micromechanics

Bumotec 1000/Cneo - Produce more and consume less energy

The new Bumotec 1000/Cneo horizontal transfer center was developed on the basis of feedback from the field and optimizes every step of the process: shorter cycles, lower energy consumption and easier handling. With its 32 motor spindles at 25,000 rpm and the new touchscreen interface, this Bumotec machine enables industrial companies to produce more while keeping energy costs under control.

The developers of the new Bumotec 1000/Cneo transfer center did not start with a blank sheet of paper, but built on the practical experience gained from the previous model. “We wanted to know what factors were limiting the customer on their Bumotec s1000/C and what would allow them to increase the production speed,” explains Sylvain Bapst, who is responsible for the development and design of the machines at Bumotec. “We first drew up a specification sheet and then developed a new machine on this basis.”

First improvement: the interaction between man and machine. A human-machine interface (HMI) from Fanuc was chosen. In combination with the 24-inch touchscreen, this allows Bumotec to display more information for the operator. By integrating the WattPilote graphics application, the operator can continue to operate their machine while monitoring the consumption of the spindles on the same screen. The operator can even add virtual buttons, e.g., a button for selecting the stations or shortcuts for the most frequently used M-codes. “We have thoroughly revised our HMI so that the operator can control their machine ergonomically and intuitively,” assures Cédric Berger, Head of the Software Department. And he emphasizes: “Our aim for our HMI was to make it easier to train new colleagues on a complex machine with 32 motor spindles and nine machining stations.” Here, too, the company listened carefully to what customers needed: “In view of the shortage of skilled labor, companies often employ people who were not trained as precision mechanics 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’s why we put so much effort into its development.”

Up to 40% shorter cycle times

Bumotec has successfully optimized all aspects of the energy required to operate the Bumotec 1000/Cneo.
Total consumption has been reduced by 30%, compressed air consumption by 52%, saving up to 2 kWh of electricity.

The machine has its own OPC UA server

Bumotec’s software department has also been working on an OPC UA server on which all the machine’s information can be consolidated. “We have gone even further because 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,” emphasizes Cédric Berger.


New motor spindles

Now let’s take a closer look at the mechanics. Here, too, we have hit the mark with several improvements. Up to 40% shorter cycle times. It should be noted that Bumotec has replaced its 8,000 rpm motor spindles with 25,000 rpm models. “We developed the new motor spindles internally at a Starrag Group site,” emphasizes Sylvain Bapst. What’s more, these new motor spindles with direct drive Bumotec 1000/Cneo Produce more and consume less energy require less maintenance thanks to the high-pressure internal cooling of the tool, which operates at 70 bar. The motor spindles are equipped with acceleration sensors to monitor their vibration patterns. This allows the user of the Bumotec 1000/Cneo to check the condition of the spindles and also enables the control system (NC) to optimize the cutting conditions. To shorten the cycle times, a pick-up arm was added that has vices with a shorter stroke. The time for a parting-off sequence is now specified as 7 seconds – a reduction of 30% – and the machining time is 10 seconds – 51% less compared to the Bumotec s1000/C model. Tool rupture can now also be detected via the machine’s software. For this purpose, a so-called “learning curve” for the current consumption of the spindle was created using a machining sequence. If there is a deviation, a “tool rupture” warning is issued.


Linear guides in the X, Y and Z axes

To improve the accuracy of the new horizontal transfer machine from Bumotec, the rigidity of the machining stations has been increased in the X, Y and Z directions. To achieve this, the manufacturer from Vuadens (canton of Fribourg in Switzerland) no longer works with dovetail joints, but instead uses linear guides with slides, as Sylvain Bapst emphasizes, “with the aim of maintaining the same rigidity.” “We carried out simulations in the workshop and confirmed them with measurements. As a result, we realized 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.”

Bumotec has opted for a semi-autonomous cutting oil filter system. As Sylvain Bapst explains, “thanks to a new concept in which filtration takes place through filter bags on the outside, the machine no longer needs to be stopped.”

To unload the finished parts, Bumotec has opted for a blowing system with which the part is conveyed into a plastic cup without being knocked. The cup, which is mounted on a linear arm, then places it on a belt.

Sylvain Bapst explains how such results were achieved. “The machine was perfectly tailored to the customer’s needs. Take the motor spindles, for example. They have been specially dimensioned for the customer’s production, and as there are 32 spindles, this also results in a factor of 32 in terms of savings. We have also selected the latest generation of components in each case. All axes are equipped with new, less energy-intensive electric motors, and the high-pressure cooling system is also more favorable in terms of consumption. We have reduced the inlet pressure of the compressed air unit. It is a mosaic of many small pieces that have enabled us to achieve such values.” Bumotec worked together with the company SIGMATools on this project. The company developed a multi-channel measurement technology that can be used to carry out detailed analyses of all components and operating states of a machine and then generate reports for optimization measures.

Finally, and this should not be underestimated, the footprint of the Bumotec 1000/Cneo has been reduced by 29%. The various functions and peripherals have been developed to minimize the space required. With a length of 254 in. (6,445 mm), a width of 195 in. (4,950 mm) and a height of 128 in. (3,251 mm), the new Bumotec transfer center takes up less than 344 sq ft (32 m²) in the workshop.


Watchstraps: Bumotec cuts times in half

The new Bumotec 1000/Cneo has now been in operation for several months at a company that manufactures elements for watchstraps. According to initial feedback, the manufacturer’s expectations were even exceeded. “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 go from one minute to 30 seconds,” confirms Sébastien Campalto, application engineer at Bumotec. He emphasizes that the customer has also noticed a “better end result” for their workpieces, which is also “achieved in less time”, with a 30% improvement in surface quality. “That is simply enormous,” says Sébastien Campalto. “The simultaneous increase in productivity and surface quality is incredible.” This machine, which he describes as a “great success” in this respect, could open the doors to new markets for the customer: Sébastien Campalto is thinking of medical technology and general mechanical engineering.

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