Modular machines gaining momentum
The larger a machine, and the more flexible options it offers, the more it stands to benefit from hardware and software composed of modular, mechatronic units. The complexity that arises from incorporating large numbers of axes and safety technology further intensifies the demands on the automation solution. B&R has added the ACOPOSmotor to its portfolio to handle precisely these types of applications. This system is the only motor-mounted servo drive on the market that doesn't require derating and can handle an entire machine module on its own.
The automation experts at B&R have developed an exceptionally compact motor-drive combination – the ACOPOSmotor – that is able to provide the same dynamic performance as a standard drive and adds the convenience of a single supply cable. This latest step in the company's continued expansion of an already impressive motion portfolio seeks to address the evolving needs of today's modular machinery.
Another B&R innovation, the longstanding ACOPOSremote, was also geared towards this growing market segment. Nevertheless, certain applications require an even more compact solution. Fillers with actuators mounted directly on the rotary plate highlight the challenge of making the most of extremely limited space. In addition, an ultra-compact motor-drive solution is just as important in many other applications that require integrated safety functions and a local POWERLINK hub for additional I/O components. In the Italian city of Parma, the ACOPOSmotor turned out to be just the answer that a customer was looking for.
The Parma region is known by gourmets the world over for its delicacies. For nearly 60 years, it has also been home to OCME, one of the largest manufacturers of packaging systems.
OCME machines are exceptionally versatile and exhibit a high degree of technological sophistication, with more than 25 patents testifying to the company's innovative prowess. With its new end-of-line system, it is therefore no surprise that OCME was looking to push the envelope – particularly in terms of machine footprint and energy consumption. As a result, a key requirement of the DryBlock system became clear early in development.
Customer requirements – The only true measure
For its new DryBlock system, OCME needed a more compact drive unit than any available on the market at the time. OCME's electrical department manager, Antonio Mosca, brought the situation to the attention of Davide Beviglieri, key account manager at B&R. "We're looking for a way to combine the motor and the servo drive into a single compact unit," explained Mosca.
After all, OCME had ambitions of revolutionizing the way a packaging line is developed, built and managed. This would include new technology to make product handling more flexible, allow handling of individual bottles and prevent contact between products. The individual modules – the labeler, shrinkwrapper and palletizer – would be operated from a single multi-touch panel and would take advantage of OMAC's PackML standard to optimize machine control, communication and synchronization. This approach would rely on full modularization with distributed I/O and motion control.
Beviglieri contacted Alois Holzleitner, manager of B&R's Motion business unit, and described the application requirements. "We've been working on a solution for just such an application," Holzleitner replied, outlining the project and the current status of product development.
Keeping the proven, innovating the rest
The goal was to leverage as much of the existing ACOPOSremote concept as possible. Through conceptual design, simulation and experimentation, it was soon evident which components could fundamentally remain the same.
Managing the temperature in such a confined space, on the other hand, proved to be quite a challenge. The electronics would be mounted on a housing that reaches 110°C during normal operation. No conventional component would last long under these conditions without additional measures. After all, the rule of thumb says that every 10°C increase in temperature doubles the rate of failure.
With less surface area to dissipate the thermal energy there would be an increased load on the motor as well. Various conventional approaches to resolving this conflict were considered. When water coolers, Peltier coolers and additional fans proved costly and unsuitable, however, B&R's developers initiated a more extensive series of trials in search of the optimal solution.
Extreme demands on motor and electronics
A test motor prepared to emulate the thermal characteristics of the final product was subjected to extreme operating loads. The temperature distribution in the windings, bearings and especially the encoder were analyzed in detail. The outcome? Without modifications, existing motors would not produce acceptable results.
The operating and limit temperatures of every single electronic component – far over 1,000 in total – were measured. It quickly became clear which options were available.
While the power electronics handled the higher temperatures well, the highly integrated digital components were much more sensitive. The same applied to many of the passive components, in particular the DC bus capacitors, which would also need to be very small in order to meet the dimensional requirements. The small size and corresponding low capacitance meant additional risk of resonance in the DC bus.
"One of our primary goals remains ensuring the interoperability of all B&R components," explains Holzleitner. "This gives our customers the freedom to decide on a project-by-project basis whether their application calls for an ACOPOSremote or ACOPOSmotor. Our customers need to be able to scale their solutions at any time."
By skillfully arranging the components, partitioning the device into various temperature zones and getting the manufacturers of critical components involved, the development team was finally rewarded with a breakthrough.
Putting ACOPOSmotor to the test
The results blew all expectations out of the water. B&R was able to ensure full compatibility with the rest of its ACOPOS drives and motors without any derating whatsoever. A single hybrid cable carries both POWERLINK communication data and power from the ACOPOSmulti DC bus directly to where it is needed. IP67 connections accommodate modules from the X67 I/O series – including the safety components – while the SafeMOTION functions defined in IEC 61800-5-2 are available as an option. A remote axis can be brought safely to a stop – independently of the STO signal on the hybrid cable – or operated at a safe speed during setup or maintenance.
Standing with B&R's Davide Beviglieri in front of a DryBlock®, OCME's head of development looks proudly on the fruits of their labor. The ACOPOS devices are installed, and the system has been running at top speed for days with ambient temperatures of nearly 50°C. "This drive is a huge step forward for us. We're now well on our way towards reaching our goal of boosting productivity while reducing energy consumption by up to 36 percent," concludes Mosca.