Machine tool controllers, HMIs add efficiency
Inside Machines: Human-machine interface and controller advancements enhance machine tool productivity by combining highly advanced graphics and open architecture of the CNC to render animated graphics and intuitive operator and programming interface. See examples in photo gallery.
Some recent and major enhancements to the graphical user interface and human-machine interface (HMI) on machine tools are rapidly improving machine productivity and operator efficiency. Chief among them combines the HMI operator and programming interfaces to create a consistent user interface for use with machine tools: turn, mill, or mill/turn types. The user interface contains animated elements and is designed to facilitate intuitive operation and programming. Even the most complex workpieces can be set up with ease and produced in one clamping operation, because of new functions. [A photo gallery of examples follows.]
All CNC process measurement cycles also are available for automatic workpiece and tool measurement processes with the familiar look-and-feel of the advanced HMI. For these efficient cycles and other new functional features, the input masks are provided with animated elements using the high-level language programming guides built into the CNC and, with advanced mill and turn technology simulation software onboard, they also include a full cycle simulation capability. Measured values can be automatically updated and used for tool correction and also zero offset.
Coupled with this advancement in the HMI are the controller upgrades, centered chiefly around the reduction of operator G-code language familiarity, so the program can be altered “on the fly” through the use of simple prompts and plain language commands onscreen. Corresponding to this improvement, technical advancements in the controller architecture allow a more uniform appearance on the pushbutton or touchscreen configuration of the HMI, which has enabled significant cross-training for operators who must run a milling machine in the morning and a turning machine in the afternoon, for example.
The considerable user convenience of animated elements, which are designed to support machine tool operators with predictive movie-like animations of operating and programming steps, will quickly establish the popularity of this new wave in machine control. Likewise, the programming functionality also offers graphical support for features such as display of the rotary axis in position patterns, pocket calculator functions with fit indication, and the ability to hide selected positions in position patterns. Cylinder surface transformation and multiple workpiece clamping are also included in these latest packages, so programmers and operators alike can perform a variety of family part setups in far less time. All these features are being incorporated into a Microsoft Windows-style representation onscreen, for operator acceptance in use.
Tool management within this emerging HMI/controller interface paradigm has likewise been expanded even further to include not only new grinding tool types, but also new measurement probe types and new depiction modes for tools using graphics and detailed picture views. As a result, all turning, milling and grinding tools are displayed with the same familiar look-and-feel. New shortcuts have also been introduced, such as the Ctrl-F function, allowing simplified search operations in most operating areas, such as files, tools, or in the editor, for substantially improved usability. Tool type, size, and condition are always accessible to the operator and maintenance personnel, as well as remotely to quality and process evaluation monitoring devices, whether onscreen or remote through a network bus.
Program management has been made more efficient by allowing PDF files or picture documents in .jpg, .png, and .bmp formats to be saved in directories on local drives for paper-free production. Programmers with slight modifications can, for example, access the current data onscreen, and, when changes are made offline, the modern CNC can accept USB or other portable device information management.
After program setup, the backup of the program is typically achieved in a pop-up window, enabling faster starts plus preview windows and multiple clamping data to be displayed. Whether turning or milling, the display shows a programmer or operator the animated run cycle or portion thereof, with complete options for changes and subsequent animation sequences. Plain language commands and the corresponding code are displayed onscreen for the reduction of time needed to make changes in the program or actual cutting conditions. This feature is useful in the job shop or prototype machining lab, where more one-off and short run production is the norm.
For easier training and operations, the HMI provides help screens, fully animated and point-to-point (broken line) graphic displays, each accessible with one screen change.
When a value is entered that does not correspond to the program or will cause another anomaly in the machining cycle, an error screen is typically displayed with the off-normal condition highlighted or flashing to quickly alert the programmer or machine operator. Such diagnostic tools previously involved a partial or complete run-through of the entire part program to determine error.
In an optional manual mode, a programmer can select a tool change with direct access to a tool management screen that displays all the relevant tools for a particular part that are resident in the tool carousel. Spindle speed and direction, M-functions, zero offsets, and machining planes can likewise be selected. On the most highly advanced controllers, the machine coordinate system and the actual workpiece coordinate system are saved in the active zero offset file for on-demand use.
Hand-in-hand with these developments is the seamless appearance of the cutting conditions, regardless of the programming language used. As more machine tools built on one continent are used on others, this flexibility in the control is absolutely critical. Whether simple workstep programming, DIN/ISO or high-level language, multichannel programming or classic G-code compatibility is desired, the most advanced CNC will adapt the command sequences to the skill level of the user, achieving the proper result both in the control and onscreen for easy interpretation.
Likewise, when changes to any position, speed, or feed rates are needed, simple program blocks can be isolated and displayed, so the resulting changes are made more easily to all relevant steps in the process.
Drives access for the machine tool and network is allowed, to make the HMI one point of information on the status of machine hardware in programming or in process. Program storage with simple name indications, as well as subroutines and external program information such as PDF, PNG, or NI files is possible.
After parts have been run, recall of the planned program and the actual run conditions and any variable occurrences allows the programmer and operator to determine possible course corrections. This is an additional useful tool for maintenance, as is the new controller ability to capture and prioritize off-normal conditions for instant diagnostics as well as subsequent error analysis. Of collateral note, many machine tool builders have begun to use this feature of the advanced CNC to conduct machine-to-machine peer review, both for customers and their own internal documentation on machine performance. Most such data were not previously available and certainly not in the easy-access mode of today’s control communication platforms. Major end-users, as an example, are today comparing machine performance on the same part run on two continents, by remote data gathering directly from the HMI. This can aid in determining the best facilities to do certain types of work.
Responding to the video-savvy generation of today’s programmers and operators, the advanced CNC can provide workpiece visualization in a manner previously impossible. As the sophistication of 3D graphics and pixel intensity have progressed in consumer products, the HMI on today’s machining centers can provide a very realistic image of a workpiece in process. The evolution of the industrial CPU has made this possible. Detail zoom, spot magnification, and rotary imaging from the CAD world also is now routine on the CNC, so the programmer, trainer, and operator alike see what the part designer required and how exactly the machine is getting to that result, in real time and with full animation of the cutting sequences.
Each programming line in the machining step editor is keyed to a function, such as facing, turning, centering, etc., or the geometric data required for said function, position pattern, or contour. The programmer decides whether the program value is to be written to the zero offset, which avoids the need for a separate backup of the zero points. Data is entered into the program in sequence and the onscreen visualization can illustrate each step in the machining sequence.
Likewise, the tool data, speeds, and feeds are entered in sequence, in a simple accumulating step editor sequence.
For more complex milling operations, the same procedure holds, while more advanced information, such as cylinder surface transformation, unmachined part input for simulation, swivel plane, high-speed settings, and even an overview of cycles for in-process measurement, can be written in a relatively simple manner, using plain language commands, onscreen prompts, and visual animation.
All machine tool kinematics are supported for full rotary axis, rotary table, robotic articulation, part manipulators, tool changers of all types, ancillary tool carousel motion, and other external devices—all in the controller with full interface to one HMI. This software development has further enhanced the multitasking machining centers for mill/turn and turn/mill work, as well as work cell concepts in the industry.
Finally, a variety of shortcut keys, not unlike those on the office PC, are provided by advanced CNC technology to permit the programmer and operator alike to further economize time.
These improvements to the CNC’s graphical user interface, as well as the full range of desired cycles and functionalities, are also typically available with the CNC manufacturer’s training software.
– Randy Pearson is business development / dealer support manager, Siemens Industry Inc., Motion Control Business—Machine Tools; edited by Mark T. Hoske, content manager, CFE Media, Control Engineering.