Tutorials:-Working with Power MILL "PART III" 3D Area Clearance.

Sourbh

2 Oct, 2013 03:31 AM

Hi Guys, Am back with new Tutorials for CAM work in power mill.
In this part you will Learn the Different Strategies for Material Removal/3d Area Clearance.

Thanks and Enjoy...!!

1. Step 1:

   The main strategies for roughing a 3D component Model are called 3D Area Clearance. These provide a choice of 2D material removal methods, which progressively machine the area (Slice), up to the component contour, down a sequence of user-defined Z Heights.
   There is also a similar group of strategies, 2.5D Area Clearance for use, exclusively with PowerMILL 2.5D Feature Sets-

   

2. Step 2:

   Sometimes known as Waterline Roughing the cutter steps down to a specified Z Height and fully clears an area (Slice) before stepping down to the next Z Height to repeat the process
   For some components a secondary Area Clearance strategy is applied using the Rest Machining options in conjunction with a smaller roughing tool. This will locally remove pockets of excess material inaccessible to the original Reference Toolpath or Stock Model. This will reduce the degree of tool overload and provide a more consistent material removal rate for any subsequent Finishing operations.

   If the original material is in the form of a casting or fabrication then it may not be necessary to apply any Area Clearance machining but to go directly for a semi-Finishing strategy

   

3. Step 3:

   "Thickness and Tolerance (Applied to 3D Area Clearance)"

   Suitable values are required to control the accuracy and amount of excess material to be left on a component by a toolpath. The parameters used for this purpose are preset and are called Thickness and Tolerance.

   Thickness is the amount of extra material specified to remain on the work-piece after machining. This can be applied generally (as shown), or independently as separate Radial and Axial values within the machining options.

   

4. Step 4:

   Raster Area Clear example

   • From the Main toolbar select the Toolpath Strategies icon.
   • Select 3D Area Clearance tab.
   • Select the option Raster AreaClear Model to open the following form.

   • Enter the Name D50T6_A1.
   • Set Stepover to 20.
   • Set Stepdown to 10.
   • Keeping all other values as default, Apply the form.
   • After the processing is complete Cancel the form.

   As soon as the Raster AreaClear Model form is opened an unprocessed Toolpath appears in the Explorer (the default name has been changed to D50T6_A1).
   The Toolpath icon can now be double-clicked to Activate and de-activate the toolpath.
   The + symbol can be clicked to open a full record of the data used to create the toolpath.
   The dotted red lines represent Rapid moves and the light blue lines are the Plunge feed moves. The Plunge moves at present are longer than necessary resulting in time wasted by the tool feeding down in free space where most of the move could be Rapid.
   The existing toolpath will now be Recycled with new settings to improve the efficiency of Rapid movements across the component.
   • Right mouse click over the Toolpath icon in the explorer to open the local pull down menu.
   • Select Settings to reopen the Raster AreaClear Model form.
   • Select the ‘Recycle toolpath’ icon (shown arrowed below).
   • Select the Rapid Moves Height icon from the main toolbar
   • Select the Skim option and change the Safe Z to 5 and Start Z to 3 as shown below.
   • Accept the above form and then click Apply in the Raster AreaClear Model form and once processing is complete click Cancel to close the form.
   The tool will now plunge locally (pale blue move) from the defined Incremental - Start Z above each slice and rapid across the roughed areas by the Incremental - Safe Z (purple move).
   The toolpath has been recycled with the Skim option set in the Rapid Move Heights form and now uses Incremental Safe Z and Start Z values (Note; In practice more than one change can be implemented when Recycling or Copying a toolpath).
   This time a Copy of the above toolpath will be created using the Area Filter options to remove the single pass tooltracks which are stepping down each of the four corners

   Note the toolpath can also be activated or deactivated from the Activate switch in the pulldown menu

   

5. Step 5:

   •Select Settings to reopen the Raster AreaClear Model form.
   •Select the ‘Copy toolpath’ icon (shown arrowed below).
   •In the form locate the Area Filter section (lower left corner) and input the settings as shown below (Note Filter Only Enclosed Areas is unticked).
   All tooltracks spanning a distance less than the Tool Diameter (TDU) will be filtered out and not appear in the final Toolpath.
   The effect of unticking Filter Only Enclosed Areas means that the areas of toolpath outside the Block will be included in the filtering process.
   • Apply the Raster AreaClear Model form and once processing is complete click Cancel to close the form.
   The default Raster Area Clear strategy steps across the model with parallel tooltracks. The remaining edges around the model, contour are then removed by a single profiling pass.

   A new toolpath called D50T6_A1_1 is created with the corner machining filtered out

   

6. Step 6:

   Simulating the toolpath

   •Perform both an Animation and a ViewMILL simulation on the final Raster Area Clearance tool-path.
   • Select the ViewMILL Suspend icon and No Image to return to the PowerMILL session.
   Note:-By toggling back to PowerMILL, the ViewMILL session will still exist in the background so that any subsequent toolpaths can later be used to continue the simulation.

   Save the Project
   •From the Main toolbar select File.
   Save Project to update the stored data.

   The Project (D:\users\training\PowerMILL-Projects\Spkr-Core) has now been updated to include the 3D Area Clearance toolpaths.
   •From the Main toolbar select File
   Delete All.
   • From the Main toolbar select Tools - Reset Forms.

   This restores all default PowerMILL settings in the forms without having to exit and re-enter.