Viscose High Twist Yarn Process Optimization for Crepe Fabric Quality

Why Viscose High Twist Yarn Needs Stricter Control

Viscose Fiber Character

Viscose comes from regenerated cellulose, usually from wood-based cellulose raw material. It gives fabric a smooth hand, cool touch, good moisture absorption, breathability, antistatic comfort, bright dyeing performance, and comfortable skin contact.

These features make viscose useful for summer apparel, light woven fabrics, underwear, socks, home textiles, and close-to-skin textile products. However, viscose reacts strongly to moisture and mechanical action. Too much beating, poor carding, or uneven humidity can quickly increase yarn defects.

High Twist Character

Regular yarn uses twist mainly to improve strength and spinning performance. Its twist coefficient often stays around 280 to 420.

Viscose high twist yarn usually needs a twist coefficient around 600 to 700. This higher twist creates stronger twist shrinkage. After weaving and finishing, that shrinkage helps the fabric form a clear and even crepe surface.

Typical viscose staple specifications include 1.33 dtex x 38 mm and 1.2 dtex x 38 mm. Common yarn counts include 36.4 tex and 19.5 tex. Twist levels often reach 1350 twists/m, 1550 twists/m, and sometimes 1750 twists/m.

S Twist and Z Twist

Crepe fabric often uses both S twist and Z twist yarns. A common structure uses two S twist yarns and two Z twist yarns together. This arrangement helps balance torque and gives the fabric a more even crepe effect.

When the fabric structure stays simple, defects become easy to see. A short thick place, hard end, nep, or unstable twist can leave a clear mark on the fabric surface.

Quality Targets for Viscose High Twist Yarn

Main Production Goal

The main target stays clear: high strength, fewer yarn defects, stable winding, and high weaving efficiency. Our factory also checks whether the yarn runs well after twist setting, because lively yarn can snarl during unwinding.

For strict crepe fabric, thin places should stay at a very low level. Neps and thick places also need tight control. Obvious short thick defects cannot pass, because the fabric surface exposes them after finishing.

Yarn Data and Fabric Feedback

Yarn test data helps, but fabric feedback matters more. A cone can pass count, twist, and evenness checks, yet still create problems during weaving. Package tension, twist liveliness, clearer joints, and humidity history all affect the final result.

We normally check yarn test data together with winding performance and fabric feedback. A small trial roll gives better feedback than yarn data alone. After a wash test, the crepe effect, hand feel, shrinkage, and visible defects become easier to judge.

Opening and Cleaning Process Optimization

Original Process Route

The original production route included FA009 bale plucker, FA125 free waste removal, FA105 single axial flow opener, FA029 multi-mixer, FA116 fine cleaner, FA156 micro-dust remover, FA179 chute feeder, FA203A carding machine, FA306 drawing, FA423 roving, FA507 ring spinning, and SMARO automatic winding.

Viscose fiber contains fewer impurities than many cotton routes. A long opening and cleaning flow can damage the fiber instead of improving quality.

Shorter Flow and Lower Speed

Our process direction follows four points: short flow, low speed, less beating, and smooth transfer. In the optimized route, the team removed FA125 free waste removal and FA156 micro-dust removal. This reduced fiber rubbing and shortened the path before carding.

The FA009 plucker speed moved from 1250 r/min to about 1000 r/min. Single axial flow opener speed moved from 600 r/min to about 500 r/min. FA116 fine cleaner beater speed moved from 420 r/min to about 360 r/min. FA179 chute feeder beater speed moved from 950 r/min to about 750 r/min.

These changes reduced beating force while keeping fiber transfer smooth. They also helped reduce short fiber and neps before carding.

Feeding and Pressure Control

Lower speed cannot mean unstable feeding. The opening and cleaning line still needs continuous delivery to the chute feeder.

Our team keeps the opening and cleaning operating rate above 90% when possible. The plucker and opener should reach about 95% in stable production. A trolley speed around 18 m/min and a smaller grabbing depth around 2.5 mm can support more even feeding.

Pressure also matters. The system negative pressure can stay around -800 Pa to -900 Pa. Carding pipe negative pressure around 650 Pa to 700 Pa helps keep fiber transfer stable.

Carding Process Optimization

Why Carding Matters

Carding plays a major role in viscose high twist yarn quality. Strong carding can damage viscose. Weak carding leaves neps and poor fiber separation.

The better direction uses lower cylinder and taker-in speed, a proper speed ratio, suitable sliver weight, controlled flat speed, and matched card clothing.

Carding Speed Trial: SR19.5 tex, 1350 Twists/m

Parameter	Plan 1	Plan 2	Plan 3
Cylinder speed	435 r/min	345 r/min	360 r/min
Taker-in speed	930 r/min	735 r/min	780 r/min
Delivery speed	120 m/min	120 m/min	65 m/min
Yarn CV	12.16%	11.87%	11.41%
-50% defects	1/km	2/km	0/km
+50% defects	13/km	6/km	10/km
+140% neps	121/km	91/km	100/km
+200% neps	15/km	4/km	15/km
Tube-to-tube CVb	2.49%	2.10%	2.30%
Breaking strength	245 cN	270 cN	260 cN

The first setting used excessive cylinder and taker-in speed, which increased fiber damage and lowered yarn strength. Although the third setting gave the best CV, its low delivery speed reduced output too much for normal bulk production. From our factory view, Plan 2 gave a more practical balance between yarn quality and production efficiency for viscose high twist yarn.

Carding Speed Trial: SR19.5 tex, 1550 Twists/m

Parameter	Plan 1	Plan 2	Plan 3	Plan 4
Cylinder speed	360 r/min	390 r/min	360 r/min	360 r/min
Taker-in speed	735 r/min	735 r/min	780 r/min	675 r/min
Delivery speed	103 m/min	103 m/min	103 m/min	103 m/min
Cylinder/taker-in ratio	2.52	2.70	2.30	2.75
Yarn CV	11.88%	12.43%	12.05%	11.24%
-50% defects	1/km	2/km	3/km	0/km
+50% defects	14/km	8/km	13/km	3/km
+140% neps	40/km	36/km	39/km	33/km
+200% neps	10/km	12/km	14/km	10/km
Tube-to-tube CVb	3.49%	2.00%	2.40%	1.90%
Clearer cuts	33.2 / 100,000 m	28.8 / 100,000 m	30.4 / 100,000 m	27.4 / 100,000 m

Plan 4 gave the best overall result. It used lower cylinder and taker-in speed with a larger speed ratio. This helped fiber transfer and carding quality without pushing fiber damage too high.

Card Sliver Weight Trial: ZR26.5 tex, 1350 Twists/m

Parameter	Plan 1	Plan 2
Card sliver weight	20.5 g/5 m	22.5 g/5 m
Cylinder speed	360 r/min	360 r/min
Taker-in speed	675 r/min	675 r/min
Delivery speed	103 m/min	103 m/min
Cylinder/taker-in ratio	2.52	2.70
Yarn CV	11.21%	11.41%
-50% defects	0/km	0/km
+50% defects	5/km	11/km
+140% neps	30/km	60/km
+200% neps	16/km	18/km
Tube-to-tube CVb	2.60%	2.40%
Breaking strength	277 cN	270 cN
Clearer cuts	21.9 / 100,000 m	24.7 / 100,000 m

The lighter 20.5 g/5 m sliver gave better yarn stability. A heavier sliver may raise output, but it can reduce carding openness and add risk in later processes.

Flat Speed Trial: ZR19.5 tex, 1550 Twists/m

Parameter	Plan 1	Plan 2
Flat speed	89 mm/min	139 mm/min
Yarn CV	11.46%	11.58%
-50% defects	1/km	0/km
+50% defects	5/km	6/km
+140% neps	28/km	30/km
+200% neps	7/km	9/km
Tube-to-tube CVb	2.70%	2.40%
Clearer cuts	21.6 / 100,000 m	21.0 / 100,000 m
Flat waste	1.3%	1.5%

Higher flat speed did not bring a clear quality gain, but it increased flat waste by 0.2%. For bulk production, that waste increase adds cost without enough benefit.

Card Clothing Service Life Trial

Parameter	Old Clothing	Newer Clothing
Pre-carding plate cycle	36 months	1 month
Rear fixed flat cycle	24 months	1 month
Pre-carding plate/taker-in gauge	0.70 mm	0.50 mm
Yarn CV	11.91%	11.81%
-50% defects	1/km	1/km
+50% defects	16/km	8/km
+140% neps	68/km	53/km
+200% neps	28/km	14/km
Tube-to-tube CVb	2.10%	2.00%

Old card clothing reduces fiber opening and transfer because the tooth tips become dull. For viscose high twist yarn, card clothing cycle control directly affects neps, thick places, and final fabric appearance.

Card Clothing Matching Trial

Parameter	Plan 1	Plan 2	Plan 3
Cylinder clothing	AC2025 x 01740	AC2030 x 01550B	AC2030 x 01740
Taker-in clothing	AT5605 x 05611	AT5610 x 05611	AT5610 x 05611
Doffer clothing	AD4030 x 01890	AD4030 x 01890	AD4030 x 01890
Flat clothing	MCH52	MCH52	MCH45
Yarn CV	12.03%	11.06%	11.63%
-50% defects	1/km	2/km	0/km
+50% defects	10/km	6/km	5/km
+140% neps	52/km	28/km	29/km
+200% neps	18/km	7/km	8/km
Tube-to-tube CVb	2.49%	1.93%	2.20%

Plan 2 gave the strongest quality result. Plan 3 offered a useful higher-output option. The trial shows that viscose high twist yarn needs matched card clothing, not only one stronger clothing part.

Drawing Process Optimization

Drawing Process Setting

Drawing helps straighten fibers and reduce irregularity. For viscose high twist yarn, the drawing process should strengthen fiber arrangement without causing fly or drafting disturbance.

Parameter	First Drawing	Second Drawing
Doublings	7 ends	8 ends
Back-zone draft	1.86	1.40
Drafting gauge	11 x 20 mm	9 x 18 mm
Delivery weight	19.8 g/5 m	18.6 g/5 m
Pressure bar position	14 mm	14 mm

The drawing process used more doublings, larger back-zone control, and a higher pressure bar position. This helped fiber arrangement while avoiding excessive pressure-bar control, fly accumulation, and drafting disturbance.

Roving Process Optimization

Roving Weight Trial: ZR24.8 tex, 1350 Twists/m

Parameter	Plan 1	Plan 2
Roving weight	5.6 g/10 m	6.1 g/10 m
Yarn CV	10.97%	10.66%
-50% defects	1/km	0/km
+50% defects	18/km	16/km
+140% neps	39/km	59/km
+200% neps	10/km	17/km
Tube-to-tube CVb	2.30%	2.20%

The heavier roving showed a slightly lower CV, but it increased severe neps and thick defects. The original production conclusion favored the slightly lighter roving for more stable quality.

Roving Twist Coefficient Trial: ZR19.5 tex, 1550 Twists/m

Parameter	Plan 1	Plan 2	Plan 3	Plan 4
Roving twist coefficient	69	71	73	78
Yarn CV	11.87%	11.68%	11.83%	11.46%
-50% defects	1/km	2/km	0/km	0/km
+50% defects	19/km	8/km	6/km	5/km
+140% neps	70/km	45/km	28/km	26/km
+200% neps	18/km	15/km	9/km	6/km
Tube-to-tube CVb	2.10%	2.20%	2.60%	2.30%
Clearer cuts	27.9 / 100,000 m	26.8 / 100,000 m	20.8 / 100,000 m	19.7 / 100,000 m

Clearer cuts dropped as the roving twist coefficient increased. A larger roving twist coefficient helped control fiber speed change in the ring spinning back zone. Still, the setting needs a practical limit, because too much roving twist can make drafting difficult and create hard ends.

Ring Spinning Process Optimization

Main Control Points

Ring spinning decides much of the final yarn quality. For viscose high twist yarn, the main control points include roller gauge, apron nip gauge, and back-zone draft.

The process needs firm fiber control and smooth drafting at the same time. Too loose creates defects. Too tight creates hard ends.

Ring Spinning Roller Gauge Trial

Parameter	Plan 1	Plan 2
Middle x back roller gauge	21 x 45 mm	19 x 45 mm
Yarn CV	12.20%	12.05%
-50% defects	1/km	0/km
+50% defects	16/km	6/km
+140% neps	38/km	38/km
+200% neps	8/km	7/km
Tube-to-tube CVb	2.30%	2.10%
Clearer cuts	27.9 / 100,000 m	24.8 / 100,000 m

A slightly tighter main drafting zone improved yarn stability and reduced clearer cuts. This setting helped concentrate fiber movement during ring spinning.

Ring Spinning Apron Nip Gauge Trial

Parameter	Plan 1	Plan 2	Plan 3
Apron nip gauge	3.0 mm	2.5 mm	3.5 mm
Yarn CV	11.90%	11.81%	12.27%
-50% defects	1/km	0/km	3/km
+50% defects	18/km	31/km	1/km
+140% neps	39/km	31/km	41/km
+200% neps	10/km	6/km	11/km
Tube-to-tube CVb	2.50%	3.20%	2.10%
Clearer cuts	23.4 / 100,000 m	32.7 / 100,000 m	22.4 / 100,000 m
Hard ends in spinning	No	Yes	No

The 2.5 mm gauge improved some yarn indicators, but it caused hard ends. The 3.5 mm gauge weakened evenness. The 3.0 mm setting gave a safer balance for actual production.

Ring Spinning Back-Zone Draft Trial

Parameter	Plan 1	Plan 2
Back-zone draft	1.25	1.17
Yarn CV	12.90%	11.80%
-50% defects	1/km	0/km
+50% defects	11/km	8/km
+140% neps	58/km	37/km
+200% neps	16/km	9/km
Tube-to-tube CVb	2.00%	2.30%

Lower back-zone draft improved yarn CV and reduced thick places. For viscose high twist yarn, a smaller back-zone draft with suitable roller gauge supports better fiber arrangement and more stable drafting.

Autowinding Optimization

Clearing and Efficiency

Autowinding acts as the final yarn fault control point before packing. For viscose high twist yarn, the machine should run at lower speed with suitable tension.

High winding speed can increase breakage, snarling, and package problems. Over-strict clearer settings can create too many joints. Loose settings may allow fabric defects to pass.

Factory Check Points

Our team checks three practical indicators during winding.

• Full bobbin run-out rate should reach about 70% or higher.
• Rewinding breakage from 10 cones should stay around 0.3 ends or lower.
• Yarn faults from 100 bobbins should be collected and classified.

This fault collection helps trace the source. Some defects come from carding. Others come from drawing, roving, ring spinning, or winding tension.

Twist Setting Optimization

Why Twist Setting Matters

High twist yarn carries internal stress. Without enough twist setting, the yarn can snarl, loop, and break during unwinding.

These problems can affect warping, sizing, and weaving. They may also cause unclear shed opening and more loom stops.

Heat Setting

Heat setting can run at about 75°C for 8 to 12 hours. Coarser yarns usually need a shorter time. Finer yarns usually need a longer time.

The exact time should match yarn count, twist level, package density, and downstream use.

Natural Moisture Recovery

Natural setting can run around 40°C room condition for 72 to 80 hours. This method gives the yarn time to reduce internal stress through moisture recovery.

In our sample room, we check unwinding behavior after setting. For important orders, we also run a small woven or knitted trial before bulk production.

Temperature and Humidity Management

Viscose Moisture Behavior

Viscose absorbs moisture strongly. Under normal atmospheric conditions, its moisture regain sits around 13%.

After moisture absorption, viscose fiber swells clearly. This can help spinnability, but uneven moisture can quickly damage yarn quality.

Low-Humidity Route

Some production routes avoid active humidification. They keep relative humidity around 40% to 50% and control roving regain around 10.5%.

This route can work when the room stays stable and the fiber flow does not dry out unevenly.

Humidified Route

Other production routes use humidification. They keep relative humidity around 60% to 70% and control roving regain around 12.0%.

This route can also work, especially when the system keeps moisture even across the room and process line.

Main Risk

The largest risk comes from uneven humidification. If one side of the spinning room runs wetter than another side, the same process setting can produce different yarn behavior.

Uneven moisture can increase neps, fly, drafting disturbance, spinning ends down, and clearer cuts. For viscose high twist yarn, stable humidity matters more than a single target number.

Yarn Testing and Fabric Testing

Yarn Test Items

Yarn tests should cover count, twist, strength, evenness, defects, hairiness, package build, and twist stability. These data points help check whether the process stays under control.

They do not replace fabric testing. High twist yarn must prove its behavior after weaving, finishing, and washing.

Fabric Test Items

Fabric tests should check crepe effect, shrinkage, wash appearance, dimensional stability, pilling, colorfastness, and hand feel. A small wash test often shows problems that yarn data cannot show.

For close-to-skin or export products, buyers may also need chemical safety documents. OEKO-TEX STANDARD 100 can support harmful-substance review. ISO 9001 quality management gives a useful reference for factory management-system expectations.

Cost Risk in Bulk Production

Yarn Price Is Not the Full Cost

For viscose high twist yarn, buyers should not judge cost only by yarn price per kilogram. A lower price can become expensive if the yarn causes fabric defects, rework, shipment delay, or claims.

Too many clearer cuts create more joints. Poor twist setting causes snarling. Unstable humidity increases yarn defects. Weak fabric testing may miss shrinkage or crepe problems before bulk shipment.

Better Bulk Confirmation

Our factory prefers a clear trial process before bulk production. The buyer should confirm yarn count, twist direction, twist level, fabric structure, color plan, and test requirement.

Then our team can run trial cones, check winding behavior, make a small trial roll, and review wash or finishing results. This approach reduces risk before the bulk lot starts.

Process Summary for Viscose High Twist Yarn

Opening and Carding

Opening and cleaning should use a short flow, low speed, less beating, and stable pressure. Carding should use lower cylinder and taker-in speed, a larger suitable speed ratio, medium sliver weight, controlled flat speed, and matched card clothing.

Drawing to Spinning

Drawing should improve fiber arrangement with proper back-zone draft and gauge. Roving should use a slightly lighter weight and a larger but controlled twist coefficient. Ring spinning should use a moderately tight main drafting zone, suitable apron nip gauge, and lower back-zone draft.

Winding, Setting, and Humidity

Autowinding should clear real defects without creating too many joints. Twist setting should reduce snarling and improve downstream running. Temperature and humidity should stay even throughout production.

For sourcing teams comparing this yarn with other special yarn routes, our functional yarn varieties and special yarns page gives broader product context. For project communication, our functional yarn supplier page explains the basic information we need for sampling and bulk follow-up.