Technology Trends In CAM Software

In the annual CIMdata survey, CAM software suppliers vendors are asked to list the top three technology trends as they see them. The results are tabulated and published in the annual CIMdata Market Assessment Report, a 225-page report that assesses the state of the industry. The findings of the most recent survey are shown below in order of frequency of mention, along with a few of my own comments. CIMdata concurs with this ranking by the vendors.

More multi-axis and multifunctional machining. There is a clear trend toward greater use of multi-configuration machine tools. Tools are becoming increasingly complex in terms of being multifunctional, multi-spindle with subspindles, multi-turret, and multi-axis. Lathes with 12 or so axes are being put into production, and the use of four-axis lathes and mill/turn machines is commonplace. The milling capability is comparable to that of some machining centers. Parts that previously required multiple turning and milling machines are now being produced on a single machine. This requires advanced software to effectively use the machines and may also require new postprocessors to drive the tools. However, the savings in setup time and the increase in production efficiency can be significant.

Increased use of continuous five-axis machining. Continuous five-axis machines are machining centers in which three mutually perpendicular axes and two rotational axes move simultaneously. This type of machining has long been employed in aerospace operations, but it is now finding use in mold and die machining. Five-axis machines have the reputation of being expensive and difficult to program. However, with prices ranging from $100,000 to $200,000 and with software that is easier to learn and execute, their use is broadening.

High-speed cutting is becoming commonplace. Most mold and die shops now employ high-speed machining. The software to support this technology must provide for fast and efficient transfer of data; smooth tool movement that minimizes any sudden change in direction; a constant chip load to maximize the life of the cutter; and support of those machine tool features necessary to produce gouge-free, high surface finish parts. Surfaces must be tangent, without gaps or overlaps. Machining is sometimes done on the actual surfaces as opposed to tessellated surfaces to obtain a higher quality output. However, quality problems sometimes occur with high speed machining, as the material can overheat, cracks can develop and the material can move. Nevertheless, the use of high speed cutting has become mandatory for toolmakers, and all CAM software vendors providing products to this industry segment must effectively support this technology.

Further automation and greater use of knowledge-based machining (KBM). Every aspect of CAM software is becoming more automated, making it easier to learn and use and more productive for the user. The utilization of KBM is the centerpiece technology for implementation of semi-automatic and automatic toolpath generation.

The two primary technologies for implementation of knowledge-based machining are adaptive and/or generative. In addition, a KBM process can be either feature-based or parts-based. When employing feature-based machining, automatic feature recognition software can be used to examine a model, determine which features exist and extract the features for subsequent processing.

More solid-base machining. Solids-based machining is increasing and is now commonplace. Seamless interoperability with solid models is occurring. Machining is often accomplished directly on a solid model. The three main elements of solid-based machining system are:

• A solid modeling system.
• The ability to import the data contained within the model into the CAM system without translation.
• A CAM system that uses the inherent intelligence and functionality with the solid model.
  

Most software vendors now support machining on a tessellated solid or surface model and solid and surface definitions can be intermixed with the same hybrid model.

Increased use of 3 + 2 machining. In five-axis positioning, also known as 3 + 2 machining, a two-axis tilting rotary figure is added to a three-axis machining center so that workpieces can be positioned at different angles. Once positioned, the workpieces are then cut in three-axis mode. This type of machining provides many of the benefits of full five-axis milling, and it can serve as an alternative approach to either three-axis or five-axis continuous machining.

This type of machining is particularly important for cutting deep cavities or deep standing cores in molds. Software is sometimes employed to optimize the tilt angle of the tool. The user defines the maximum tilt angle but does not need to define the specific tilt angles. The software finds the locations where tilt of the cutter is required and the calculates minimum tilt angle to avoid hitting the side. The software will maintain that angle until a collision is apparent. At that point, it will change the angle in order to avoid a collision. If an area is encountered that does not require a tilt, then the software reverts the tool to a position normal to surface or one with less tilt. All repositioning of the tool can be done automatically with a minimum amount of tilt. The tool path from this process will look like a continuous five-axis tool path. This technique is becoming increasingly common in mold machining.

Introduction of process-focused automation. Software is evolving from the use of basic instructions to full-process automation. A process-focused approach is better able to consider the full needs of a specific type of user. For instance, wizards can be used for processes such as electrode design or tooling assembly creation. A number of vendors have introduced application suites for design and cutting of progressive dies. Full five-axis processes including the machine tool, controller, toolpath generator and postprocessor, are available from some vendors for milling of intricate products such as impellers, blisks, turbine blades, tubes, pipes, tire molds, aerospace components, dies and deep cavities within molds. Software is usually customized to enhance a process.

Emergence of more realistic simulation. Significant improvement is being made in software for machine simulation, toolpath verification, and rendering. Realistic simulation of the entire machining process including the machine tool, holders, machine components, cutting tools and stock can be made. Simulation of the tool path is provided to verify its accuracy. Gouges, undercuts and any discrepancies between the target part and the machined part are shown. Users can compare the in-process model with the designed workpiece. Rendering software provides for photorealistic images of the machined part.