The Need for Speed
Packaging OEMs look to advanced software solutions and linear servos to boost system performance
Al Presher, Contributing Editor -- Design News, August 31, 2008
What are the key trends in motion control for packaging?
Flexibility, connectivity and the need for speed are the main goals for packaging OEMs. The ability to handle different size packages, bottles and even different product lines means the machines need to be flexible. The need for speed is making manufacturers look for ways to decrease changeover times and drives automation to fully utilize product recipes to adjust automatically to new product requirements. There is also a requirement to report activity, so connectivity in terms of both reporting and receiving information and providing production data to nearby machines is key.
OEMs are moving to more sophisticated automated systems and the continuing move to servos requires controllers with more intelligence on the machines. Some OEMs are offering a higher end line of machines with servos that offer higher production speeds with more accuracy.
What technologies are impacting packaging machine design?
More sophisticated automation solutions are utilizing more software. One technology engineers are embracing is .NET and there are more PCs on machines using Microsoft technologies. Other OEMs are using more sophisticated automation controllers that have good software capabilities without using a PC and the decision on the controller to use is often not based on a technical decision.
Users of .NET feel it provides flexibility and offers an efficient and solid visual environment for programmers. The definite trend toward software is driven by the need for more sophisticated automation to handle more complex requirements. The way to achieve these goals is to encapsulate the more complex functions required in software.
Why is there an increasing interest in linear motor solutions?
More engineers are interested in linear servos, as well as rotary motors. That's a new direction. Many machines are operating 24 x 7 and linear motors offer inherent advantages because there are no contacts, wear and reliability increases. Sometimes to conserve dollars, engineers buy a small servomotor and gearbox but, when the system requires higher precision, they eliminate the gearbox and move to a larger rotary servo to provide the torque needed. But sometimes the next step is to upgrade the machine by using a linear servo because it offers significant advantages.
What are some of the challenges or misconceptions with linear motor solutions?
Engineers are sometimes surprised by the force linear motor solutions can provide. We have even stacked the linear motors, as many as six together, to produce higher forces because the systems are additive, as well. The systems are direct drive and very precise. In automation systems, there is always a trade-off between precision and production rates. Linear motors provide a way to maintain precision while increasing production rates.
The biggest challenge of building linear motors into a machine is the environment because it needs to be protected. You have an exposed linear magnet, but suppliers including Aerotech will put the linear motor into a stage that is already covered and has the motor integrated with the encoder.
Cable management is the second challenge. It is essential to use the proper cable and bend radius to ensure long life. In some cases, it makes more sense to fix the forcer and move the magnet track, eliminating any moving cables.
How is automation impacting next generation packaging machine design?
Distributed servo architectures are making an impact on packaging machine design and the design of control systems for machines is definitely moving toward more distributed solutions. Smaller cabinets are placed strategically throughout the machines, versus all of the controls coming back to a central cabinet. Connectivity using either Ethernet or a serial bus allows engineers to string cables from drive-to-drive, shortening cable runs and providing coordinated communications.
Festo Corp. Introduces Tubular Linear Motors
12/31/2009Solar Nears Tipping Point
12/31/2009Whirlpool Washer Corrosion Saga: Update
12/18/2009
