Textile Yarn and Package Winding Machine Automation

On a fancy (effect) yarn machine the effect comes from changing feed roller speeds. The core yarn is fed at constant speed while the roller feeding the effect yarn briefly speeds up or slows down according to the pattern; the overfed yarn forms effects such as slub (flamme), knop or bouclé. On an electronic machine the pattern is defined as effect length, effect thickness (speed ratio) and distance between effects, and turned into a speed profile for the servo axis. The pattern can be a fixed sequence or random within set limits; a random pattern prevents a regularly repeating mark in the fabric.

Twist is the ratio of spindle speed to yarn delivery speed: twist (turns/m) = spindle speed (rpm) / delivery speed (m/min). On a mechanical machine this ratio is set by change gears; on an electronic machine the spindle and the delivery roller are coupled to the same master axis with an electronic gear, so twist stays constant while the machine accelerates, decelerates and stops. On hollow-spindle fancy twisting machines the binder yarn's wraps per metre are set by the same ratio.

In package winding the traverse guide moves the yarn back and forth across the package to build a cross-wound package. The guide is coupled to the package spindle with an electronic cam: the cam profile defines the reversal at the stroke ends and the acceleration there; the reversal points are shifted slightly from stroke to stroke so that the package edges are neither hard nor bulging. Precision winding keeps the ratio between package turns and double strokes (wind ratio) constant; random winding keeps the crossing angle constant, so the ratio changes as the diameter grows. When the ratio passes certain values the yarn stacks on itself (ribbon formation); to prevent this the traverse speed is varied around those values. Step precision winding combines both: the ratio is held constant and switched to the next ratio when the crossing angle leaves its band.

Two layouts are common on multi-position machines. With group drive, the spindles on one side of the machine are driven by one motor through a tangential belt or line shaft, and the traverse guides by one servo motor through a common traverse rod running along the machine; the mass and elasticity of the rod then limit the acceleration at the reversal points. With individual drive each position has its own motors and a yarn break stops only that position. In both layouts all axes follow the same master axis, so ratios are kept while the machine accelerates, decelerates or stops.

In the ONX architecture machine speed is a virtual master axis in CODESYS SoftMotion running on CODESYS Control RTE on an industrial PC. Feed and effect rollers, spindles, package spindles and traverse are coupled to it with electronic gears or cams; the effect pattern and the traverse cam profile are calculated in the controller and reloaded on the fly when the recipe changes. Servo drives and remote I/O share one time base over EtherCAT.

Axes that need fast, precise motion (effect roller, traverse) use servo drives and servo motors; axes with high power but slowly changing speed (spindle group, main drive, fans and suction) use AC drives and induction motors, which follow the same master speed reference. On a mains failure the drives' DC bus is fed by the kinetic energy of the motors and all axes are brought to a controlled stop while keeping their ratios; how long this takes depends on machine inertia.

Textile machine builders are one of the main industries ONX Control supplies with servo systems, AC drives and control components. We share application examples close to your machine, and our proposed axis layout, in a meeting.

A typical picture on older textile machines: motion distributed from one main motor through gearboxes and belts, change gears for pattern and twist, a mechanical cam box for the traverse and an old control board with no spare parts. Changing pattern or twist means changing gears and stopping the machine. In a retrofit the machine frame, spindles and rollers are usually kept; mechanical links are removed, the relevant axes get servo or AC drives, and pattern, twist and winding settings move into recipes.