The document discusses various techniques for manufacturing composites, including hand layup, pultrusion, resin transfer molding, and injection molding. It provides details on the hand layup process, describing how dry fibers and resins are layered by hand in an open mold. Pultrusion is defined as a continuous process that pulls reinforced fibers through a resin bath and heated die to produce cured, constant cross-section parts. Resin transfer molding involves packing dry fibers into a mold, injecting resin under pressure, and curing the mold to produce complex, net-shape parts in medium volumes. Each technique has advantages for certain applications in industries like aerospace, transportation, and construction.
Autoclave is a closed vessel (Round or Cylindrical) in which processes occur under simultaneous application of high temperature and pressure. Autoclave molding technique is similar to vacuum bag and pressure bag molding method with some modifications. This method employs an autoclave to provide heat and pressure to the composite product during curing.
My presentation on resin transfer molding. Not much description included. For reference i would recommend
" Composite manufacturing by Sanjay Mazumdar".
Autoclave is a closed vessel (Round or Cylindrical) in which processes occur under simultaneous application of high temperature and pressure. Autoclave molding technique is similar to vacuum bag and pressure bag molding method with some modifications. This method employs an autoclave to provide heat and pressure to the composite product during curing.
My presentation on resin transfer molding. Not much description included. For reference i would recommend
" Composite manufacturing by Sanjay Mazumdar".
The fabrication methodology of a composite part depends mainly on three factors:
(i) the characteristics of matrices and reinforcements,
(ii) the shapes, sizes and engineering details of products, and
(iii) end uses.
The composite products are too many and cover a very wide domain of applications ranging from an engine valve to an aircraft wing.
The fabrication technique varies from one product to the other.
FIBER SELECTION
Factors to consider when choosing glass type include thermal properties; fiber cost, type of manufacturing process being used, and forms of reinforcement
Metal matrix composites (MMCs) possess significantly improved properties including highspecific strength; specific modulus, damping capacity and good wear resistance compared to unreinforced alloys. There has been an increasing interest in composites containing low density and low cost reinforcements. Among various discontinuous dispersoids used, fly ash is one of the most inexpensive and low density reinforcement available in large quantities as solid waste by-product during combustion of coal in thermal power plants. Hence, composites with fly ash as reinforcement are likely to overcome the cost barrier for wide spread applications in automotive and small engine applications.
RTM is a low-pressure molding process, where a mixed resin and catalyst are injected into a closed mold containing a fiber pack or preform . when the resin has cured the mold can be opened and finished component removed.
Composites are made by combination of two or more natural or artificial materials to maximize their useful properties and minimize their weaknesses.
Example: The oldest and best-known composites,
Natural: Wood combination of cellulose fibre provides strength and lignin is the "glue" that bonds and stabilizes. Bamboo is a very efficient wood composite structure.
o is a very efficient wood composite structure
Artificial: The glass-fibre reinforced plastic (GRP), combines glass fiber (which are strong but brittle) with plastic (which is flexible) to make a composite material that is tough but not brittle.
70 to 90% of load carried by fibers
Provide structural properties to the composite
Stiffness
Strength
Thermal stability
Provide electrical conductivity or insulation
Example: Glass, Carbon, Organic Boron, Ceramic, Metallic
Function of Fiber/Dispersion phase
Composite Materials: A composite material can be defined as a combination of two or more materials that results in better properties than those of the individual components used alone. The two constituents of a composite are a reinforcement and a matrix.
Matrix: The continuous phase is the matrix, made of polymer, metal, or ceramic.
Reinforcement: A strong, inert, woven and nonwoven fibrous material incorporated into the matrix to improve its mechanical and physical properties. For example, fibers, whiskers, particulate etc.
Lecture notes on Structure and Properties of Engineering Polymers
Course Objectives:
The main objective is to introduce polymers as an engineering material and emphasize the basic concepts of their nature, production and properties. Polymers are introduced at three levels; namely, the molecular level, the micro level, and macro-level. Through knowledge of all three levels, student can understand and predict the properties of various polymers and their performance in different products. The course also aims at introducing the students to the principles of polymer processing techniques and considerations of design using engineering polymers.
The fabrication methodology of a composite part depends mainly on three factors:
(i) the characteristics of matrices and reinforcements,
(ii) the shapes, sizes and engineering details of products, and
(iii) end uses.
The composite products are too many and cover a very wide domain of applications ranging from an engine valve to an aircraft wing.
The fabrication technique varies from one product to the other.
FIBER SELECTION
Factors to consider when choosing glass type include thermal properties; fiber cost, type of manufacturing process being used, and forms of reinforcement
Metal matrix composites (MMCs) possess significantly improved properties including highspecific strength; specific modulus, damping capacity and good wear resistance compared to unreinforced alloys. There has been an increasing interest in composites containing low density and low cost reinforcements. Among various discontinuous dispersoids used, fly ash is one of the most inexpensive and low density reinforcement available in large quantities as solid waste by-product during combustion of coal in thermal power plants. Hence, composites with fly ash as reinforcement are likely to overcome the cost barrier for wide spread applications in automotive and small engine applications.
RTM is a low-pressure molding process, where a mixed resin and catalyst are injected into a closed mold containing a fiber pack or preform . when the resin has cured the mold can be opened and finished component removed.
Composites are made by combination of two or more natural or artificial materials to maximize their useful properties and minimize their weaknesses.
Example: The oldest and best-known composites,
Natural: Wood combination of cellulose fibre provides strength and lignin is the "glue" that bonds and stabilizes. Bamboo is a very efficient wood composite structure.
o is a very efficient wood composite structure
Artificial: The glass-fibre reinforced plastic (GRP), combines glass fiber (which are strong but brittle) with plastic (which is flexible) to make a composite material that is tough but not brittle.
70 to 90% of load carried by fibers
Provide structural properties to the composite
Stiffness
Strength
Thermal stability
Provide electrical conductivity or insulation
Example: Glass, Carbon, Organic Boron, Ceramic, Metallic
Function of Fiber/Dispersion phase
Composite Materials: A composite material can be defined as a combination of two or more materials that results in better properties than those of the individual components used alone. The two constituents of a composite are a reinforcement and a matrix.
Matrix: The continuous phase is the matrix, made of polymer, metal, or ceramic.
Reinforcement: A strong, inert, woven and nonwoven fibrous material incorporated into the matrix to improve its mechanical and physical properties. For example, fibers, whiskers, particulate etc.
Lecture notes on Structure and Properties of Engineering Polymers
Course Objectives:
The main objective is to introduce polymers as an engineering material and emphasize the basic concepts of their nature, production and properties. Polymers are introduced at three levels; namely, the molecular level, the micro level, and macro-level. Through knowledge of all three levels, student can understand and predict the properties of various polymers and their performance in different products. The course also aims at introducing the students to the principles of polymer processing techniques and considerations of design using engineering polymers.
Series of powerpoint slides showing 6 different composite forming techniques: Hand lay-up, vacuum bagging, compression moulding, filament winding, pultrusion and resin transfer moulding. The slides are adapted from the University of Liverpool "Composite Materials" lectures [MATS311] by Prof. W. Cantwell.
Fibre Reinforced Plastic manufacturing methodsjeff jose
Composites manufacturing processes are complex, and involve combinations of the following physical processes:
1) Reinforcement Shaping
2) Resin Infusion
3) Composite Consolidation
Advantages and disadvantages of processing techniques
plastic composite manufacturing
Hand Lay-up
Spray up method
Filament winding
Match die molding
Pultrusion
Resin transfer molding
Reaction injection molding
Hand Lay-Up is well suited for low volume production of product.
This method can be used for both corrosion barrier and the structural portion
Fiber is chopped in a hand-held gun and fed into a spray of catalyzed resin directed at the mold. The deposited materials are left to cure under standard atmospheric conditions.
Composite materials have transformed numerous sectors by providing a mix of strength, durability, and lightweight qualities. Among the numerous manufacturing processes, resin infusion and resin transfer moulding stand out as innovative techniques driving efficiency and precision in composite production. In this guest blog, we delve into the intricacies of resin infusion and resin transfer moulding, exploring their benefits, applications, and impact on modern manufacturing.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
Contact with Dawood Bhai Just call on +92322-6382012 and we'll help you. We'll solve all your problems within 12 to 24 hours and with 101% guarantee and with astrology systematic. If you want to take any personal or professional advice then also you can call us on +92322-6382012 , ONLINE LOVE PROBLEM & Other all types of Daily Life Problem's.Then CALL or WHATSAPP us on +92322-6382012 and Get all these problems solutions here by Amil Baba DAWOOD BANGALI
#vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore#blackmagicformarriage #aamilbaba #kalajadu #kalailam #taweez #wazifaexpert #jadumantar #vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore #blackmagicforlove #blackmagicformarriage #aamilbaba #kalajadu #kalailam #taweez #wazifaexpert #jadumantar #vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore #Amilbabainuk #amilbabainspain #amilbabaindubai #Amilbabainnorway #amilbabainkrachi #amilbabainlahore #amilbabaingujranwalan #amilbabainislamabad
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
1. MANUFACTURE OF COMPOSITES
University College of Engineering , RTU ,
Kota
Submitted To –
S.S Godara
Aditya
Gaurav
Submitted by - Govind
Jenendra
Rajat
2. MANUFACTURE OF COMPOSITES -
Hand lay up Technique
Pressure bag and vacuum bag techni
Pultrusion
Resin – transfer Moulding
Injection Moulding
3. INTRODUCTION
Composites consist of two distinct materials, which
together improve product performance and lower
production costs.
Composite materials typically include plated, clad, or
coated metals, however the term 'composites' has
evolved to mean a material containing a matrix, or base
substance, and a reinforcement material.
The matrix acts as a binder for the reinforcement
while controlling the physical shape and dimensions of
the part. Its primary purpose however is to transfer the
load, or stress, applied to the part to the reinforcement.
The matrix also protects the reinforcement from
adverse environmental effects.
4. INTRODUCTION
The reinforcement’s function is to enhance the
mechanical properties of the composite and is typically
the main load bearing element.
Reinforcements are usually in the form of either
fibers or particles.
Matrix and reinforcement materials can be polymers,
metals, ceramics, or carbon.
The most widely used composite materials are fiber-
reinforced thermosetting polymers.
A composite can be defined as a combination of two
or more materials that retain their macro-structure
resulting in a material that can be designed to have
improved properties than the constituents alone.
5. INTRODUCTION
Advanced composite materials have been used to
fabricate many structural parts in engineering
applications.
This is due to their many attractive characteristics
such as light weight, high strength, high stiffness,
good fatigue resistance and good corrosion
resistance.
Also, the ability to manufacture parts with
complicated geometry using fewer components
enables manufacturers to save cost as compared
with the same parts made of conventional metallic
6. The different stages of existence of composite
constituents up to the final product :-
Stage a: At this stage, the materials appear in raw basic form.
For fibers, these consist of fiber either in the form of filaments or
fiber bundles. Fibers may also be woven into fabrics or braided
into braided perform. For matrix, the material usually appears in
liquid form for thermoset resin or in granular form in the case of
thermoplastics.
Stage b: At this stage, the fibers and matrix may be combined
into a single layer. For the case of thermoset matrix composite,the
matrix may appear in a semi-liquid, semi-solid form so that the
sheet can hold its shape. For the case of thermoplastic composite,
the matrix is solidified. This form for thermoset matrix composites
is called prepreg. For thermoplastic composites, it is called
towpreg.
7. Stage c: At this stage, the layers in stage b are stacked
on top of each other to make flat plate laminates. This
intermediate step is important for the analysis where
material properties are tested or calculated. However
this step is usually bypassed in the manufacturing
process of practical composite parts.
Stage d: This is the final stage where the final product
configuration is formed.
8. Figure : 1 Stages of existence of constituents in the
manufacturing of composites
9. The involvement of these stages in the
different manufacturing processes is as
follows:
1. Hand lay up Technique :- Stages a, b and d are
involved. Stage c is bypassed.
2. Pultrusion :- Stages a and d are involved. Stages b
and c are bypassed.
10. Theoretically, manufacturing of composites
can be broken down into the following items :-
• Aligning of fibers
• Single filaments
• Fabrics (mats, weaves, braids, knits)
• Bed consisting of many layers of fabrics
• Filling the interstices between filaments with liquid
matrix •Wetting the fibers
• Curing the resin
Filling interstices between the filaments with liquid
resin can be done at the levels of single filaments, tows,
fabrics, or a bed consisting of many layers of fabrics .
11. For making a composite part, a manufacturer can
combine or alternate these steps, depending on the
requirements
for quality and cost, as follows :-
For hand-lay-up in open mold for fiber glass/polyester, dry
tows or dry fabrics are laid on a mold, liquid resin is then
poured and spread onto the fiber beds. A few layers are
wetted and left to cure in open air. After these layers are
cured, more layers are added.
For pultrusion, the dry tows are run through a bath of resin
to be wetted. These are then fed into a heated die. The fibers
and resin are subjected to compaction and heating. When
the assembly of fibers and resin exit the die, they are
compacted and cured.
12. HAND-LAY-UP TECHNIQUE
Figure : 2 hand-lay-up fabrication method and a representative
lay-up sequence. Individual layers can be cut by hand or by a
computerized machine cutter. The layers can be stacked one on
top of the other by hand or by a robot.
15. Manual lay-up involves cutting the reinforcement material to size
using a variety of hand and power-operated devices.
These cut pieces are then impregnated with wet matrix
material, and laid over a mold surface that has been coated with a
release agent and then typically a resin gel-coat.
The impregnated reinforcement material is then hand-rolled to
ensure uniform distribution and to remove trapped air. More
reinforcement material is added until the required part thickness
has been built-up.
Manual lay-up can also be performed using pre impregnated
reinforcement material, called 'prepreg'.
The use of prepreg material eliminates separate handling of the
reinforcement and resin, and can improve part quality by providing
more consistent control of reinforcement and resin contents.
Prepreg must be kept refrigerated prior to use, however, to
prevent premature curing.
16. The productivity of the manual lay-up can be
automated using CNC machines.
These machines are used for both prepreg tape-laying
and prepreg fiber-placement primarily in the aerospace
industry.
There is virtually no limit to the size of the work that
can be tape-rolled, but the shape has to be relatively flat
to butt each successive row without gaps, overlaps or
wrinkles.
Automatic, multi axis fiber placement machines
overcome this limitation by dispensing numerous,
narrow individual tapes of material which are collimated
as they are laid on the mold surface.
17. Resins are impregnated by hand into fibers in the form
of weaves and fabrics.
Rollers or brushes are typically used.
The composite is left to cure under standard
atmospheric conditions.
The major disadvantage is the lack of consistency;
The quality of the product is highly dependent on the
skill of the laminator.
Resins need to be low in viscosity to be workable by
hand.
This generally compromises the mechanical and
thermal properties of the composite and creates a health
risk for the laminator.
18. Advantages:-
low cost tools
versatile: wide range of products
Disadvantages:-
time consuming
easy to form air bubbles
disorientation of fibers
inconsistency
19. APPLICATIONS
Making of custom parts in low to
medium volume quantities.
Bathtubs,
Swimming pools,
Boat hulls,
Storage tanks,
Duct and air handling equipment,
Furniture components
23. Process of pultrusion
1 - Continuous roll of reinforced fibers/woven fiber
mat
2 - Tension roller
3 - Resin Impregnator
4 - Resin soaked fiber
5 - Die and heat source
6 - Pull mechanism
7 - Finished hardened fiber reinforced polymer
24. Fibers are pulled from a creel through a resin bath
and then on through a heated die.
As the fiber passes through the die, the resin
cures.
This process is limited to components with
constant, or near constant, cross-sections.
Additionally, the cost of the heated die can be
high.
Pultrusion yields smooth finished parts that
typically do not require post processing.
A wide range of continuous, consistent, solid and
hollow profiles are pultruded, and the process can be
custom-tailored to fit specific applications such as
the constant cross-section spar in some windmill
25. Pultrusion is a continuous process used primarily to produce
long, straight shapes of constant cross-section.
Pultrusion is similar to extrusion except that the composite
material is pulled, rather than pushed, through a die.
Pultrusions are produced using continuous reinforcing fibers
called 'roving' that provide longitudinal reinforcement, and
transverse reinforcement in the form of mat or cloth materials.
These reinforcements are resin impregnated by drawing
through a resin wet-out station; and generally shaped within a
guiding, or preforming, system.
They are then subsequently shaped and cured through a
preheated die or set of dies.
Once cured, the pultrusion is saw-cut to length.
Pultrusions can be hollow or solid, and applications include
bar and rod, pipe, tubing, ladder rails and rungs, and supports
of many kinds.
27. RESIN – TRANSFER MOULDING
Figure 7 : Resin transfer moulding
process
28.
29. Introduction
Resin transfer moulding (RTM) is an increasingly common
form of moulding, using liquid composites.
It is primarily used to mold components with large surface
areas, complex shapes and smooth finishes.
RTM is unlike reaction injection moulding and structural
reaction injection moulding processes (SRIM), in which
the chemical reaction is induced by the mixture of reactants.
The chemical reaction for resins used in RTM are
thermally activated from the fiber mat or preform and mold
wall.
The reaction speed of RTM is much slower than that in
SRIM, allowing for a longer fill time at lower injection
pressure.
Final RTM products will be light in weight and high in
31. RTM is a closed-mold, vacuum-assisted process that
employs a flexible solid counter tool used for the B-side
surface compression.
This process yields excellent strength-to-weight
characteristics, high glass-to-resin ratio and increased
laminate compression.
In this process, fiber preform or dry fiber
reinforcement is packed into a mold cavity that has the
shape of the desired part. The mold is then closed and
clamped.
Catalyzed, low viscosity resin is then pumped into the
mold under pressure, displacing the air at the edges,
until the mold is filled.
After the fill cycle, the cure cycle starts during which
the mold is heated, and the resin polymerizes to become
rigid plastic.
32. Gel coats may be used to provide a high-quality,
durable finished product.
This process is well-suited for mass production of 100
to 10,000 units/year of high-quality composite fiberglass
or fiber-reinforced plastic parts.
It is recommended for products that require high
strength-to-weight requirements. Tooling used in this
process can be made from various materials including
aluminum, nickel shell, mild steel and polyester.
The light RTM (LRTM) process, on the other hand, is
similar to that of RTM, but differs in the method of
closing the mould. The closure of the mould is done
mechanically or by applying vacuum between two seals
in the mould peripheral flange.
33. Advantages
Components will have good surface finish on both sides
Selective reinforcement and accurate fiber management is
achievable
Ability to build-in fiber volume fraction loadings up to 65%
Uniformity of thickness and fiber loading, uniform shrinkage
Inserts may be incorporated into moldings
Tooling costs comparatively low
Uses only low pressure injection
Low volatile emission during processing
Ability to produce near net shape moldings
Process can be automated, resulting in higher production
rates
Ability to mould complex structural and hollow shapes
Low resultant voids
Ability to achieve from 0.5mm to 90mm laminate thickness
34. Disadvantages
waste some material (spill)
curing time long
hard for intricate parts
high tooling cost
35. Applications
RTM is of major interest for various moulding
applications as it promises performance improvements
and cost savings over traditional methods. Some of the
major applications of the RTM process include:-
Truck panels
Boat hulls
Wind turbine blades
Aerospace and automobile parts
Medical composites
Bathroom fixtures, car body, helmet, etc.