Exceeds 90 Degrees will appear and you must re-specify the tilt angle. If the Lead or Lag angle falls outside the same range, the system displays the following error message:</p>
      <p class="para_topic">Abs Value Of Lead/Lag Angle Exceeds 90 Degrees.</p>
      <p class="para_topic">When this message appears, you must re-specify the Lead or Lag angle.</p>
      <p class="para_topic">If both angles fall within the allowable range but the absolute value of the Lead or Lag angle exceeds the absolute value of the Tilt angle as illustrated below, the cones do not intersect and it is impossible to compute a valid tool axis. If this error occurs, the system displays the following error message:</p>
      <p class="para_topic">Abs Value Of Lead/Lag Exceeds Abs Value Of Tilt.</p>
      <p class="para_topic">When this message appears, you must respecify at least one of the angles.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/seqmill_enat05.gif"></p>
      </div>
      <div class="title_figure">Unable to Compute a Valid Tool Axis</div>
      <p class="para_topic">The Tool Ring Option menu allows you to specify a ring for the controlling surface or to indicate that no ring is used for the surface. If the Tilt Angle plus the tool taper angle equals 90 degrees, the side of the tool will be tangent to the controlling surface and you will probably want to use a ring to indicate the height where contact occurs. Otherwise, you will probably want the Tool Ring status to be None to prevent the tool from gouging the controlling surface.</p>
      <p class="para_topic">If you are performing an Engage sub-operation using a Lead or Lag Angle, you must specify a Next Cut Direction vector pointing in the general direction that the tool moves during the first continuous path motion sub-operation to guarantee that the tool leans the right way at the end of the startup.</p>
      <p class="para_topic">Fan is an even distribution of tool axis change from the start to the stop position. This can be useful, for example, when the tool is canted at either or both positions.</p>
      <p class="para_topic">For an Engege suboperation without a Check Surface, the side of the tool is tangent to the Drive Surface at the contact point when the tool is at the startup position. There is no Lead or Lag angle.</p>
      <p class="para_topic">For an Engege suboperation with a Check Surface, the side of the tool is tangent to both the Drive Surface and Check Surface at the contact point when the tool is at the startup position.</p>
      <p class="para_topic">For a continuous path motion sub-operation, the side of the tool is always tangent to the Drive Surface at each contact point along the tool path. In addition, the side of the tool is tangent to the Check Surface at the contact point when the tool reaches its final position. The system distributes the change in the tool axis as evenly as possible throughout the entire length of the path. Because the Check Surface is used to determine the tool orientation at each point of the path, you cannot use multiple Check Surfaces with the Fan option.</p>
      <table border="0">
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            <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"> NOTE: It is possible to use a tool whose taper angle is not zero.</p>
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            </td>
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      </table>
      <p class="para_topic">The Fan option requires specification of a tool ring to determine where the tool contacts the Drive Surface in cases where the tool end tip does not lie on the Drive Surface. Note that the edge of the ring is in contact with the Check Surface (if specified) at the final position whenever the tool end does not lie on the Check Surface. This makes it possible to use the Check Surface as the new Drive Surface and fan to the next Check Surface (the full cutter is used only for the Part Surface).</p>
      <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"> NOTE: The Fan option should not be used in a continuous path motion sub-operation if one or more of the following conditions are true:</p>
               </div>
            </td>
         </tr>
      </table>
      <ol type="1" start="1">
         <li>
            <p class="para_item">The total angular change in the tool axis is greater than 60 degrees.</p>
         </li>
         <li>
            <p class="para_item">The total angular change in the direction of motion is greater than 60 degrees.</p>
         </li>
         <li>
            <p class="para_item">The tool moves farther away from or parallel to the check surface (or its extension) at one or more points in the path.</p>
         </li>
         <li>
            <p class="para_item">The length of the path is relatively small while the total change in the tool axis is relatively large.</p>
         </li>
      </ol>
      <p class="para_topic">Although there is no solution to the fourth condition, the first three can be overcome by inserting one or more intermediate check planes at suitable points along the tool path and splitting the continuous path sub-operation into two or more shorter sub-operations. Fan the tool successively into the intermediate check planes and then into the final check surface.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/seqmill_enat04.gif"></p>
      </div>
      <div class="title_figure">5-Axis, Fan</div>
      <p class="para_topic">Thru Fixed Point indicates that the tool axis always lies along the line joining the tool end tip and a user-defined point. Use the Point Subfunction dialog to define the point.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/seqmill_figuressm20.gif"></p>
      </div>
      <div class="title_figure">5-Axis, Thru Fixed Point</div>
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