Simulation Simulation blocks bad NC code, ends fears of crashed spindles
Lego’s Engineering, Prototypes & Tooling department uses Vericut to simulate all NC programs so engineers can sleep soundly.
Being closely involved in the production of complex moulds and dies and facing the daily risk of a costly and damaging collision between a machine tool spindle and the workpiece can make getting a good night’s sleep difficult. That was the situation at the Billund, Denmark, headquarters of world-renowned toymaker Lego Group until the company installed the advanced NC simulation software Vericut in its Engineering, Prototypes & Tooling department. The software was supplied by UK-based CGTech Ltd.
All the facts
“With the traditional simulation that many CAM packages are capable of, there are certain parameters that you cannot take into consideration,” explains Christian Wissing Kruse, project manager in Engineering, Prototypes & Tooling. “Often, the programs do not consider the individual CNC machine’s kinematic properties; and, most programs simulate internal CAM movements and not postprocessed data. These shortcomings can be fatal if, for example, you plan to operate with the machine’s spindle in close proximity to the workpiece.”
Kruse notes that the Lego department has measured its CNC machines so that Vericut knows them inside and out. “When the final NC program has been written,” he continues, “we send it to a shortcut on the PC’s desktop from where a simulation is conducted on a dedicated PC-server through a system of Windows batch-scripts and VB-scripts. We do not need to watch the program as it is simulated and, when the simulation is complete, an email message is sent to the relevant person with a green go-ahead or red stop in the message field.”
No costly risks
The simulations demand serious computing power, so it makes sense to use a dedicated server, allowing users to work on other tasks at their workstations without their capabilities being cramped by a massive CPU drain. “This is necessary, as the simulations often run for up to six hours,” says Kruse. “And, even if it does take a lot of time to do the simulations, it is time well spent, as a collision may cost a ruined spindle—not to mention a full week of production for the remedial work to be carried out.”