Simple System-Building Developed for Unique Winding Machine
03 November 2008
The Ethernet-compatible Powerlink motion control network is helping the Swiss company Carbo-Link to create carbon fibre components for challenging applications such as rigging for racing yachts.
Carbo- Link used the Powerlink compatible controller and drives from Baldor to build a machine that winds carbon fibres to form lightweight yet ultra-strong tubes or rods of up to 14 metres in length. The machine proved so successful that the company decided to build 50 metre long version to capable of supporting a much broader range of applications.
Established in 2003 by researchers from Empa, the Swiss Federal Institute for Material Testing and Research, Carbo-Link had to build its own machinery in order to gain the precise control over the orientation and position of the fibres during the winding process. Standard winding machines on the market are simply too inflexible (as well as being too expensive) for the type and constantly changing variety of special-purpose components that the young Carbo-Link company produces.
Cost and flexibility were key drivers in the selection of the motion control technology. For the new machine, there were five axes of motion to control. This number made Carbo-Link's engineer, Iwan Stoecklin, think about using one of the new high-speed motion control networks, as he did not want to buy two controllers. From previous experience with conventional analog drives and motion controllers he knew that one standard low-cost motion controller might well not have enough control to handle the entire system.
Powerlink also promised to reduce the cabling complexity and size of the control system. This was another attractive attribute of the new technology, as part of the motion control system moves along the 14 metre carriage as the tube or rod is formed.
Baldor's Powerlink-compatible controller, NextMove e100, provided Carbo-Link with a flexible solution. The 100Mbits/second datarates of the Ethernet-compatible network, in conjunction with a high-performance DSP, allows the single controller to manage as many as 16 interpolated axes as well as all the other machinery I/O components required. The network's intrinsic immunity to noise also means that it can be installed over very long distances. This was very useful for the 14 metre winder, and will be even more important on the forthcoming 50 metre version of the machine.
Carbo-Link's unique winder is made from a precision steel frame with winding elements, plus a moving tool that slides along the length of the machine as the carbon fibre component is made. Two servomotor axes provide the synchronised winding action that can be configured to create ropes and solid rod structures, or to wind tubular shapes around a mandrel former. The moving tool has two servomotor axes of movement. One provides lateral movement to accurately position the fibre with respect to the structure that is being created. The second provides rotational control of an 'eye' that guides the fibres as they are wound. The last axis controls the linear motion of the tool along the machine.
In addition to precise control over the winding action, the machine gives Carbo-Link complete software programmability and flexibility to allow it to make a wide range of different components. The machine has been used to make carbon fibre ropes for rigging on 'round the world' racing yachts for example. It has also fabricated very small diameter tubes with ultra-thin walls measuring just 0.15 mm, for structural use in advanced aerospace applications.
The Baldor Powerlink-compatible controller and drives are housed in a small enclosure that sits at one end of the machine. The Powerlink network has made substantial contributions to reducing the weight, size and footprint of the system because of the simple daisy-chained interconnection that is employed to link the major system components.
The system was programmed using Baldor's motion and machine control language, Mint. This BASIC-like language includes high-level keywords for common motion control tasks. A number of these keywords helped Iwan Stoecklin to simplify the complexity of the software program, including FOLLOW and VECTORA which provide a means of moving all the axes simultaneously, in synchronisation with each other but at defined gearing ratios.
"Powerlink provides a very powerful control platform for motion machinery builders," notes Carbo-Link's Iwan Stoecklin. "The prime benefit was a reduction in the complexity of system building, as the one Baldor controller with its built-in multi-tasking kernel handled the complete multi-axis motion, HMI and I/O requirements of the machine, allowing me to focus the majority of my time on developing unique winding movements and mechanics."
"Powerlink is excellent at reducing the complexity of machine control systems, and this application is a good example of that with one controller handling five axes plus all the other I/O required — as well as minimising the electrical footprint," says Baldor's Marc Gottenkieny. "It would be just as efficient at controlling a much more complex machine with tens of axes, and this broad ranging applicability makes it especially suitable for smaller machine builders."
