Micro-machines poised to revolutionize machining

Manufacture small series, get closer to the consumer, produce tailor-made, innovate faster... Born in Japan, micro -machines meet many of the expectations of manufacturers, in search of agility and concerned about limiting their environmental footprint. . Decryption with Alain Auffret, technical director of Pracartis and creator of the Précibot mini machining center.

The race for machine tool productivity has led to the construction of ever larger and ever more complex machines with innumerable functions. Significant investments that require large order volumes. But over the past ten years, machines with fewer functions (a deliberate choice of the manufacturer) and more compact have also appeared on the market, especially in Asia.

In Japan, some micro-machines, constituting a micro-factory, can fit on a 2m x 1m table. They are able to carry out machining, surface treatments, dimensional control for small parts in small series. If Japanese SMEs have not managed to agree to find partners to develop them on a global scale, the idea has gained ground, particularly in Europe.

Précibot, very high precision mini machining center

Born in 2015 as part of EcoSwissMade, one of the six thematic programs of the Engineering and Architecture field of the University of Applied Sciences and Arts of Western Switzerland (HES-SO), the 5-axis micro ⁵ milling machine – barely larger than a coffee machine – has been designed to machine a cube with a 50 mm edge while consuming a minimum of energy, without loss of machining quality. All in aluminum and carbon, Précibot (precision and robot) is a mini 3 or 5 axis machining center capable of ensuring very high precision (3μ) despite a weight (less than 100 kg) and dimensions very low (about 1m ³ ).

“ We are pioneers in France in terms of mini-machining centers,” says Alain Auffret. In fact, there is also the micro ⁵ in Europe. The two ideas came almost at the same time with the idea of reducing the moving masses in both cases. They chose a ball screw solution and we opted for oversized linear motors. There were already micro-machines before, but they were not advancing as fast as ours. Here, we are really in the field of high-speed machining. »

Précibot, awarded a GI Award at the Global Industrie trade fair in March 2022, has two applications. In its portable version, its lightness allows it to be carried by a robotic arm before being attached to a tool in order to carry out high-speed machining (UGV) during high-precision operations (large choice of spindles in option depending on the applications, with rotation speeds between 20,000 and 80,000 revolutions per minute). It can thus be used on large parts that are difficult to transport, such as maintenance carried out on damaged aircraft parts, repairs to nuclear power plants or even assembly operations on a submarine or a boat.

Energy consumption ten times lower than a conventional machine

Précibot can also become an innovative high-precision mini-machining center for applications in watchmaking, micromechanics, medicine, optics or even dentistry. It is then offered in a 5-axis version with 2 tilting rotary tables. Designed in Peillonnex (Haute-Savoie) on the premises of the Precise France company (Pracartis group), it works dry at very high speed while consuming very little energy. Its manufacture, use and recycling thus make it possible to divide by ten the CO ₂ emitted compared to a traditional machine tool.

Micro-machines are attracting more and more interest as energy prices soar. Without loss of machining quality (quite the contrary), the miniaturization of production equipment is indeed a guarantee of high precision, low energy consumption, flexibility of use and reduced space requirements within production workshops. . “ To further reduce energy consumption, we have eliminated the cooling system and eliminated the cutting oils,” explains Alain Auffret. We would even like to go so far as to remove the air to have a 100% electric machine. »

Currently in the customer trial phase on prototypes, Précibot should be marketed in the coming months. “ We want to be sure that our solution is reliable before proposing it on the market, we are not missing much, he specifies. Our first target is manufacturers who are considering reducing their energy consumption as well as their floor space. We have projects in wind power, nuclear power, watchmaking… ” A masterpiece of technology, this solution with multiple uses could, in the near future, revolutionize the field of machining.

© Alexandre CHAMBET – PRACARTIS Group