Set for success

6 mins read

All machining operations should begin with precise setting of tools, but many are ignoring this fundamental practice. Steed Webzell reveals why this can be a costly error

Manufacturing high quality parts economically is the key to business success. However, for machine shops still not setting their cutting tools offline, money is being lost. Offline tool setting is a subject often considered, but seldom tried. One reason is the hassle factor: setting tools offline may require the re-evaluation of job set-up and planning, and many simply stick with the age-old method. Traditionally, a busy machine shop will finish one job, clear the swarf (maybe), and then start reloading tools and the next program. When ready, parts will be clamped in a vice or fixture, and the operator will touch the tool off the top and edge of the workpiece. This method is wasteful and offline tool setting eliminates some of this waste. Furthermore, presetting can help reduce scrap and accidental machine damage. According to some reports, certain manufacturers are beginning to realise the cost and performance benefits afforded by the introduction of tool presetting. "We have recently completed a tool presetting project at BAE Systems for the F-35 fighter facility at Samlesbury and C-series wing production in Bombardier Belfast," says Peter Horgan, director at Kelch UK (01604 583800), by way of example. Kelch is a supplier of presetting technology that places product development among its top priorities. For instance, amid the newest developments at Kelch is the Kali-tec CNC presetter range, which combines tool setting with induction shrink technology. According to Mr Horgan, Kelch has already supplied these to Bombardier, BMW and CNC Speedwell (see also http://bit.ly/i4hjqe), a large West Midlands-based supplier of machined parts to the international truck and automotive industries, which has taken two Kali-tec models. Image: Kelc's Kali-tec presetter, used by a number of UK manufacturers, including BMW Of benefit to Kali-tec users is the fact that there are two methods available for tool setting. Also, the cooling station is completely detached from the thermo-critical setting device, so as not to compromise accuracy. In the dynamic setting phase, the chuck is opened by the induction heating process and the tool is automatically set to the exact nominal length. The advantages of this method are short cycle times, as well as the opportunity to change the tool in one cycle. However, if measurements are necessary (which would not allow setting during the open phase of the chuck), the length of the shank tool is determined with the help of setting adapters before heating. Through intelligent calculation and pre-positioning of the setting pin, the tool is finally shrunk to nominal length. This method is designed specially for complex measuring tasks or tools made of HSS. Presetters, of course, fill many functions: the inspection of new tools to ensure they meet specifications; the checking of production tools to determine wear levels; and the checking of tools that have been reground. Another tool presetting specialist to unveil a fully automatic, combined presetter and heat-shrink unit recently is Royal Tool Control (0114 244 1411). Based on the established Variset tool presetter, it incorporates the company's new Variset 4 tool management software and features a fully integrated HSK toolholder spindle, mounted directly into the presetting and shrinking station. The preset length is calculated and set automatically using the software and then measured using the Royal Variset vision system to obtain the actual dimension, ready for transfer to the machine tool. An optional cooling station reduces the time to set each tool and therefore increases productivity by reducing tool turnaround time. CAST IRON CERTAINTY Royal's latest product is the Tool Master Octa, a unit where the measuring data from the scales is transferred to a PC via a USB cable. The measuring software, IP Soft, has been developed by PWB systems AG, based in Switzerland. Among the other new features is an image-processing CMOS camera; a new cast iron body that enlarges the measuring range; and new linear twin guiding on both axes for better accuracy and long-term stability. Image: Royal Tool Control's latest, Octa The pace of development in the tool presetting and measuring technology area is fierce, as vendors vie for market share from customers keen to boost efficiency. Among a raft of new market entrants is Uniscale-M from Mapal (01788 574700) for measuring lengths, angles and radii on any type of drill, milling cutter or reamer. Based on a high resolution camera system, the Uniscale-M incorporates user-friendly software to measure parameters such as face geometries, peripheral geometries and step lengths on solid carbide cutting tools. Coating thicknesses can also be measured, while surface details on the tool can be viewed and analysed as an aid to evaluating wear. Image: Mapal's Uniscale-M measures lengths, angles and radii on any type of drill, milling cutter or reamer Tools with diameters up to 30 mm can be accommodated and are secured to the tool adaptor with the aid of a simple clamping system. The tool adaptor can be pivoted through 180º to facilitate measurements of, for example, the tip angle on solid carbide drills. Uniscale-M also incorporates a granite slab to maximise stability, adjustable vibration-damped feet and a precision guide. These features eliminate measurement errors due to vibration and oscillations, and the use of the granite slab also means that the measurements are free from errors produced by temperature fluctuations. Accuracy is, of course, everything when it comes to tool presetting and measurement. With this in mind, the new Airmatrix 20-50 from DMG Microset features a patented air-drive concept, offering an absolute measuring accuracy of ± 2 micron. According to DMG Microset, the new method allows unrestricted measuring of any tool, making differentiation into horizontal and vertical setting units a thing of the past. The camera holder moves freely on the glass pane by means of air bearings and can be transferred from any position to the tool that is to be horizontally inserted. As the result of a recently announced marketing collaboration, Walter Machines (01926 485047) is offering DMG Microset tool presetting products to UK customers. Image: The Airmatrix 20-50 from DMG Microset features a patented air-drive concept AXIAL AND RADIAL MEASUREMENT New from PCM Tooling (01424 753174) is the Alfa Set 44/46 with new Vision 4 image processing system, an auxiliary second colour camera for axial and radial measuring with frontal illumination, and a Heidenhain rotary encoder for the B-axis. All measurements using the second camera, radial and axial, are made with frontal illumination at 20x/40x or 80x magnification. The 12.1 inch TFT colour touch screen acts as a measuring surface for all major tool parameters. Measuring points can also be set on the screen, using the mouse pointer. In principle, all angles and radii visible by the camera can be measured. Since 2005, Gewefa (01225 811666) has been the sole UK distributor of presetters manufactured by Parlec. In this time, the company says it has supplied over 40 Parlec presetters to the UK aerospace sector alone, along with growing numbers in the automotive industry. The latest addition to the range, the Parlec 1800 TMM presetter, is a completely self-contained, free-standing machine that offers 13 measuring, presetting and inspection routines on a standard PSC software configuration, with a single-button execution for most functions. The measuring range is 420 mm diameter (with an additional 50 mm travel to the right of the spindle for reamer and turning applications) and the length range is 400-600 mm. In another new development announced by Gewefa, Parlec tool presetters and measuring systems now come with features that make them compatible with the Cyber tool management system from Mazak (01905 755755). A typical package comprises a Mazak Cyber tool LCD terminal, integrated data transfer from the TMM presetter to the Cyber tool database, multiple data resource configurations to support additional non-Mazak interfaces, and a dual tag read/write station for Mazak and Balluff RFID systems. Image: Shining a light on things, Parlec style Bowers Metrology (0870 850 9050) has also been working hard to develop new presetter technology and can now offer its Trimos Optima Plus, a modular unit that features a camera system with telemetric optics, a patented needle bearing system, Dymo LabelWriter, and light for tool inspection and free software updates. Options include various spindle pots and adaptors (including ISO, VDI, HSK), a vacuum clamping system, and a choice of PCs and printers. Three-format post-processor software is offered, along with extended database and point measure software modules. Over at Fenn Tool (01376 347566), which represents Zoller in the UK, the company's new process-oriented measuring system (POM) is a machine designed for applications involving grinding or sharpening. Equipped with special functionality for milling cutters and drills, the unit is specifically for sample inspection and quick tool checks. High resolution CCD cameras enable inspection of the cutting edge in incident light, while six-fold magnification provides the option to simultaneously measure tool geometries. The user defines measuring points and lines, depending on the cutting edge contour, via mouse click. Ultimately, machine tools cost too much to sit idle while tools are being set. Offline tool presetting offers quicker set-ups, higher up-time and fewer crashes due to improperly set tools. In short, it can make any manufacturer more profitable. Box item Italian technology pointers [] Having won the Speroni agency in September 2009, NCMT (0208 398 4277) highlights the latest addition to this line of Italy-built presetters: the Speroni Esperia STP44. This model incorporates a novel taper adaptor and a claw system that accommodates all pull-stud designs, allowing changeover for setting the next tool in 8 secs. Repeatability of positioning is to within half a micron. As with all Speroni tool presetters, the thermo-balanced structure is made of artificially aged pearlitic cast iron to ensure the equipment is fully isostatic and will not deform or distort over time or as the temperature changes. NCMT says that this structure avoids the drawbacks of systems that use light alloys and/or granite, which have different and unstable reactions to changes in temperature and the environment. Recalibration due to temperature changes is, therefore, unnecessary. [] Another company representing an Italian presetter manufacturer is Nikken (01709 366306), which now offers the Elbo Controlli range. The five models – Sethy, Hathor, Khyan, Ankh and Amon Ra – all feature tool inspection as standard, with most offering mechanical clamping of the toolholder pull-stud through an innovative vacuum confirmation system to ensure correct taper location (preventing tool run-out errors through incorrect loading of the holder). All models also utilise a Linux-based operating system and offer SD card data back-up. Linux is the preferred choice for Elbo Controlli, which says the system offers more software stability than similar presetters running with Windows-based PCs. First published in Machinery, February 2011