CAM Software @ the Cutting Edge
Computer-aided manufacturing is changing. So is the software to do it.
The economic meltdown last fall has put even more pressure on the factory floor to speed things up, to be more productive, to do more with less. Right in the thick of this is computer-aided manufacturing (CAM). CAM software is helping machinists use more complex and advanced machine tools, increase their productivity, and produce parts of higher quality. And this is being done by a reduced number of experienced workers in an environment where there are additional factors like lean manufacturing initiatives, higher demands for product innovation and functionality, and the demand for increasing profitability. Here’s how some CAM software is meeting those pressures.
Multi is the norm
“Complex” machine tools feature multiple axes, multiple spindles, and or multiple turrets. There are milling machines, turning machines, and even mill-turn machines. This equipment can perform multiple metal removal operations on the fronts and backs of workpieces, often from a single setup, while providing superior part quality. “To effectively utilize these multi-faceted machines requires specialized software to program the tool movements, simulate the operations, and post-process the output,” explains Alan Christman, chairman of CIMdata’s board of directors (Ann Arbor, MI; www.cimdata.com). “CAM software must provide individual control of each turret, together with turret synchronization and accurate cycle time calculation.” For example, SolidCAM from SolidCAM Inc. (Fort Wayne, In; www.solidcam.com) includes 5-axis machining strategies for swarfing and trimming, and for machining complex geometry parts, such as mold cores and cavities, cutting tools, cylinder heads, turbine blades, and impellers. The software can separate machining for steep and shallow areas. Machinists can define 2.5D and 3D machining operations on any face, and can limit machining to specific areas by defining a planar boundary projected on a solids model.
Emphasis on speed
Money can be made through fast, accurate production. This is why many shops have moved to high-speed machining (HSM), which has the added advantage of creating high-quality surface finishes. CAM software for HSM operations must be quick at interpolating and directing machine components and tool paths so that tool movements are smooth. The software must calculate and maintain constant chip load to maximize tool life. And the software must match machining and toolpath programs with part topology to best produce gouge-free parts and high-quality surfaces while minimizing air cutting. The HSM enhancements included in GibbsCAM SolidSurfacer from Gibbs and Associates (Moorpark, CA; www.GibbsCAM.com), for example, include tool paths optimized for high-speed and hard-material machining; tool paths with smoother corners, stepovers, and arc fitting; and improved use of boundaries and precise control within a machining area. The software supports rough machining and a variety of finish machining operations (such as lace cut raster, radial, and spiral; constant stepover cut; steep shallow cut; and multiple passes on either side of an intersection). The HSM-based software also supports tapered tool shapes, multi-surface flowline machining, and automatic core/cavity detection for inside out or outside in milling.
In the know
As automated machining becomes more pervasive, more automation and automated assistance is required to yield higher quality parts. Enter feature-based machining (FBM). Mastercam from CNC Software, Inc. (Tolland CT; www.mastercam.com) is a good example of software with FBM. Mastercam evaluates a part’s features and then automatically chooses the tools and operations, sequences the operations, calculates feeds and speeds, and generates the machine code for optimized metal removal. (CAM software can also generate the coordinate measuring machine code for inspection.) Mastercam can detect solid features for pocketing, contouring, and drilling routines. As necessary, it will machine pockets using high-speed roughing, rest mill, and finish operations; automatically create drilled, tapped, counterbore, and countersink holes; and automatically perform spot drilling and pre-drilling based on user-controlled settings. All tool paths are fully associative and editable after creation.
Seeing is believing
CAM software is simply becoming easier to use and, among other things, easier to learn to use. First, the graphical user interface often includes prompts and wizards and automated calculations and context help. Second, lifelike simulations let machinist setup and “machine” before actually cutting. These visualizations go well beyond photo-realistic displays of parts. Machinists can now verify all aspects of machining: tools, holders, and other components, tool paths, feeds and speeds, potential collisions, undercuts, production time, and material stock before, during, and after becoming a finished part.
Many CAM vendors have rewritten their CAM software for 64-bit and multi-core computers, computer technology that’s now easily found even in laptop computers. Individually and together, these hardware elements enable computers to process more information, calculate faster, and multi-task (such as crunch data and display simulations in real time). For example, consider the French company Missler Software Inc. (www.topsolid.com; in America, Clear Cut Solutions, Inc.; Addison, IL; www.clear-cut.com). Missler plans to release two versions of its TopSolid CAD/CAM software in 2009. TopSolid 2009 includes a variety of mold-making enhancements. The second release is being rewritten from scratch. Called TopSolid 7, this next-generation product will be a Microsoft.NET application, which includes out-of-the-box support for multi-threading/multi-tasking, 64-bit technology, and everything the Microsoft Windows operating system has to offer.
Missler is one of the few companies to write both its own CAD and CAM software, versus gaining one or the other through acquisition. TopSolid CAD is a hybrid parametric modeler. The CAM product offers 2- to 6-axis milling and 2- to basically unlimited-axes mill turning. Machine simulation is included—with a difference. Most CAM software pass vector information to a post-processor, which in turn creates and displays the machine simulations. TopSolid CAM does all the calculations for machine kinematics, fixtures, collision checks, and part states, and then displays accurate simulations of the machining operation. The post-processor? That’s basically a language converter.
