Interview - 2023-02-20
World-renowned Spanish lathe manufacturer CMZ is lauding more than 25 years of high-level technological collaboration with linear motion and bearing specialist NSK. The company’s machines incorporate NSK innovations that include ground ball screws, linear guides and super-precision bearings. This ongoing partnership helps to consolidate CMZ’s leading position in Europe, exporting over 80% of its production thanks to the high performance and efficiency of its lathes.
CMZ is a family-operated business and technology leader in lathe manufacture, with a history dating back more than 75 years. For the past three decades, the company’s technological evolution has continued through partnerships with premium suppliers such as NSK, helping it to produce more than 500 machines a year.
Collaboration between CMZ and NSK began in 1996 with the TBI series lathe. This machine was the first to use NSK ball screws, which offered external ball recirculation and numerous other features adapted to machine tools. CMZ soon became convinced that NSK offered the most appropriate technology for the company’s lathes, commencing the exclusive use of its ball screws.
In 2000, CMZ launched the TL series lathe, constituting a significant technological leap due, on one hand, to its turret technology which moved beyond reliance on electro-mechanics to incorporate servo control. CMZ also experimented with the production of a new headstock design featuring an integrated motor.
To increase rigidity and achieve a compact design, the company began using NSK double-row cylindrical roller bearings together with BTR angular contact ball bearings to absorb axial loads. This decision represented a highly beneficial step forward in support of the headstock’s requirement to offer strong performance at high speed.
NSK developed its high-performance ROBUST BAR and BTR roller bearing series specifically for the market’s latest-generation lathes, which must deliver maximum performance with minimum temperature fluctuations to achieve high precision. To meet the demands of specific customer requirements, these bearings are available in contact angles of 30º or 40º and can incorporate ceramic rolling elements for applications requiring higher speeds.
CMZ headstocks demand a precise assembly process. The company constructed its first clean room at its Zaldibar facilities in 2000 and has since added a second at its Seuner plant. Specific air treatment within the clean rooms is indispensable to the correct assembly of this type of headstock, including temperature and relative humidity control, as well as pressurisation to expel dust and particles in accordance with the ISO Class 8 standard.
A further innovation that benefits CMZ is NSK ball screws with nut cooling, which are setting new standards in machine tool precision and speed. The benefits of adjusted cost, compact design and system simplification improve over the hollow-shaft cooling design. These advantages also support temperature control at high speeds to maintain micron precision, a basic requirement of modern machine tools. In addition, the system facilitates effective spindle cooling.
When CMZ developed the TD series machine for large-scale turning applications, it incorporated NSK ball screws with nut cooling into axes that require more repetitive movements and where heat generation could cause inaccuracies in turning operations. Thanks to this design, the CMZ product catalogue today features lathes capable of working at higher levels of precision with large-scale workpieces.
There is an awareness at CMZ that NSK can handle any of its development needs thanks to close contact with technical departments in Japan. This communication channel keeps CMZ up to date on technological innovations, including roller linear guides with special systems to protect against contamination and the latest ball screw and bearing solutions.
Among the latest CMZ machines to receive a market introduction is the TTL series twin-spindle CNC lathe, a model that ably demonstrates the successful collaboration between CMZ and NSK.
The highly productive TTL model uses NSK RA series roller linear guides specially arranged to allow a combination of movements between the turrets and spindle heads, with power provided by synchronous motors. Here, NSK developed a set of linear guides to incorporate its pioneering K1 lubrication system, which applies oil throughout a machine’s operating life, converting it into a sustainable and environmentally friendly solution that meets CMZ’s expectations. Today, the company produces around 100 TTL series lathes every year.
CMZ is constantly innovating. For example, digitisation is a further ongoing project, with NSK closely involved in the process. CMZ has raised the prospect of digital monitoring and data gathering on spindles and bearings.
Sustainability is also a priority, specifically regarding oil consumption. Here, NSK solutions feature protection and lubrication systems that never require replacement, leading to a significant reduction in oil consumption. Accordingly, CMZ and NSK are discussing various solutions to minimise waste in the company’s latest lathe designs.
Like all of the development projects over the past 25+ years, NSK will continue supporting CMZ in its ambition to stay ahead of the market. The partnership between the two companies is strong thanks to a foundation of mutual trust and understanding.
Picture 1): NSK double-row cylindrical roller bearings being prepared for assembly to the spindles of CMZ lathes under clean room conditions
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