Choosing a Loom: Weft Insertion, Shedding and the Parts Around Them

Start with the weft, not the loom

All three systems move a short piece of weft across the open shed. They differ in what carries it, and that sets the yarn range.

Rapier. A rigid, flexible or telescopic rapier carries the weft. The Istanbul Technical University lecture notes describe rapier machines as known for versatility across a wide range of fabrics. The giver rapier starts slowly, so the weft only has to be presented in its path. That is why colour changes are simple. The same notes show flexible-rapier machines with up to 12 weft colours and working widths up to 5 m. Rigid rapiers need floor space of at least twice the fabric width. A rapier listing can also show how unusual a "fabric" may be. The SJ758 from Shaoxing Textile Machinery Group names paper cord, nylon filament and mat grass as intended materials.

Air-jet. A main nozzle accelerates the weft. Relay nozzles, spaced along a profiled reed, keep the air fast across the shed. Air has very low viscosity, so the same lecture notes say air-jet picking was designed mainly for spun weft. It became suitable for filament after main-nozzle developments. The notes list spun and continuous-filament yarns as suitable, textured yarns as especially suitable and monofilament as unsuitable. They name count, structure and twist as the factors that decide whether a yarn can be inserted. Twist is covered in our page on twist level and direction. The supply side matters too. Compressed air is filtered, compressed, cooled and dried before it reaches the looms, so ask for consumption figures alongside the loom's installed power and electrical supply.

Water-jet. A pump drives a water jet that carries the weft. The weft's wetting behaviour affects the pull it receives. A University of Moratuwa study notes that water-jet looms are common for synthetic fabrics. It also notes that cotton absorbs much more water during insertion and does not pass properly through the warp. The ITU notes set out working conditions:

• filtered water without sediment-forming elements (Fe, Mg, Ca, Si)
• hardness of 5–10 German degrees
• 16–24 °C operating temperature
• corrosion-resistant reeds, temples and healds
• squeezing or suction to remove water from the wet cloth

The LH2000 water-jet series from Qifang is listed for synthetic-filament fabrics, including nylon and polyester. Its catalogue offers several reed widths, shedding arrangements and weft-insertion choices.

Reed width is not fabric width

A quoted reed width is the machine's nominal capacity. Your greige fabric width, plus any weft contraction, has to fall inside the range the supplier will commit to for your construction. Ask for that usable range in writing, together with what has to change to weave a narrower fabric. On the rapier drive described in the ITU notes, adjusting the rapier stroke for width needs only one connecting-rod setting. The reed is a separate matter: air-jet looms with relay nozzles guide the weft through the tunnel of a profiled reed. Dingfeng's air-jet profile reeds form a family of loom-specific variants, including a double-air-channel terry reed. Such reeds should be approved against a drawing and the actual loom, not a brand name.

Dobby or jacquard

Shedding decides how many warp ends can move independently. A dobby lifts heald frames, so every end on one frame moves together. A jacquard controls ends individually through hooks and a harness. A *Textile World* report on a presentation by Dr Abdel-Fattah Seyam (NC State) makes several points:

• Standard jacquards had 448 to 1,792 hooks, which forced repeats into fixed harness ties.
• Larger machines reach 18,432 hooks.
• Electronic dobbies with one actuator per frame allow shed timing to vary pick by pick.

Hook count, harness tie and loom width therefore have to be specified together. Jiabao's NH electronic jacquard publishes four hook-count configurations, from 5,376 to 10,752, with a listed maximum of 650 r/min. Its listing stresses that harness load and the supporting structure must be agreed as part of the installation. For dobby looms, the control unit is often the part that gets replaced. The SXACT-GT2003-II is listed as an electronic pattern operating unit for closed electronic dobbies. Its public page gives no full interface specification, so confirm the existing dobby, electronics and pattern-file workflow before treating it as a retrofit. Other controls and spares are listed under parts and accessories.

The peripherals that decide whether it weaves

Weft feeders. A feeder draws yarn off the package and stores coils on a drum. The weft then unwinds from a constant diameter at a defined tension, monitored by a sensor. Sanhe's SHRP rapier weft feeder publishes a maximum feed rate of 1,600 m/min. Its page also notes two yarn-count ranges that are not equivalent conversions, so check them against our yarn count conversions. Weft packages also need to unwind cleanly. Sanfang's SGD2012 rewinder is described as preparing weft packages for rapier, water-jet and air-jet weaving, and its two package entries differ in tube dimensions. See package and tube specifications for what to state.

Selvedge devices. Selvedge equipment is fitted to a particular loom and position. Micheng's K88 middle-head assembly belongs to a rapier selvedge range, but it has no published mounting specification. Selection therefore starts with the loom and the required head position.

Warp preparation. Stäubli separates drawing-in, used for complete style changes, from warp knotting, which ties a new warp to the old one to shorten warp changes. Boqiu's BQ198 warp knotter describes up to 600 knots per minute and frames from 1 to 4 m. Its configuration tabs do not describe identical yarn capability, though, so test a complete warp change.

What to specify

Use the structure in preparing a weaving enquiry, and add the following:

1. Warp and weft yarns (fibre, count, twist, filament or spun), plus any stretch weft. Stretch yarn construction is covered in covered and textured yarn machines.
2. Fabric construction, greige width, weave and number of weft colours.
3. Shedding: number of frames, or jacquard hook count and harness tie.
4. For water-jet looms, your water analysis and treatment plan. For air-jet looms, your compressor capacity.
5. Feeder, selvedge, reed and knotting items, each identified by drawing.

Then compare the configurations item by item. Ask for a trial with your own yarn, and write the agreed fabric result into the factory acceptance test. More looms are listed under weaving machinery.

Sources

1. E. Önder and Ö. B. Berkalp, *Jet Weaving* (Weaving lecture, Chapter 8), Istanbul Technical University. (accessed 2026-11-04) View source
2. E. Önder and Ö. B. Berkalp, *Rapier Weaving* (Weaving lecture, Chapter 7), Istanbul Technical University. (accessed 2026-11-04) View source
3. J. Borneman, "Woven Fabric Formation: Shedding Systems", *Textile World*, March/April 2015 (based on a presentation by Dr A.-F. M. Seyam, NC State University). (accessed 2026-11-04) View source
4. M. A. A. U. Prasanna et al., "Developing a technological process to weave cotton fabrics on water jet loom", 2016 Moratuwa Engineering Research Conference (MERCon), IEEE, pp. 283–288; University of Moratuwa repository record. (accessed 2026-11-04) View source
5. "Automatic warp knotting machine" and "Weaving preparation solutions", Stäubli International AG. (accessed 2026-11-04) View source