With improved CNC gear, manufacturers boost productivity and keep metalcutting
By Patrick Waurzyniak
Machine controls and control software govern the factory, enabling machine tools to work most efficiently for any machining task. With the latest advances in CNC hardware and software, manufacturers can boost productivity and efficiency by deploying machine tool control systems equipped with faster processors, improved networking, and enhanced software applications.
Shop-floor controls today often feature the latest in PC-based front ends for easy programming, as well as newer communication capabilities including faster Ethernet networking and other productivity-oriented software, to increase part-making efficiency. Among the latest systems, the new iTNC 320 compact contouring control from Heidenhain Corp. (Schaumburg, IL) offers users more advanced features in an affordable analog control aimed at general-purpose machining applications.
Heidenhain’s new iTNC 320 adds several new capabilities over its predecessor, the iTNC 310, including 10 MB of memory, faster networking with 100-Mbps 100BaseT Ethernet, more I/O expansion, flash memory and USB ports, and a crisp 15” (381-mm) thin-film transistor (TFT) color flat-panel display that replaces the 310’s monochrome screen.
A compact, workshop-oriented control, the iTNC 320 can control up to five axes and with its analog drive interface, easily upgrades machines with existing analog drive systems on retrofit applications. Capable for milling, drilling, and boring operations, the control features Heidenhain’s conversational programming, as well as G-code programming with addition of an optional USB keyboard.
“There’s still a market out there for analog controls, but the iTNC 310 was not quite cutting it,” notes Chris Weber, Heidenhain product manager. “The 320 has a color screen with much superior graphics, a faster processor, more I/O on board plus expansion capabilities, more memory and a 100BaseT Ethernet interface. You can also add a standard USB keyboard, plug it in, and you have a full QWERTY keyboard to do G-code programming.”
In addition, the new Heidenhain control is the first to use the company’s updated NC Kernel, which is said to offer several benefits including a more powerful interface between the PLC and NC, allowing elimination of redundant operations. “This will now be the standard going forward for all future Heidenhain controls,” Weber adds. “It has a little bit of difference with respect to the PLC structure, the parameter system, and in terms of the commissioning, but they’re all positive enhancements. This is the first in the next generation of Heidenhain controls; what’s interesting is we chose a very simple control to do this with.”
For higher-end five-axis machining applications, the company still offers its iTNC 530 digital contouring control. With the 530 control, the company is now adding as an option its new Dynamic Collision Monitoring (DCM) software, which allows users to define machine elements in 3-D simulation to avoid costly collisions during machining processes. “If I’m a machine builder, I don’t want to crash my machine, so I basically define everything in the work envelope that could possibly collide,” Weber notes of the DCM software. “It’s in the control itself, and with it, all of these different elements—toolchangers, an integrated rotary table, a tool touch-probe—nothing can hit anything anymore. As soon as I change the tool, the control knows that I’m working with a different tool, it knows where the tip of that tool is and that if I make this move, it’s going hit the rotary table.
“The main goal here is machine uptime,” Weber adds. “If I crash my machine, broke a tool, damaged a spindle, or the toolchanger, I did something wrong and now my machine’s down. If I can avoid those collisions, I never have a machine down.”
For integrated control systems, the IndraMotion for Handling solution from Bosch Rexroth Corp. (Hoffman Estates, IL) offers manufacturers a turnkey gantry solution that combines a Rexroth IndraMotion control with linear motion modules and hardware aimed at pick-and-place applications for machine tools deployed in automotive and other industries. “In many cases, an OEM does not have enough engineering staff to develop a motion-control system from scratch, and the cost associated with developing a full motion-control system also may not be justifiable,” notes Young Chon, senior applications engineer, Bosch Rexroth Corp.’s Electric Drives and Controls group.
The Bosch Rexroth system is a scalable gantry solution for handling applications, and it includes all the necessary hardware and software components with predefined motion function blocks to run pick-and-place and loading/unloading machinery. Powered by Rexroth’s IndraControl L40 Motion Logic controller, Cartesian gantries with up to three linear axes, X-Y-Z, and three rotary axes, A-B-C, of motion can be precisely controlled. The PLC-based turnkey solution is based on the IEC 61131 PLC programming standard, notes Chon. “This solution is an open PLC source code, so that an OEM can use the PLC program as is or customize sections of PLC code,” Chon says. “With this approach, an OEM can minimize the machine development time. Bosch Rexroth also provides several scalable HMI solutions with standard screens.
“Customers want flexible, cost-effective solutions that can be supported globally for installation and operation,” Chon adds. “For flexibility, an OEM is looking for different types of interfaces to the drives, I/Os, and HMI. OEMs want to have a choice of different Fieldbus technologies, such as SERCOS, Profibus or DeviceNet, so they can pick and choose to satisfy different end-user requirements.”
Configuration of the Rexroth IndraMotion for Handling system is easy, with the integrated, prewritten IEC 61131-based motion function blocks requiring only a few basic parameters to be set before the system is running. Users can easily define points with robotic programming language using Rexroth’s IndraControl VEH 30 mobile WinCE HMI, and the control calculates the optimum coordinated moves between the points.
“Easy programming and maintenance for the user are the main factors,” Chon states. “If a part program changes frequently or if frequent adjustments are required, then having a user-friendly HMI is a key factor to the system design. The motion controller also should have capabilities to handle complex motions without being too complicated to implement and use.”
Software enhancements as well as hardware improvements are key to offering customers optimal performance and reliability, notes Jim Spearman, manager, CNC Technology & Machine Tool Solutions, GE Fanuc Automation Americas Inc. (Charlottesville, VA). With the latest GE Fanuc Series 30 platform, which consists of the 30i, 31i, and 32i CNC controls, users can run 10 different part programs per control on any three to five-axis machine tool. “Today’s technology is one control, 10 different machines being run and various different operations being performed, so that’s a huge productivity gain—you don’t need 10 operators,” Spearman says. “One operator stands at one console, and looks at 10 stations and a transfer or dial index without going around in a circle looking at all 10 CNCs.”
With more than 40 factory productivity software solutions, GE Fanuc engineers are focusing on plant-wide operations productivity as well as improving the individual productivity of CNC operators. “In that suite of products, we continue our quest for the utmost reliability,” Spearman says. “One of the trends on the control side is that people want to get the PC off the shop floor. The wave of open systems has kind of run its course, to a certain degree. People need to prevent viruses and for security concerns, there’s a whole host of reasons to get that PC off the shop floor. You’ll see us as a control supplier put more and more PC-like functionality into the core CNC, a lot around HMI, a lot around visualization. We’ll develop tools and systems that allow you to do that kind of work inside the core CNC, without actually having the actual PC hooked to the system.
“With new programming tools and the new graphic capability within the core CNC, we can emulate the PCs, the graphical PC front end, without having the PC,” Spearman adds. “That’s the drive in today’s world, especially in automotive sector today—how can you give us the same HMI, the same visualization, and the same capabilities, but remove that PC from the equation?”
High-speed machining applications get a boost from the latest GE Fanuc controls offering much higher throughput than previous offerings. “In the area of high-speed machining, we have faster block-processing times,” says Bill Griffith, GE Fanuc CNC product manager, “and we’re down to 0.4 milliseconds per block. We have faster interpolation rates and we have our nanometer interpolation, which allows us to command the servos at a thousand times finer than most other CNC products, to get smoother acceleration and deceleration. We have a feature called Machine Condition Select that allows us to have the machine set for one set of parameters when we’re doing roughing, then another set for doing semi-roughing, another for finishing, and we can switch between these parameters.
“Specialized settings allow a machine to perform at its best for the type of process it’s doing. When we’re doing roughing, for example, we don’t need accuracy—we want speed,” Griffith states. “On the other hand, when we’re doing finishing, we want accuracy and we need to be less concerned about speed. Those two variables—speed and accuracy—need to be adjusted in order to get the best performance out of the machine tool. If your speed is real high, you can’t get real good accuracy.”
Network-centric thin-client technology is featured in the latest offering from Siemens with its Sinumerik 802D solution line, the first of a series of Siemens solution lines aimed at providing lower-cost controls for milling and turning applications. Introduced at WESTEC, the Siemens 802D solution line targets the low-to-medium milling and turning segments.
“It’s four axis plus one spindle for milling, two axis plus one spindle for turning, for basic machines,” notes Randy Pearson, manager, dealer & end user support, Siemens Energy & Automation Inc., Machine Tool Business Unit (Elk Grove Village, IL) of the 802D solution line CNCs. “It’s a back-powered display, and it’s a low-cost, simple-to-use interface. The solution line portion of it is actually when it gets through the drives and the motors, with the Sinamics drive package, which interfaces now through industrial Ethernet, which we call DriveCliq.”
With its first solution line entry, Siemens offers Ethernet communications, which Pearson says is less expensive with simpler cabling, as well as use of the Profibus protocol for machine tool communication. The operator panel-based control system combines the NC, PLC, and HMI in a single unit, and it has the capability of five-axis machining, including two spindles. The systems offer advanced programming through the Siemens ShopMill and ShopTurn packages, and CompactFlash memory capability for storage, transmission, and processing of part programs.
With the solution line, Siemens has a lower-cost control that is easier to integrate into smaller machine shops and for retrofits applications. “This offers users simplicity as well as a low-cost solution,” notes John Meyer of Siemens. “People recognize Siemens as being high-tech, five-axis machining, highly complex machining, but we do have the low to mid-range with an 802 control for milling and turning applications.”
Simplicity of operation can be critical for many control users when getting started with new equipment on the shop floor. “With today’s technology, customers are finding it harder and harder to implement the technology in real-time on the shop floor,” notes Todd Drane of Fagor Automation Corp. (Elk Grove Village, IL, and Mondragón, Spain). “Customers want to see how easy it is to use before they purchase, and CNC manufacturers have to pay close attention to operating systems if they want the order. Having the latest technology on your CNC isn’t enough, it has to be easily accessed by the manufacturer.”
To aid users, Fagor has recently introduced its CNC Dual-Mode Operating System for Fagor’s 8040 and 8055 CNC controls for milling and turning, offering either conversational programming or conventional G-code programming in the same control. “This provides the capability to create part programs with either a powerful ISO G-code operating system including high-level language statements or a 100% conversational ICON key programming system,” Drane says. “The ICON key programming system allows customers to simply press an ICON key with a picture of the operation they wish to perform. then simply fill in the blanks based upon the blueprint and the graphic example we provide on the CNC display.
“We initially felt this operating system would only be embraced by new inexperienced operators and programmers, but we quickly learned that many very experienced G-code programmers prefer the system for quick and easy short production runs,” Drane notes. “We have seen operators who have never created a single part program before, literally walk up and create and execute their first program within 30 minutes.”
Wireless remote operation with the Advantage 900 CNC package’s remote pendant from Delta Tau Data Systems Inc. (Chatsworth, CA) frees operators from working directly at the machine control panel. The Advantage 900 CNC features a Windows front end, but offers a real-time DSP for motion-related tasks.
“This frees you up from cabling,” says Vince Burokas, Delta Tau’s CNC product manager, of the wireless remote pendant. “If you’re setting up, it has all the buttons on here. You have some customizable buttons—all your mode-select buttons and typical machine tool type functionality, such as axis select, select a feed rate—that allow you to handle everything in a wireless package.”
This article was first published in the June 2006 edition of Manufacturing Engineering magazine.