Motion control for textile machinery

In short:Textile machines are many-axis machines: each winding position, yarn feeder or needle bed has its own small motor, and the hardest axis is usually the traverse, which reverses many times a second. Size it from yarn speed, wind ratio and reversal distance, keep moving mass low, and protect motors and encoders from lint.

Typical requirements

Machinery we specify motion for

• Yarn winding machines
• Yarn guides and traverse units
• Yarn feeders and tension control
• Circular and flat knitting machines
• Industrial sewing machines
• Button-sewing and automatic sewing units
• Yarn and material testing devices
• Creels and take-up units

What textile machines demand from motion

Textile machinery is built around one material, yarn or fabric, that must never be stretched, slackened or snagged. So most of the motion problem is about keeping speed and tension constant while something else changes: a package growing on a spindle, a guide reversing at the end of its stroke, a needle punching through a seam. The loads are small. The speeds, cycle counts and number of axes are not.

Three things set textile machines apart:

• Many identical axes. A winder has one winding position after another, each with its own spindle, traverse and feeder. Cost and reliability per axis decide the design.
• Reversing duty. A yarn guide reverses at both ends of every stroke, many times a second, all day.
• A dirty environment. Lint and fibre fly settle on motors, encoders and contacts, and many machines carry oil mist from lubricated needles or cylinders.

FAULHABER sums up the guide duty well: high positioning accuracy, rapid start-stop and frequent reversals. That is why it supplies stepper motors for yarn guiding. For yarn feeders it stresses a drive that reacts quickly to load changes and meters power finely, so the yarn does not break, in a space where the motor must not set the maintenance interval.

Where motion sits in textile machinery

LinMot lists linear and rotary actuators for gentle process control in textile machines, and WITTENSTEIN includes textile processing among the industries using its gearheads and mechatronic drives.

Winding machines: spindle, traverse and tension

Filament winding runs fast. Oerlikon Barmag’s WINGS 1800 winds HOY at up to 5,200 m/min, on 12 ends as standard with a 16-end variant. At that speed every winding position must hold its yarn speed while the package diameter grows, so the spindle speed falls continuously as the package builds.

The traverse is the hard axis. Grooved drums and scroll cams were the traditional answer. A servo traverse patent explains why builders moved away from them: cam traverses are limited in speed, wear, and must be swapped to change the winding pattern. With a servo-driven guide, traverse length and wind ratio become controller settings. The patent’s example uses a 10 in (254 mm) stroke, a wind ratio between 3.5 and 6.5, and yarn at up to 1,000 yd/min, driven through a low-mass cable so the guide can reciprocate quickly.

Worked example: sizing an electronic traverse

Take a precision winder at 1,000 m/min, a 150 mm traverse stroke, a wind ratio of 5 (spindle turns per double stroke) and a package that starts at 100 mm diameter.

1. Spindle speed. 1,000 / (π × 0.1) ≈ 3,180 rpm at the start of the package.
2. Double strokes per minute. 3,180 / 5 ≈ 640, or about 10.6 per second.
3. Traverse speed. 2 × 0.15 m × 10.6 ≈ 3.2 m/s average.
4. Crossing angle. Yarn speed is 16.7 m/s, so the angle is about atan(3.2 / 16.7) ≈ 11°.
5. Reversal. Stop and reverse from 3.2 m/s within 10 mm at each end: a = v² / (2s) = 3.2² / 0.02 ≈ 510 m/s², about 52 g.
6. Force. With 50 g of moving guide, that needs about 26 N. With 200 g, once you add a carriage and a moving coil, it needs about 100 N, four times the motor.

The lesson is that moving mass decides the motor. Keep the guide light, and if you use a linear motor, consider a moving-magnet or ironless design with a light forcer. The traverse runs close to 100% duty, so size the motor on RMS force and plan its cooling. As the package grows and spindle speed falls, the controller keeps the wind ratio or crossing angle correct, depending on the winding method. These numbers are an illustration, not a design.

Yarn feeders and tensioners are the other half of winding. FAULHABER notes that some customers use DC motors with graphite commutation here and lists brushless motors of up to 100 W continuous for textile drives. A voice coil can also make a fast, programmable tensioner.

Knitting machines

Circular knitting machines quote output as a production factor: feeders × rpm × diameter in inches. Mayer & Cie’s OVJA 2.4 EM double-knit jacquard machine reaches 2,300 (92 feeders × 25 rpm at 38 in), with electronic needle selection in the cylinder. For motion that means a cylinder drive with smooth, constant speed, a take-down whose tension follows the fabric, and positive yarn feeders on every feed. Electronic needle selection relies on accurate cylinder angle, so the main drive’s encoder matters as much as its torque.

Flat knitting machines traverse a carriage over the needle beds and reverse at each end, which is a smaller version of the traverse problem above.

Industrial sewing machines

Industrial sewing heads increasingly use direct-drive servos. JUKI’s DDL-9000C couples a compact 400 W AC servo motor straight to the main shaft and sews at up to 5,000 stitches per minute at stitch lengths up to 4 mm, with an automatic thread trimmer and, on some models, an electronically controlled presser foot. For automatic sewing units and button-sewing machines, add stepper or servo X-Y axes to move the clamp, plus small actuators for trimming, wiping and stacking. Size the clamp axes on acceleration between stitches and positional stiffness at the needle.

Lint, oil mist and the mill environment

Specify for the mill, not the test bench. Fibre fly builds up on fan inlets and heat sinks, so a motor that runs cool on the bench can overheat after a week in production. Prefer fan-less or sealed motors and drives in enclosures that can be blown down. Open optical encoders and exposed slip ring tracks collect lint too; magnetic and capacitive feedback, such as the dirt-tolerant KappaSense FLEXe linear encoder, is more forgiving. Route cables away from yarn paths, and confirm that seals and cable jackets resist the needle and cylinder oils in use.

Typical pitfalls

1. Sizing a traverse on average speed. Reversal acceleration and moving mass set the force.
2. Ignoring resonance. Steppers driving guides at a fixed reversal rate can hit a resonance band; check across the full recipe range.
3. Open optical scales in a mill. Lint clogs them. Magnetic or capacitive feedback is more forgiving.
4. One drive per axis by habit. Multi-axis drives and a shared bus cut cost and wiring on many-position machines.
5. Forgetting the restart. Without absolute feedback every head must home after a stop, which costs production time.

What to send us

Tell us the machine type, how many identical positions it has, and for each axis the motion, stroke or speed, load and duty. For winders add yarn speed, package size, wind ratio range and traverse stroke. Include the bus voltage, fieldbus, safety functions and target cost per axis. Our specialist engineering and supply partners will propose motors, drives and feedback to suit.

Standards to have in view

• ISO 11111-1 (textile machinery: safety requirements, common requirements)
• ISO 10821 (industrial sewing machines: safety requirements)
• EN 60204-1 (electrical equipment of machines)
• ISO 13849-1 (safety-related parts of control systems)
• IEC 61800-5-2 (drive safety functions such as STO)
• IEC 60529 (IP codes)

Which standards apply depends on the end product and its market. Your engineer will confirm what the component itself needs to meet.