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Tornos CNC Machinery Makes The As Standard

Tornos CNC Machinery Makes The As Standard

Added to MTDCNC by Tornos Technologies UK Ltd on 08 November 2011

A robot used in spinal surgery can now guarantee the positioning of pedicle screws to within a few microns. This is credit to precision actuators and the respective ball bearing components on the hexapod robot being produced by Micro Precision Systems (MPS) with an EvoDeco 16 turning centre from Tornos.

 

MPS manufactures micro-precision ball bearings and ball-bearing mounted precision systems for highly specialised use in almost all industries. In order to do so, the company relies on machinery that provides the high degree of accuracy it needs.

 

"For us, micro precision is not just a production feature. We live and breathe it each and every day," says Nicola Thibaudeau, CEO at MPS. The company and its 150 employees focus on precision guidance systems for linear and rotary movements for demanding applications with customers in the watchmaking, medical devices and optical industries. The manufacturing range includes both ball screw bearings for linear guidance systems and miniature ball bearings for the watchmaking industry. Defining the companies micro precision credentials, Nicola Thibaudeau continues: "With stainless steel or ceramic ball bearings we are working with diameters from 0.200 to 1.588mm at a roundness precision of 0.08µ and a maximum surface roughness of 0.01µ. In the case of ball-bearing mounted precision systems, we have an ingenious ion process that means we can achieve play of just 6 to 12µ between precisely fitting ball bearings and ball tracks."

 

The demand for such precision is apparent, for example, in the guidance system for a robot used in surgery: "The surgeon uses a robot arm to guide a laser beam to the operating site with high precision. This robot arm features four joints and the laser can be guided within a tolerance of just 0.5mm with arm extended. And with our ball bearing systems it can do this successfully and repeatedly. In order for us to achieve such a result, we need capable employees and superior machinery," explains Nicola Thibaudeau.

 

A homogeneous machine shop brings flexibility

The immaculately clean hall of machines at MPS is full of automatic turning machines from Tornos. Jean-François Bilat, Head of Machining and Surface Technology, justifies this choice: "We are fundamentally satisfied with Tornos, which is why we continue to rely on it. If there is a fault, the service staff are on site within a short time and any spare parts we need also reach us promptly. This is very important for safeguarding our production. In addition, there is the fact that as a rule we work with production runs of between 100 and 50,000 pieces, sometimes even less. To achieve this, our staff are flexibly deployed on the various automatic turning machines. A homogeneous machine shop permits this kind of rotation with no loss in production or quality. On top of that there is an important opportunity to make savings. Our machine shop allows us to use the same tools on various machines from the same manufacturer. This gives our machining department a very high degree of flexibility."

 

The machining department has been so busy that there has been a call to expand the machine shop. Eric Pesselier, Head of Machining, comments: "We had initially decided in favour of a new Deco 13 from Tornos, and then we saw the EvoDeco 16 at the last Prodex show. Since this new model brought several improvements compared to the Deco 13, we decided to investigate the matter more extensively and also checked out the new automatic turning machines at the Tornos factory in Moutier. We found the concept so convincing that we opted for this machine."

 

Jean-François Bilat adds: "The machine meets our specifications with regard to swapping the tools around. Programming the control and operating the machine is comparable with the Deco 13, which additionally helps us maintain our advantage of being able to rotate our staff. In addition, the fact that we can use bigger bars with a diameter of 16mm opens up new potential for future projects."

 

Pleasing ergonomics

The two specialists were quickly convinced by the EvoDeco 16, as Jean-François Bilat confirms: "The machine's ergonomics compared with the Deco 13 have been significantly enhanced and improved illumination in the working area makes it considerably easier to set up and monitor operation during production. Given our relatively small production runs, this is very important to us. Also, the fact that the control panel is now attached to the rotary arm and can support employees at the machining area for setting up and any other interventions is not only convenient but makes it considerably easier to work on this machine."

 

Surprising stability

The new automatic turning machine demonstrates its great strengths in production runs. Eric Pesselier is pleasantly surprised: "Precision has always been our core competence. And this is where the Evo Deco 16 gives us considerable support. We very quickly saw that the machine was extremely stable. Running-in after a weekend standstill has become much briefer. After producing three parts or so, this automatic turning machine has already reached high long-term thermal stability. In very general terms, this automatic turning machine demonstrates impressively high uniformity in the productive phase. Even with high-precision turned parts we achieve a constant precision of +/- 5µ, and that also applies to large production runs. Because the machine is so reliable, the employee working on the machine has more freedom now to do other things." Despite everything, the turning machine operator checks the parts every 20 minutes. Any corrections are very easily introduced during productive operation, although according to Eric Pesselier: "Such corrections have become relatively rare on this machine."

 

Plenty of power and yet still as quiet as a mouse

The machining department at MPS continually manufactures parts from highly resistant chrome steels or titanium. Turned parts vary in terms of dimensions from a diameter of 2 to 13mm and a length of 2 to 250mm. According to Eric Pesselier: "Both the main and counter spindles are directly driven with synchronous motors and their removal rate is discernibly and convincingly superior. For this reason, and thanks also to the stability of this machine, we prefer to machine bigger parts on this machine with higher chip volumes. We are pleasantly surprised that this machine also makes less noise than other automatic turning machines even under heavy loads."

 

Rigorous checks

MPS is certified to ISO: 13485 and has a clean room for putting together assemblies that are used in the field of medicine. Nonetheless, this kind of production facility is also checked regularly explains Jean-François Bilat: "We record and analyse our part checks statistically so that we can identify any deviation trends very early on. In addition, internal audits ensure that our quality is always to our high standard, because even though our customers are scattered around the world they regularly check our operation, especially our production equipment. This is another reason why each of our automatic turning machines stands in a trough to collect any lubricant or cutting emulsion that might drip down. And that is where the EvoDeco 16 has given us another surprise: as yet it has not been necessary to clean the trough. So the machine is also very leak-proof."

 

Totally convinced

Both Jean-François Bilat and Eric Pesselier are very impressed by the new EvoDeco 16 and they are not the only ones. Eric Pesselier comments: "Our team of turning machine operators prefer working on this automatic turning machine." No wonder, the next automatic turning machine that has already been ordered as part of the production capacity expansion is another EvoDeco 16.

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