Virtual 3-D models improve simulation

More part manufacturers are recognizing the value of CNC simulation. Simulation software helps eliminate or significantly reduce the need to manually or physically prove out NC programs, freeing engineers, operators and expensive machines to produce good parts.

Some CNC simulation software, such as VERICUT from CGTech, can also optimize NC programs to decrease machining time and produce higher quality parts. However, 3-D simulation requires 3-D CAD models of machines, cutting tools and fixtures. Traditionally, these models were built by the end user or software supplier, but they are increasingly being offered by machine tool, fixture and cutting tool suppliers. Having 3-D models readily available from OEMs can reduce the time required to get CNC simulations up and running.

Accurate simulation of a machining process requires virtual 3-D model equivalents of the stock, fixtures, tools and CNC machine. However, creating these models in a CAD system, either by measuring the physical pieces or transferring the dimensions from 2-D drawings, can be tedious, costly and time-consuming.

By obtaining “simulation-ready” 3-D models from OEMs, end users don’t have to create the models or hire someone to do it. Fortunately, several machine tool, cutting tool and fixture suppliers realize this need and have taken steps to meet it.

Major toolmakers recently started offering 3-D models to end users from their Web sites. Those offering 3-D models to their customers gain a competitive advantage. Shops simulating CNC programs can save a significant amount of time and improve the accuracy and reliability of their machining processes by choosing a supplier that provides 3-D tool models.

Sandvik Coromant was one of the first toolmakers to recognize its customers’ need for 3-D models for simulation, but the company determined there was no standard for the model content. Therefore, Sandvik Coromant helped develop ISO 13399, which describes a general data model for representing the main categories of cutting tools and outlines the data-exchange requirements.

Customer demand has also encouraged machine tool builders to begin providing 3-D models. Increasing machine complexity increases the need to include the entire machine tool and simulate the NC program from post-processed NC code. Using simulation to detect potential collisions and near misses among all machine components prevents downtime caused by catastrophic failures and is critical to meet the delivery demands of a lean manufacturing process.

Simulating the entire machine tool requires a virtual machine configuration, consisting of machine geometry, kinematics and CNC and programmable-logic-controller emulation logic. Obtaining the virtual machine’s geometry from accurate 3-D models supplied by the machine tool builder is much more efficient than translating it from 2-D drawings or physical measurements.