The demand for high-speed machining is compelling manufacturers of CNC machines to come up with new technologies.
by Madhukar Joshi
Manufacturing companies are always inclined to invest in new technologies. Considering that shop floor activities demand production to constantly move, it is necessary that companies keep automation in mind to meet demand. CNC machines and machine tools form an integral part to a manufacturing unit. The high demand for CNC machine technologies is well positioned with product portfolios focused on every end market. Most of them have solutions for various sectors including aerospace, defence, railways, and of course, automotive, which has been their mainstay.
Machining in general is a way to transform a stock piece of material such as a block of plastic and arrive at a finished product (typically a prototype part) by means of a controlled material removal process. Similar to the other prototype development technology, FDM (3D printing), CNC relies on digital instructions from a Computer Aided Manufacturing (CAM) or Computer Aided Design (CAD) file. The CNC machine interprets the design as instructions for cutting prototype parts. The ability to programme computer devices to control machine tools rapidly advances shop productivity by automating the highly technical and labour intensive processes. Automated cuts improve both the speed and the accuracy with which prototype parts can be created – especially when the material is critical.
Ambrish Nasit, assistant manager, technical sales support, Jyoti CNC Machines, says, “Adopting multitasking concept is the latest trend in machine tool sector. Multitasking enables reduction in multi set-up and provides great flexibility to complexity. Jyoti has developed a special software 7th Sense which focuses on HMI (Human Machine Interface) which would integrate machine to factory digitisation. We have developed a wide variety of spindle option with machines to incorporate and suit special applications and optimum requirement. Special modifications in design help in efficient chip management system and provide cost effectiveness.”
Oftentimes machining processes require the use of multiple tools to make the desired cuts (e.g. different sized drill bits). CNC machines commonly combine tools into common units or cells from which the machine can draw. Santoshkumar Ullal, director, Emuge-Franken India says, “The biggest risks in high speed machining are the minute errors creeping in workpiece clamping and possibility of vibrations due to weakening/wear and tear of parts in the whole set-up.”
Machine tool manufacturers and manufacturing companies are benefiting much from the opportunities created by digitalisation, and are systematically enhancing their competitive edge. For instance, one company that has been at the forefront of solutions is Siemens, which has brought out an extensive range of automation and digitalisation solutions, which can reduce the time to market and increase production flexibility and efficiency increased significantly. It is the only company to offer both an end-to-end CAD/CAM-CNC process chain and solutions for networking machine tools and higher-level IT systems.
Enhancements in technology
Average growth rates of over 7% make aerospace one of the global growth branches. DMG MORI supports OEMs and suppliers with productive manufacturing processes thus participating to a disproportionally high degree in the growth of this sector. In order to meet the high requirements of demanding users DMG MORI concentrates its entire expertise in the DMG MORI Aerospace Excellence Centre. “Sales of several hundred million euros certainly make us the leader in the aerospace sector where machining is concerned. It is our aim to double this figure over the next few years”, says Michael Kirbach, head of the DMG MORI Aerospace Excellence Centre. In 2016 alone, DMG MORI sold around 450 machines in this market in 25 countries. Early involvement in customer projects is a basic condition here for developing production solutions that have a promising future.
In the automotive industry, mainly in power train engineering, companies are now concerned with greenhouse emissions and energy efficiency. Importantly, other aspects at play are light-weighting and friction reduction. In both these strategies, what companies need to work out is a stringent surface finish and geometry parameters on critical power train components such as crankshafts, camshafts, gearbox shafts, etc. What they prefer to adopt is micro-finishing that helps them achieve the specifications for these mission critical work. Over the last few years micro-finishing technology has crossed several milestones and made possible key advances in vehicle performance. Micro-finishing generates lubricating characteristics at surface contact through a highly engineered surface finish so that the surface provides maximum bearing area to take up heavy loads and at the same time retain enough oil on the surface for adequate lubrication.
More often than not, companies are required to take up preventive measures so as to arrest spindle failure. “Regular preventive maintenance of the spindle like lubrication and run-out checks, replacement of wear parts, etc. is of utmost importance,” says Ullal.
Detection and indication of abnormal vibration pattern are prime preventive measures concerned with spindle failure. “Running the spindle under optimum spindle usage limit would also prevent spindle failure. Real time machine interaction for Condition Monitoring through different sensing element would help to detect and arrest failure. Also, selection of quality cutting tool would reduce impact on spindle and increases machining quality & performance,” says Nasit of Jyoti CNC.
Inefficiencies related to process and machining are two major contributors which would count for cost to the user. Increasing frequency of such incidence would add on to the excess non-productive cost. “Process related inefficiency is directly related to process capabilities. First time part setup preparedness and controlled first setup quality check can avoid the cumulative setup inefficiency. “Machining related inefficiencies are related to tool monitoring, thermal load monitoring, efficient chip management system, and fixture & envelope cleaning. Missing focus on such factors can increase non-productive machine engagement, thus rising cost to the users,” he adds.
Another company that has been at the forefront of introducing new machines for customers is BFW. Last year, at IMTEX, the company introduced a range of new machines in both milling/turning and complex solutions. It also unveiled its IRIS software platform designed to make manufacturing efficient and cost-effective It’s on the lines of Industry 4.0, and the machines have the ability to talk to the entire ecosystem. Ravi Raghavan, MD, BFW, believes that the industry needs to move to smart manufacturing. Moreover, the manufacturers need to understand that buying one smart machine will not do the trick. All the other machines in the manufacturing units need to be smart, or will have to be made smart. There is a misunderstanding that investing in technology is expensive. But few know that installing small sensors can help them go on live. The company is targeting SMEs with some of its smallest machines. Smart is not only for large companies, even small companies can adopt them because the gains will be much higher. He offers a simple definition of Industry 4.0: When all the machines talk to each other, it is Industry 4.0.
Early this year, Yamazaki Mazak India launched Smooth Technology, which have the latest six generation controller in all the machines. All the machines that Yamazaki Mazak India sells come with thermal control and cooled ball screws and spindle and temperature sensors which is taken care of by the machine itself. Globally, Mazak is a leading supplier to the aerospace industry. The aerospace industry buys machines from Mazak for engine parts, wing parts, the structurals, among other things.
The digital factory and digital enterprise remain key targets for aerospace, and the power of the CNC on all operational machine motion control, data gathering, and communications levels continue to feed that process, evolving at light speed.