Carding Behavior and Bearing Capacity of a Newly Developed Cylinder Card-Clothing Compatible with Cotton and Terylene Fibers by Nb Alloying of AISI 1090 Steel

Abstract

Changing the metallic card clothing on a carding machine is costly when the spinning mills want to card different fibers from cotton to terylene or vice versa. This article proposes a newly developed cylinder card clothing compatible with cotton and terylene fibers by Nb alloying of AISI 1090 steel so that the spinning mills can change the type of fiber without changing the card clothing. Based on an idea developed from classical carding balance theory to study the adaptability of the cylinder card clothing for cotton and terylene fibers, the wall shear stress was used as the basis for compatibility analysis of carding behavior and bearing capacity with cotton and terylene fibers and as the focus of this study. Nb alloying of AISI 1090 steel showed good wear resistance in carding areas after heat treatment with high hardness above 840 Hv0.2 and extremely fine grain grade of 13.5 class, which increased about 25% compared to conventional 80 WV. The testing results in the spinning mills, including one cotton and two terylene fibers, showed good performance with this newly developed card clothing. In conclusion, the card clothing made of Nb alloying of AISI 1090 steel can handle different fibers with acceptable carding performance.

Full text

Citation: Gu, W.; Li, F.; Cao, Y.; Gao,
Q.; Zhuo, C. Carding Behavior and
Bearing Capacity of a Newly
Developed Cylinder Card-Clothing
Compatible with Cotton and Terylene
Fibers by Nb Alloying of AISI 1090
Steel. Materials 2024,17, 1511.
https://doi.org/10.3390/
ma17071511
Academic Editors: Daniela Kovacheva
and Andrea Di Schino
Received: 6 December 2023
Revised: 12 March 2024
Accepted: 19 March 2024
Published: 27 March 2024
Copyright: © 2024 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
materials
Article
Carding Behavior and Bearing Capacity of a Newly Developed
Cylinder Card-Clothing Compatible with Cotton and Terylene
Fibers by Nb Alloying of AISI 1090 Steel
Weihua Gu 1,2, Fuguo Li 2,3, * , Youchang Cao 4, Qinchao Gao 1and Chengzhi Zhuo 1,3
1Geron Card Clothing Co., Ltd., Nantong 226009, China; guwh@geron-card.com (W.G.);
gaoqc@geron-card.com (Q.G.); zhuocz@geron-card.com (C.Z.)
2School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072, China
3Joint R&D Center for Metallic Materials, Metallic Wire and Metallic Card Clothing, Xi’an 710002, China
4Texhong International Group Limited, Hong Kong, China
*Correspondence: fuguolx@nwpu.edu.cn; Tel.: +86-180-925-210-22
Abstract: Changing the metallic card clothing on a carding machine is costly when the spinning
mills want to card different fibers from cotton to terylene or vice versa. This article proposes a newly
developed cylinder card clothing compatible with cotton and terylene fibers by Nb alloying of AISI
1090 steel so that the spinning mills can change the type of fiber without changing the card clothing.
Based on an idea developed from classical carding balance theory to study the adaptability of the
cylinder card clothing for cotton and terylene fibers, the wall shear stress was used as the basis for
compatibility analysis of carding behavior and bearing capacity with cotton and terylene fibers and
as the focus of this study. Nb alloying of AISI 1090 steel showed good wear resistance in carding
areas after heat treatment with high hardness above 840 Hv
0.2
and extremely fine grain grade of
13.5 class, which increased about 25% compared to conventional 80 WV. The testing results in the
spinning mills, including one cotton and two terylene fibers, showed good performance with this
newly developed card clothing. In conclusion, the card clothing made of Nb alloying of AISI 1090
steel can handle different fibers with acceptable carding performance.
Keywords: carding; metallic card clothing (MCC); computational fluid dynamics (CFD); Nb alloying
of AISI 1090 steel; wear resistance
1. Introduction
Carding is a critical process in the production of yarn. During the process, fiber turfs
are separated into paralleled single fibers to remove dust, impurities, and short fibers.
The carding performance is strongly influenced by the application of various types of
card clothing [
1
], especially metallic card clothing installed on the main cylinder and
flat-top card clothing installed oppositely in a carding machine. In classical operating
experiences, the card clothing types for cotton fibers differ from those for man-made fibers.
This phenomenon is a drawback for spinning mills when they want to change the types
of yarn repeatedly to quickly adapt to the market demands because of the high cost of
changing card clothing due to extended machine downtime and expensive card clothing.
The MAGNOTOP system [
2
] for the quick change of a flat top developed by Trutzschler can
reduce the downtime to several hours to avoid the drawbacks and improve adaptability to
fibers. However, the system was not cheap enough and could not be applied to most types
of carding machines due to technical problems.
A cheaper method was developing a type of card clothing that could adapt to several
different fibers without changing the card clothing. Before designing the unique card
clothing, we should know how the card clothing works in the carding process.
A classical theory points out that the carding process was just the fiber transfer
competition balance between the flat-top needles and the tooth tips of the cylinder card
Materials 2024,17, 1511. https://doi.org/10.3390/ma17071511 https://www.mdpi.com/journal/materials

Materials 2024,17, 1511 2 of 17
clothing. In their classical article [
3
–
5
], Singh and Swani proposed a value of pf to describe
the ratio of the fiber load held between the flat-top needles and cylinder teeth in the carding
state to the fiber load on the cylinder. The pf was defined as the ratio of the fiber load on
the flattop and the fiber load on the surface of the cylinder.
In their opinion, better carding performance needs a higher pf. The experience told us
that pf had limitations because too high of a pf could result in the fill-up of the flat top and
shut down the machine. Once a type of card clothing was installed, the value of pf would
be limited to a narrow range. The value may be suitable for cotton, but for man-made
fibers, it could be too small to have good performance or too big to avoid the shut-down of
the carding machine. This was why the spinning mill had to change the card clothing to
adapt to different fibers.
However, which dimension of the card clothing affected the pf was unclear. A Japanese
engineer suggested that the working angle of metallic card clothing was the critical pa-
rameter that influenced the balance in the carding process [
6
]. So, card clothing with
three different working surfaces on one tooth tip was invented. Thus, the range of pf
was expanded. The top on the teeth gave a suitable pf range for cotton, and the middle
gave another range for man-made fibers. In brief, the card clothing provided at least two
different carding positions, one for cotton and one for man-made fiber. However, the truth
was that only the fibers held at the top of the teeth would be well carded. The middle of
the card clothing was not a good position for any fibers. Not only does the working angle
impact the balance but also the carding position from the tips. The main reason for this pity
was a lack of a systematic estimation method to describe the card clothing quantitatively.
Fortunately, with the development of simulation methods, the complex airflow be-
tween the narrow space of cylinder card clothing and flat-top needles can be well inves-
tigated. This will significantly help us understand the balance in the carding process,
which could make the adaptable cylinder card clothing compatible with cotton and man-
made fibers.
Since the first attempt from RWTH Aachen University by Mahlmann I [
7
], com-
putational fluid dynamics have been recommended as one of the essential methods to
investigate carding progress. One of the reasons was that the airflow was so strong that
it would influence the movement of the fibers, while the spacing between the cylinder
and the flat top was too small to easily put any device for measurement [
8
]. The airflow
drag that could be strong enough to pull a single fiber out of the turfs was then verified
according to the simulation by Shanshan He in 2019 [
9
]. However, the simulation was
needed to improve accuracy further to investigate more carding details because of its
abstract and simple flat-top needles and rough mesh grid. The carding area was a complex
geometry with too many faces, so the simulation consumption was always a big problem.
Thus, our group applied a simplified carding area with a uniform flat-top needle model
for simulation in developing double-tooth carding clothing in 2021 [
10
]. In that article, the
airflow distribution around tooth tips was taken as a physical indicator to describe the
carding performance of metallic card clothing. This indicated the development direction of
high-output card clothing and was corroborated by several patents from other card clothing
providers [
11
–
13
]. However, the geometry was still not accurate enough to distinguish
between any match of the metallic cylinder card clothing and the flat-top needles.
Due to the primary function of the card clothing being influenced by the shape, the
wear resistance of the card clothing was significant. So, the material of the card clothing
was an essential issue in designing the new metallic card clothing. Studies investigating the
effect of alloying elements on the local microstructure and mechanical behavior have been
carried out recently [
14
,
15
]. The development of steel in card clothing was slow because of
the extreme property requirements of high ductility in its annealed state for drawing to
wire less than
Φ
1 mm and extremely high hardness of more than 800 Hv
0.2
after quenching.
Tungsten and vanadium alloyed steel, also known as 80 WV in the field of textile equipment,
has been chosen as the primary material for card clothing since the 1990s [
16
], and it is still
applied to most high-end card clothing. This was a big drawback because of the increased

Materials 2024,17, 1511 3 of 17
wear resistance requirement in modern high-speed and output carding machines. The
unclear wear mechanism between fiber and steel mainly caused the difficulty with the
development of steel. Fortunately, the attempts at niobium alloying of high carbon steel
showed that niobium could generate much finer grain size and increase the eutectoid
content in the martensite, which could increase the wear resistance of steel when the fiber
was chosen to be the grinding material, similar to the polishing process [
17
–
19
]. In this
article, a first attempt of this method on AISI 1090 steel was carried out with the production
and wear test of metallic cylinder card clothing, which showed an evident increase in the
wear resistance.
The friction and wear of metallic card clothing is a significant problem in the textile
industry. By adopting appropriate design and material manufacturing processes, the wear
resistance of metallic card clothing can be effectively improved. Especially when a new
design of metallic card clothing is compatible with different fiber materials, the above
problems become more urgent. It is necessary to analyze and understand the carding
behavior and bearing capacity of a newly developed cylinder card clothing from the
perspective of simulation calculation so as to provide basic design parameters for materials
and material processes and lay the foundation for explaining the deep mechanism of
friction and wear of cylinder card clothing in the next step.
This article employed a novel and precise geometry to analyze a cylinder card clothing
compatible with both cotton and terylene fibers through computational fluid dynamics.
This approach posed numerous challenges, including mesh generation and fine-tuning
the algorithm to ensure convergence. Wall shear stress was chosen as a metric to depict
the equilibrium of fiber movement between the cylinder card clothing and the flat-top
needles. In the following parts of the article, we demonstrate that the method shows the
potential to estimate the carding balance quantitatively, in other words, pf. The wall shear
ratio between the flat-top needles and the cylinder teeth show the potential to be a positive
correlation quantity of pf.
Consequently, an adaptable cylinder clothing was developed by Nb alloying of AISI
1090 steel, renowned for its exceptional strength and wearability. This innovative cylinder
card clothing boasts at least two distinct tooth shapes within a repeat section along the
tooth wire, enabling fibers to occupy two positions for optimal carding balance in cotton
and synthetic fibers. In the present study, the tooth shape design parameters and wear
resistance of the tooth were thoroughly analyzed using this carding simulation method. The
cylinder wire made from AISI 1090 steel with Nb alloying and new tooth shapes underwent
testing in the spinning mills of Texhong International Group Limited. The findings reveal
that this metallic card clothing could be utilized for both cotton and terylene fibers, yielding
satisfactory sliver quality through mere adjustments to the carding parameters. This
eliminated the need to replace the card clothing or incur excessive downtime.
2. Design and Experiment
2.1. Metallic Card Clothing Design
Similar to the previous idea from Japanese engineers [
16
], the new card clothing was
also invented with fewer than two positions for holding fibers on the working surface.
Different from the previous invention, in the new card clothing, the two different positions
would be located on two different teeth with different tooth profiles (Figure 1). The
advantage of the new one is that fibers would always be held at the top area of the teeth
so that the fibers have a higher probability of being caught up by a flat-top needle, which
would help improve the carding performance. The theory here was verified with the
invention of double-tooth card clothing, published in 2021 [
10
]. The newly designed
cylinder card clothing seems to obey this rule worldwide from different card clothing
providers, including famous European factories [11–13].

Materials 2024,17, 1511 4 of 17
Materials 2024, 17, x FOR PEER REVIEW 4 of 17
(A) (B)
Figure 1. Tooth profiles of the card clothing: (A) The previous invention from the patent of
JPH01306625A [14], (a) the carding position for cotton fibers, (b) the carding position for synthetic
fibers, (c) the concave face between a and b; (B) the newly invented card clothing with two teeth, h1
and h2—the tooth depth, R1 and R2—the bottom arc, α1 and α2—the working angle, l—the humb
length. A typical dimension is also marked in the graph.
One of the difficulties with the design of the card clothing is how the card clothing
can be made on classical rotary punching machines with few changes. This is important
because rotary punching is the most efficient card clothing manufacturing process. Rotary
punching is one of the punching technologies described in U.S. Pat. No. 6195843. The doc-
ument is now included in Reference [20]. To meet the demand, the working angles of the
different teeth are the same as each other (Figure 1). In other words, to ensure this card
clothing could be manufactured in quantity, the angles α1 and α2 should preferably be
the same. In conventional card clothing, the working angle of the cylinder card clothing
for cotton is about 40°, while for terylene, it is about 20–25°. In this newly designed card
clothing, the working angle was designed as 35° for compatibility. The risk of this angle
design is that it would not have enough holding force to hold the cotton fiber or have too
large a holding force that would lead to the terylene fiber being warped on the cylinder
teeth. As an application-oriented design result, the holding force of the teeth can be dis-
tinguished not only by the working angle but also by the tooth depth and bottom arc.
Tooth II (Figure 1) has a deep tooth depth and a small bottom arc for a higher holding
force of the fibers, so it is the position for cotton fibers. The huge hump on the back of the
teeth guides airflow to avoid the intertwinement from man-made fibers, which always
has higher contact friction with metal surfaces. The end of the long man-made fibers are
lifted by the airflow so that the flat-top needles can easily catch them.
The PPSI (point per square inch) of the card clothing is another critical issue that
needed to be carefully considered. Based on experience, the PPSI for cotton is always
around 900–1000, while for terylene, it is about 700–860. The carding performance of the
card clothing for cotton could be improved by shortening the tooth depth to make up for
the loss caused by the reduction in PPSI. Finally, the tooth depth was designed to be 0.30–
0.35 mm, and the PPSI was designed to be 850–950.
2.2. Material of Card Clothing
Since this new card clothing was designed to be compatible with different fibers, the
robustness of the carding clothing needed to be improved to deal with a much more com-
plex and severe environment. Not only would the shape of the teeth need to be controlled
at a high level with few burrs even though the tooth shape is more complex than before,
but also the wear resistance of the card clothing would need to be improved. This always
means a definite improvement in the steel’s strength and toughness. According to the
classical Hall–Petch relationship, a grain size refinement could be a suitable method. For
the steel of card clothing, high carbon steel, for example, AISI 1070 and AISI 1080, have
always been appropriate choices for producing medium-end card clothing with low cost
and excellent ductility with a spheroidizing annealing state and high hardness after
quenching. However, AISI 1090 would not be a good choice even though it has a poten-
tially higher hardness because of its lousy ductility in the drawing of wire and teeth
Figure 1. Tooth profiles of the card clothing: (A) The previous invention from the patent of
JPH01306625A [
14
], (a) the carding position for cotton fibers, (b) the carding position for synthetic
fibers, (c) the concave face between a and b; (B) the newly invented card clothing with two teeth, h1
and h2—the tooth depth, R1 and R2—the bottom arc,
α
1 and
α
2—the working angle, l—the humb
length. A typical dimension is also marked in the graph.
One of the difficulties with the design of the card clothing is how the card clothing
can be made on classical rotary punching machines with few changes. This is important
because rotary punching is the most efficient card clothing manufacturing process. Rotary
punching is one of the punching technologies described in U.S. Pat. No. 6195843. The
document is now included in Reference [
20
]. To meet the demand, the working angles of
the different teeth are the same as each other (Figure 1). In other words, to ensure this card
clothing could be manufactured in quantity, the angles
α
1 and
α
2 should preferably be
the same. In conventional card clothing, the working angle of the cylinder card clothing
for cotton is about 40
◦
, while for terylene, it is about 20–25
◦
. In this newly designed
card clothing, the working angle was designed as 35
◦
for compatibility. The risk of this
angle design is that it would not have enough holding force to hold the cotton fiber or
have too large a holding force that would lead to the terylene fiber being warped on the
cylinder teeth. As an application-oriented design result, the holding force of the teeth can
be distinguished not only by the working angle but also by the tooth depth and bottom
arc. Tooth II (Figure 1) has a deep tooth depth and a small bottom arc for a higher holding
force of the fibers, so it is the position for cotton fibers. The huge hump on the back of the
teeth guides airflow to avoid the intertwinement from man-made fibers, which always has
higher contact friction with metal surfaces. The end of the long man-made fibers are lifted
by the airflow so that the flat-top needles can easily catch them.
The PPSI (point per square inch) of the card clothing is another critical issue that
needed to be carefully considered. Based on experience, the PPSI for cotton is always
around 900–1000, while for terylene, it is about 700–860. The carding performance of the
card clothing for cotton could be improved by shortening the tooth depth to make up
for the loss caused by the reduction in PPSI. Finally, the tooth depth was designed to be
0.30–0.35 mm, and the PPSI was designed to be 850–950.
2.2. Material of Card Clothing
Since this new card clothing was designed to be compatible with different fibers,
the robustness of the carding clothing needed to be improved to deal with a much more
complex and severe environment. Not only would the shape of the teeth need to be
controlled at a high level with few burrs even though the tooth shape is more complex than
before, but also the wear resistance of the card clothing would need to be improved. This
always means a definite improvement in the steel’s strength and toughness. According to
the classical Hall–Petch relationship, a grain size refinement could be a suitable method.
For the steel of card clothing, high carbon steel, for example, AISI 1070 and AISI 1080,
have always been appropriate choices for producing medium-end card clothing with low

Materials 2024,17, 1511 5 of 17
cost and excellent ductility with a spheroidizing annealing state and high hardness after
quenching. However, AISI 1090 would not be a good choice even though it has a potentially
higher hardness because of its lousy ductility in the drawing of wire and teeth punching
with a much higher risk of breakage. Hence, refining the grain size with the help of niobium
with a micro-content of 0.03% and vanadium could be an excellent method to improve its
ductility. The content of the newly developed steel is shown in Table 1with the comparison
of Nb alloying of AISI 1090 steel.
Table 1. The main chemical composition of different steels.
Elements Weight
Content/% Fe C Si Mn P S Cr Ni Cu V Nb
New 97.54 0.90 0.22 0.68 0.013 0.012 0.09 0.21 0.17 0.14 0.028
AISI 1090 97.65 0.91 0.23 0.67 0.015 0.011 0.11 0.22 0.16 0.02 0.0
The steel was initially manufactured in a steel mill into
Φ
5.5 mm standard wire in a
sorbite state, which was subsequently utilized for producing metallic card clothing. To
remove the scale, the
Φ
5.5 mm wire underwent treatment with hydrochloric acid at a
temperature of 60
◦
C. Following this, the steel wire was drawn down to
Φ
2.2 mm before
being sent for normalizing. This normalization process involved heating the wire to
approximately 780
◦
C using propane fire and subsequently cooling it with liquid lead.
Later, the wire was air-cooled to room temperature. Several cold drawing steps further
reduced the steel wire to
Φ
1.04 mm. Finally, the steel wire was introduced into a 4 m-high
bell furnace for spheroidizing annealing and maintained at 700
◦
C for 8 h. The fine wire
underwent a cold-rolling process to achieve the desired cross-section. Following rolling,
the specially shaped wire was placed on a rotary punching machine to form the final
tooth shapes. Subsequently, a high-frequency coil heated the card clothing to 750
◦
C in
less than 1 s. Immediately after that, it was heated to 900
◦
C using a methane–oxygen
flame, exceeding the austenite transformation temperature within 0.15 s. The subsequent
quenching process was conducted online using an oil-quenching bath at room temperature,
lasting approximately 4 s.
The teeth tips of the card clothing were then tested with a metallographic analyzer to
identify the grain grade and with a microhardness tester to test the hardness. The teeth
tips were tested to determine their wear resistance with a specially designed tester [
21
],
which contained an abrasive disk made of soft cloth to simulate the fiber and a platform to
install metallic card clothing, compared with other materials, including 80 WV for high-end
card clothing.
2.3. Model Analysis by CFD
2.3.1. Geometry Set-Up
The geometric model of computational fluid dynamics is shown in Figure 2, with a
simplified repeat unit between the cylinder and flat-top domains. The rotational/periodic
symmetric boundaries can be regarded as an approximate model of the central carding
region. Different from the previous study [
10
], the flat-top part could now represent a total
repeat unit of any flat-top needle patterns, including uniform and non-uniform needle
arrangements. The domain at two sides of the flat-top area restored the distance between
two adjacent flat-top strips. The whole flat-top region was tilted slightly to consider the
heel–toe difference, a classical carding parameter. The entire area took 1/120 of the circle
with a degree of accuracy of 3.00
◦
. Consequently, the cylinder region acquired a cambered
shape featuring more than 200 teeth.

Materials 2024,17, 1511 6 of 17
1
Figure 2. The 3D structure of the simulation airflow domain between flat-top needles and cylinder
teeth: (a) from the front, 1—flat domain with actual non-uniform needle arrangement, 2—the cylinder
wire domain; (b) from the right; (c) an overall view; (d) the split regions, 3—needle tips, 4—tooth I
tips, 5—tooth II tips.
The flat-top needles and the cylinder teeth surfaces were then split into different parts
to distinguish the functions of the regions. Figure 2shows the areas involved that are in
contact with the fibers in the carding process in green. There are three sections, named
“needle tips”, “tooth I tips”, and “tooth II tips”. These surfaces have a much finer mesh
because of their importance in carding, and these regions are also used to monitor the
calculation steps.
The boundary types of the whole geometry of the simulation airflow domain are
shown in Figure 3. The domain was closed without any airflow entrances or exits. The
outer surfaces were all mirror and rotational/periodic symmetry planes. This was the
nearest simulation condition compared to the actual carding situation. Ensuring all the
corresponding symmetry planes had the same surface area was essential. Only in this way
could the following calculation always converge with the residual error of less than 10
−4
in
fewer than 500 steps with steady-state simulation.

Materials 2024,17, 1511 7 of 17
1
Figure 3. The boundary type of the simulation airflow domain: 1—the rotational/periodic symmetry
plane group of the left and right surfaces; 2—the mirror symmetry plane group of the front and
back covers.
2.3.2. Mesh Generated and Independence Checking
The mesh was generated by Fluent meshing software (Version 2021R3) in the form of
a polyhedral. Then, the mesh quality was improved by the “Improve Volume Mesh” tools
with a target element quality of more than 0.2. The reason for using a polyhedral was the
better convergence performance, lower calculation consumption, and faster generalization
of high-quality mesh elements [
22
]. The classical tetrahedral mesh was tested at the
beginning of the present research. However, it was abandoned after several tests because
of its lousy convergence stability and too-high calculation consumption. The brick mesh
could not be applied in this study because of the complexity of the fluid domain.
The cross-section of this type of generated mesh is shown in Figure 4. The interfaces
of the flat top and the cylinder fluid domain were filled with fine mesh grids, as they
aided in reducing the residual error of the carding simulation. This enhancement may
also have contributed to the resolution of the intricacy and intensity. The surfaces of the
flat-top needles and the metallic cylinder teeth were filled with ten boundary layers. The
test shown in Table 2yielded the grid independence-checking results of different boundary
layers. Table 3shows the grid independence checking of the needles’ and the teeth’s surface,
including coarse and fine mesh settings. The difference in monitored results was less than
3.5% between the medium and fine mesh. Finally, the total mesh elements were about
15–22 million, which took over 12 h of calculation on a small server with 64 CPU cores. It
should be noted that the geometry used in the grid independence tests was a draft design,
which showed a minor difference from the final tooth shape calculated below.
Table 2. Grid independence checking of the number of boundary layers *.
Test No. 1 2 3
Number of boundary layers 5 8 10
Total mesh elements (million) 12.07 15.52 17.84
Monitored wall
shear stress
(Pa)
Needle tips 12.72 12.60 12.67
Tooth I tips 11.40 11.40 11.45
Tooth II tips 9.81 9.80 9.96
* The calculation carding parameters: cylinder speed 420 rpm (revolutions per minute); carding gauge 0.21 mm;
heel–toe difference 0.56 mm; sampling area 0.0159 mm
2
for each tooth and 0.0641 mm
2
for each needle. The area
strongly affected the results, so the area must be stated clearly.

Materials 2024,17, 1511 8 of 17
2
Figure 4. Typical mesh grid in polyhedral form with delicate boundary layers: 1—flat-top needle
region with refined mesh and boundary layers; 2—cylinder teeth region with fine mesh and boundary
layers; 3—refined mesh between the interface of the two fluid domains.
Table 3. Grid independence checking of the surface mesh density *.
Test Coarse Medium Fine
Surface mesh
Size (mm)
Tooth tips 0.0211 0.0150 0.0106
Needle tips 0.0282 0.0200 0.0141
Total mesh elements (million) 11.63 17.84 29.52
Monitored wall
shear stress (Pa)
Needle tips 12.20 12.67 13.08
Tooth I tips 11.04 11.45 11.75
Tooth II tips 9.24 9.96 10.25
* The calculation carding parameters: cylinder speed 420 rpm; carding gauge 0.21 mm; carding heel–toe difference
0.56 mm; sampling area 0.0159 mm
2
for each tooth and 0.0641 mm
2
for each needle. The area strongly affected the
results, so the area must be stated clearly.
2.3.3. Adjustment of Algorithm and Convergence Test
The simulation was carried out by Fluent software (Version 2021R3) with its MRF
(Multiple Reference Frame) models, and the simulation was set to be in a steady state.
The transient simulation with SMM (Sliding Mesh Model) could also be carried out with
the same geometry and meshes. But due to the fact that it was easy to converge with the
steady-state results as its initial conditions, the transient simulation took too much time
to finish a single calculation test for more than several days, and the transient simulation
showed little difference in the physical data, which we were concerned about based on
the steady-state simulation. As a result, the steady-state simulation with the MRF model
became the first choice in this study. The turbulence model was chosen as the k-
ω
SST
model, with room temperature air as the fluid material. Because of the significant number
of mesh elements, the convergence of this model was a big problem at the beginning of
the project. After several adjustments, the double precision option in Fluent needed to be
opened even if it would cost massive memory usage. The algorithm options are shown
in Table 4. As a result, the simulation could always be stably convergent with a residual
error of less than 10
−4
in fewer than 500 steps with a steady state. The convergence step
depended on the structures of the card clothing, varying between 150 and 500. Figure 5
shows the typical convergence curves of a single test.

Materials 2024,17, 1511 9 of 17
Table 4. The algorithm options for stable convergence.
Spatial Discretization
Pressure standard
Momentum first-order upwind
Turbulent kinetic energy first-order upwind
Specific dissipation rate first-order upwind
Relaxation Factors
Turbulent kinetic energy 0.4
Specific dissipation rate 0.4
Materials 2024, 17, x FOR PEER REVIEW 9 of 17
model, with room temperature air as the fluid material. Because of the significant number
of mesh elements, the convergence of this model was a big problem at the beginning of
the project. After several adjustments, the double precision option in Fluent needed to be
opened even if it would cost massive memory usage. The algorithm options are shown in
Table 4. As a result, the simulation could always be stably convergent with a residual error
of less than 10
−4
in fewer than 500 steps with a steady state. The convergence step de-
pended on the structures of the card clothing, varying between 150 and 500. Figure 5
shows the typical convergence curves of a single test.
Table 4. The algorithm options for stable convergence.
Spatial Discretization
Pressure standard
Momentum first-order upwind
Turbulent kinetic energy first-order upwind
Specific dissipation rate first-order upwind
Relaxation Factors
Turbulent kinetic energy 0.4
Specific dissipation rate 0.4
Figure 5. The typical convergence curves of a single test with low residual error.
2.4. Experiments in Spinning Mills
The tests of the new card clothing were carried out in one of the spinning mills at
Texhong International Group Limited. The new card clothing was applied on three fibers,
including cotton and terylene. The carding results were compared with the average qual-
ity of the spinning mill to estimate the carding performance of the new card clothing. The
carding process parameters, including the carding gauge and cylinder speed, were ad-
justed to meet better carding performance, and the carded sliver was then tested.
Figure 5. The typical convergence curves of a single test with low residual error.
2.4. Experiments in Spinning Mills
The tests of the new card clothing were carried out in one of the spinning mills at
Texhong International Group Limited. The new card clothing was applied on three fibers,
including cotton and terylene. The carding results were compared with the average quality
of the spinning mill to estimate the carding performance of the new card clothing. The
carding process parameters, including the carding gauge and cylinder speed, were adjusted
to meet better carding performance, and the carded sliver was then tested.
3. Results Analysis and Discussion
3.1. Material and Wear Testing Results
Figure 6shows the grain size before and after the addition of niobium. The grain grade
was improved to about 13.5, which was fine enough to handle the deformation during the
process. The cut edge of the card clothing was also identified with an optical microscope,
and the results showed a smaller burr after punching compared with other conventional
materials (Figure 7).

Materials 2024,17, 1511 10 of 17
Materials 2024, 17, x FOR PEER REVIEW 10 of 17
3. Results Analysis and Discussion
3.1. Material and Wear Testing Results
Figure 6 shows the grain size before and after the addition of niobium. The grain
grade was improved to about 13.5, which was fine enough to handle the deformation dur-
ing the process. The cut edge of the card clothing was also identified with an optical mi-
croscope, and the results showed a smaller burr after punching compared with other con-
ventional materials (Figure 7).
The hardness test results showed a noticeable improvement in the new steel, with at
least 20 Hv
0.2
. As a result, the wear resistance of Nb alloying of AISI 1090 steel was also
improved by about 25% compared with 80 WV, which showed less weight loss in the wear
test lasting about 9 h, with five examples for each material (Figure 8). The 80 WV always
had a grain grade of 13 with suitable heat treatment because of the micro alloyed vana-
dium and tungsten, so the wear resistance increased a lot compared with carbon steel
without alloyed elements like AISI 1080. The Nb alloying of AISI 1090 steel had a slightly
smaller grain size and a higher hardness, so the wear resistance was also improved. These
results show that a suggestion to improve the wear resistance of steel for card clothing is
that a higher hardness and a finer grain size could be a better choice for the mechanism of
wearability with high strength and toughness.
(a) (b)
Figure 6. The grain structure diagrams of the steel on the tooth tips of the card clothing: (a) AISI
1090; (b) Nb alloying of AISI 1090.
(a) (b) (c) (d)
Figure 7. The burrs on the tooth tips of the card clothing: (a) AISI 1070; (b) AISI 1080; (c) 80 WV; (d)
Nb alloying of AISI 1090.
Figure 6. The grain structure diagrams of the steel on the tooth tips of the card clothing: (a) AISI 1090;
(b) Nb alloying of AISI 1090.
Materials 2024, 17, x FOR PEER REVIEW 10 of 17
3. Results Analysis and Discussion
3.1. Material and Wear Testing Results
Figure 6 shows the grain size before and after the addition of niobium. The grain
grade was improved to about 13.5, which was fine enough to handle the deformation dur-
ing the process. The cut edge of the card clothing was also identified with an optical mi-
croscope, and the results showed a smaller burr after punching compared with other con-
ventional materials (Figure 7).
The hardness test results showed a noticeable improvement in the new steel, with at
least 20 Hv
0.2
. As a result, the wear resistance of Nb alloying of AISI 1090 steel was also
improved by about 25% compared with 80 WV, which showed less weight loss in the wear
test lasting about 9 h, with five examples for each material (Figure 8). The 80 WV always
had a grain grade of 13 with suitable heat treatment because of the micro alloyed vana-
dium and tungsten, so the wear resistance increased a lot compared with carbon steel
without alloyed elements like AISI 1080. The Nb alloying of AISI 1090 steel had a slightly
smaller grain size and a higher hardness, so the wear resistance was also improved. These
results show that a suggestion to improve the wear resistance of steel for card clothing is
that a higher hardness and a finer grain size could be a better choice for the mechanism of
wearability with high strength and toughness.
(a) (b)
Figure 6. The grain structure diagrams of the steel on the tooth tips of the card clothing: (a) AISI
1090; (b) Nb alloying of AISI 1090.
(a) (b) (c) (d)
Figure 7. The burrs on the tooth tips of the card clothing: (a) AISI 1070; (b) AISI 1080; (c) 80 WV; (d)
Nb alloying of AISI 1090.
Figure 7. The burrs on the tooth tips of the card clothing: (a) AISI 1070; (b) AISI 1080; (c) 80 WV;
(d) Nb alloying of AISI 1090.
The hardness test results showed a noticeable improvement in the new steel, with
at least 20 Hv
0.2
. As a result, the wear resistance of Nb alloying of AISI 1090 steel was
also improved by about 25% compared with 80 WV, which showed less weight loss in the
wear test lasting about 9 h, with five examples for each material (Figure 8). The 80 WV
always had a grain grade of 13 with suitable heat treatment because of the micro alloyed
vanadium and tungsten, so the wear resistance increased a lot compared with carbon steel
without alloyed elements like AISI 1080. The Nb alloying of AISI 1090 steel had a slightly
smaller grain size and a higher hardness, so the wear resistance was also improved. These
results show that a suggestion to improve the wear resistance of steel for card clothing is
that a higher hardness and a finer grain size could be a better choice for the mechanism of
wearability with high strength and toughness.
According to the Hall–Petch effect, the hardness and toughness of the steel would be
improved with refinement of the grain. Thus, the wear resistance of the steel would be
enhanced. However, the average grain size of the AISI 1090 was about 2–3
µ
m, approaching
the boundary where the Hall–Petch effect could be practical and showing a better wear
resistance than expected. This meant there could be an unknown wear mechanism for
the AISI 1090 steel. The wear mechanism could have a relationship with the size of soft
abrasive particles, for the diameter of the fiber was about 10
µ
m, much smaller than
common abrasive particles. It was still a problem to explain why soft materials could
wear down hard materials. Recent research [
23
] showed that the detailed arrangement of
the metallographic structure and the contact modes could significantly impact the wear
resistance. The addition of Nb to AISI 1090 may have a similar mechanism, which should
be further studied. Anyhow, Nb alloying AISI 1090 may be a good choice when the fiber is
an abrasive particle in the textile industry.

Materials 2024,17, 1511 11 of 17
Materials 2024, 17, x FOR PEER REVIEW 11 of 17
(a) (b)
Figure 8. The wear resistance tests of the card clothing: (a) the hardness tests of the teeth tips; (b)
the weight loss tests with a specially designed tester.
According to the Hall–Petch effect, the hardness and toughness of the steel would be
improved with refinement of the grain. Thus, the wear resistance of the steel would be
enhanced. However, the average grain size of the AISI 1090 was about 2–3 μm, approach-
ing the boundary where the Hall–Petch effect could be practical and showing a better
wear resistance than expected. This meant there could be an unknown wear mechanism
for the AISI 1090 steel. The wear mechanism could have a relationship with the size of soft
abrasive particles, for the diameter of the fiber was about 10 μm, much smaller than com-
mon abrasive particles. It was still a problem to explain why soft materials could wear
down hard materials. Recent research [23] showed that the detailed arrangement of the
metallographic structure and the contact modes could significantly impact the wear re-
sistance. The addition of Nb to AISI 1090 may have a similar mechanism, which should
be further studied. Anyhow, Nb alloying AISI 1090 may be a good choice when the fiber
is an abrasive particle in the textile industry.
3.2. Simulation Results with Conventional Card Clothing
This study selected wall shear stress as the physical quantity to describe the hold
force of the carding elements, an indistinct experienced concept. The reason was that the
wall shear stress had the same distribution as the wear on the surface of the containers in
some references [24]. The wall shear stress distribution on card clothing seemed similar to
the wear distribution (Figure 9), and the wall shear stress implied the carding position
and changes in carding position in the simulation analysis. The higher the contact friction
force between the fibers and tooth surface, the higher the loss of tooth tips because of the
wear. This way, wall shear stress can be selected to act as a physical indicator to describe
the holding force in the carding process.
(a) (b) (c)
Figure 9. Wall shear stress distribution on the working surfaces of the card clothing and the wear
distribution of it: (a) wall shear stress distribution; (b) worn tooth tip of cylinder card clothing; (c)
new tooth tip.
Figure 8. The wear resistance tests of the card clothing: (a) the hardness tests of the teeth tips; (b) the
weight loss tests with a specially designed tester.
3.2. Simulation Results with Conventional Card Clothing
This study selected wall shear stress as the physical quantity to describe the hold force
of the carding elements, an indistinct experienced concept. The reason was that the wall
shear stress had the same distribution as the wear on the surface of the containers in some
references [
24
]. The wall shear stress distribution on card clothing seemed similar to the
wear distribution (Figure 9), and the wall shear stress implied the carding position and
changes in carding position in the simulation analysis. The higher the contact friction force
between the fibers and tooth surface, the higher the loss of tooth tips because of the wear.
This way, wall shear stress can be selected to act as a physical indicator to describe the
holding force in the carding process.
Materials 2024, 17, x FOR PEER REVIEW 11 of 17
(a) (b)
Figure 8. The wear resistance tests of the card clothing: (a) the hardness tests of the teeth tips; (b)
the weight loss tests with a specially designed tester.
According to the Hall–Petch effect, the hardness and toughness of the steel would be
improved with refinement of the grain. Thus, the wear resistance of the steel would be
enhanced. However, the average grain size of the AISI 1090 was about 2–3 μm, approach-
ing the boundary where the Hall–Petch effect could be practical and showing a better
wear resistance than expected. This meant there could be an unknown wear mechanism
for the AISI 1090 steel. The wear mechanism could have a relationship with the size of soft
abrasive particles, for the diameter of the fiber was about 10 μm, much smaller than com-
mon abrasive particles. It was still a problem to explain why soft materials could wear
down hard materials. Recent research [23] showed that the detailed arrangement of the
metallographic structure and the contact modes could significantly impact the wear re-
sistance. The addition of Nb to AISI 1090 may have a similar mechanism, which should
be further studied. Anyhow, Nb alloying AISI 1090 may be a good choice when the fiber
is an abrasive particle in the textile industry.
3.2. Simulation Results with Conventional Card Clothing
This study selected wall shear stress as the physical quantity to describe the hold
force of the carding elements, an indistinct experienced concept. The reason was that the
wall shear stress had the same distribution as the wear on the surface of the containers in
some references [24]. The wall shear stress distribution on card clothing seemed similar to
the wear distribution (Figure 9), and the wall shear stress implied the carding position
and changes in carding position in the simulation analysis. The higher the contact friction
force between the fibers and tooth surface, the higher the loss of tooth tips because of the
wear. This way, wall shear stress can be selected to act as a physical indicator to describe
the holding force in the carding process.
(a) (b) (c)
Figure 9. Wall shear stress distribution on the working surfaces of the card clothing and the wear
distribution of it: (a) wall shear stress distribution; (b) worn tooth tip of cylinder card clothing; (c)
new tooth tip.
Figure 9. Wall shear stress distribution on the working surfaces of the card clothing and the wear
distribution of it: (a) wall shear stress distribution; (b) worn tooth tip of cylinder card clothing; (c) new
tooth tip.
Table 5shows several matches of the card clothing applied in the spinning mills.
The rules of the model name of each metallic card clothing can be found in the FZ/T
93038-2018 national standard of China [
25
]. MCH55/AC2040
×
01740 is a classical match
that was used for decades due to its stable performance. However, this match always
has good but not excellent performance with relatively higher neps in the sliver in recent
years. MCBH58/AC1745
×
01835 was developed to obtain extremely low neps in the
yarn. The wall shear stress ratio was raised between the flat-top and cylinder teeth, which
showed that the fibers carried by the cylinder teeth were more likely to be caught by
flat-top needles. The mechanism of the carding performance improvement was similar

Materials 2024,17, 1511 12 of 17
to that in the development of double teeth. The matches in the terylene were identical.
Classical
AC2520 ×01560
had lower breaking stress of the yarn with higher neps in the
sliver, according to the carding result from a spinning mill in China. The carding parameters
in Table 5were all true and were carefully collected from real and typical spinning mills.
Table 5. Matches of the card clothing with their simulation results.
Fiber Type Carding Process
Parameters
Type of Card Clothing Average Wall Shear Stress of Tips and
Ratio/Pa *
Flat Top Cylinder Flat Top Cylinder Flat Top/Cylinder
Cotton Cylinder speed: 400 rpm
Carding gauge: 0.21 mm
MCH55 AC2040 ×01740 12.67 12.83 0.9875
MCBH58 AC1745 ×01835 11.02 9.175 1.2010
Terylene Cylinder speed: 420 rpm
Carding gauge: 0.21 mm
MCBH40S AC1730 ×01550 13.70 12.96 1.0570
MCBH45 AC2520 ×01560 15.32 18.13 0.8450
* The sampling area was 0.0159 mm
2
for each tooth and 0.0641 mm
2
for each needle (Figure 10). The area strongly
affected the results, so the area must be stated clearly.
Materials 2024, 17, x FOR PEER REVIEW 12 of 17
Table 5 shows several matches of the card clothing applied in the spinning mills. The
rules of the model name of each metallic card clothing can be found in the FZ/T 93038-
2018 national standard of China [25]. MCH55/AC2040 × 01740 is a classical match that was
used for decades due to its stable performance. However, this match always has good but
not excellent performance with relatively higher neps in the sliver in recent years.
MCBH58/AC1745 × 01835 was developed to obtain extremely low neps in the yarn. The
wall shear stress ratio was raised between the flat-top and cylinder teeth, which showed
that the fibers carried by the cylinder teeth were more likely to be caught by flat-top nee-
dles. The mechanism of the carding performance improvement was similar to that in the
development of double teeth. The matches in the terylene were identical. Classical AC2520
× 01560 had lower breaking stress of the yarn with higher neps in the sliver, according to
the carding result from a spinning mill in China. The carding parameters in Table 5 were
all true and were carefully collected from real and typical spinning mills.
This way, the development direction of the card clothing seemed to be clear. For the
carding of cotton, the ratio of shear stress needed to be between 0.9875~1.2010, while for
terylene, it needed to be between 0.8450~1.0570. A higher ratio limit in these ranges meant
better performance. So, the balance of fiber transfer between the flat top and the cylinder
can be described in mathematical values. The ratio of cotton and terylene was different,
but they still had overlaps. The excellent performance in MCBH40S/AC1730 × 01550 and
the good performance within an acceptable range in MCH 55/AC2040 × 01740 had a sim-
ilar ratio of around 1. In a sense, this was the physical basis of the invention of the adapt-
able cylinder card clothing.
Table 5. Matches of the card clothing with their simulation results.
Fiber Type Carding Process
Parameters
Type of Card Clothing Average Wall Shear Stress of Tips and
Ratio/Pa *
Flat Top Cylinder Flat Top Cylinder Flat Top
/
Cylinder
Cotton Cylinder speed: 400 rpm
Carding gauge: 0.21 mm
MCH55 AC2040 × 01740 12.67 12.83 0.9875
MCBH58 AC1745 × 01835 11.02 9.175 1.2010
Terylene Cylinder speed: 420 rpm
Carding gauge: 0.21 mm
MCBH40S AC1730 × 01550 13.70 12.96 1.0570
MCBH45 AC2520 × 01560 15.32 18.13 0.8450
* The sampling area was 0.0159 mm
2
for each tooth and 0.0641 mm
2
for each needle (Figure 10). The
area strongly affected the results, so the area must be stated clearly.
(a) (b)
Figure 10. The sampling method of the wall shear stress: (a) tooth tips; (b) needle tips.
3.3. Simulation Result of the Adaptable Cylinder Card Clothing
The results show that the ratios of the wall shear stress between the flat-top needles
and the cylinder teeth were not influenced by the cylinder speed. The competition be-
tween the flat-top needles and cylinder teeth was changed a little by adjusting the cylinder
speed. This meant that the spinning mills could flexibly adjust the cylinder speed
Figure 10. The sampling method of the wall shear stress: (a) tooth tips; (b) needle tips.
This way, the development direction of the card clothing seemed to be clear. For the
carding of cotton, the ratio of shear stress needed to be between 0.9875~1.2010, while for
terylene, it needed to be between 0.8450~1.0570. A higher ratio limit in these ranges meant
better performance. So, the balance of fiber transfer between the flat top and the cylinder
can be described in mathematical values. The ratio of cotton and terylene was different, but
they still had overlaps. The excellent performance in MCBH40S/AC1730
×
01550 and the
good performance within an acceptable range in MCH 55/AC2040
×
01740 had a similar
ratio of around 1. In a sense, this was the physical basis of the invention of the adaptable
cylinder card clothing.
3.3. Simulation Result of the Adaptable Cylinder Card Clothing
The results show that the ratios of the wall shear stress between the flat-top needles
and the cylinder teeth were not influenced by the cylinder speed. The competition between
the flat-top needles and cylinder teeth was changed a little by adjusting the cylinder speed.
This meant that the spinning mills could flexibly adjust the cylinder speed depending
on their output and the yarn-quality requirement. The increased wall shear stress on the
cylinder tooth tips and flat-top needle tips indicated a higher interaction with the fiber turfs,
meaning a better opening effect, and could result in a better performance if the breakage
of fibers was well controlled. However, as a disadvantage, the tooth and needle would
suffer more wear and have a shorter service life at high cylinder speed. These inferences
concluded by the simulation results were similar to the operation experiences concluded
by engineers. The carding gauge did not affect the ratio of wall shear stress between

Materials 2024,17, 1511 13 of 17
flat-top needles and cylinder teeth. Consequently, these results imply that once the card
clothing was determined, the fiber would be restricted to a limited number of similar types.
Therefore, in conventional design, it is necessary to alter the card clothing if the fiber is
changed from cotton to terylene.
In Tables 6and 7, the ratios were around 1 and 1.2, similar to the simulation results in
Table 5, with cotton as the carding fiber. Tooth I in the card clothing yielded the standard
carding performance, for its ratio was near 1, while tooth II performed better. For the
carding of terylene, the results were different. Tooth I performed well, but tooth II needed
to be taken care of. The ratio was a little bigger than the matches mentioned in Table 5.
This meant the breaking of the balance. The cylinder teeth took too small a part in the
carding, so the performance was not as good. There was better performance for tooth I and
worse performance for tooth II, so the carding performance was still acceptable. As a result,
this type of carding clothing could be acceptable in the cotton carding process, with good
carding performance.
Table 6. The simulation results of the new adaptable cylinder card clothing with different cylinder
speeds and the same carding gauge.
Cylinder
Speed
(rpm)
Type of Card Clothing Average Wall Shear Stress of Tips and Ratio/Pa *
Flat Top Cylinder Flat Top Cylinder
Tooth I
Flat
Top/Cylinder
Tooth I
Cylinder
Tooth II
Flat
Top/Cylinder
Tooth II
420
MCH55
New developed
AC1835 ×1740
(tooth depth:
0.35 and 0.30 mm;
PPSI: 950)
12.41 11.49 1.08 9.96 1.25
440 13.36 12.34 1.08 10.77 1.24
460 14.65 13.27 1.10 11.61 1.26
480 15.69 14.19 1.10 12.49 1.26
500 16.73 15.14 1.10 13.37 1.25
* The sampling area was 0.0159 mm
2
for each tooth and 0.0641 mm
2
for each needle. The area strongly affected
the results, so the area must be stated clearly. The carding gauge of this simulation was 0.21 mm.
Table 7. The simulation results of adaptable cylinder card clothing with different carding gauges and
the same cylinder speed.
Carding
Gauge
(mm)
Type of Card Clothing Average Wall Shear Stress of Tips and Ratio/Pa *
Flat Top Cylinder Flat Top Cylinder
Tooth I
Flat
Top/Cylinder
Tooth I
Cylinder
Tooth II
Flat
Top/Cylinder
Tooth II
0.30
MCH55
New developed
AC1835 ×1740
(tooth depth:
0.35 and 0.30 mm;
PPSI: 950)
11.84 11.03 1.07 9.68 1.22
0.28 12.04 11.21 1.07 9.84 1.22
0.25 12.16 11.30 1.08 9.83 1.24
0.23 12.33 11.42 1.08 10.04 1.22
0.21 12.41 11.49 1.08 9.96 1.25
* The sampling area was 0.0159 mm
2
for each tooth and 0.0641 mm
2
for each needle. The area strongly affected
the results, so the area must be stated clearly. The cylinder speed was 420 rpm.
The design of card clothing is tailored to enhance cotton’s performance due to the
varying components of its raw material. Cotton typically contains significantly more
impurities compared to synthetic fibers, necessitating meticulous carding.
The results also showed the possibility of a single-tooth shape card clothing design
with a ratio of nearly 1. Therefore, the performance of cotton would be common and
terylene would be better. However, as mentioned above, the spinning mill is always more
concerned about the quality of the cotton yarn, whether ring spinning or rotor spinning,
because the quality of cotton yarn has an essential impact on the trading value. As a
result, this design method is particularly suitable for specific target applications and unique
environments and may not be widespread in the present climate.

Materials 2024,17, 1511 14 of 17
3.4. Results of the Wear Resistance
Figure 11 shows an approximate anticorrelation between the average wall shear stress
and the fiber throughput. After gathering the information from several spinning mills
producing similar cotton yarn with similar raw material and the same yarn-forming process,
the average wall shear stress calculated from the simulation showed an approximate
anticorrelation between the life span of the card clothing measured by the fiber throughput.
The higher the wall shear stress was, the lower the life span the card clothing could acquire.
However, the quantity relationship was never built because too many factors could have an
impact on the life span of card clothing. This anti-relationship is just a glance at the wear
mechanism in the carding process. Still, the dominant role of soft materials in the shear
stress of hard materials provides theoretical support for this. In the article, the wall shear
stress was considered the holding force of the teeth tips, and it was also an essential factor
that influenced the carding performance. In general, a higher carding force could yield
better carding performance. It was interesting to find that the life span of the card clothing
and the carding performance were contradictory, and this is a common phenomenon in
most industrial processes.
Materials 2024, 17, x FOR PEER REVIEW 14 of 17
0.30
MCH55
New developed
AC1835 × 1740
(tooth depth:
0.35 and 0.30 mm;
PPSI: 950)
11.84 11.03 1.07 9.68 1.22
0.28 12.04 11.21 1.07 9.84 1.22
0.25 12.16 11.30 1.08 9.83 1.24
0.23 12.33 11.42 1.08 10.04 1.22
0.21 12.41 11.49 1.08 9.96 1.25
* The sampling area was 0.0159 mm2 for each tooth and 0.0641 mm2 for each needle. The area
strongly affected the results, so the area must be stated clearly. The cylinder speed was 420 rpm.
3.4. Results of the Wear Resistance
Figure 11 shows an approximate anticorrelation between the average wall shear
stress and the fiber throughput. After gathering the information from several spinning
mills producing similar cotton yarn with similar raw material and the same yarn-forming
process, the average wall shear stress calculated from the simulation showed an approxi-
mate anticorrelation between the life span of the card clothing measured by the fiber
throughput. The higher the wall shear stress was, the lower the life span the card clothing
could acquire. However, the quantity relationship was never built because too many fac-
tors could have an impact on the life span of card clothing. This anti-relationship is just a
glance at the wear mechanism in the carding process. Still, the dominant role of soft ma-
terials in the shear stress of hard materials provides theoretical support for this. In the
article, the wall shear stress was considered the holding force of the teeth tips, and it was
also an essential factor that influenced the carding performance. In general, a higher card-
ing force could yield better carding performance. It was interesting to find that the life
span of the card clothing and the carding performance were contradictory, and this is a
common phenomenon in most industrial processes.
Figure 11. An approximate anticorrelation between average wall shear stress and the total fiber
throughput during the whole service life. (■ A sample point of the service life provided by spin-
ning mills; the line was an approximate fit).
3.5. Results in Spinning Mills
The test results of the yarn quality in spinning mills are shown in Table 8. In the first
two types of fibers, including cotton 40S and terylene 16S, the adaptable cylinder card
clothing showed better results than the average level in the spinning mill, regardless of
CV%, neps, and A1 yarn defects. However, the neps increased when the fiber was
changed to terylene 40S. This spinning mill was more concerned with A1 yarn defects, so
the results were still acceptable. In conclusion, the better performance for cotton and the
acceptable performance for terylene are consistent with the simulation results.
Figure 11. An approximate anticorrelation between average wall shear stress and the total fiber
throughput during the whole service life. (
■
A sample point of the service life provided by spinning
mills; the line was an approximate fit).
3.5. Results in Spinning Mills
The test results of the yarn quality in spinning mills are shown in Table 8. In the first
two types of fibers, including cotton 40S and terylene 16S, the adaptable cylinder card
clothing showed better results than the average level in the spinning mill, regardless of
CV%, neps, and A1 yarn defects. However, the neps increased when the fiber was changed
to terylene 40S. This spinning mill was more concerned with A1 yarn defects, so the results
were still acceptable. In conclusion, the better performance for cotton and the acceptable
performance for terylene are consistent with the simulation results.
The reason for the excellent performance of the card clothing is that it yielded two
ratios of wall shear stress, meaning two platforms for exchanging fibers between flat top
needles and the cylinder teeth. Conventional card clothing has only one ratio, which is
only suitable for several fibers. What is good for cotton is bad for terylene.
The parameters for any fiber were almost the same between the conventional and
adaptable card clothing listed in Table 8. However, the carding process parameters were

Materials 2024,17, 1511 15 of 17
quite different between cotton and terylene, including the carding gauge and the speed
of the cylinder, and they were all within the scope of simulation calculations and design
considerations.
Table 8. Yarn quality with different types of fibers.
Type of Fibers
Cylinder Card Clothing
CV% Neps (+140%) Neps (+200%) A1 Yarn Defects
Cotton 40S (machine-picked,
Xinjiang, fiber length <32 mm)
Conventional 8.24 12.5 5.5 83.1
Adaptable 8.28 8.5 1.5 39.2
Terylene 16S
(Sateri®, 1.33dtex, 38 mm, white)
Conventional 8.08 17 2 126
Adaptable 7.72 9 0 36.2
Terylene 40S
(Sateri®, 1.33dtex, 38 mm, white)
Conventional 11.51 122 14 354.2
Adaptable 11.65 163 20 273.9
Another factor that needed to be considered was whether the types of flat tops were
the same. If the types were the same, according to the beginning of this article, the problem
of changing fibers without changing the card clothing could be solved. However, this test
was imperfect because of a minor difference in the flat-top types for about 3% PPSI with
the same needle arrangements. If the yarn quality was not so strict, the problem seemed to
be solved by this newly designed cylinder card clothing.
However, the reason for the relative medium difference between terylene 16S and 40S
was unclear. Perhaps the carding parameters should be further investigated with the help
of the simulation method and more experiments in the spinning mills, and these will be
carried out in subsequent work. The adaptable cylinder card clothing is now being utilized
in spinning mills in Vietnam, with a scale of hundreds, for robustness testing.
3.6. Discussion about the Carding Simulation
The simulation of the carding process still has three critical problems worth consid-
ering. The first problem is the accuracy of the simulation. The airflow around the teeth
and needles has a Reynolds number of 1000–3000, where the transition from laminar to
turbulence may happen. The transition simulation is still a complex problem in CFD
because of too many unexpected flow behaviors. The shape of the airflow domain infinitely
influenced the transition model, so the applied standard k-
ω
SST model in this article had
the risk of being inaccurate.
The second problem is the simulation of fibers for too much consumption in the
calculation. The discrete element method could be used to describe the fiber behavior in the
airflow coupled by CFD [
26
–
28
]. However, it was still too complex to simulate the carding
process in the research of industrial application orientation at the enterprise level.
The third problem was how to analyze the results even better. How to create a
correspondence between the calculated physical quantity and the carding performance is
a crucial problem. In this article, the calculated results were associated with the carding
performance by extending traditional carding theory [
3
] using the so-called carding balance
as the bridge. As discussed in this article, the wall shear stress of needles and teeth offers a
promising avenue for soft materials in the shear stress of worn hard materials. Additionally,
the velocity distribution provides another example of the development of double teeth [
10
].
More and more related physical quantities would be found to describe the carding process if
we continue to focus on improving the simulation model. Then, only by obtaining accurate
simulation results can we provide a basis for explaining the deep mechanism of the friction
and wear of cylinder card clothing made of Nb alloying of AISI 1090 steel in the next step.
4. Conclusions
In this article, a new card clothing compatible with cotton and terylene fibers by Nb
alloying of AISI 1090 steel was successfully developed. Several conclusions were drawn,
as follows:

Materials 2024,17, 1511 16 of 17
1.
The carding mechanism was explained quantitively by computational fluid dynamics.
The wall shear stress ratio between the flat-top needles and the cylinder teeth was
a key parameter to estimate the carding performance. The ratio was significantly
affected by the shape of the card clothing other than the process parameters of carding,
showing why the spinning mills must change the classical card clothing to adapt to
different fibers.
2.
The wear trend of the card clothing could be quantitively described by the simulation.
The results showed good relevance to the Archard law. It was the first method to
evaluate the wear of the card clothing during the design step for card clothing. With
this method, the service life of card clothing under different situations could also
be estimated.
3.
An Nb alloying of AISI 1090 steel was developed to improve the wear resistance of the
card clothing. Nb alloying of AISI 1090 steel showed good wear resistance in carding
areas after heat treatment, with a high hardness above 840 Hv0.2 and an extremely
fine grain grade of 13.5, which increased about 25% compared to conventional 80 WV.
The wear resistance of the card clothing could be enhanced by the refinement of the
grain size and the improvement of the hardness. This result would be an example of
the research on soft abrasive wear.
Author Contributions: Conceptualization, W.G.; Methodology, F.L.; Software, F.L.; Formal analysis,
Q.G. and C.Z.; Investigation, W.G., Y.C., Q.G. and C.Z.; Resources, Y.C. and C.Z.; Data curation, Y.C.
and C.Z.; Writing—original draft, W.G.; Writing—review & editing, F.L. All authors have read and
agreed to the published version of the manuscript.
Funding: The authors are very grateful for the support received from the National Natural Science
Foundation of China (grant No. 51275414, No. 51605387); the Fundamental Research Funds for
the Central Universities with grant No. 3102015BJ (II) ZS007; the Research Fund of the State Key
Laboratory of Solidification Processing (NWPU), China (grant No. 130-QP-2015); the Key Research
and Development Program of Shaanxi Province (No. 2020ZDLGY12-07); and the Tianshan Innovative
group’s project of Xinjiang Uygur Autonomous Region (No. 2020D14041).
Data Availability Statement: Data are contained within the article.
Conflicts of Interest: Authors Weihua Gu, Qinchao Gao and Chengzhi Zhuo were employed by
the company Geron Card Clothing Co., Ltd. Author Youchang Cao was employed by the company
Texhong International Group Limited. The remaining authors declare that the research was conducted
in the absence of any commercial or financial relationships that could be construed as a potential
conflict of interest.
References
1.
Goodall, J.; Lynch, W.K.; Parr, J.S.; Townend, P.P. The Influence of Wire Profile on the Quality of Wool-type Carded Webs. J. Text.
Inst. 1970,61, 612–614. [CrossRef]
2.
Landmesser, T. Device at Card Cotton, Synthetic Fibers, and the Like, in Which at Least One Flat Bar Having Flat Clothing Is
Present. Patent US2007006424A1, 11 January 2007.
3.
Singh, A.; Swani, N.M. 8—A Quantitative Analysis of The Carding Action by The Flats and Doffer in a Revolving-Flat Card. J.
Text. Inst. 1973,64, 115–123. [CrossRef]
4. Balasubramanian, N.; Nerurkar, S.K. The Carding Action in a Revolving-flat Card. J. Text. Inst. 1974,65, 327–328. [CrossRef]
5. Singh, A.; Swani, N.M. The Carding Action in a Revolving-flat Card—Reply. J. Text. Inst. 1974,65, 329. [CrossRef]
6. Yuzuru, N. Metallic Card Clothing for Spinning Machine. Patent JPH01306625A, 11 December 1989.
7. Mahlmann, I.; Seide, G.; Mathis, P. CFD analysis of the airflow in the card. Melliand Eng. 2007,89, 96–97.
8.
Veit, D. Simulation in Textile Technology: Theory and Applications; Woodhead Publishing Limited: Cambridge, UK, 2012; pp. 161–162.
9.
He, S. Three-dimensional numerical simulation of airflow and fiber dynamic in carding region in carding machine. Text. Res. J.
2019,89, 3916–3926. [CrossRef]
10.
Gu, W.; Li, F.; Gao, Q.; Zhuo, C.; Lu, Z. Design of double teeth metallic card clothing for the high-efficiency carding process by
computational fluid dynamics. Text. Res. J. 2021,92, 2909–2921. [CrossRef]
11. Gabler, P.; Haarer, F. Sawtooth Wire for Rollers of Spinning Preparation Machines. Patent US2019169769A1, 6 June 2019.
12. Zhang, Y.N. Metallic Card Wire. Patent US2014259537A1, 18 September 2014.
13. Worner, C. Card Wire. Patent WO2021214680A1, 28 October 2021.

Materials 2024,17, 1511 17 of 17
14.
Umar, M.; Qayyum, F.; Farooq, M.U.; Khan, L.A.; Guk, S.; Prahl, U. Investigating the Effect of Cementite Particle Size and
Distribution on Local Stress and Strain Evolution in Spheroidized Medium Carbon Steels using Crystal Plasticity-Based Numerical
Simulations. Steel Res. Int. 2020,92, 2000407. [CrossRef]
15.
Qayyum, F.; Guk, S.; Kawalla, R.; Prahl, U. Experimental Investigations and Multiscale Modeling to Study the Effect of Sulfur
Content on Formability of 16MnCr5 Alloy Steel. Steel Res. Int. 2018,90, 1800369. [CrossRef]
16. Kanai, H. Metallic Wire for Spinning Frame. Patent JPS6350533, 3 March 1988.
17.
Lu, Z.; Yong, Q.; Zhuo, C.; Li, Z.; Qian, D.; Zhang, Y. Composite design and property of high quality microalloyed steel combing
equipment. Mater. Mech. Eng. 2019,43, 36–39.
18.
Zhuo, C.; Gao, L.; Gu, W.; Yong, Q.; Lu, Z. Application of Nb-V microalloyed high carbon steel in steel wire for flexible flat-top
card clothing. Heat Treat. Met. 2022,47, 69–72.
19.
Gu, W.; Zhuo, C.; Lu, Z.; Gao, L.; Zhang, Y.; Yong, Q. Effect of carbon content on wear resistance of metal clothing made of Nb
microalloyed high carbon steel. Heat Treat. Met. 2021,46, 72–75.
20. Sutton, J. Draf-Equalizer. Patent US695843A, 18 March 1902.
21.
Gao, L. A Kind of Metallic Card Clothing Service Life Method for Rapidly Testing and Device. Patent CN107589028A, 17 August
2017.
22. ANSYS Inc. ANSYS Fluent 2021 User’Guide; ANSYS Inc.: Canonsburg, PA, USA, 2021.
23. Roscioli, G.; Taheri-Mousavi, S.M.; Tasan, C.C. How hair deforms steel. Science 2020,369, 689–694. [CrossRef]
24. Wang, Q. A CFD Study on refractory wear in RH degassing process. ISIJ Int. 2020,60, 1938–1947. [CrossRef]
25.
FZ/T 93038-2018; Wires for Metallic Card Clothing of the Card. Ministry of Industry and Information Technology, PRC: Beijing,
China, 2018.
26.
Zeng, Y.C. Numerical simulation of fiber motion in the nozzle of an air-jet spinning machine. Text. Res. J. 2004,74, 117–122.
[CrossRef]
27.
Jungbecker, P.; Seide, G.; Gries, T. Kinematic Model for Yarn movement in Turbulent Air Flows. Autex Res. J. 2008,8, 94–99.
[CrossRef]
28. Seide, G.; Jungbecker, P.; Gries, T. Simulation of staple fiber kinematics in a turbulent air stream. Melliand Int. 2008,14, 22–23.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual
author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to
people or property resulting from any ideas, methods, instructions or products referred to in the content.