Today’s CAD/CAM software is not only expected to construct the very best toolpaths and machining plans, but must also be interoperable with software from partner companies and other third-party vendors.
It wasn’t so long ago that machinists programmed CNC lathes and mills by hand. Some still do. Yet most manufacturers today would agree that investment in a modern CAD/CAM system—one driven by knowledgeable, well-trained programmers—brings numerous benefits to the shop floor, manual programming abilities notwithstanding. Chief among these are accurate, productive toolpaths, resulting in improved tool life, greater equipment uptime, and reduced wear and tear on humans and machinery alike.
Perhaps most importantly, a well-oiled CAD/CAM system significantly increases shop floor efficiency, providing shorter cycle times and fewer chances of a costly mistake during machine setup. In this age of interoperability, however, effective toolpaths are only part of the machine shop best practices story.
Toolpath simulation and optimization, machine tool monitoring, electronic work instructions, offline presetting and tool management systems (TMS), cloud-based tooling libraries, inline probing and metrology, manufacturing execution systems (MES)—companies everywhere have either implemented or are in the process of implementing these and other manufacturing systems, raising countless improvement opportunities for those willing to tackle such transformative projects.
The challenge, then, is how to get these disparate software systems to speak to one another. Must shops now hire a software developer or two to augment their team of CAD/CAM programmers? Once these systems are talking, what information should they be made to share? Which will serve as the master, or system of record? And what happens when one or more of them requires a routine update?
These are all relevant questions. Chuck Mathews, executive vice president of ESPRIT CAM, Camarillo, Calif., part of Hexagon’s Manufacturing Intelligence Division, has thoughts on all of them. He started by saying that manufacturers are most likely to succeed on their interoperability journey by first adopting a CAM-centered workflow, one with the digital twin as its foundation.
“In the past, application of the digital twin within a machining environment was primarily limited to post-processed G-code simulation. Now, we’re able to leverage it much earlier in the process, using digital twin data to generate part programs that provide shorter cycle times and longer tool life.”
Mathews noted that one key element of this data is product manufacturing information (PMI). As he and others explained for this article, PMI refers to all of the design, quality, and manufacturing-related data—or metadata—that can and should accompany a 3D CAD model. It includes geometric dimensioning and tolerancing (GD&T) information, material specifications, design annotations, surface finish requirements, engineering change orders, and any other digital data associated with the part or assembly.
When married to a 3D CAD model, PMI eliminates the need for a 2D part drawing. This concept is known as a model-based definition (MBD), an important piece of the Industry 4.0 puzzle. Because the information conveyed through MBD and its subset PMI are machine-readable, interoperability becomes much easier. A CAM system can harvest the data within to generate smarter toolpaths, for example, just as CAI (computer-aided inspection) might use it to generate a first-article inspection plan.
PMI is described in ASME Y14.41-2019, Digital Product Definition Data Practices. There’s one big hurdle to its widespread adoption, though: educating design engineering teams to properly and fully document the geometry of the workpiece. “If you want to eliminate paper on the shop floor and really streamline the manufacturing process, it starts there, with PMI data,” said Mathews.
PMI will be especially important as the current generation of workers retire, he added, suggesting that the next generation will be unwilling to work with the lower level of detail and manual data input common in today’s classic CAM products. Artificial intelligence (AI) and machine learning (ML) will deliver greater automation and improved data flow between software systems and manufacturing equipment, making it possible for those with even minimal expertise to successfully program and operate machine tools.
Ben Mund agrees with Mathews on the importance of seamless data flow. A senior market analyst for CNC Software Inc., Tolland, Conn., developers of Mastercam, he said the industry has done a good job on interoperability but still has room for improvement. “There’s no universal solution yet. We still have standards issues. We still have communications issues. But, by and large, most of us have platforms open enough to share information from external sources, and many have formed direct partnerships with companies willing to collaborate on that goal.”
Nobody offers everything, he added, which is why it’s critical that CAD/CAM providers and their partners continue the push for solutions that allow manufacturers to accept “whatever files are thrown at them, and then make those files machinable,” said Mund. This might mean correcting surface errors in a solid model, or temporarily filling holes and pockets in order to program cutter paths for an adjoining part feature. “Even if an incoming CAD file is completely perfect, there are still certain steps a programmer might take that a designer’s never going to think about.”
One of these steps is the importation of cutting tool and toolholder information. Like other CAD/CAM systems, Mastercam is interoperable with services such as MachiningCloud and Sandvik Coromant’s CoroPlus Tool Library. According to Mund, the use of these and comparable cloud-based information sources has expanded significantly over recent years. And while the initial road might have been a bit rocky for some, online tooling libraries and CAD/CAM systems like Mastercam now get along swimmingly.
The same is true for model-based inspection and measurement software. Aside from the automated generation of inspection plans from PMI data mentioned earlier, these systems can create data for use in CAD/CAM software. Said Mund, “Let’s say you need to machine a replacement for an airplane propeller but don’t have the original CAD file, or you want to repair a damaged engine block. Here, it’s a fairly straightforward exercise to scan the object with a laser or CMM, generate a point cloud, and then mesh that into an existing CAD model. This is one example of how some third-party companies really shine, as they focus on specific industry needs and then develop the tools required for interoperability.”
The tool in this instance comes from Verisurf Software Inc., Anaheim, Calif., one of CNC Software’s longest-running and most integrated partners. Verisurf’s Director of Sales and Marketing David Olson explained that the metrology interoperability gap is closing, but there are still many companies and users stuck in the digital divide, trying to connect the dots.
“CAD/CAM/CAE has been a collective term and reality for years,” he said. “The critical missing link that maintains digital continuity and the all-important digital thread is computer-aided inspection. Once you’ve added CAI to your digital workflow, you’re at the doorstep of true model-based definition, which starts with an intelligent 3D CAD model and extends to reverse engineering, automated inspection and reporting, assembly guidance, product lifecycle management (PLM), statistical process control (SPC) and more.”
The digital thread concept is big, Olson pointed out, and can be overwhelming for some OEMs and job shops to get their arms around. Implementation begins with a commitment to intelligent CAD models and maintaining digital continuity, after which they might tackle model-based measurement for reverse engineering and automated inspection. Both are great places for shops to start, and both will help them bridge the gap to true CAD/CAM/CAE/CAI integration and become compliant with emerging OEM requirements that address digital continuity.
“Bringing efficiency to the customer’s workflow from initial design to first article inspection of the manufactured product is the practical objective of most technology platforms,” Olson stated. “The more seamless you are through this process, the faster you can ship quality parts and the faster you can get paid. The key parts of this interoperability are an open platform, along with the tools needed to quickly communicate, connect, and drive processes. This is why Verisurf offers an SDK (software development kit), as it allows users to quickly integrate different software and hardware for extended automation.”
Alan Levine, managing director of Open Mind Technologies USA Inc., pointed to another area where CAD/CAM interoperability is becoming essential: additive. The Needham Mass.-based hyperMILL developer is adding to its extensive product suite with programming software for the robots used in DED (direct energy deposition), a type of additive manufacturing (AM) process that is frequently combined with traditional machining operations.
Here, part models are often delivered in STL format, the standard by which most 3D printing occurs, or via the 3D-scanned point cloud mentioned previously. These datasets are then imported into the CAM system—either manually or automatically—and used to produce the “toolpaths” needed to drive a cladding head attached to a seven-axis robot. Once multiple layers of metal have been added and the part is sufficiently built-up, a milling cutter is typically used to machine away any excess material, creating the final part shape.
“This is a great example of the niche technologies that CAM providers are now getting involved in, making it necessary to talk about how we will interact with this data,” Levine said. “Up until fairly recently, our job was to make good paths, but that’s not enough anymore. The vision has become much larger. Our customers now want to exchange information with tool management systems (TMS) and offline presetters, third-party simulation software, 3D printers, and much more. It has required us to develop various read-and-write interfaces, as well as APIs (application programming interfaces), where a deeper level of integration might be needed.”
Levine seconded the value of accurate PMI data, as it reduces the chance of human error and makes CAD file interaction more efficient. Yet he also suggested that a fairly large number of machine shops and their owners are not yet on board with all this Industry 4.0 functionality, preferring instead to stick with their legacy software. “The message doesn’t always resonate, especially if they have thousands of CAM files that they’ll need to convert somehow. That said, we find that the shops who are willing to make the change and stay current on technology fare quite well.”
One of the third parties that Open Mind and its CAD/CAM competitors need to share information with is tool management and offline presetting system provider Zoller Inc., Ann Arbor, Mich. As Cedric Hasenfratz, national sales and partnership manager, pointed out, the company currently supports 30 different CAM systems, with more on the way. “As the number of partners and the amount of data increases, it’s become critical that we keep these different systems integrated and communicating with one another.”
It’s challenging work. To keep up with the demand, Zoller has found it necessary to hire software programmers who are also CAM specialists, and who understand the inner workings of CNC machine shops. But even more challenging are the different tooling standards in place today. Being an international supplier, Zoller must accept data on tooling made to DIN and ISO standards, and, as Hasenfratz explained, they’re not exactly the same.
“Interoperability is becoming more and more complicated,” he said. “We’ve found that these two standardized geometry standards don’t communicate as well as we all thought. And there are so many different machine tools and tooling systems that it’s hard for everyone involved to keep up. That said, it’s critical that we as an industry continue to do so.”
Difficulties notwithstanding, Zoller is seeing great interest from the manufacturing community in integrating offline presetting and tool management software with their CAD/CAM systems. The TMS part of this equation has expanded recently thanks to Zoller’s addition of inventory and gauge management functionality, as well as the call for RFID tool tagging, a technology that raises the bar on interoperability.
Someone who shares many of the same concerns and works through the same challenges is Ely Wahbeh, product specialist at CGTech Inc., Irvine, Calif., developer of VERICUT toolpath simulation and verification software. Like Zoller, CGTech must work closely with its customers and partner network to assure interoperability between its systems and theirs. “One of the biggest challenges with developing interfaces is learning how each CAM provider’s API works to see what information we can pull out of there,” he said.
As Zoller’s Hasenfratz implied, much of this effort is spent on the accurate exchange of tooling data. “Simulation used to be much simpler,” Wahbeh noted. “There were drills, end mills, and turning tools, and CAM systems that supported two or three axes of motion. Now there’s all manner of indexable tooling out there, each with unique 3D geometries and machining information that has to be pulled into our software, not to mention machine tools with five or more axes, live-tooling, and so on. And the rate of change is only increasing.”
Some of the “machining information” he’s referring to are the feeds, speeds, depths of cut, and other application parameters that most cutting tool manufacturers publish on their websites or as part of the cloud-based tooling libraries described earlier. If so desired, these can then be used to populate the VERICUT database for toolpath optimization purposes. Wahbeh is quick to point out that such values might also come from the company’s Force system, a physics-based optimization package that provides “the most effective NC program for the given material, cutting tool, and machining conditions.”
Optimization approaches aside, CGTech is actively looking for ways to “close the loop,” Wahbeh said. “We currently gather all of the information needed for the user to see what’s going to happen on the shop floor in advance, allowing them to find any mistakes and address any potential problems. No matter how accurate the simulation, though, variables can pop up that no one anticipated—maybe a different cutting tool was used or the fixture changed at the last minute. We’re looking at ways to run a quick simulation to verify that everything is still okay, although that will probably require an even higher level of interoperability than currently exists.”
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