As part of its UGS NX™ 5 CAM functionality, UGS PLM Software introduces Free Flow Machining. This completely new approach to creating tool paths, enables the NC programmer to develop an ideal, efficient cutting strategy quickly and easily.

The new Free Flow Machining technology is used to drive machining strategies that follow the natural characteristics of the overall shape or area to be machined. It allows programmers to create smooth, continuous flowing tool paths with far fewer engages and retracts, along with highly consistent tool loading to deliver increased tool life and excellent surface finish. The Free Flow Machining technology, used as the basis for the new Streamline finishing tool path, is an element of the Freedom Technologies introduced into UGS NX with NX® 5, along with Design Freedom

Free Flow Machining creates machining strategies, which follow the natural shape of the area or the volume being machined

Traditional methods typically utilize cutting strategies that address a part with rigidly defined cutting patterns that are fitted to the area or volume to be machined. These strategies can force tool paths to be created that do not follow the natural shape of the part. Often special finishing operations are then needed to clean up, such as in corners or along fillets. This takes more time and the end result may be a less than perfect finish on the part. In other cases the alternative area milling strategies can be thrown off by the inappropriate or inconsistent surface mathematics of the underlying part model, especially where the area to be machined has been modeled using multiple surfaces. In these cases the only option is to construct new model surfaces in an attempt to drive the tool path correctly.

The constraints imposed by the mathematical definition of the underlying surfaces are overcome by Free Flow Machining technology. When used to power machining strategies such as that offered by the new Streamline tool path in UGS NX 5, Free Flow Machining technology enables NC programmers to overcome the limitations of traditional machining methods. Free Flow Machining identifies key flow curves that define the area with an automatic assessment of surface boundaries and edges across multiple surfaces. The user can interact with the technology to select as many additional curves as required to perfectly direct the machining flow relative to key part features or shapes.

Key Advantages:

• Establishes a new approach to generating tool paths
• Creates free flowing paths that follow the natural characteristics of the shape to be machined
• Ignores the constraints caused by the way the part was modeled.
• Is driven by fast automated selections
• Is optimized by easy user interaction directing the flow

New Streamline tool path

Streamline, released in UGS NX 5, is a new surface contouring tool path that applies the Free Flow Machining technology as a finishing strategy. The Streamline tool path overcomes the constraints of the underlying model geometry, across multiple surfaces, and creates a tool path that flows with the natural characteristics of the shape.

The Streamline tool path is driven by flow curves that are automatically identified by the system for a given area to be machined. The software interpolates automatically between these flow curves and will morph smoothly from the start geometry to the finish geometry.

Any number of additional flow or cross curves may be selected to direct the flow of the tool path. These curves may be fined tuned by the user to provide an added degree of precision and flexibility, enabling the programmer to align the tool path flow with the direction of key features within the part.

The Streamline tool path is available in both fixed and variable axis machining.

Streamline supports both helical and spiral options allowing the programmer to create paths with smooth continuous cutting, eliminating stepovers and producing a superior surface finish.

Key Advantages:

• Provides surface contouring tool path for finishing
• Applies Free Flow Machining technology
• Overcomes constraints of the underlying model
• Flows with the natural characteristics of the shape
• Path morphs between curves
• Tool path flow can be directed by selecting any number of additional flow or cross curves
• Available in both fixed and variable axis machining
• Supports helical and spiral patterns

Benefits:

• Superb part finish
• Reduced tool wear and breakage
• Increased productivity
  • Fast creation of optimum tool paths across multiple surfaces
  • Reduction in machining time
  • Reduced need for separate part finishing

Dual contact boundary condition

Built into the Streamline tool path function is an automatic “dual contact” boundary condition option. In conditions where the area to be machined meets a wall, NX adjusts the tool path so the last pass touches both wall and floor – the extreme “dual contact position.” This extremely valuable capability can eliminate the need for a subsequent flow cut or pencil mill style operation to clean up the material that would be left by traditional systems, which abandon their fixed machining patterns once they approach a distance from the wall that is less than one step over.

Key Differentiators

The main differentiator for Free Flow Machining is linked to the fact that when incorporated into tool path options such as the new Streamline Tool path in UGS NX 5, it frees the programmer from the constraints imposed by the underlying surface geometry.

At the first look some observers will suggest that the patterns created by the Streamline tool path could be obtained with other systems. In reality these tool paths are hard to achieve with other systems unless the surface area to be machined is a single surface. In most cases the surfaces of the 3D part model will be made up of multiple surfaces and the mathematical definitions of these will not be consistent from surface to surface. These definitions are often referred to as the “UV lines” that relate the surface curvature. Most area milling functions in most CAM systems are linked to these UV lines and creating tool paths of this type that run across surfaces with inconsistent UV lines is a problem.

To address this with conventional CAM software the programmer has two basic choices. The first is to remake the surface geometry across the area to be machined – a time consuming solution that requires modeling skill and assumes that the programmer has access to adequate CAD modeling software to do this. The alternative is to run a standard 3D milling path in some form of regular pattern across the entire area to be machined. This is an easy option but in most cases the resulting tool path does not then follow the natural shape of the part. The tool is likely to traverse features at less than ideal angles. Even with clever options to control the step over distances the strategy typically leads to less than ideal surface finish, and causes widely varying tool loading conditions.

With the Streamline tool path, the user simply identifies the surface area to be machined and the system takes care of the topology issues. Even across many surface patches the system will offer a smooth, flowing tool path. The simple selection of additional curves (as many as needed) will direct the flow so that it maps to key features, such as a groove or ridge in the geometry of the final part. This is like diverting the flow of a liquid in a stream so that it flows smoothly and naturally along the feature.

The result is faster programming, no need to remodel, and the ability to use existing model geometry regardless of source. The use of the Streamline tool path can eliminate the need for subsequent finishing paths such as flow cuts or pencil milling along details of the part. The Streamline tool path will already have created paths that flowed along these details as a part of the single finishing operation.