Automatic Winding Machine

Overview

An automatic winding machine takes the small, hard ring-spun bobbins that come off a spinning frame and rewinds the yarn from them onto large cross-wound packages. The spinning frame can only put a short length on each bobbin, a few thousand metres, because the bobbin has to be small enough to circle inside the ring. A loom or a knitting machine wants a much larger package so it does not stop every few minutes to change supply. The winder joins the yarn from many bobbins into one continuous length on a single cone or cheese, often a hundred times the size of the supply bobbin.

The second job is just as important. While the yarn is running off the bobbin and onto the package, the machine inspects every metre of it and cuts out the faults. Ring-spun yarn carries thick places, thin places, slubs and the occasional foreign fiber, and the winding step is the one chance to remove them before the yarn is woven or knitted into cloth where a fault is permanent. So the winder is both a packaging machine and a quality gate.

Supply and unwinding

A run starts at the Bobbin Supply & Feed. Each position has a rotary magazine holding several full bobbins, and when the running bobbin is empty the magazine indexes the next one down through the Bobbin Feed Chute onto the unwinding peg. A Reserve Thread Finder catches the reserve winding from the new bobbin and threads it up to the splicer so the change happens with no operator.

The bobbin sits in the Unwinding Station and pays its yarn off over the top of the tube. At winding speed the yarn forms a spinning balloon as it comes off, and that balloon grows longer as the bobbin empties, which would make the tension rise. The Balloon Control Breaker and the Unwinding Accelerator Tube keep the balloon short and steady from a full bobbin down to an empty one, so the tension on the yarn stays in a narrow band the whole way.

Tension and waxing

From the unwinding station the yarn passes through the Yarn Tension Device. The disc tensioner nips the yarn between two polished Tension Disc faces under a set load, adding a steady, repeatable pull. A Tension Actuator sets that load from the recipe so the operator does not adjust it by hand for each yarn count. Correct tension matters because it decides how hard the package is wound: too loose and the package collapses or sloughs off, too tight and the yarn loses elasticity and the package is hard to unwind later.

Most positions also carry a Waxing Unit. The yarn drags across a slowly turning Solid Wax Disc and picks up a thin film of paraffin wax. The wax lowers the friction of the yarn so it slides freely through the needles of a knitting machine. A Waxing Monitor Sensor watches the disc so unwaxed yarn is not wound on when the disc runs out.

Clearing and splicing

The heart of the quality function is the Electronic Yarn Clearer. The Capacitive/Optical Clearer Head measures the yarn as it runs, either by capacitance, which reads the mass in the sensing field, or by light, which reads the diameter. The signal is sampled thousands of times a second and compared against fault limits set for thick places, thin places and count variation. A separate Foreign-Fiber Sensor looks for dark or coloured matter that the mass channel would miss. When a fault falls outside the limits the Clearer Cutter snips the yarn and the bad length is sucked away.

Every cut, every bobbin change and every break has to be repaired, and that is the job of the Yarn Splicer. The Upper Thread Catcher swings up to the package and finds the yarn end coming off it, while the Lower Thread Catcher catches the end from the bobbin side. Both ends are laid into the Air Splice Chamber, stripped of twist in the Untwisting Tube pair, then overlapped and intermingled by a timed air blast. The result is a knotless joint nearly as fine and as strong as the yarn itself. A knot would snag in weaving and show in the cloth, so the air splice is what lets the winder remove faults without leaving a worse defect behind.

Winding the package

The cleared, spliced yarn is laid onto the package at the Winding Head. A Grooved Winding Drum turns against the package and drives it by friction, and the crossing groove cut in the drum face guides the yarn back and forth across the package width to build the cross-wind. The Package Cradle holds the empty tube and presses the growing package against the drum at constant force as it fills. An Anti-Patterning Drive drive shifts the drum speed slightly so successive coils do not stack into a hard ribbon that would unwind badly. The package builds as a cone for weaving or a cheese for knitting and dyeing, cross-wound so it pays off over the end without rolling.

Doffing, suction and control

When a package reaches size the Auto Doffing System system ejects it onto the conveyor, loads an empty tube from the Empty Tube Magazine and restarts winding. The whole machine depends on a Machine Frame & Guards with a central Central Suction Duct that carries vacuum from a Suction Blower to every thread catcher and cutter, pulling away cut yarn and fluff. The Machine Control cabinet holds the recipe of tension, speed, clearer limits and splice timing, while a Position Controller at each head runs the splice cycle and drives that position. The central data link gathers production and quality figures per position, so a mill can see which bobbins, which counts and which positions are producing the most faults and act on it.