Overview
The ICAM Virtual Machine (VM) simulator graphically depicts the operation and motions of a CNC machine during post processing and MCD simulation.
VM is integrated with CAM-POST GENER (the post processor), which uses the virtual CNC machine model to detect collisions and overtravel conditions. Collision detection can account for the effects of work piece and tool compensation, given experimental or actual values for compensation offsets. Collision detection is a natural part of the look-ahead optimizations that GENER performs during path planning, meaning that GENER can automatically choose an appropriate tool path to avoid collisions where possible. The machine simulation can be displayed in one of the GENER output windows, synchronized with other GENER output. Collision detection and avoidance can be active even when the simulation is not being show, for example, when running GENER in a minimized state.
VM is also integrated with CERUN (the control emulator), which uses the virtual CNC machine model to detect and report collisions and overtravel conditions during MCD based machine simulation. As with GENER, collision detection with CERUN can account for the effects of work piece and tool compensation, given experimental or actual values for compensation offsets. The machine simulation can be displayed in one of the CERUN output windows, synchronized with other CERUN output. Collision detection can be active even when the simulation is not being show.
A complete machine simulation requires the following:
A computerized model of the machine
A post-processor or control emulator to drive the simulation
Cutting tool, holding fixture, finish part and rough stock definitions
Workpiece and tool compensation amounts
The CNC machine model is developed and maintained using the ICAM QUEST Developer’s System. A model describes both the kinematics and the physical characteristics of the machine. Kinematics include at a minimum the linear and rotary axes of the machine, and if desired, other moving components such as tool changers, pallet indexers, flexible holding devices, doors and the like. The physical components of the machine can be created using rudimentary design features of QUEST, or can be imported as STL objects from any CAM system. The model designer can define standard viewpoints and lighting arrangements to best view the simulation. Models can also be customized using ICAM’s macro programming facility to match special requirements of the machine.
Post-processors and control emulators are developed and maintained using the same QUEST system used for models. When GENER (the post-processor) controls VM, model motions reflect the post-processor’s understanding of the state of the machine. When CERUN (the control emulator) controls VM, model motions reflect the state of the machine as defined by the MCD (machine control data) itself.
Models, post-processors and control emulators are all stored in a proprietary format in an ICAM database (.dbf) file.
An accurate simulation involves more than just moving the machine through its paces. Cutting tools and tool compensation amounts, holding fixtures and workpiece compensation amounts, and rough stock and finished part definitions should all be present in order to produce a meaningful result. Once defined, this information is saved in a verification setup (.vsw ) file named after the input file (i.e., the CLDATA file when running GENER; or the MCD file when running CERUN). This verification setup file can be reused on subsequent runs to quickly reestablish the conditions necessary for the simulation.