Clever boxes exercise control

4 min read

Behind every good CNC machine is a good CNC. Steed Webzell takes a look at developments in this key technology area and at CNC's application

Many modern CNC systems simplify and speed the programming process through the use of graphical prompts or conversational input requests. One such control is WinMax, the proprietary CNC from Hurco (01494 442222), which offers conversation-based shop floor programming capability and a second screen on which a graphic of the part is generated as cycles are built up. It is a key differentiator, as reported by customers. Having recently acquired a Hurco DCX32 bridge-type vertical machining centre fitted with WinMax, West Midlands-based toolmaker and subcontractor Cube Precision Engineering is constantly discovering new benefits of the control. For instance, like many machine shops, Cube says most of its 3D cycles are prepared off-line from customer models, imported into CAD, via IGES if necessary, and processed using CAM software. However, it is usual for simpler, 2D elements of a program to be processed at the control by the machine operator. "One of the benefits of WinMax is that such cycles can be easily merged with the 3D cutter paths prepared externally," says Neil Clifton, one of three director-owners at Cube. "Previously, such an approach would have resulted in two separate cutting cycles." SPEAKING PLAINLY Programming in 'plain English' clearly means there is no need for skilled machinists to be conversant with G and M coding, and this is among the important values espoused by the ProtoTrak control offered on models supplied by XYZ Machine Tools (01823 674200). Among those championing the advantages of ProtoTrak is Tyne & Wear-based subcontractor Arconia Engineering, which has just taken delivery of an XYZ ProTurn SLX 555 CNC/manual gap bed lathe, equipped with the latest generation ProtoTrak SLX control featuring constant surface speed (CSS) and 'Traking' as standard. CSS is particularly relevant, because, as co-founder Steven Plummer points out, "we always seek to improve on surface finish requirements – if a customer is multi-sourcing, it's worth investing the extra time and effort to make our products stand out from the rest". Traking allows operators to execute a program by turning the apron-mounted hand-wheels. This boosts operator confidence, as the machine will move through the program at that speed, thereby contributing to safe and collision-free machining. Switching between Traking and CNC automated running can be performed at any point during the machining process. Of course, a time that CNC potential truly gets assessed is typically during a machine tool refurbishment or retrofit exercise. In one recent case, the use of Heidenhain (01444 247711) motors, drive amplifiers and iTNC 530 CNC transformed a 22-year-old, 4-axis milling and boring centre into a 21st century, 6-axis machining centre, able to undertake complex and accurate contour machining operations. Re-engineered by Nutech Machinery Services (02476 667770), the revitalised Boko F63-100 has been exported to a customer in North America and will be dedicated to a range of contouring applications on satellite propulsion fuel tanks. Originally featuring a Heidenhain 355 control, the Boko F63-100 was a speculative purchase by Nutech some time ago, "but always with the intention of re-engineering it as a 6-axis model", says joint owner John Campbell. "Of course, with the Heidenhain iTNC 530 CNC being well suited to high surface definition and accurate contouring – it features ultra fast look-ahead processing, for example – our choice of retrofit CNC was obvious." POLISHED PERFORMANCE Naturally, the benefits of CNC technology apply across the entire spectrum of machine tools. For instance, Fanuc (01895 634182) is now a core supplier of control systems to polishing machine specialist, Zeeko. These machines, known as Intelligent Robotic Polishers (IRP), are used in the production of surfaces requiring nanometre accuracy. They include telescope mirrors, from a few millimetres across up to those measuring several metres, such as the 1.4 m segments of the 'European Extremely Large Telescope project' (E-ELT). Dr David Loke, machine control systems manager at Zeeko, says: "We are not as knowledgeable as Fanuc about their controllers, so at an early stage in new projects we meet to specify control systems, motors and drive kits. On our machines,we have two encoders per axis, back checking each other, resolving down to nanometric levels, and we clearly understand that you can use the best encoders available, but, without an excellent controller, the system falls down. It's a combination of the two that is essential. "For instance, with our integrated interferometer there's a lot of mathematics going on pictures are taken of different segments of the component being polished to tell the system about the current state of the component," he continues. "This information is plotted against what is required and an error map is fed into Zeeko Precessions software, which creates a corrective toolpath on the Fanuc controller." Box item Key (pad) innovations [] The latest CNC innovation from Siemens (0161 446 6400) is an entry-level control solution for standard lathes and milling machines. The company's Sinumerik 808D works hand-in-hand with the Sinamics V60 drive system and the Simotics 1FL5 servomotor, and is said to be well suited as a CNC system for the lower end of the performance range. However, even though it is the smallest member of the Sinumerik family, the 808D comes with intelligent MDynamics path control, including a look-ahead function. Claimed to be a major bonus for 808D users is the 'programGuide Basic' feature, which permits simple programming, with the aid of graphically-supported cycle screens and a contour calculator. It is also easy to reuse part programs from other controllers which support ISO code, making it possible to alternate between DIN and ISO programming languages, even within a single part program. [] At the other end of the scale, French CNC specialist NUM (0871 750 4020) has recently introduced Flexium+ (www.machinery.co.uk/45256), a modular, safety-equipped control platform that is said to enable machine tool OEMs to standardise on a single cost- and performance-optimised CNC architecture for a spectrum of model types – from small machines with a few axes to large, multi-cell manufacturing systems with over 200 axes and spindles. New support software for Flexium+ includes a precision operating system and soft automation PLC, complete with a customisable HMI that recognises touch gestures, an extensive suite of optional machining functions, and a 3D simulator for part program verification and visualisation of machining processes. [] Fagor Automation (01327 300067) is another control system developer with a new innovation, in the shape of its geometric language ProGTL3, which has been introduced in the company's CNC 8065. Based on the geometry-oriented paradigm, ProGTL3 (Professional Geometric and Technological Language – level 3), it is said to resolve any geometrical profile without mathematical calculations, additional trigonometry or the use of external CADCAM software. Furthermore, simulation takes place in real time. [] From Osai (01908 642687), an expert in control systems for specialist, high speed metal cutting machines, comes a new CNC family called OPENcontrol, an evolution of the former Osai 10 series. The system is based on a Windows CE platform and offers full integration of the original 10 series for retrofit applications. Within the system, OPENcontrol SW can move up to 64 axes using 40 channels, each one interpolating up to 12 axes simultaneously. The system allows users to explore general motion control applications with production process management and axis interpolation, which is implemented within the OPEN-10 machine logic, along with CNC applications for 2½D and 3D machining with TCP, HSM and volumetric compensation. First published in Machinery, January 2013