New Level In Knowledge-Based CAM

The CAM system is a repository of manufacturing process knowledge that, once it recognizes workpiece geometry as meeting a predefined set of conditions, can automatically generate both process plan and tool paths with little or no operator input at all.

Article From: 6/15/1998 Modern Machine Shop

For the past ten years, many CAM vendors have aimed at developing an almost completely automatic NC programming solution. Early on, the technology was referred to as "generative" numerical control; more recently it has taken on the monikers of "intelligent" or "knowledge-based." Whatever you call it, the basic idea is the same. The CAM system is no longer just an interactive tool for laying tool paths on an underlying piece of geometry. Rather, it is a repository of manufacturing process knowledge that, once it recognizes workpiece geometry as meeting a predefined set of conditions, can automatically generate both process plan and tool paths with little or no operator input at all.

At least that's the objective. It's been slow to come to fruition, however, in a large part due to the difficulty of capturing a broadly applicable set of machining methods in software and in the ability to automatically recognize workpiece features in the first place. That is changing quickly, however, with the advent of truly intelligent systems that are finally living up to the solutions promised a decade ago. A good example of such technology is the recently released CAMWorks 98 system from TekSoft, Inc. (Phoenix, Arizona).

The first release of the system came last year in a partnership agreement with SolidWorks Corporation (Concord, Massachusetts). According to CAMWorks product manager Bruce Wiener, "This close integration uses SolidWorks geometry to generate tool paths to ensure that the part you machine is the same part you've modeled."

The CAM software allows users to associate a manufacturing process with a given workpiece feature. For example, if a counterbored hole—a feature—is to be machined, a typical process might be to center drill, drill, ream and counterbore. If that process were programmed with an interactive process, the programmer would have to indicate each operation individually, specifying tools and perhaps feeds and speeds for each process step. With true knowledge-based CAM, however, the system already knows the process. All that need be indicated is what kind of feature the hole is, and the system does the rest, automatically picking up geometry information from the model and selecting appropriate tools and process parameters for the material.

The new CAMWorks system takes this concept one step further with its ability to automatically recognize a range of standard features (features can be identified with an interactive process as well) if the workpiece is properly defined in SolidWorks. Moreover, the strong integration between solid modeling and tool path generation functionality allows full associativity between CAD and CAM functions, meaning that once a change is made to geometry or other product data, it is automatically propagated throughout the system. So by changing the depth of a pocket, for example, the pocketing tool paths can be updated automatically.

Developers of knowledge-based systems today recognize that shops need to be productive with their CAM systems right away, rather than having to wait as a sufficient measure of a shop's methods are captured. As such, the system includes a selection of standardized machining processes that can be used as defaults or be edited to methods more to the user's liking. In cases where a standard process doesn't apply, routines can be generated with a more interactive programming process as well.

According to the company, still more functions have been added with the latest release. For instance, multiple features can be associated together into a pattern feature simply by dropping and dragging. The new "Profile Feature Wizard" enhances feature definition by maintaining profile and depth associativity, automatic detection of islands and their heights, and a filter for edge selection. A new multi-axis wizard highlights faces to be cut in one color and faces to avoid in another color. Plus, there are two different new modes for selecting faces—window selection and adjacent pick. And a new 2.5-axis "rest machining" capability allows the system to automatically machine material left over from a roughing operation.

Verification capabilities have been enhanced as well with the ability to step through programs in a number of ways. The system allows users to quickly pass through areas of little interest, yet also to concentrate on portions of the program deserving greater scrutiny. Also, functions have been added that provide both greater control of individual tool path strategies, and to automatically optimize other tool paths such as drilling, boring and tapping routines.

Enhancements to the system's technology database include the ability to define the specific machines in a shop, which can have an impact on the machining methods chosen for a given workpiece. There is also a "tool crib subset" of available tools in the library. Additional enhancements include user interface changes that allow shops to capture more machining methods and processes in the database. In fact, every operation's default values can be user defined.

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