CAM gets smarter

Manufacturing Engineering, Jul 2000 by Waurzyniak, Patrick

Newest releases add associativity, knowledge-based machining, feature recognition

As manufacturing operations demand greater efficiencies, CAD/GAM software used by shops to machine parts has evolved into a more precise tool for cutting complex products. With the latest releases, CAM software's getting smarter, packed full of features including complete associativity between model geometry and toolpaths, knowledge-based machining; feature recognition, high-speed machining, and solid-based machining capabilities.

In the months preceding IMTS 2000, several CAM vendors as well as CAD/CAM giant IBM Corp. (Armonk, NY) have updated their CAM software systems with the goal of significantly adding to the functionality in users' toolboxes. New releases of Mastercam, GibbsCAM, EdgeCAM, PartMaker, and others, join an updated CATIA Version 5, which IBM and CATIA developer Dassault Systemes S.A. (Paris, France) introduced last fall. Dassault and IBM plan several CAM additions for CATIA VS that IBM says will begin appearing in a few months.

"Knowledge-based machining, feature recognition, and associa tivity usually appear on everybody's wish list," says Ed ladzinski, IBM's analysis and manufacturing domain manager for the Americas. "If you talk to a programmer, he'd like to have a lot of control over his program, but at the same time, he'd like to take out the redundant, or tedious functions."

Many CAM systems increasingly employ a type of artificial interngence in knowledge-based machining techniques, as with IBM's Prismatic Machining Assistant and its Mold & Die Machining Assistant modules, Ladzinski notes, which are available under CATIA V4, but will be updated for Version 5 in the near future. With such KBM capability, programmers are able to designate which portions of machining processes to automate, he adds. "We took great pains in saying, you don't have to do this, it doesn't have to be completely automatic," says Ladzinski. "You can say `I only want a section to be automatic, and I want more control.' So it's mix and match, which is what customers wish for."

Full associativity, high-speed machining (HSM) and solid-based machining are but a few of the 100-some new features in Mastercam 8, the latest offering from CNC Software Inc. (Tolland, CT). Along with a substantially revamped user interface, Mastercam 8's full associativity now allows machinists much more simplified programming and modification of all milling and turning operations, including pocketing, contouring, drilling, multisurface roughing and finishing, and multiaxis machining. The system's geometry and toolpath are linked so that when a model or tooling information changes, an updated toolpath can be generated with a single mouse click. Users also can "drag-and-drop" parameters, toolpaths, and tool definitions from one operation to another, and create a library of common operations to apply to new models. The programmer simply chooses a set of saved operations and a new part, and Mastercam adapts the processes to the new model.

"We've had associativity for two years, but not for all of our toolpaths, notes CNC Software's Vice President Mark Summers. "The toolpaths that were associative were two-dimensional-drilling, contouring, pocketing. But with Version 8, all toolpaths, including turning, 3-D surface machining, and even fiveaxis toolpaths, are associative."

With HSM techniques becoming more widespread, Mastercam's Version 8 delivers a suite of highspeed motion toolpaths that achieve HSM's primary goal of tool control. The software's HSM capabilities allow users to reduce sharp angular moves in order to allow for continuous, smooth tool motion. Version 8 includes several crucial methods for running standard toolpaths in high-speed format, as well as several toolpaths developed specifically for highspeed machines.

"We spent a lot of time on highspeed machining in this release," says Summers. "It's a new approach to machining that's in its infancy. High-speed machining is really going to take over a lot of mold shops. I've spoken to a number of people that have bought high-speed machines, and they've been pretty vocal about how much time they've saved on the typical jobs they do."

High-speed machining can be a gray term, adds Summers. "Everybody has their own definition of what high-speed machining is. There's two aspects to high-speed machining, one from the hardware point of view, the machine-tool manufacturers and what they view as a high-speed machine. What I describe as a high-speed machine is a machine that has been constructed differently than a typical bed mill. Typically the X and/or Y axes do not move the machine table.

"There are a lot of things that make up high-speed machining, there's a lot of pieces to it," he adds. "The spindle speed, of course, is important, and the real high-speed machines go about 40,000 rpm. The cutting feed rates are 100-300 ipm. It typically takes small, light cuts instead of big, heavy cuts. From a software point of view, we need to output toolpaths that benefit highspeed machines."