CNC and DRO technology catch-up

Such has been the success of a batch of retrofitted Acu-Rite VUE digital readout systems (Heidenhain, 01444 247711) on 3-axis milling machines at the North West Training Council (NWTC), near Aintree racecourse, that Shane Parkes, head of the engineering workshops, is investigating the application of the high functionality, easy-to-use systems on the 12 2-axis lathes used by NWTC engineering apprentices. Installed on the Bridgeport mills by Style Machine Tools (01772 624114) – an approved Acu-Rite distributor and retrofitter – the introduction of the six VUE systems was prompted by the realisation by NWTC that it is imperative its apprentices train and use equipment of appropriate technology level before encountering CNC. Image: NWTC believes it is imperative for apprentices to use equipment of an appropriate technology level before encountering CNC "We searched the Internet and looked at various systems, and found that the Acu-Rite VUE was actually miles ahead of anything else we saw," explains Mr Parkes. "The DRO incorporates a myriad of powerful functionality, yet is very user-friendly; it has everything we need. "The decision was made even easier by the fact that Style Machine Tools already undertakes all of our machine maintenance and repairs, so we knew that the retrofitting would be professionally undertaken." In fact, all six machines were completed in just two days. While the ageing Bridgeports were in good mechanical condition – the need to keep the machines 'neat and tidy' is a good housekeeping rule for the apprentices – the machines' original LED DROs were becoming 'a bit tired' and their machining performance was suffering," he reflects. That has now changed. VUE is an entry-level 2/3-axis DRO that transforms the performance and operation of manual machines. Displaying full text on an LCD display, standard functionality includes job clock, feed rate display, absolute/incremental, near-zero warning, 16 tool offsets/diameters, preset and zero reset, Trig calculator and instant inch/mm conversion, in addition to content-sensitive help function. FUNCTIONS ABOUND Specific functions for milling include graphically-supported bolt hole pattern calculations (full and partial circles/linear patterns) and centreline calculation, while for turning the system also features 'lock axis' functionality (establish tool offsets under load), and instant radius and diameter compensation. Linear and non-linear error compensation can be configured up to +/- 9.999 ppm. As well as being supplied complete with all appropriate armoured cabling, VUE's cost-to-performance tag is reinforced by its availability as a ready-to-use package – as fitted at NWTC by Style Machine Tools – with Acu-Rite's high-end SENC 150 precision glass linear encoders that were applied to the machines' X and Y axes. NWTC instructor Steve Finnegan adds: "Once the machines were retrofitted, we immediately saw that they were able to position much faster and hold tolerances better, and it was clear that the apprentices found them very easy to operate. Importantly, the available functionality means that the Acu-Rite VUE is the ideal stepping stone for the apprentices into full-blown CNC." And moving on to CNC developments and from Siemens (0161 446 6400) the latest development, announced last month, is its Sinumerik 828D Basic M. With this, the company has extended its product range for its CNC compact class series, with it now offering an entry-level CNC version that is tailored to standard milling machines and which offers a high level of performance, precision, and availability, according to Siemens. Image: Sinumerik 828D Basic M is an entry-level CNC, tailored to standard milling machines FIVE AXES/SPINDLES It is suitable for standard milling machines with up to 5 axes/spindles. The screen, keyboard, and CNC electronics form a single unit that only requires a few interfaces and cables, and offers maximum availability. Thanks to a new operator panel made of die-cast magnesium, the new Siemens CNC is also extremely reliable under harsh operating conditions, while the control dispenses with wear parts such as fans, hard disks and batteries, making it maintenance free. To achieve the speed and surface quality, the Sinumerik 828D Basic M includes the Sinumerik MDynamics technology package familiar from the high-end 840D controls with the 'Advanced Surface' intelligent motion feature. And, by employing Sinumerik Operate, the Basic M variant has been able to integrate a user-friendly CNC user interface with programming and set-up procedures in a reliable and intuitive manner, says the company. One special feature of this system is the 'Easy Message' function, which communicates essential information to operators via SMS. From Fanuc, the latest innovations remain the upgrade to its Series 30i/31i/32i technology, with the units now called Model B (or 3xi-B, for short). Intended for control of sophisticated machines, compared to previous models, the new B Series units feature significant advances, numerous detail improvements, and additional functions for punch presses and laser cutting machines. Fanuc also offers the CNC 35i-B Series, based on the technology of the 30i-B Series, and developed primarily for transfer line and handling applications. The servo system, with high speed servo-processor, increases the basic output of the digital axis drive, enabling a higher number of axes to be activated, without an additional board. The new FSSB (Fanuc Serial Servo Bus) is even faster and offers a decisive advantage: it now transfers spindle data. Servo and spindle amplifiers are connected to the CNC control by a single optical cable, with reduced wiring complexity saving time and cutting costs, while also eliminating potential sources of fault – in keeping with Fanuc's goal of maximising system availability. Other improvements in the servo system are new Alpha i servo amplifiers, which use low-loss power devices designed to save energy. The new pulse coder backup unit has a rechargeable battery and charging circuit, which eliminates the need for battery replacement. Furthermore, the integrated programmable controller is three times as fast and program memory has also been tripled. And the I/O Link I can transmit twice as many PMC DI/DO signals per channel, and allows 24 groups to be connected, as compared to the previous 16. This also benefits the integrated Dual Check Safety function, because a single I/O Link i cable is all that is needed to transfer the secure signals. No additional channel is required. I/O Link i also opens up new diagnostic options. Finally, a recent development from Spanish CNC maker Fagor (01327 300067) is its Finetuning software. This is an application developed by Fagor Aotek (Research centre of Fagor Automation) within the BEAMTEK project financed by the GAITEK program of the Basque government. Following CNC system set-up by the machine tool builder, Finetune automatically optimises the various control loops of the machine to obtain highest machining quality. Combining the benefits of Finetune and the high speed machining features of the 8065 CNC reduces mechanical stress on a machine and expands its lifespan, while lowering vibration and offering tool path optimisation that result in very high machining quality. First published in Machinery, May 2011