Numerical control tool paths

Once a geometric model of data base is created it may be shared for many of the product development steps described earlier. The data base may be copied and scaled for shrink factors to enable a mold designer to do preliminary mold design, or an engineer can use the same data base to perform structural analysis. Numerical control tool paths may be developed concurrently with the final mold design. Such modeling tools as finite element analysis, mold fill, and mold thermal... 

Plastics with their inherent complex geometries are typically better suited to boundary representation models. Also functions such as finite element modeling or numerical control tool paths require explicit surface definitions which are only available with boundary representations. With constructive solid geometry systems, surface information must be evaluated before it is user accessible. Wireframe models again may be used as the base and are easily transferred to a boundary representation system. Conversely a boundary representation model may be readily converted to a wireframe. Many current commercial systems combine the features of both constructive solid geometry and boundary representation. A project consisting of simple machineable shapes may be done faster in a constructive solid geometry mode while a sculptured surface model would be more easily created in a boundary representation mode. The separate models can... 

In the near future, the solid model data base will be directly accessible to allow product drawings, finite element models, and numerical control tool path generation directly from the solid model. Sculptured surfaces will be generated easily and changed readily. The... 

Another important capability of the CAD system is in the manufacturing of molds or dies to produce the designed product. A database can be copied for numerically controlled tool paths already scaled for shrink factors, to enable the mold or die designer to prepare a preliminary or production mold or die design. 

Computer-aided manufacturing (CAM) refers to the production or alteration of control data for manufacturing. Often the term is used to specifically refer to computer numerically controlled (CNC) machine tooling. With regard to the plastics industry, CAM generally refers to the generation of CNC cutter paths for the production of molds and dies. More recently, plastics CAM has been extended by the availability of smart controllers for injection-molding machines. This is an important development and will be discussed in detail subsequently. 

The system s software must provide the CAM feature and then the tool path of working cycles can be produced automatically. It also can process the technical information and produce the numerical control data for numerical control machining. 

The software system must be the best CAD/CAM system which is rich in excellent features, such as the 3-dimensional solid modeling software, curved surface producer, finite element analysis package, 3-5 axis surface cutting, cavity cutting, and tool path calculation ability for many types of machine tools with numerical control. 

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