The Ideal Interface for Machining

The Ideal Interface for Machining
SME Media March 2022
By Kip Hanson

One day, programming a CNC machine tool will be as easy as uploading a CAD model with attached product manufacturing information.

The machine’s control will use artificial intelligence (AI) to analyze the part’s geometry and material properties, select the correct cutting tools, apply the appropriate feeds and speeds, verify there will be no collisions and that its self-generated toolpaths will neither gouge the workpiece nor leave any material uncut, and instruct the machine to get cutting. It will then monitor the machining process, adjusting parameters and replacing cutting tools as needed—all the while ensuring the part is within its GD&T specified tolerances. And if something goes awry that it’s unable to fix on its own, the control will stop the machine and patiently wait for assistance from its human masters.

This future CNC will perform each of these functions autonomously, much like the self-driving cars that bring the machine’s flesh-and-blood companions to work each day, the robots that load the truck and wash the parts, or countless other soon-to-be commonplace examples of AI-powered technology.

Until that auspicious day, humans must continue programming the old-fashioned way—via CAM software, conversational programming systems, or punching in G code at the machine one character at a time. The good news is, the first two of these methods are becoming both easier and more capable, while even the latter is becoming less painful, thanks to control interfaces that make machine operation much like texting a close friend or visiting your favorite website.

Surfing the Web-enabled Control

It’s the technology behind this last activity that has Harsh Bibra most excited. The general manager for North America at Fagor Automation Corp., Elk Grove Village, Ill., Bibra explained that he and others at Fagor have spent the past few years developing HMIelite, a “scalable, portable, customizable, and interactive” control interface powered by a programming language that even many school-aged children are familiar with: HTML 5, the language of the internet.

“Any young person will grasp it immediately, which given the skilled labor shortage and the need to bring the next generation into the trades, was at least part of our goal,” said Bibra.

As its name implies, HTML 5 is the fifth and final version of the ubiquitous hypertext markup language standard, or HTML. According to the World Wide Web Consortium (W3C), HTML gives web developers the ability to “publish online documents with headings, text, tables, and photos, retrieve online information via hypertext links, design forms for transactions with remote services, and include spreadsheets, media clips, and other applications directly in their documents.” Simply put, if you see it on the internet, you can thank HTML.

But what does programming machine tools and making parts have to do with building web pages? Nothing, at least not yet. By developing a control interface that practically anyone can easily manipulate, however, Fagor has given machine builders and end-users alike a powerful tool that Bibra suggests is very much the future of machine tool interfaces. “Basically, HTML 5 allows our customers to modify any screen or create a completely new interface very quickly and easily, using talent that is readily available.”

He also noted that HMIelite is currently an option, and that the company’s standard interface offering remains in place. For those in search of extreme flexibility, however, an HTML-capable control gives users some intriguing capabilities. A medical device manufacturer might use it to make “surgeon-friendly” machine tools. An automaker could easily customize the interface to a specific high-volume application, while a global manufacturing company might add geotagging, secure remote monitoring from any mobile device, and similar location-aware features to its fleet of CNC equipment.

Said Bibra, “The needs and skillsets of the people operating the machine in each of these examples are completely different, which is why the ability to customize the control to unique environments is so important. That said, you still have all the critical technology residing inside the CNC; so the HTML 5-based human-machine interface, or HMI, does not require a connection to the internet or the cloud to function.”

Clear Text

Gisbert Ledvon, director of business development for machine tools at Heidenhain Corp., Schaumburg, Ill., agreed on the need for easy customizability. “Our latest control, the TNC7, takes it to the next level in terms of user-friendliness,” he said. “Here, the operator can not only determine how they want the various screens to look and function, but can also program the part graphically directly at the machine tool. There’s no other control on the market quite like it.”

Hold on, though: conversational controls with graphical programming capabilities have been around since Francis Reintjes and Douglas Ross of MIT’s Servomechanisms Laboratory first introduced APT (automatically programmed tool), now more than 60 years ago. Yet Ledvon is referring to a self-programming capability on par with that described at the start of this article, one that needs nothing more than a solid model to generate machining code. What’s more, the resulting programs do not use G code, the industry-standard CNC programming language for the past several decades.

Ledvon described a control that accepts CAD files as readily as it does freeform shapes drawn on its touchscreen. In the latter case, operators can use their fingers to sketch circles, lines, and other part geometries, assign dimensional values to them, and when done, push a button to begin the programming process. “The first time I saw it, I was completely blown away,” he said. “The control writes the entire program for you in Klartext, a human-readable language. You can go back and forth, making changes and simulating them on the screen until everything is the way you want it before executing the program.”

The control builder has simplified the programming process in other ways as well. For instance, where a typical G code program might use dozens or even hundreds of commands to complete a specific operation, Heidenhain’s Klartext might use just a single line of code to accomplish the same thing.

Ledvon also pointed out that, due to their condensed length, these multifunction commands make it easier to troubleshoot programs. “We’ve had such advanced functions available for some time now, but continue to expand on their capabilities,” he said. “One recent example of this is OCM, short for optimized contour milling. This function allows the operator to interactively program a trochoidal milling toolpath, simulate it and check for interference, and then push a button to chamfer the entire part profile, or move a slider to automatically determine the perfect feeds and speeds based on the material, the cutting tool, and how aggressively you wish to machine the part.”

Lending a Helping Hand

Automatic machine tool programming is nothing new. Sodick and other EDM builders have been using “fuzzy logic” in their control systems for many decades. Here, an operator enters values for the desired surface roughness, rate of electrode wear, machining speed, and other variables; the control then determines what operating parameters will best achieve those targets. Nor are the interactive control features that Ledvon just described especially new, although they’re clearly far more powerful than they once were.

So is conversational programming, which made its industry debut a decade or so before fuzzy logic. Paul Webster, director of FA Engineering at FANUC America Corp. in Rochester Hills, Mich., noted that FAPT—the FANUC version of APT—has since been replaced by MANUAL GUIDE i, a control option that the company’s website describes as “a user-friendly conversational programming platform that makes it easy to create part programs right on the shop floor without needing to know G code.”

Yet the same can be said for many CAM systems, which begs the question: has conversational programming gone the way of paper tape and HSS tool bits? Not at all, said Webster. “CAM systems and laptop computers are now inexpensive enough that practically anyone can afford one, so many manufacturers have taken that route, but for job shops, tool and die makers, and other environments where people are building one or two of a particular item, MANUAL GUIDE i remains quite popular.”

Conversational or not, Webster noted that the user interface on newer FANUC controls straddles the fence between traditional, G code-only interfaces and those that are graphic-driven. “Our 30iB or 0iF are a lot more operator-centric than legacy controls,” he said. “Both have our iHMI interface, which helps walk the operator through everyday tasks. The control will prompt users when they’re entering values for a threading cycle, for example, and is much more graphical and easier to use than ever before.”

The push for greater usability is in large part driven by the ongoing labor crunch, he added, and the entry to the workforce of young people comfortable with smartphone apps and browser-like interfaces. But despite this kinder, gentler CNC world, FANUC controls remain backward compatible, and the old-timers who cut their teeth on decades-old 16B or earlier controls will have no problem picking up a current model 30iB.

Regarding customization, Webster pointed to FANUC’s FOCAS API (application programming interface), currently on its second generation. With it, machine builders can modify control screens, write software interfaces and connect with third-party systems, and collect data from FANUC and MTConnect or OPC compatible brands of CNC equipment. “FOCAS supports these and other software development functions using C++, C#, Visual Basic, or whatever other programming languages you want to use,” he said. “In addition, the iHMI itself is very customizable, so our customers have many options when it comes to interoperability and interface modifications.”

It’s All About the Teamwork

Jim Kosmala sees the same need for conversational programming, at least when it comes to the basic onesie-twosie type scenario just described. For higher volume or more complex work, though, the vice president of engineering and technology at Okuma America Corp., Charlotte, N.C., suggested that a CAM system is practically a prerequisite. “Our Advanced OneTouch, or AOT, is good for the first group of shops, but frankly, the human brain just can’t process more than a few axes simultaneously. This is why anyone who wants to leverage the full capabilities of their five-axis machining centers and multitasking lathes generally does their programming offline.”

And yet, offline doesn’t preclude conversational. Like many such programming systems, AOT is available for use on a PC as well as the machine. For that matter, many CNCs now support a host of PC-based software applications, Okuma’s machine controls among them. This has proven fortuitous over the past two years as shops everywhere struggled with support and training in the face of COVID-related lockdowns and travel bans, leading Kosmala’s team to leverage a solution that many of us have become familiar with during the pandemic: Microsoft Teams.

“Because our OSP controls run on an Intel chip using the Windows operating system, they support most PC-based software packages,” he said. “So when one of our distributors had a problem with a machine in Mexico early last year and we couldn’t go there due to travel restrictions, we told them to install MS Teams directly onto the Okuma machine tool. One of our electrical engineers here in Charlotte was then able to connect remotely, diagnose the error, and get them up and running quickly. There was no need to get on an airplane, no car rental or hotel expenses, and minimal downtime. Everyone loved it, especially the customer.”

MS Teams has since found a more permanent home at Okuma America for training purposes and to walk customers through application questions. In fact, the machine builder has flipped the camera around, so to speak, inviting customers to attend virtual programming and maintenance classes on MS Teams via the Internet. Kosmala added “As they say, necessity is the mother of all invention, and in this case, COVID drove us to leveraging MS Teams running directly on the machine tool control. In hindsight, we could have been using these tools prior to COVID.”

When asked what’s next for Okuma, Kosmala stated that, “Like everyone else, we’re continuously developing new technology, and are working diligently to make our products both friendlier and more powerful. Part of this effort will be focused on AI-based functions like our Spindle AI, Feed Axis AI, Machining Navi, and other adaptive controls, as well as closed-loop machining functions, optimized cutting, and data collection.”

Natively Digital

Last but certainly not least is Siemens Industry U.S., Elk Grove Village, Ill., where virtual technical application center manager Chris Pollack stressed the importance of the digital twin and its use in machining simulation. “We’ve been building advanced machine tool controls for many decades, and our newest product, the Sinumerik One, is the latest rendition of that technology,” he said. “Its main purpose is to finally merge the digital and physical worlds together as one, allowing manufacturers to conceptualize, design, test, and virtually machine parts before cutting the first chip.”

These capabilities might seem like nothing new for those who’ve invested in third-party toolpath simulation software, yet Pollack said the two are like apples and oranges. “There’s a brain in the CNC that a third-party software company does not possess, and never will. By having a digital version of that brain, you have access to the closest, most accurate representation of what the physical machine’s going to do when you push the cycle start button. It’s really the only way you can achieve that.”

As Pollack explained, this virtual brain might reside in software located on the control’s PC, a PC in the programming office, or a PC sitting alongside the CNC lathe or machining center. Whatever the location and however the CNC program is generated, its user has the ability to model the entire machining process. They can load virtual vises and toolholders, check for interference, validate probing routines and make certain everything about the setup will work as intended, all while the machine tool is busy making parts.

How does this make programming or machine operation friendlier? It doesn’t, until you consider that standing in front of a crashed machine is a decidedly unfriendly place to be, an event that the digital twin is designed to prevent. It also serves to increase spindle uptime and give all involved the opportunity to improve everything about the machining process well in advance. And while it might seem that Pollock is making a case against conversational controls, appearances can be deceiving—the company delivered a revamped control and user-centric interface in 2010, complete with graphics-driven, easy-to-use machining cycles.

“We recognized well before the release of our Sinumerik Operate HMI that skill levels within the workforce were declining, and that we had to get away from what was admittedly a highly complex control that many found difficult to use,” he said. “Today, our controls are completely conversational. You can operate everything without knowing even the simplest of G and M codes. In fact, we developed the control in a way that’s very similar to the technology that people were beginning to move towards, which was smartphones, apps, and touchscreen gestures. It’s that easy.”