Easy access to the parts conveyor belt for quality control and unloading on the Bumotec 1000/CneoStarrag has introduced the new Bumotec 1000/Cneo horizontal transfer centre in response to industry feedback, with the aim of optimising every stage of the machining process. The result is a machine that delivers shorter cycle times, lower energy consumption and easier handling. Equipped with 32 motor spindles running at 25,000rev/min and a new touchscreen interface, the Bumotec 1000/Cneo enables manufacturers to produce more while keeping energy costs under control.
The development team did not start from scratch, but built on the practical experience gained from the previous model. Sylvain Bapst, who is responsible for the development and design of the machines at Bumotec, said: “We wanted to know what factors were limiting the customer on their Bumotec s1000/C and what would allow them to increase their production speed. We first drew up a specification sheet and then developed a new machine on this basis.”
One of the first areas to be improved was the interaction between man and machine. A human-machine interface (HMI) from
Fanuc was chosen, and in combination with a 24in touchscreen, this allows Bumotec to display more information for the operator. Furthermore, by integrating the WattPilote graphics application, the operator can continue to operate the machine while monitoring spindle consumption on the same screen.
Virtual buttons can also be added, such as station selection or shortcuts for frequently used M-codes. Cédric Berger, head of the software department said: “We have thoroughly revised our HMI so that the operator can control their machine ergonomically and intuitively. Our aim for our HMI was to make it easier to train new colleagues on a complex machine with 32 spindles and nine machining stations.”
Extremely user-friendly HMIThe company listened carefully to customer needs, particularly in light of the shortage of skilled labour. Mr Berger said: “Companies often employ people who were not trained as precision engineers in machining technology and who previously worked in other professions. For this reason, it is all the more important that the HMI is designed to be extremely user-friendly. That is why we put so much effort into its development.”
Bumotec’s software department has also developed an OPC UA server to consolidate all machine information. Mr Berger added: “We have gone even further. Instead of using FANUC’s OPC UA server, we have developed our own server to give users more flexibility so that they can decide for themselves what information they want to transmit at factory level.”
Cycle times have been cut by up to 40%, thanks in part to the replacement of 8,000rev/min motor spindles with 25,000rev/min models. Mr Bapst said: “We developed the new motor spindles internally at a Starrag Group site.” These new spindles feature direct drive and require less maintenance thanks to high-pressure internal cooling at 70 bar. They are equipped with acceleration sensors to monitor vibration patterns, allowing users to check spindle condition and enabling the NC control system to optimise cutting conditions. A pick-up arm with vices featuring a shorter stroke has also been added, reducing parting-off time to 7sec — a 30% reduction. Machining time is now just 10sec, 51% less than the previous model.
Tool rupture detection is now possible via the machine’s software, using a ‘learning curve’ for spindle current consumption during machining. Deviations trigger a warning. Rigidity has also been improved in the X, Y and Z axes by replacing dovetail joints with linear guides and slides.
Mr Bapst explained: “With the aim of maintaining the same rigidity, we carried out simulations in the workshop and confirmed them with measurements. As a result, we realised that we had not only increased the rigidity, but also reduced the friction so that we could move faster on the axes, so you could say that we have managed to achieve the same precision as a machine with just one rod.”
Finished parts are unloaded using a blowing system that transfers them to a plastic cup mounted on a linear arm, which then places them on a belt. Energy consumption monitoring is another highlight. Integrated sensors display values for compressed air and power consumption, as well as temperature conditions, on the 24in screen. Mr Berger said: “To cool the cutting oil, cold water is fed into the machine, which is then heated and flows back into the company’s ice water network. So, we installed sensors at the inlet and outlet to obtain information about the machine’s heat consumption — the energy required to keep the machine at the right temperature.”
Improved surface qualityThe WattPilote system also contributes to part quality. Sébastien Campalto, application engineer at Bumotec, explained: “By gaining a better understanding of certain machine phenomena, we could increase production, but also improve the surface quality of the workpiece. WattPilote is a small oscilloscope that measures power consumption and creates a curve while the tool is machining the workpiece. This means the operator knows in real time whether the machine is working properly or not.”
The new HMI offers various operating modes in accordance with ISO 14955. Mr Berger said: “In particular, the operator can switch more easily from one operating mode to another. When production is finished, for example, the operator can choose whether their machine returns to standby mode, where practically everything is switched off, or the machine returns to heating mode because a new production run is about to follow. If production has still not started after one hour in heating mode, the machine switches back to standby. Everything is well thought-out and designed so that the customer can save energy.”
Overall, Bumotec has successfully optimised all aspects of energy use. Total consumption has been reduced by 30%, compressed air consumption by 52%, saving up to 2kWh of electricity. The machine now requires only 245 litres of air, six litres of hydraulic oil and 600 litres of cutting oil to operate. Depending on the workpiece and production conditions, costs in watt hours per workpiece have been reduced by 30%, corresponding to a production efficiency of over 98.3% and a reduction from 0.177kWh to 0.136kWh. The footprint has also been reduced by 29%, with the machine occupying less than 32m² in the workshop.
The Bumotec 1000/Cneo has already proven its worth at a company manufacturing watchstrap parts. According to initial feedback, expectations were exceeded. Mr Campalto concluded: “The increase in productivity is between 40 and 50% compared to the same workpiece machined on the Bumotec s1000/C. The customer was able to reduce manufacturing time from 1min to 30sec.”