Special bearings for award-winning robots

Comau, a giant in the automation and robotics sectors, relies on special bearings produced by CPM. We are telling a story where “Made in Italy” is protagonist.

Test phase of an inner ring for a Comau bearing.
Test phase of an inner ring for a Comau bearing.

The Italian CPM S.p.A., located in Nova Milanese (Monza Brianza), is one of the Italian reference enterprises in the design and production of special rolling bearings. Every year, the staff of over 170 employees produces more than three million special bearings for the national and international markets. Paolo Salgari, Sales Engineer & Marketing Manager, says: «CPM is specialized in the production of special bearings in medium and high volumes, based upon customers’ specifications. Production includes ball bearings, roller bearings, slewing rings and precision rings, in a dimensional range between 10 mm of internal diameter and 800 mm of external diameter».

CPM bearings are designed and manufactured for many different application sectors, especially for the manufacturing of planetary gearboxes, and are used by leading Italian and German producers, who then export their final products around the world.

«Our prerogatives – adds Salgari – are product quality, timeliness and the flexibility in satisfying our customers. One of our strengths is the fact that the complete production process is carried out in-house. In this way, we can manage potential manufacturing variations in real time, manage job orders in a fast and versatile manner and constantly monitor product quality». CPM is positioned as a real partner and not a mere supplier, since it is at its customers’ disposal in order to implement bearings perfectly suiting their requirements. This is especially the case during co-design activities.

Fig3 Technical office, study and design of a CPM 2568 bearing.
Technical office, study and design of a CPM 2568 bearing.

What we are narrating in this in-depth analysis is the story of how CPM, a medium-size reality, has succeeded in becoming a reference partner to a worldwide giant within the automation and robotics fields, beating the competition made of large multinationals operating in the bearings sector. The giant to which we are referring is Comau, an Italian multinational manufacturer and a member of FCA Group, which delivers welding and body welding lines and systems, powertrain machining and assembly systems and a wide range of industrial robots for all application fields.

A special solution

Paolo Salgari explains: «The relationship with Comau was established about ten years ago, when the Group demanded alternative bearings to those generally used. The strong point of CPM consisted in proposing itself as a much more reactive and faster reality compared to the giants operating in this sector that offer various types of standard, catalog version bearings. These companies, therefore, tend to be slow or unwilling to study “tailor made” solutions for customers».

The DNA of CPM, on the other hand, is based on our willingness to implement “tailor-made” solutions according to customers’ requirements, a characteristic that was evidenced at the time: «Thanks to this approach – adds Salgari – we were able to understand what type of product could bring real technical advantages to Comau. More precisely, we started replacing some of the cross roller bearings, which are able to resist axial and radial loads, with 4-points contact ball bearings that were, obviously, made with the same overall dimensions».

The choice of replacing cross roller bearings with 4-points contact ball bearings turned out to be a winning solution, as they not only withstand axial loads better but are also cheaper, since their manufacturing process is less expensive. Additionally, cross rollers are generally positioned at 90° to one another and consequently the load acts at 45° in respect to the axis. With 4-points contact bearings, however, the contact angle can be “customized” according to the specific need and, depending on the project’s requirements, it can be prevailingly radial or axial. This characteristic allows the internal geometry of the bearing to be designed according to the application, which then optimizes the efficiency of the bearing itself.

On the left, Giovanni Degrà, General Manager of CPM S.p.A. (Nova Milanese, MB). Then, Paolo Salgari, Sales Engineer & Marketing Manager, and Lorenzo Santambrogio, Technical Department Manager.
On the left, Giovanni Degrà, General Manager of CPM S.p.A. (Nova Milanese,  Monza, Italy). Then, Paolo Salgari, Sales Engineer & Marketing Manager, and Lorenzo Santambrogio, Technical Department Manager.

Lorenzo Santambrogio, manager of CPM’s technical department, explains the technical details: «Cross roller bearings assure higher stiffness than ball bearings, because the load is applied on a line and not by points. Nevertheless, using bigger-size rolling elements within the rollers section of

Santambrogio: «At the beginning it was not easy at all. The new bearings were intended to be used in robots that were already in production and then they had to be totally interchangeable and fully compatible with the previous ones. We adapted sizes, geometries and technical details, we studied opportune solutions and, in collaboration with the customer, we carried out specific tests for the testing and to verify the requested stiffness. Then we started replacing the bearings. The results were successful, satisfying our expectations and, especially, satisfying Comau». The year was 2004. Today, 10 years later, CPM produces and supplies the Comau Group with 4-points contact ball bearings, in various sizes, for several robot typologies. Over the years, there have been improvements deployed. An example is the introduction of a precision hole, for a specific product, that passes on an inner ring for the assembly of a safety plug, or the introduction of rubber seals to improve the tightness against pollutants while reducing costs.

Excellent results

Today CPM bearings are successfully used on several Comau robots, as explains Alessio Cocchi, Marketing Manager, Comau Robotics: «CPM is a very valid partner and has become our supplier both for the quality of its products and also for its high flexibility in terms of the ability to define and customize its bearings according to our needs and in a much shorter timeframe than competitive suppliers. The reaction speed is certainly a key advantage of CPM, as is the fact that it has always adopted a very confidential approach to our proposals/requirements. Its technicians have always proved reliable, willing and straight-forward, and have met our requests, in all respects, on multiple occasions».

Alessio Cocchi, Marketing Manager, Comau Robotics.
Alessio Cocchi, Marketing Manager, Comau Robotics.

It is not a question of luck that CPM bearings are mounted on the award-winning Racer robot, the latest robot developed by the Turin-based company. Cocchi highlights: «Racer is designed to grant the best performances to users in terms of speed and precision. It is ideal for processes such as handling, automation, polishing, measuring, arc welding, sealing and so on». The robot, designed to ensure top performance, was presented to the public just last year and quickly became a “star” of the world market.

As for the bearings themselves, Cocchi specifies: «CPM bearings proved to be better than those offered by other competitors in terms of performance and reliability, and they contribute to making Racer one highest performing robots in the industry».

Lorenzo Santambrogio confirms: «The advantages of our ball bearings with four contact points, compared to cross roller bearings, consist in granting lower wear which means longer service life, thereby assuring the necessary stiffness while decreasing costs».

Alessio Cocchi concludes: «CPM is certainly a company able to develop “Made in Italy” and this means double satisfaction for us, since CPM bearings contribute in making Comau robots, and Racer in particular, even more technological and with a truly Italian heart. The excellence, the high performance, the reliability and the design of Comau robots export their purely “Italian” character worldwide».

Open market to high technology

The visit to the CPM production facilities was also an opportunity to highlight the current market situation.

In the opinion of Paolo Salgari, the current economic period is not very positive, despite a recovery phase that characterized the beginning of 2014: «CPM, however, has never been particularly affected by these stagnation phases because, after the onset of the crisis in 2009, the company has always focused on high-level products for top engineering industries. What we can affirm, in general, is that the market is fluctuating; it alternates between euphoria times and stagnation. Month-to-month the situation changes completely and it is difficult to dare long-term forecasts».

Fig5 Base slewing ring (axis 1) for Comau robots.
Base slewing ring (axis 1) for Comau robots.

Alessio Cocchi proposes his point of view about the automation and robotics market: «The data on a global scale is very significant for us, because since 2008, the year that preceded the crisis, until 2013, we have grown by 35%. During 2013, 178,000 industrial robots were sold in the world, of which 120,000 were articulated robots, which represents our core business. The world trend is currently growing, mainly in China and more in general within Asian markets that are increasingly interested in automation solutions. In USA, the growth is contained while in Europe it is slower than the other continents». What about Italy? «Even if the Italian market is generally affected by troubles, our Country is experiencing a stable period in terms of robot sales, thanks to the increasing demand for System Integrators. Italy has excellent companies, especially small-medium enterprises, which are competitive and succeed in exporting their products abroad where the “Made in Italy” of automation is highly appreciated for its creativity and the capability of proposing innovative solutions».



Comau SpA is the worldwide leader in manufacturing flexible, automatic systems and integrating products, processes and services that increase efficiency while lowering overall costs. Headquartered in Turin, Italy, with an international network that spans 17 countries, Comau uses the latest technology and processes to deliver advanced turnkey systems that consistently exceed the expectations of its customers. Comau specializes in body welding & assembly, powertrain machining & assembly, robotics and maintenance as well as environmental services for a wide range of industrial sectors. The continuous expansion and improvement of its product range enables Comau to guarantee customized assistance at all phases of a project – from design, implementation and installation, to production start-up and maintenance services. www.comau.com


Conceived for high performances

The Racer robot by Comau.
The Racer robot by Comau.

Racer 7-1.4 is the Comau robot with 7 kg payload and maximum horizontal range of 1,400 mm. The machine has been designed and implemented with the most cutting-edge technology and with obsessive attention to details, and is the result of an intense design activity and in-depth study of shapes. The excellent results obtained on the market by Racer 7-1.4 gave birth to Racer 999, which was launched in January 2015. The new robot also features a 7 kg payload and range under one meter. Both robots are articulated with six axes, and both are compact with high stability and rigidity. They are also extraordinarily fast thanks to the very low reduction ratios and to E-motion, the new software release for Comau robots. These robots deliver a significant reduction in cycle times as well as energy consumption.