Manual inspection of cutting tools requires machine down-time, adding to production cost. As we transition to Industry 4.0, there is an expectation that such manual condition monitoring will be replaced with embedded sensors. Companies such as Sandvik are developing Cyber Physical systems for machine tools to enhance the quality and efficiency of these operations. Embedded sensors will provide continuous streams of real-time data without requiring any stoppages. We’ve seen attempts to produce this type of low-cost, durable sensor required to monitor tool wear in the past.
Now, researchers at the University of Sheffield’s Advanced Manufacturing Research Centre (AMRC) have now developed an intelligent, low-cost tooling insert, embedded with smart sensors. This will deliver in-process condition monitoring that reduces machining stoppages. The aim of the project was to improvethe efficiency, performance and quality of production operations, which is vital to improving the productivity of the wider economy. TheInnovate UK funded project involved a collaboration between fellow High Value Manufacturing Catapult partner CPI, alongside Element Six, Advanced Manufacturing (Sheffield) Limited, BAE Systems, Printed Electronics Ltd, National Physical Laboratory, and DMG MORI UK.
The resulting device—currently in the prototype stage—allows a machine tool operator to determine the condition of a cutting tool without manual inspection and is the first ‘plug and play’ system of its kind, with no process learning time required on installation. This will enable tools to be replaced at the optimum time, maintain the required product quality, while also minimizing down-time.
This is a dramatic improvement on the current process which involves an operator stopping the machine tool to monitor wear on the tool’s cutting edges using a laser or touch probe system. These stoppages reduce productivity and increase costs. The need to stop the machine also reduces the frequency of inspection, meaning that there is a risk of tool wear causing damage to parts or machinery.The embedded sensor has been designed using low-cost electronics, making it affordable to small and medium-sized companies. These companies are always looking for ways toimprove the efficiency, performance and quality of their operations.
“These are real concerns for manufacturers as stoppage costs in production can be high.Manual inspection also varies according to the skills and experience of the operator monitoring the tool wear. When tools are not changed at the right time, damage can be caused to a work piece, leading to increased costs due to scrappages and rework. Equally, if tools are changed before the end of their useful life, this can increase consumable costs.”
- HatimLaalej, AMRC Machining Group Technical Lead for Control Systems, Sensors and Data Acquisition
In order to achieve the highest accuracy and surface finish of a work piece, tool wear must be monitored frequently during a machining process. The tooling insert has a number of embedded sensors which generate data documenting the current condition of the cutting tool. This data is converted and wirelessly transmitted to the machine panel or a machine operator’s control pad. The operator can then evaluate the data and decide when the condition of the cutting tool requires routine maintenance or program corrections, all while machining is in-process.
“The sensor monitors the resistance generated within the tool-embedded sensor, so if its resistance increases, this indicates tool wear, chipping or breakage. This means errors can be recorded and operators can move to preventative maintenance planning to free up valuable time on the shop floor when operators could utilize extra capabilities increasing productivity.”
- HatimLaalej, AMRC Machining Group Technical Lead for Control Systems, Sensors and Data Acquisition
Current testing is being carried out on a DMG Mori NT5400 DCG five-axis turning machine.Polycrystalline diamond and Polycrystalline cubic boron nitride cutting inserts with embedded sensors were used to machine Titanium Ti-6AI-4V and Inconel 718 bars respectively.These tests have successfully validated its capabilities during cutting operations.Prior to this experimental work, simulation was used to develop the device.
Another key player in the transition to Industry 4.0 is Siemens—they describe a vision for a digitalized, automated world with digital communications linking people, machinery and systems. They believe this will provide manufacturers with greater efficiency, quality and performance, but they also acknowledge a number of challenges in making the shift. Siemens states that a successful transition to Industry 4.0 will probably involve a number of small steps, rather than a sudden and dramatic change. They have identified that the main challenges for manufacturers are a gap in digital skills, access to finance, changing company culture to embrace the more collaborative nature of Industry 4.0, data security, demonstrating return on investment, and the lack of incremental change plans. Easy-to-use and low-cost embedded sensors, which provide immediate cost savings, are exactly the type of technology required to enable this transition.
Next, the AMRC team aims to further develop the technology to “eliminate tool wear, machine downtime and eventually tool breakage altogether.”Further development of the technology will look at extending the process for various milling processes as well as turning and adapting the system to send diagnosis and data to a portable device, such as a laptop, so an operator can be working remotely with the machine.
The current prototype device is ready to be scaled up into an industry-ready solution right now. The AMRC is hoping to identify industry partners, for example tool-holding manufacturers, with the technical and commercial capability to develop the prototype into a commercial product and take it to market. The system will have massive benefits for machinists in all manufacturing sectors.If you’re interested in developing it further get in touch with the AMRC.The University of Sheffield Advanced Manufacturing Research Centre (AMRC) is a world-class center for research focused onadvanced manufacturing technologies used in the aerospace, automotive, medical and other high-value manufacturing sectors. It has a global reputation for helping companies overcome manufacturing problems and is a model for collaborative research involving universities, academics and industry worldwide.