When building a simulation model in CAM-POST Virtual Machine, it is important to ensure that the 3D models of the machine elements in close proximity to the part (spindle, rotary heads and/or tables, chucks, etc.) are as accurate as possible. These elements are typically the most susceptible of entering in collision. Other elements such as bedplates, slides, columns, rams and quills, as well as doors, cabinets and enclosures, can be either simplified or even omitted if desired.
If CAD assembly models are available from the machine vendor, they should be simplified such that only the essential machine elements are kept. Otherwise, the necessary machine elements must be modelled or reverse-engineered in a CAD system. For 3D models lacking in accuracy, Virtual Machine provides an option to add a safety clearance around collision-enabled objects. This option will offset the original surfaces of the object by a specified distance, so collisions will be signalled even when another object intersects the safety zone. Safety zones are also used to detect near collisions.
Optionally, the geometry of machine elements can be stripped out of unnecessary details, especially those located inside the model or on unexposed surfaces. This will dramatically improve the efficiency of collision computation during simulation process.
Regardless of the format of the CAD models (CAD-native, STEP, IGES, Parasolid, etc.), all models that constitute distinctive machine elements must be exported in STL format.
The following best practices are recommended:
1. All machine elements should be exported positioned at the absolute machine zero. This will considerably simplify the process of configuring the virtual machine.
2. Rotary axes pivot distances should be precisely consistent with the parameters defined in the machine tool controller.
3. Tool change coordinates and machine home positions should be precise.
Benefit to User
To understand which elements are needed to build a Virtual Machine simulation model.
For more information or comments, please do not hesitate to contact Phil at TechTipTuesday@icam.com