Materials

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Materials and Design 28 (2007) 234–239

& Design

Technical report

Design and fabrication of low cost filament winding machine

F.H. Abdalla, S.A. Mutasher, Y.A. Khalid, S.M. Sapuan *,A.M.S. Hamouda, B.B. Sahari, M.M. Hamdan

Department of Mechanical and Manufacturing Engineering, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia

Received 2 March 2005; accepted 20 June 2005Available online 24 August 2005

Abstract

In general, the composite pipes are fabricated using glass fiber and polyester resin matrix by hand lay-up and also by 2-axis fil-ament winding machine. In this work, a filament winding machine was designed and developed for the fabrication of pipes andround shape specimens. A lathe-type machine and a wet winding method were used in the design of the machine. It provides a capa-bility for producing pipe specimens with an internal diameter up to 100 mm and lengths up to 1000 mm. The range of the windingangle, or the fiber orientation angle, starts from 20� to 90� depending on the mandrel diameter used. Mandrel speed is kept constantas 13.6 revolutions per minute (rpm) while the speed of screw of delivery unit varies from 0 rpm to a maximum of 250 rpm. In thefilament winding process used, a single glass roving is drawn through a bath of pre-catalyzed resin which is mounted on the leadscrew by the rotating mandrel. A control unit was used to control the whole process and achieve regular winding and good surfacefinish. Tube samples and other circular specimens of different dimensions were produced using this machine for the differentmechanical tests and applications.� 2005 Published by Elsevier Ltd.

Keywords: Filament winding; Composite tube; Glass fiber; Matrix; Fiber orientation angle

1. Introduction

Filament winding has emerged as the primary processfor composite cylindrical structures fabrication at lowcost. In this process, composite layers are successivelywound on a rotating mandrel, as presented in Fig. 1.The layers may be wrapped at different angles varyingfrom hoop layers, which are perpendicular to the cylin-der axis, to helical layers which are at an angle to the cyl-inder axis. The construction of composite cylinder byfilament winding consists of three major steps [1], thefirst is the design, which includes the selection of mate-rials, geometry, and fiber orientations while the secondis fiber placement, the mechanical means by which thefibers are placed in their proper positions. Finally, thethird is the selection and control of conditions which

0261-3069/$ - see front matter � 2005 Published by Elsevier Ltd.doi:10.1016/j.matdes.2005.06.015

* Corresponding author. +60 3 86567101; fax: +60 3 86567099.E-mail address: sapuan@eng.upm.edu.my (S.M. Sapuan).

must be maintained during the manufacturing process.A process for fabricating a composite structure in whichcontinuous reinforcements (filament, wire, yarn, tape, orother), either previously impregnated with a matrixmaterial or impregnated during the winding, are placedover a rotating and removable form or mandrel in a pre-scribed way to meet certain stress conditions. The rein-forced fibers are usually made of glass, Kevlar orcarbon. Owing to simplicity of process, the hardwareconfiguration is quite standard, and generally involvestwo main sub-systems; the rotary assembly and thedelivery system.

The rotary assembly consists of two structural blocks;one fixed and the other linearly movable unit in which a2-axis mechanically driven mandrel is mounted onto itsholders. On the fixed end, the holder is connected to arotating shaft, which is coupled to either a gear or achain or belt reduction system, or directly to the motorunit. Generally, an AC or servo-motor is used because

Fig. 2. Circumferential or hoop winding [2].

θ

Fig. 1. Schematic of the wet filament winding process [1].

F.H. Abdalla et al. / Materials and Design 28 (2007) 234–239 235

of its greater torque capabilities and accuracy whenoperating under conditions of heavy loading. Fordelivery system, rolls of continuous fibers are fed intoa resin bath which is mounted onto the carriage railsthat are commonly placed overhead to provide greaterworkroom. Generally, the shape is a surface of revolu-tion and may or may not include end closures. Whenthe required number of layers is applied, the woundform is cured and the mandrel removed. The materialproperties in each layer are constant but may vary fromlayer to layer. The mandrel is represented by a hollowcylinder with uniform effective wall thickness. The man-drel and the cylinder are of equal length and are axisym-metrical, so that neither the geometry nor the propertiesvary in the circumferential direction. Filament windingis defined as [2] a technique which ‘‘produces high-strength and lightweight products; consists basically oftwo ingredients; namely, a filament or tape type rein-forcement and a matrix or resin’’. The concept of fila-ment winding process had been introduced in early1940s and the first attempt was made to develop fila-ment-winding equipment. The equipment that was de-signed in 1950s was very basic; performing thesimplest tasks using only two axes of motion (spindlerotation and horizontal carriage). By mid-1970s,machine design once again made a dramatic shift. Thistime the advancement of servo technology entered therealm of the machine design. High-speed computers al-lowed for rapid data processing, resulting in smoothermotion and greater fiber placement accuracy. The1980s and 1990s saw the increased use of computer tech-nology. Computers and motion control cards becamethe essential pieces of hardware that were included in al-most every machine. Machine speed control was greatlyimproved; computer control systems could track posi-tion and velocity with increased accuracy. Additionalaxes of motions were also incorporated into machine de-sign; allowing for four, five and even six axes of con-trolled motion.

2. Manufacturing techniques

The properties of a composite product are not onlydependent on the properties of fiber and resin matrix, butare also dependent on the way by which they are processed.There are a variety of processing techniques for fabricatingcomposite parts/structure; resin transfer moulding, auto-clave moulding, pultrusion and filament winding. Out ofthese processes, filament winding involves low cost and isthe fastest technique for manufacturing of fiber reinforcedcylindrical components as high-pressure pipes and tanks.

3. Winding methods

There are two different winding methods: (I) wetwinding, in which the fibers are passed through a resinbath and wound onto a rotating mandrel (II) prepregwinding, in which the preimpregnated fiber tows areplaced on the rotating mandrel. Among these windingmethods, wet winding is more common and widely usedfor manufacturing fiber reinforced thermosetting matrixcomposite cylinders. Compared with prepreg winding,wet winding has several advantages: low material cost;short winding time; and the resin formulation whichcan be easily varied to meet specific requirements.

3.1. Winding patterns

In filament winding process, the winding tension caneasily be controlled. Winding tension, winding angleand/or resin content in each layer of reinforcement canbe varied until the desired thickness and strength ofthe composite are achieved. The properties of the fin-ished composite can be varied by the type of windingpattern selected. In general, there are three basic fila-ment winding patterns which are as follows.

3.1.1. Hoop winding

It is known as the girth or circumferential winding. Inhoop winding, a high-angle helical winding approachesan angle of 90�. Each full rotation of the mandreladvances the band delivery by one full bandwidth asshown in Fig. 2.

Fig. 3. Helical winding [2].

Fig. 4. Polar winding [2].

236 F.H. Abdalla et al. / Materials and Design 28 (2007) 234–239

3.1.2. Helical winding

In helical winding, the mandrel rotates at a constantspeed while the fiber feed carriage transverses back andforth at a speed regulated to generate the desired helicalangles as shown in Fig. 3.

3.1.3. Polar windingIn polar winding, the fiber passes tangentially to the

polar opening at one end of the chamber, reverses direc-tion, and passes tangentially to the opposite side of thepolar opening at the other end. In other words, fibersare wrapped from pole to pole, as the mandrel arm ro-tates about the longitudinal axis as shown in Fig. 4. Itis used to wind almost axial fibers on domed end typeof pressure vessels. On vessels with parallel sides, a sub-sequent circumferential winding would be done.

4. The proposed filament winding machine

Schematic layout of the hardware configuration forproposed filament-winding machine is shown in Fig. 5.It consists of three main units: the rotary assembly unit,the delivery unit and the control unit.

4.1. The rotary assembly unit

The rotary assembly consists of two pillar blocks whichwere held onto horizontal frame work and motor with agearbox. One of the two blocks is fixed and serves as a ref-

erence, while the other one is movable and can be adjustedlinearly for varying the mandrel length. Once the mandrelis seated properly into two freely rotating cup holders, themovable pillar block is then locked. At the fixed pillar end,the holder is coupled to the motor gearbox by a system ofpulleys and belt. The gear ratio between the motor and thegearbox is selected as 1:60 and the reduction ratio betweenthe pulleys was taken as 1:2, so that the velocity of themandrel is fixed to 13.6 rpm as shown in Fig. 6.

4.2. The delivery unit

The delivery unit consists of filament fibers holder,carriage and lead screw with a guide shaft. The leadscrew is driven by a reversible variable speed motor.The filament fiber holder is just a table with two shafts,one used for carrying one or more of the filament fiberrolls while the other one is used as a guide for the fila-ment fiber during the fabrication process. The carriageconsists of a container and a system of polished guidepins. The container was used for carrying the resin mix-ture while the pins were used as a way to guide the fiberto the resin bath and to smear off excess resin from thewetted fibers after the resin bath. Also, the pins were usedto generate tension in the wetted fibers before reachingthe mandrel. A simple mechanism was used to bring backthe smeared resin from the wetted fiber to the containerand reused again in order to reduce the amount of resinused for preparing the product. An optimum tension of10 N has been used through this work. This gave a fairlyconsistent volume fraction of fibers. It was found [3] thatit is important to generate tension in the later stage of theresin path when the fibers are well wetted to avoid fiberdamage. Greater tension on wetted fiber produced exces-sive fiber damage and low tensions produced specimenswith unacceptably small fiber fractions.

4.3. The control unit

The control unit consists of relays, limit switches,timer and counter as shown in Fig. 7. The functionof the control unit is to control the winding processin order to get the proper winding sequence, whichis difficult to reach manually, and to safeguard themotor during operation. The control unit also controlsthe amount of end over wind which is required to pre-vent slippage of the roving when the traverse is re-versed and the mandrel indexing to ensure that eachroving slightly overlaps the previous one to producea uniform lay-up of fibers.

5. Specimen fabrication

The setup of the specimen on the winding machine isshown in Fig. 6. The fabrication process consists of five

Fig. 5. Schematic diagram for proposed winding machine.

Fig. 6. Setup of the specimen on the winding machine.

F.H. Abdalla et al. / Materials and Design 28 (2007) 234–239 237

steps as follows: the first step is to fix the mandrel whichmay be as aluminum or plastic PVC tubes or any differ-ent cylindrical mandrel shape on the machine blocksusing end fixtures. The second step is to prepare the re-

sin bath, which is a mixture of epoxy resin and hardener,using a specific ratio and putting it in the container. Thetype of epoxy resin and hardeners used in this investiga-tion were MW 215 TA and MW 215 TB, respectively.

20

30

40

50

60

70

80

90

0 50 100 150 200 250 300

Screw speed (rpm)

Ang

le o

f win

ding

(de

gree

)

Fig. 8. Winding angle versus screw speed.

98 4

10 11 12

3

2

1

7

6

51413

CW

OFF

CCW

7

14 138

9

12

5

1

11 11

14

1

12

7

9

813

5

1 2 3

SW4

62

88

2

77

6

ON

OFF

6

5

781

23 4

SW2

N

Auto

Manual

ON

OFF

SW3

SpeedController

Timer_1 Timer_2Counter

Limit Switch

Relay_1 Relay_2 Relay_3

CCW

CW

Variable SpeedMotor

98 4

10 11 12

3

2

1

7

6

51413

CW

OFF

CCW

7

14 138

9

12

5

1

11 11

14

1

12

7

9

813

5

1 2 3

SW4

62

88

2

77

6

ON

OFF

6

5

781

23 4

SW2

N

Auto

Manual

ON

OFF

SW3

SpeedController

Timer_1 Timer_2Counter

Limit Switch

Relay_1 Relay_2 Relay_3

CCW

CW

Variable SpeedMotor

Fig. 7. Control system circuit for the winding machine.

238 F.H. Abdalla et al. / Materials and Design 28 (2007) 234–239

They were mixed in a ratio of 4:1, respectively. Thethird step is to pass the fiber tow through the resinbath and then on the mandrel through a series ofpins. These pins make the fiber straight and reducethe amount of resin in the fibers. The fourth step isto control the speed of screw to give the proposedwinding angle. The fifth step comes after the layersof fibers were wound onto the mandrel, the specimenleft to rotate on the mandrel for 3 h at room temper-ature to prevent resin dropping, then after solidifica-tion the specimen pulled off the mandrel and thencut to the required lengths.

The relation between winding angle and the speed ofthe screw for mandrel of diameter 12.7 mm is shown inFig. 8. This has been calculated using the relationsbelow

h ¼ 2prN m

V c

; ð1Þ

where h is the winding angle, r is the Mandrel radius, Nm

is the Mandrel speed, VC is the carriage linear velocity.

V C ¼ NS � d; ð2Þ

where NS is the screw speed, d is the screw threaddistance.

It has been found [4], especially for angles between0� and 90�, that the pattern is considered as a com-plete cover of glass on the mandrel. This has been

Fig. 9. Specimen fabricated (a) glass fiber, (b) carbon fiber.

F.H. Abdalla et al. / Materials and Design 28 (2007) 234–239 239

obtained after several passes of the carriage forwardand backward so that one cover will be consistingof ±U that means one cover is actually consisting of

two layers. Samples of the final specimens of differentdimensions after fabrication and machining are shownin Fig. 9.

6. Conclusion

In a filament winding process, a band of continuousresin impregnated rovings or monofilaments is wrappedaround a rotating mandrel and then cured either atroom temperature or in an oven to produce the finalproduct. The technique offers high-speed and precisemethod for placing many composite layers. The mandrelcan be cylindrical, round or any shape that does nothave re-entrant curvature. Among the applications offilament winding are cylindrical and spherical pressurevessels, pipe lines. Modern winding machines are numer-ically controlled with higher degrees of freedom for lay-ing the exact number of layers of reinforcement.Mechanical strength of the filament wound parts notonly depends on the composition of component materialbut also on process parameters like winding angle, fibertension, resin chemistry and curing cycle. Good prod-ucts of different dimensions were produced using thismachine.

Acknowledgments

The authors express their gratitude and sincere appre-ciation to the Ministry of Science, Technology andInnovation, Malaysia (MOSTI, Project No. 09-02-04-0824-EA001) for the financial support, and the Depart-ment of Mechanical and Manufacturing Engineering ofthe University Putra Malaysia for supporting the groupin undertaking the project.

References

[1] Gutowski TG. Advanced composites manufacturing. NewYork: Wiley; 1997.

[2] Babu MS, Srikanth G, Biswas S. Composite fabrication byfilament winding-an insight, 2000. Available from: http://www.Ti-fac.org.in/news/acfil.html.

[3] Hull D, Legg MJ, Spencer B. Failure of glass/polyester filamentwound pipe. Composites 1978.

[4] Mallick PM. Fiber reinforced composites, materials, manufac-turing and design. 2nd ed. New York: Marcel Dekker, Inc.;1993.