The new sense in cutting tools
Advancements in milling and turning tools come with a certain level of modernity
Milling and turning has come a long way from merely being up on machines and running them on objects. According to a science website, circumstantial evidence for early tools rose years ago. Scraps of animal bones dated to around 3.4 million years ago bear slice marks that seem to be intentional.
Materials of tools too have evolved. From steel, it has come a long way to diamond coating and somewhere along the way carbide, ceramic, cemented carbide and several others were a part of the cutting tools. However, certain materials exhibit poor machineability due to their low thermal conductivity, potential for adhering to cutting tools and the presence of abrasive particles within the alloy structure. L Krishnan, MD, TaeguTec India, says,
Machinability of different materials vary based on composition, grain structure and heat treatment. Realising this, several years ago, ISO classification according to application grouped them under six broad categories: P/M/K/N/S/H.”
Each category would mean the following:
• P: for long chipping material like steel
• M: Stainless steel and similar materials
• K: For cast iron and short chipping materials
• N: Non-ferrous
• H: Hard materials
• S: Super alloys
Over the years, cutting tool manufacturers have upgraded basic tool materials and its capabilities. This together with advanced CVD & PVD coatings give customers adequately large number of options for machining different types of materials. Krishnan adds, “Industrial sectors like aerospace and medical are relatively new and growing segments in the country. Materials, machining strategies and the types of machines used like 5- or 6-axis machines are often similar. However, some parts/components in the medical industry remain relatively smaller than what is normally seen in aerospace industry. Cutting tool materials together with appropriate geometry and cutting parameters help customers to optimise machining results and productivity.”
Applications like medical, aerospace, oil and gas, are likely to use difficult-to-cut materials. To help customers, Tungaloy has launched many grades and chipbreaker geometries to ensure that customers get good tool life and productivity. Jay Shah, MD, Tungaloy India, says, “We have launched new grades like AH8000 series in turning and milling along with suitable chip-breakers that are working well at customers end for such applications. Besides this, we also help customers establish parameters on their CNC machines for the same.”
Speaking about the solutions that LT Tools India has, Vivek Kumthekar, GM, sales and CoC head, milling & threading, LMT Tools India, says, “We are prepared to handle the customer’s requirement of difficult to machine materials. Our DHC Hardline range of endmills is specially designed to handle CoCr material. HSCline H endmills and taps are part of our standard programme to machine hard materials. We also offer indexable milling tools in different geometries and grades for such materials. For the aerospace sector, LMT Onsrud has a dedicated programme for machining aerospace materials with specialised geometry and coating.”
Tools work well when used on suitable machines with proper work- and tool holders, coolant, and cutting parameters. The quality of work material, tools used before and after also play a significant role. Most tool manufacturers do make customers aware so that the end result is consistent. Sashi Menon, technical head, Hoffmann Group, says, “Based on the complexity of the geometry and material, the higher is more will be the requirement for complex machining processes, which can only be done by modern milling and turning centres. With the growth expectation in infrastructure-related industries, energy, road and railway construction, automobile and aerospace, the overall cutting tool inserts market will continue to grow.”
However, considering that most machine shops are SMEs and MSMEs, they need to be taught the importance of investing in new tools after wear. Kumthekar says, “If a worn-out tool worth Rs 3000 is used for machining one extra job then there is a possibility of the work getting rejected or leading to low productivity.”
For this reason, Tungaloy India has a training module for the shop floor team on usage and maintenance. “We discuss the basics of machining and help them understand the features and longevity of the tool. There is a need for training, so we conduct seminars at plants which leads to consistent machining,” says Shah.
Companies like TaeguTec India prefer to underline the importance of total cost of manufacturing. “Many a times, tools cost 2-3% of the total cost of manufacturing. Productivity is a bigger influencer when it comes to total cost of manufacturing. At times, customers focus on tool cost and lose the opportunity of reducing manufacturing cost or cost per part to a much larger extent,” says Krishnan.
Using low quality tools that are cheaper but offer no predictability and consistency can damage the workpiece and the machine. Tools also need to be maintained, otherwise it can increase the hazard for the operator. “Training must include all aspects of a tool, such as handling, replacement, understanding its longevity, etc. We ensure that the team and our customers have the right training before application/selection of a tool, says Menon.
Demand for cutting tool industry is driven by metal cutting and manufacturing across the sectors. “Several factors like introduction of electric vehicles, growth of the aerospace industry, and 3D printing technologies may have a significant impact – one way or another – in the time to come on demand of cutting tools,” says Krishnan.
“Customers are looking for customised solutions to reduce their cutting time and for this reason we develop specialised solutions. We have launched new range of turning inserts T9200 series with strengthened wear resistance due to thick Al2O3 coating. Customers also seek to reduce operating costs and our new applications should help,” says Shah.
Recession affects everything. “However, these are evergreen operations and will continue to be required in all industry segments for years to come. The risk is for individual companies who do not upgrade their product in line with market requirement or in terms of cost per component, says Kumthekar.
There are advancements in turning and milling tools. It would helps vendors to keep a sharp eye on customers to know what best to offer.