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      <title>Engage and Retract</title>
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      <div class="title_topic4" id="xps10_pagetitle">Engage and Retract</div>
      <hr noshade="true">
      <p class="para_topic">Engage and Retract allow you to specify parameters associated with movements to and from the Part surface. The parameters you define are associated with the specific Case of the Engage or Retract. For example, one set of parameters may pertain to Initial Engages, while another set of parameters pertain to Local Engages.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/engretr_difpar.gif"></p>
      </div>
      <div class="title_figure">Various Cases of Engage and Retract with Different Parameters</div>
      <p class="para_topic">The above figure illustrates how various Cases of Engages and Retracts can have different parameters associated with them. The Initial Engage and Final Retract, for example, follow the tool axis a specified vertical distance to and from the Part surface while the Reposition Engages follow an angular vector from a clearance plane to the Part surface.</p>
      <p class="para_topic">The Engage and Retract buttons display the following dialog box that allows you to define parameters for specific Cases of Engages and Retracts.</p>
      <p align="center"><img align="bottom" src="graphics/engretr_param_dialg.gif"></p>
      <div class="title_division">Status</div>
      <p class="para_division">Status determines what motion parameters the system will use to execute the selected Case of Engage or Retract. You may specify the status directly by defining Clearance Geometry, by keying distance and direction values manually, or you may use parameters that were previously defined for another case.</p>
      <p class="para_division">Status allows you choose from the following options when using Engage and Retract:</p>
      <p align="center"><img align="bottom" src="graphics/status.gif"></p>
      <p class="para_division">None specifies that the selected Case of Engage or Retract will not be used in the tool path.</p>
      <p class="para_division">Clearance allows you to specify the Engage or Retract as the movement from or to the Clearance Geometry. This option activates the Clearance button which then allows you to define clearance geometry by specifying a plane, point, sphere, or cylinder. This selection also activates the Movement and Direction options described below which allow you to define the path of travel to and from the clearance geometry.</p>
      <p class="para_division">Manual allows you to define the tool movement by specifying the type of tool movement, the direction of travel, and the distance.</p>
      <p class="para_division">The remaining Status options allow you to utilize the parameters in a previously defined Status. These options allow you to use the same set of parameters in several Cases without having to redefine them for each Case.</p>
      <ul>
         <li>
            <p class="para_item">Use Initial</p>
         </li>
         <li>
            <p class="para_item">Use Final</p>
         </li>
         <li>
            <p class="para_item">Use Check</p>
         </li>
         <li>
            <p class="para_item">Use Local</p>
         </li>
         <li>
            <p class="para_item">Use Reposition</p>
         </li>
         <li>
            <p class="para_item">Use Default</p>
         </li>
      </ul>
      <p class="para_division">You may, for example, select Clearance for the Initial Engage and then specify Use Initial for all subsequent Reposition and Local Engages. This saves you from having to redefine the same clearance plane again and again. Using parameters that have been previously specified for another Case is called &quot;linking&quot;.</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: You cannot link to the Case for which you are specifying parameters. For example, if you are specifying parameters for Local, you will not be able to choose Use Local.</p>
                  <p class="para_note_body"></p>
               </div>
            </td>
         </tr>
      </table>
      <div class="title_division">Movement</div>
      <p class="para_division">Movement allows you to specify the shape of the tool path. You may specify a linear, semi-circular (arc), or helical path. This option becomes active when you choose Manual or Clearance for the Status.</p>
      <p align="center"><img align="bottom" src="graphics/mvmnt_apprch.gif"></p>
      <p align="center"><img align="bottom" src="graphics/mvmnt_deprt.gif"></p>
      <p class="para_division">Arc Movements allow you to specify both a Radius and a Distance when the Status is set to Manual. The system resolves conflicts between these values by always maintaining the specified Radius and adjusting to use the greater Distance as illustrated below.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/sysreslvconfl_radist.gif"></p>
      </div>
      <div class="title_figure">System Resolves Conflicts between Radius and Distance</div>
      <p class="para_division">In the first case, the system extends the distance to maintain the specified arc radius. In the second case, the system maintains both the specified distance and the arc radius, but connects them with a linear tool movement tangent to the arc. By resolving conflicts between Radius and Distance in this way, the system always determines the safest clearance.</p>
      <p class="para_division">If it is important to maintain the radius for Arc movements, you should specify a value for the radius and the system will adjust the distance or tool movement accordingly. If it is important to maintain the specified distance, you should select Automatic for the radius and the system will determine the appropriate radius.</p>
      <p class="para_division">Linear causes the tool to travel directly along the Engage or Retract Vector specified under the Direction option.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/linr_mvmnt.gif"></p>
      </div>
      <div class="title_figure">Linear Movement</div>
      <p class="para_division">Arc: Parallel to Cut uses the Engage or Retract Vector and the Cut Vector to define a plane containing the arc tool move. The Arc end is always tangent to the Cut Vector.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/arc_parallelcut.gif"></p>
      </div>
      <div class="title_figure">Arc: Parallel to Cut</div>
      <p class="para_division">Arc: Parallel Tool Axis uses the Engage or Retract Vector and Tool Axis to define a plane containing the arc tool move. The arc end may not necessarily be tangent to the Cut Vector.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/arc_parall_toolax.gif"></p>
      </div>
      <div class="title_figure">Arc: Parallel Tool Axis</div>
      <p class="para_division">Arc: Normal Tool Axis uses the plane normal to the Tool Axis to define a plane containing the arc tool move. The arc end is perpendicular to the Tool Axis but not necessarily tangent to the Cut Vector. This movement type enables the output of a G02/G03 record in the machine file.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/arc_norm_toolax.gif"></p>
      </div>
      <div class="title_figure">Arc: Normal Tool Axis</div>
      <p class="para_division">Arc: Tangent to Approach uses the tangent vector at the end of the approach move and the cut vector to define a plane containing the arc tool move.&nbsp; The arc move will be tangent to both the cut vector and the approach move.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/arc_tangappr.gif"></p>
         <p align="center"><img align="bottom" src="graphics/appr_cutvector.gif"></p>
      </div>
      <div class="title_figure">Arc: Tangent to Approach</div>
      <p class="para_division">Arc: Tangent to Departure uses the tangent vector at the beginning of the departure move and the cut vector to define a plane containing the arc tool move.&nbsp; The arc move will be tangent to both the cut vector and the departure move.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/arc_tangdeprt.gif"></p>
         <p align="center"><img align="bottom" src="graphics/deprt_cutvector.gif"></p>
      </div>
      <div class="title_figure">Arc: Tangent to Departure</div>
      <p class="para_division">Helical: Climb (or Conventional) creates an Engage that ramps in a circular fashion about a fixed axis downward into the material. The center line of the helix is always parallel to the tool axis. This option is best used with cut patterns such as Follow Pocket or Concentric Arcs that allow enough material around the Engage Axis to avoid gouging boundary walls or Check Surfaces. Helical is available for Engage moves only. The steepness of a Helical Engage is determined by the Max Ramp Angle value.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/hel_convfolpock.gif"></p>
      </div>
      <div class="title_figure">Helical:Conventional Used with Follow Pocket Cut Pattern</div>
      <div class="title_division">Radius Type</div>
      <p class="para_division">Radius type defines how the system to determine the radius of Arc Movements based on the length of the Engage or Retract Vector as illustrated below.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/radius_type.gif"></p>
         <p align="center"><img align="bottom" src="graphics/auto_radius.gif"></p>
      </div>
      <div class="title_figure">Automatic</div>
      <p class="para_division">Automatic allows the system to determine the radius of Helical Engages based on the tool radius. The radius of the helix is always slightly less than the radius of the tool to allow all of the material to be removed from the center.</p>
      <p class="para_division">Radius allows you to specify the radius of Arc and Helical movements by keying in a value. If there is a conflict between the specified radius and the specified distance, the system maintains the radius.</p>
      <p class="para_division">Variable Radius allows you to specify a maximum and minimum radius for arc motion by keying in two values.&nbsp; The system will output an arc move having the maximum radius if the move does not gouge the part.&nbsp; If this would gouge, the system will sample a number of values in the range between the maximum and minimum radii and output an arc move having the largest radius of the sampled values which does not gouge the part.&nbsp; If no value in the range will produce a non-gouging move, the system defaults to a linear move along the tool axis.</p>
      <div class="title_division">Direction</div>
      <p class="para_division">Direction allows you to specify the orientation of the Engage or Retract vector. This option is available when using Manual or Clearance Status. You may choose from the following options:</p>
      <p align="center"><img align="bottom" src="graphics/direction.gif"></p>
      <p class="para_division">Automatic Automatic causes the system to define the length of the engage and retract vector by using the combined Safe Clearance distance and Part Offset while considering the angle between the tool axis and surface normal. The bigger the angle, the bigger the length. If the angle is close to 90 degrees, the system will use 20 times of the combined Safe Clearance and Part Offset as the engage/retract length.</p>
      <p class="para_division">Instead of using the Automatic option, you can use the Distance option to specify the required engage/retract distance. </p>
      <p class="para_division">Tool-axis orients the Engage or Retract vector along the tool axis.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/toolax_linarc.gif"></p>
      </div>
      <div class="title_figure">Tool-Axis Engage Vector Direction for Linear and Arc Movement</div>
      <p class="para_division">Vector allows you to specify the direction of the Engage or Retract vector by using the Vector Subfunction.</p>
      <p class="para_division">Relative to Cut allows you to specify the direction of the Engage or Retract vector in terms of the Azimuth and Latitude angles. The Azimuth angle is measured in a plane tangent to the Part surface at the first contact point. The angle is measured in a counter-clockwise direction and is referenced from the direction of the first cut.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/azimuthangle.gif"></p>
      </div>
      <div class="title_figure">Azimuth Angle</div>
      <p class="para_division">The above figure illustrates a twenty degree Azimuth and a zero degree Latitude. Notice that the Azimuth angle is not measured in the X-Y plane, but rather in the plane tangent to the Part surface at the first cut point. A positive Azimuth angle is measured counterclockwise in the Top View.</p>
      <p class="para_division">The Latitude angle determines how high the Azimuth vector is elevated above the plane tangent to the Part surface. The Latitude is measured in a plane containing both the Azimuth vector and the surface normal vector.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/azimuth_latangle.gif"></p>
      </div>
      <div class="title_figure">Azimuth and Latitude Angles</div>
      <p class="para_division">The above figure illustrates a twenty degree Azimuth and a negative thirty degree Latitude. A negative Latitude angle is required for the tool to engage in a downward direction to the Part surface. A positive Latitude is required for the tool to retract in an upward.</p>
      <div class="title_division">Max Ramp Angle</div>
      <p class="para_division">The Maximum Ramp Angle option allows you to specify the maximum angle for Helical Engages. The system may be required to slightly reduce the specified Maximum Ramp Angle to produce an integer number of full helical revolutions. The angle is referenced from a plane normal to the center line of the helix. This option is only available if Helical:Climb or Helical:Conventional are selected.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/25degmaxrampang.gif"></p>
      </div>
      <div class="title_figure">Twenty-Five Degree Maximum Ramp Angle</div>
      <div class="title_division">Automatic and Distance</div>
      <p class="para_division">The Automatic and Distance options allow you to specify the length of the Engage and Retract vector. These options are available only when the Status is set to Manual.</p>
      <p class="para_division">Automatic causes the system to define a length of the Engage and Retract vector by considering the combined distance of the Safe Clearance and Part Stock Offset, with the surface normal of the Engage/Retract location. &nbsp;For the flat surface, the length is the combined distance of the Safe Clearance and Part Stock Offset. If the surface becomes steeper, the length becomes larger in order to engage from or retract to a safe place.</p>
      <p class="para_division">Distance activates the adjacent text field, allowing you to enter a distance value manually.</p>
      <div class="title_division">Example of Directions and Movements</div>
      <p class="para_division">Here is an example of how to define Directions and Movements for Engages and Retracts.</p>
      <p align="center"><img align="bottom" src="graphics/def_directn_mvmnt.gif"></p>
      <div class="title_division">The Following Steps Describe How to Define the Engages</div>
      <ul>
         <li>
            <p class="para_item">Select Non-Cutting.</p>
         </li>
         <li>
            <p class="para_item">Specify Default for the Case, toggle the Engage button to the ON position, and specify Clearance for the Status.</p>
         </li>
         <li>
            <p class="para_item">Select the Clearance button and define the Clearance Plane. Select Return Current.</p>
         </li>
         <li>
            <p class="para_item">Specify Arc: Parallel to Cut</p>
         </li>
         <li>
            <p class="para_item">Specify Automatic for the Radius. This allows the system to determine the best radius for the vector Distance.</p>
         </li>
         <li>
            <p class="para_item">Specify Vector for the Direction.</p>
         </li>
         <li>
            <p class="para_item">Use the appropriate method to define the orientation of the vector illustrated below.</p>
         </li>
      </ul>
      <p align="center"><img align="bottom" src="graphics/def_orient_vec.gif"></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: A value for the Distance (X) cannot be specified because Clearance was selected for the Status. The system determines the Distance based on the vector orientation and the Clearance Plane position.</p>
                  <p class="para_note_body"></p>
               </div>
            </td>
         </tr>
      </table>
      <p class="para_division">The following steps describe how to define the Retracts.</p>
      <ul>
         <li>
            <p class="para_item">Toggle the Retract button to the ON position, Specify Default for the Case, and specify Clearance for the Status.</p>
         </li>
         <li>
            <p class="para_item">Specify Linear for the Movement and specify Tool Axis for the Direction.</p>
            <p align="center"><img align="bottom" src="graphics/def_retrct.gif"></p>
         </li>
         <li>
            <p class="para_item">Select OK to accept the Non-Cutting Moves parameters.</p>
         </li>
      </ul>
      <p class="para_division">The final Tool Path will be similar to the one illustrated below.</p>
      <p align="center"><img align="bottom" src="graphics/retract_toolpth.gif"></p>
      <div class="title_division">Collision Check</div>
      <p class="para_division">Collision Check allows the system to detect and respond to collisions with Part and Check geometry.</p>
      <p class="para_division">Collision allows you to specify one of the following actions:</p>
      <p align="center"><img align="bottom" src="graphics/collision.gif"></p>
      <p class="para_division">For Traverse, Approach, and Departure moves, Collision does not provide all of the above options. Instead, you are provided with an On/Off toggle which enables you to generate or to not generate a warning to the tool path and CLSF.</p>
      <p class="para_division">Off causes the system to ignore collisions.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/collisionoff.gif"></p>
      </div>
      <div class="title_figure">Collision on Initial Engage Ignored</div>
      <p class="para_division">Warn writes a warning to the tool path, but does not alter the Engage or Retract move to avoid the collision.</p>
      <p class="para_division">Truncate shortens the Engage or Retract to avoid the collision. All tool positions beyond the truncation are deleted.</p>
      <p align="center"><img align="bottom" src="checkmark.gif"></p>
      <p class="para_division">Note: When the Engage or Retract move is truncated due to collision, the end of Approach (or start of Departure) move will be closer to the Part Geometry. When the Collision Check option for Approach/Departure is enabled, the system will output warning messages in the tool path if the truncation of Engage/Retract causes the Approach/Departure to get closer to the part geometry than the specified Safe Clearance.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/truncat_initial_eng.gif"></p>
      </div>
      <div class="title_figure">Truncated Initial Engage</div>
      <p class="para_division">Automatic alters the tool path to contour around the geometry to avoid a collision while maintaining the desired travel. The specified Safe Clearance Distance is maintained while the tool contours around the geometry.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/auto_initial_eng.gif"></p>
      </div>
      <div class="title_figure">Automatic Initial Engage</div>
      <p class="para_division">Interval determines how often the system checks for collisions.</p>
      <p align="center"><img align="bottom" src="graphics/interval_coll.gif"></p>
      <p class="para_division">None specifies that there will be no Collision Checking.</p>
      <p class="para_division">Tool Radius specifies to check for collision each time the tool has traveled the length of its radius.</p>
      <p class="para_division">Manual activates the adjacent text field, allowing you to enter a value for the distance between collision checks.</p>
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