Simulating NC Tool Paths and Milling Operations  

Two types of simulation are possible:

• Machine Simulation : This form of simulation works for NC and milling machines.
• Simulate MillTurn Machine : An explanation of how to use this command is provided here. To determine whether you need to use this command, look at the complexity of the machines:
  • Machine having single turret- single spindle: This is a conventional lathe machine. For the simulation of this type of process Simulate MillTurn Machine should be used.
  • Machine having multi turrets -single spindle: In this case the job mounted on a spindle can be operated on by more than one turret. That is two or more of the machining operations can be parallel to each other. Only Simulate MillTurn Machine can be used in this case.
  • Machine having multiple turrets-multiple spindles: This case arises when jobs mounted on different spindles are operated on by different turrets simultaneously. More than one manufacturing operations are parallel to each other. Only Simulate MillTurn Machine can be used in this case.

All machining operations need to be up-to-date and tool paths computed before Machine Simulation is started.

Simulate the Entire Machining Operation

1. In the PPR tree, select Facing.1.

2. Click Machine Simulation .

   	For more general information on running simulations, please see Viewing a Simulation.  Machine Simulation differs from the more generic Process Simulation command in that Machine Simulation requires the user to select a machining activity. This could be a complete part operation, a manufacturing program, or a single machining operation. If there are multiple part operations in the process, the entire process cannot be simulated with Machine Simulation . Also, multiple machining operations (within a manufacturing program) can be pre-selected before the simulation is started, by holding down Shift while selecting them. Also, Process Simulation calls up a Simulation Controls pop-up toolbar.  For Machine Simulation , this pop-up toolbar does not appear. One of its commands (Visualization Options) is on the Process Simulation pop-up toolbar; the remainder do not apply.
   The Process Simulation toolbar appears.

3. Run the simulation.

   	A number of commands can be run while you run the Machine Simulation command, as is the case with the Process Simulation command.  These shared commands include simulation commands such as Analysis Configuration and view commands such as Zoom In .  When you click on other commands (e.g., Zoom In), the simulation pauses.  Once the command has finished, you can start a paused simulation from the pause point by clicking Run.
   	When you use the Zoom In command icon or menu option, you are using a shared command.  Using the mouse to zoom in is not the same as using the Zoom In in this context.
   	During simulation of a Manufacturing Program, the following rules are used to decide machine configuration: If there are multiple configurations to reach a point, the configuration that is within travel limits is chosen If multiple configurations are within limits, then the one that causes minimum motion is chosen If all possible configurations are out of limits, the one that causes minimum motion is chosen. Travel limit warnings are generated. The user can enforce a specific configuration to be used for a Machining Activity by introducing a Machine Instruction activity before the Machining Activity. The above rules also apply for simulation of a single Machining Operation. However, single MO simulation is meant to be a quick validation of the tool path, and therefore does not consider the configuration of the machine for the previous activities.

Simulate Part of the Machining Operation

This functionality is helpful when you want to simulate just a part of the machining operation. Note that partial simulation is possible only after the entire machining operation has been simulated once. Partial simulation is not possible with a machine instruction activity because no tool path is created.

1. Simulate the entire machining operation by following the steps above, then click Machine Simulation .

   The Process Simulation toolbar disappears; the tool path is displayed as shown below:

2. Right-click on any segment of the tool path displayed in the 3D view and select Partial Simulation.  

   Once you select Partial Simulation, the machine is placed at the end point of the selected range of tool path segment (the tool path segment is highlighted in green).
   	See Tool > Options > Machining Simulation > Machine Tool Path Simulation > Simulation tab for information on setting the Modification Range option.  The number of segments highlighted when you select Partial Simulation depends on the Modification Range.
   Also, the Partial Simulation dialog box is displayed.

3. Use the buttons in the Partial Simulation dialog box to simulate the path segment you selected.

   Field/Button Effect Current Point Selecting a point from the Current Point list makes the simulation jump to the point on the geometry. Rewind Pause Play Step Size In the Step Size box, type the value or use the arrows to change the value. This option enables you to change the simulation rate for each step.  You can make the sub-steps: smaller, which makes the simulation run more slowly, or larger, which makes the simulation run more quickly.

4. Click Close when the Partial Simulation is complete.

Simulation with Interchangeable heads

Simulation of milling operations which have inclined tool path/tool axis on a universal milling center, can be done by attaching interchangeable heads to the tool mount point of the machine.

Machine Simulation of Milling machines with interchangeable heads enables you to verify NC tool paths for travel limits, collisions and modify, if necessary.

A master or universal milling head can be coupled selectively and automatically with a variety of individual milling heads for different machining purposes. This allows you to choose an optimal milling head for a particular machining operation. The individual milling heads will be a part of the machine itself. There will be no change in the assignment of the machine to the part operation.

Please refer to the NC Machine Tool Builder User's Guide for the methodology to create such machines.

1. Define a Head Change Position and Head Mount Point on the master/universal milling head, and a Head Base Point on the individual milling heads, in the Machine Tool Builder workbench.

2. Define Head change activities while creating the process in the Manufacturing Infrastructure workbench.

   During simulation, the sequence of milling operations after these activities, will use the corresponding Milling heads defined in the Head change activities. For more details on how to define Head Change activities, see Inserting Head Changes in the NC Manufacturing Infrastructure User's Guide.

3. Once the process is ready, mount the job on the table.

4. Click Machine Simulation to launch the simulation. Simulation can be selected at Part Operation, Manufacturing Program and Machining Operation levels, only.

   During simulation, the interchangeable head will be equipped to the head mount point of the master/universal milling machine at the head change position. The orientation of the attached milling head will depend on its head base point and the head mount point of the master milling head. Also note that, when an interchangeable head is equipped to the master milling head, the tool will be mounted at the tool mount point of the attached milling head.

Note: Only one milling head can be attached to the Milling machine at a particular time during the simulation.

Using Simulate MillTurn Machine

to simulate a part operation involves the steps outlined above for Machine Simulation .  However, the preliminary steps for Simulate MillTurn Machine

1. To use Simulate MillTurn Machine , each manufacturing program must have a turret defined.

   • To define a turret, right-click on the manufacturing program in the tree, and select Definition.  The Manufacturing Program dialog box appears.  In the Turret field, select the desired turret from the list.

2. Once the turret is defined, set up any desired tool changes.

3. Load jobs onto the spindle or spindles using Auto Mount.  If multiple spindles are available, Auto Mount asks you to specify the spindle for the part operation.

About the Context Menu

About the Information Message

Change in Machine configuration required to reach the next point.
Please check travel limits of the machine OR insert Machine Instruction activity to select a different start configuration.

This message appears if the simulation cannot be carried out any farther using the current machine configuration, while keeping the machine within the travel limits. This message appears when the machine reaches the last feasible point of the tool path using the current machine configuration. You can continue the simulation because the machine axis moves back into the limits. 

The simulation relies upon the following rules:

• If there are multiple configurations to reach a point, the configuration that is within travel limits is chosen
• If multiple configurations are within limits, the one that causes minimum motion is chosen
• If all possible configurations are out of limits, the one that causes minimum motion is chosen. An out-of-limits configuration generates travel limit warnings.