final report

DESIGN AND
DEVELOPMENT OF
SEAT CUSHION
MOULD
2014
sahjanand
[Type the company name]
5/6/2014

DESIGN AND DEVELOPMENT OF SEAT CUSHION
MOULD
A PROJECT REPORT
Submitted by
PATEL JAIVIKKUMAR N. (100520134016)
GUPTA ABHAYKUMAR B. (100520134019)
PANCHAL DHRUV R. (100520134026)
GURJAR AJAY T. (100520134034)
In fulfillment for the award of the degree
Of
BACHELOR OF ENGINEERING
In
MANUFACTURING ENGINEERING
Central Institute of Plastics
Engineering& Technology, Ahmedabad
Gujarat Technological University, Ahmedabad
May 2014

Central Institute of Plastics Engineering & Technology
MANUFACTURING ENGINEERING DEPARTMENT
2014
CERTIFICATE
Date:
This is to certify that the dissertation entitled “DESIGN AND
DEVELOPMENT OF SEAT CUSHION MOULD” has been carried out by
Patel Jaivik, Gupta Abhay, Panchal Dhruv and Gurjar Ajay under my
guidance in fulfillment of the degree of Bachelor of Engineering in
Manufacturing Engineering (8th
Semester) of Gujarat Technological University,
Ahmedabad during the academic year 2013-2014.
Guide: Head of the Department:
Mr. Ravindra Reddy Mr. J. Bosco
Sr. Lecturer Sr. Lecturer,
Manufacturing department, Manufacturing department,
CIPET, Ahmedabad. CIPET, Ahmedabad

ACKNOWLEDGEMENT
We would like to express our deepest gratitude to our guide and motivator Mr. R. Reddy,
Manufacturing Department, CIPET, Ahmedabad for his valuable guidance, sympathy and co-
operation for providing necessary facilities and sources during the entire period of this
project.
We wish to convey our sincere gratitude to Sr. Lect. J. Bosco, Manufacturing Department,
CIPET, Ahmedabad for his inspiring guidance, and valuable suggestion throughout this
project work.
We are very thankful to Mr. Satyapal Mahade for sparing his precious time in sharing details
about seat cushion mould and helped us wherever required in completing our project.
SUBMITTERS

ABSTRACT
Improvements in passenger compartment comfort continue to be one of the key needs of the
global transportation industry. Since their introduction more than 40 years ago, flexible
molded polyethylene foams have successfully contributed to the comfort provided by all
forms of transportation seating. Initially required to provide just a wide range of load bearing,
seating foams are now being designed for longer service life and better vibration damping
and are considered to be a functional part of the overall acoustical package. New performance
requirements are being placed on the NVH grade of foams and all interior components of
passenger compartments must contribute to a reduction in odor and emissions.
Comfort experience is a combination of many different factors, including aesthetics. Design
for comfort is intimately linked to vibration research. Hence the design should be very
effective.
In these report below we have designed the mould for seat cushion followed by the
development process.

LIST OF TABLES
Table No. Table Description Page No
Table 1 bill of materials for lower assembly 36
Table 2 bill of materials for upper assembly 38
Table 3 types of heater cutoff circuit with dimensions 48

LIST OF FIGURES
Fig No Figure Description Page No
Fig. 1 Seat cushion 6
Fig. 2 Types of cushion 8
Fig. 3 various types of seat cushions 9
Fig. 4 Location of a seat cushion in a car seat 10
Fig. 5 various types of polyethylene foam 19
Fig.6 Mould along with dimensions 27
Fig 7 Mould along with given plates 28
Fig 8 The entire mould assembly 30
Fig 9 The side view of the mould assembly 30
Fig 10 Lower mould assembly 31
Fig 11 The upper mould assembly 31
Fig 12 The sectional view of mould upper assembly 32
Fig 13 Lever 32
Fig 14 Bottom aluminum plate 32
Fig 15 Bottom steel plate 33
Fig 16 Side block 33
Fig 17 Side taper block 33
Fig 18 Tapper block 33
Fig 19 Top aluminum plate 34
Fig 20: The entire assembly in rendered form 35
Fig 21: Snapshot of the designing part other mould in Creo design 36

Fig 22: Snapshot of a given part in Creo 37
Fig 23: Ceramic heater 38

TABLE OF CONTENTS
Acknowledgement i
Abstract ii
List of Tables iii
List of Figures iv
1. Introduction
1.1 Automobile seats. 4
1.2 Seat cushion 6
1.3 Types of cushion 7
1.4 The role of seat cushion 11
1.5 Advantages of seat cushion 13
1.6 material details 15
1.7 What is foam? 18
2 Phase-1 : design phase
2.1 introduction 23
2.2 About Creo parametric 29
2.3 The mould and its design in Creo 30
2.3.1. The entire assembly 30
2.3.2 The lower assembly 31
2.3.3. The upper assembly 32
2.3.4 The detail part drawings 34

3. Phase-2: development phase
3.1 The machining process required 43
3.2 heaters used 45
3.3 Thermocouple 46
3.4 The molding process 49
4. Conclusion and Reference
4.1 Conclusion 52
4.2 References 53

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DESIGN AND DEVELOPMENT OF
SEAT CUSHION MOLD

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CHAPTER 1
INTRODUCTION
Automobile seats
Seat Cushion
Types of Cushion
The Role of Seat Cushion
Advantages of Seat Cushion
Material Details
What is Foam?

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1.1 Automobile seats
Flexible and semi-flexible polyethylene foams are used extensively for interior components
of automobiles, in seats, headrests, armrests, roof liners, dashboards and instrument panels.
Polyethylene is used to make automobile seats in a remarkable manner. The seat
manufacturer has a mold for each seat model. The mold is a closeable "clamshell" sort of
structure that will allow quick casting of the seat cushion, so-called molded flexible foam,
which is then upholstered after removal from the mold.
It is possible to combine these two steps, so-called in-situ, foam-in-fabric or direct molding.
A complete, fully assembled seat cover is placed in the mold and held in place by vacuum
drawn through small holes in the mold. Sometimes a thin pliable plastic film backing on the
fabric is used to help the vacuum work more effectively. The metal seat frame is placed into
the mold and the mold closed. At this point the mold contains what could be visualized as a
"hollow seat", a seat fabric held in the correct position by the vacuum and containing a space
with the metal frame in place.
Polyethylene chemicals are injected by a mixing head into the mold cavity. Then the mold is
held at a preset reaction temperature until the chemical mixture has foamed, filled the mold,
and formed stable soft foam. The time required is two to three minutes, depending on the size
of the seat and the precise formulation and operating conditions. Then the mold is usually
opened slightly for a minute or two for an additional cure time, before the fully upholstered
seat is removed.
Polyethylene molded flexible foams are key components of automobile interiors and
contribute to passenger comfort in many different ways.
More than 40 years after their introduction, the foam use per vehicle is still growing
worldwide.

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Indeed, by virtue of their superior vibration damping capability over a wide range of
frequencies at low material density, polyethylene foams are found today not only in
automotive seats but also in various acoustical parts.
Comfort experience is a combination of many different factors, including aesthetics.
During a journey, car occupants are subjected to both mental and physical stresses when
exposed to road vibrations, dense traffic, noise and different weather conditions.
Polyethylene foams found in seats and in sound insulating packages are instrumental in
reducing those stresses.
Design for comfort is intimately linked to vibration research.
Vibration isolation in the low frequency range by the seat assembly and the attenuation of
high frequency vibrations from the running engine, or other sources, transmitted into the
passenger compartment, with
NVH (Noise, Vibration, Harshness) components, allows the construction of comfortable cars.
In addition, polyethylene foams show high durability and perform well from the beginning to
the end of a journey and over a vehicle life of more than one hundred thousand miles.
The trend towards density reduction, while maintaining technical performance specifications
is continuing.
In addition of that, elimination of all types of chemical emissions and/or odors is becoming
an important issue.
Dow Chemical is developing new raw materials to respond to these needs.

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Figure.1 seat cushion
1.2 SEAT CUSHION
Flexible Polyethylene Seat Cushion
Seat cushion (or carpet underlay) is a primary use for flexible polyethylene foam. Over 400
million pounds of foam are used each year in the production of seat cushion. More than 85
percent of the cushion sold in the United States is a form of flexible polyethylene foam.
Foam commands such a high percentage of market shares for a number of reasons. Foam
provides a wide range of cushion "feels," ranging from very soft to very firm.
Foam is easily transported and installed under carpet. It resists mildew and microbial attack,
which means that household spills tend not to affect it, and it can be installed below grade.
Different grades of flexible polyethylene foam carpet cushion provide different performance
levels suitable for virtually any residential or commercial cushion application.
For less expensive grades of cushion, foam can be extremely price competitive.

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1.3 Types of Cushion
There are two basic types of flexible polyethylene foam seat cushion. Prime polyethylene
carpet cushion is made from slab stock polyethylene foam.
Blocks of foam are slit into sheets of specified thickness, typically ranging from 1/4" to
9/16". A plastic film backing or non-woven backing is applied and the material packaged in
rolls.
The foam used in prime polyethylene seat cushion can vary from relatively low to relatively
high density, depending on the intended application.
Special “high performance” foam types may also be used. Some “high performance” foams
have been developed especially for seat cushion use. Bonded polyethylene seat cushion is
made in an entirely different manner.
Scrap foam of various types is shredded into small pieces and placed into a processing unit
with a chemical adhesive. The mixture is pressurized and injected with steam to form a large
foam cylinder or block. This material is then “peeled” into the proper thicknesses for seat
cushion use, a plastic film backing or backing is applied, and the finished seat cushion
packaged in rolls.
Figure 2: types of seat cushion

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Bonded polyethylene foam carpet cushion is also one of the world's greatest recycling
success stories.
Virtually all scrap foam from polyethylene foam manufacturing is recycled for use in bonded
foams.
In many cases, recycling centers have been established to accept old carpet cushion removed
from people's homes, old furniture cushions, mattresses, auto seats, and other types of foam
for use in making new bonded carpet cushion.
Cushions are of various forms and color. It is as per the requirement of the end user or the
customer. The various forms with various different colors are shown as follows.
Figure 3: various types of seat cushion

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Fig 4: location of seat cushion in a car seat
Above figure shows the location of seat cushion. It is also according to the user requirement.
The cushion can be either located at the upper side of the side or below the seat. It’s as per
the user requirement.
1.4 The Role of Seat Cushion
Carpet cushion provides a number of important functions. It helps absorb the initial shock of
foot traffic on carpet, which can cause carpet fibers to compact and lose height, creating
"matting" effects in the carpet.
So carpet – even "no mat, no crush" styles - tend to look better longer if proper carpet cushion
is used.
Many carpets with appearance retention warranties require the selection of a proper carpet
cushion to validate the warranty.
Carpets installed with proper cushion also tend to feel more comfortable underfoot.
The layer of cushion makes vacuuming more efficient, because it allows the vacuum cleaner
to "lift" the carpet (because of better air flow) and collect dirt that would otherwise be trapped
and cause carpet fiber to fray. Carpet cushion helps absorb noise, so rooms are quieter. Carpet
installed over cushion is more economical in the long run.

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The extra life that cushions gives to carpet means that the original investment in the floor-
covering has more value. And for commercial installations, carpet over cushion is less costly
to remove and replace than carpet that is glued directly to the floor.
The Cushion Performance Issue
There is no universal industry "standard" for carpet cushion. However, there does exist a set
of guidelines established by the Department of Housing and Urban Development (HUD)
dealing with carpet cushion installed in FHA built or financed housing. This standard, HUD
UM72 (being updated as UM72a), covers all major carpet cushion types and is recognized by
many sources as providing good minimum criteria for proper cushion selection.
Testing Seat Cushion Performance
Concerns over carpet cushion performance, particularly in relation to new, longer, appearance
warranties being applied to carpet, have created a need for additional information on how
carpet and carpet cushion work together as a floor-covering system.
The Polyethylene Foam Association has helped coordinate a massive research program
designed to gather information about flexible polyethylene foam carpet cushion performance.
Involved in this study were many of the key organizations in the floor-covering industry. The
majority of the program was done at the Georgia Tech University School of Textile
Engineering.
Testing was based on a contract "walk-on" test, where people walked over the carpet/cushion
assembly for a specified number of times. A variety of factors - including carpet cushion
durability, installation, and carpet appearance – were evaluated on traffic counts ranging from
20,000 to 180,000. A traffic count of 20,000 is equivalent to one year of residential life.
Other carpet and cushion tests were done at different locations and the results correlated.
1.5 Advantages of Seat Cushion
Durability of Cushion Grades
One key factor evaluated by the "walk-on" test was the ability of cushion products to retain
their original properties. This has a significant impact on cushion performance under carpet.

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The chart below shows test results for different grades and densities of polyethylene carpet
cushion products and indicates that a variety of products have good performance in this area.
Retention of original properties is the main advantage and characteristic of seat cushion.
It offers better comfort, better durability. It offers an extraordinary support during longer
exposure to driving. It offers required support to the spinal cord while long drives. It
improves seating position and posture.
Comfortable
As the driver is a special profession, so a set of comfortable cushions is very important to the
driver's body! Especially for a long time driving staff, a comfortable, docile and
humanization design seat is highly recommended, the best seat in relatively good moisture
absorption and breathability. Of course, if necessary, you should also add a lumbar support,
which relief can fatigue to some extent.
Protect the leather seats:
A lot of cars equipped with leather chairs, smooth, naked and slippery. Key, pens and knives
and other sharp things can poke a hole on the leather seat in a unguarded moment, besides,
leather seats get oil or chemical stains are more difficult to clean. Therefore, the protective
function of a seat cover is very critical; Of course the premise is that the bottom of the car
seat cover is not rough material. Otherwise, leather will be worn "severely".
Beautiful
Now many car seats on the appearance is newly breakthrough, a good cushion will add
esthetics taste to the automotive, a bad seat is counterproductive. So, pick out a good look
seat is necessary.
1.6 Material Details
The material used in developing seat cushion is Polyethylene solution.

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About Polyethylene
Polyethylene (abbreviated PE) or polythene is the most common plastic. The annual global
production is approximately 80 million tons. Its primary use is in packaging (plastic bag,
plastic films, geo-membranes, containers including bottles, etc.). Many kinds of polyethylene
are known, with most having the chemical formula (C2H4) nH2. Thus PE is usually a
mixture of similar organic compounds that differ in terms of the value of n.
Properties
Physical properties
Polyethylene is a thermoplastic polymer consisting of long hydrocarbon chains. Depending
on the crystalline and molecular weight, a melting point and glass transition may or may not
be observable. The temperature at which these occur varies strongly with the type of
polyethylene. For common commercial grades of medium- and high-density polyethylene the
melting point is typically in the range 120 to 180 °C (248 to 356 °F). The melting point for
average, commercial, low-density polyethylene is typically 105 to 115 °C (221 to 239 °F).
Chemical properties
Most LDPE, MDPE and HDPE grades have excellent chemical resistance, meaning that it is
not attacked by strong acids or strong bases. It is also resistant to gentle oxidants and
reducing agents. Polyethylene burns slowly with a blue flame having a yellow tip and gives
off an odor of paraffin. The material continues burning on removal of the flame source and
produces a drip. Crystalline samples do not dissolve at room temperature.
Polyethylene (other than cross-linked polyethylene) usually can be dissolved at elevated
temperatures in aromatic hydrocarbons such as toluene or xylem, or in chlorinated solvents
such as trichloroethane or dichlorobenzene.
Process
The ingredient or monomer is ethylene (IUPAC name ethane), a gaseous hydrocarbon with
the formula C2H4, which can be viewed as a pair of methylene groups connected to each
other. Because the catalysts are highly reactive, the ethylene must be of high purity. Typical
specifications are <5 ppm for water, oxygen, as well as other alkenes. Acceptable

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contaminants include N2, ethane (common precursor to ethylene), and methane. Ethylene is
usually produced from petrochemical sources, but also is generated by dehydration of
ethanol.
Polymerization
Ethylene is a rather stable molecule that polymerizes only upon contact with catalysts. The
conversion is highly exothermic, that is the process releases a lot of heat. Coordination
polymerization is the most pervasive technology, which means that metal chlorides or metal
oxides are used. The most common catalysts consist of titanium (III) chloride, the so-called
Ziegler-Natta catalysts. Another common catalyst is the Phillips catalyst, prepared by
depositing chromium (VI) oxide on silica. Ethylene can be produced through radical
polymerization, but this route has only limited utility and typically requires high pressure
apparatus.
Classification
Polyethylene is classified into several different categories based mostly on its density and
branching. Its mechanical properties depend significantly on variables such as the extent and
type of branching, the crystal structure and the molecular weight. With regard to sold
volumes, the most important polyethylene grades are HDPE, LLDPE and LDPE.
 Ultra-high-molecular-weight polyethylene (UHMWPE)
 Ultra-low-molecular-weight polyethylene (ULMWPE or PE-WAX)
 High-molecular-weight polyethylene (HMWPE)
 High-density polyethylene (HDPE)
 High-density cross-linked polyethylene (HDXLPE)
 Cross-linked polyethylene (PEX or XLPE)
 Medium-density polyethylene (MDPE)
 Linear low-density polyethylene (LLDPE)
 Low-density polyethylene (LDPE)
 Very-low-density polyethylene (VLDPE)

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1.7 What is Foam?
Foam is a substance that is formed by trapping pockets of gas in a liquid or solid. A bath
sponge and the head on a glass of beer are examples of foams. In most foam, the volume of
gas is large, with thin films of liquid or solid separating the regions of gas.
Some of the products formed by polyethylene foam are shown in the pictures below

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Figure 5: various forms of polyethylene foams
Proper Handling and Storage of Flexible Polyethylene Foam
Flexible polyethylene foam is an organic material and is combustible like all organic
materials. Organic materials include a wide variety of substances like wood, wool, paper,
cotton, nylon, polyester, and polyethylene.
Polyethylene foam, once ignited, can burn rapidly, consuming oxygen at a high rate and
generating great heat. Like any other organic material, when it ignites and burns,
polyethylene foam liberates smoke containing toxic gases, the primary one being carbon
monoxide. Hazardous gases released by burning foam can be incapacitating or fatal to human
beings if inhaled in sufficient quantities. Oxygen depletion in an enclosed space can present a
danger of suffocation.
Therefore, fire safety is critical in relation to any storage and handling of
flexible polyethylene foam.
Foam should not be exposed to open flames or other direct or indirect high-temperature
ignition sources such as burning cigarettes, matches, fireplaces, space heaters, forklift
tailpipes, welding sparks, or bare light bulbs.
Foam is often stored in large quantities. Foam fabricators may keep large blocks of foam in
inventory. Finished goods manufacturers may store individual cushions or cores for use in
products such as furniture, bedding, packaging, or automobiles.

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Retailers and wholesalers may warehouse quantities of slab foam for resale to customers, or
in the form of products such as replacement parts or carpet cushion.
As with any combustible material, proper care must be taken with foam to minimize potential
fire hazards. Even foams formulated to meet specific flammability regulations will burn,
including those foams specifically identified as meeting flammability requirements.
Safe and proper storage and handling of the material is essential.
Different business will face different foam storage situations, depending on the amount of
foam they use and the manner in which it is stored.
Storage and Handling in Foam Manufacturing and Fabrication Operations
Foam manufacturing and fabrication companies are likely to inventory the largest quantities
of flexible polyethylene foam.
Depending on the size of a particular manufacturing or fabrication operation, small pieces of
foam or large "bun" sections containing hundreds of cubic feet of foam may be stored.
Large amounts of foam represent a significant fuel source for a fire. Flexible polyethylene
fires generally tend to create very high temperatures - high enough to damage steel
framework of buildings if enough of a fuel load is involved. Once ignited, foam fires can
spread rapidly, producing intense heat, dense smoke, flammable liquids, and toxic gases.

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CHAPTER 2
DESIGN PHASE
Design Platform
Design of the Product
Mold Design
Mold Assembly
Complete Mold Setup

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2.1 Design Platform
Designing software: Creo Parametric 2.0
About Creo parametric 2.0:
Creo is a family or suite of design software supporting product design for discrete
manufacturers and is developed by PTC. The suite consists of apps, each delivering a distinct
set of capabilities for a user role within product development.
Creo runs on Microsoft Windows and provides apps for 2D design, 3D CAD parametric
feature solid modeling, 3D direct modeling, Finite Element Analysis and simulation,
schematic design, technical illustrations, and viewing and visualization.
The Creo suite of apps replaces and supersedes PTC’s products formerly known as
Pro/ENGINEER, CoCreate, and ProductView.
PTC began developing Creo in 2009, and announced it using the code name Project
Lightning at PlanetPTC Live, in Las Vegas, in June 2010. In October 2010, PTC unveiled the
product name for Project Lightning to be Creo. PTC released Creo 1.0 in June 2011.
Creo Parametric is a 3D design app for parametric modeling (parametric featured based solid
modeling). Creo Parametric provides all the capabilities of Creo Elements/Pro (also known as
Pro/ENGINEER).
The design needs to be done in 3 phases:
 Design of product
 Design of mould parts
 Assembly of mold.

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2.2 Design of the product:
Fig 6: Product
Product design:
Fig 7: side view of product with dimensions
Fig.8: Top view of product

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Fig. 9: 3-d view of product
2.3 Mold design:
Fig. 10: mold

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2.3.1 Upper assembly design:
Fig.11: Top view of upper assembly
Fig.12: front view
Bill of Materials for upper assembly
Sr. No. Part name Quantity Material
1 Top st plate 1 Steel
2 Top al plate 1 Aluminium
3 Allen screw 8 steel
Table 1: BOM for upper assembly

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The detail drawing of upper assembly parts:
Fig 13: top al plate
Fig 14: top steel plate

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2.3.2 Lower assembly
Fig. 15: 3-d view of lower assembly
Fig 16: lower assembly top view

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Fig 17: side view of lower assembly
Bill of Materials for lower assembly
Sr. No. Part name Quantity material
1 Bottom al plate 1 Aluminium
2 Bottom st plate 1 Steel
3 Side block 2 Aluminium
4 Side block lever 1 Aluminium
5 Side block tapper 1 Aluminium
6 Tapper block 1 Aluminium
7 Allen screw 14 Steel
Table 2: BOM for lower assembly

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The detail drawing of lower assembly parts:
Fig 18: bottom al plate
Fig 19: bottom steel plate

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Fig 20: side block
Fig 21: side block with lever hole

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Fig 22: side block for tapper block
Fig 23: tapper block

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2.3.3: Lever.
Lever detail drawing
Fig 24: lever_1
Fig 25: lever_2

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fig. 26: lever assembly.
2.3.4. DESIGN OF TABLE:
Fig. 27: 3-d design of table

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Fig 28: front view of table
Fig 29: top view of table

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2.4 mold assembly:
Fig. 30: 3-d view mold assembly
Fig. 31: mold in open condition

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Fig. 32: exploded view of mold assembly
Fig. 33: sectional view

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2.5 complete mold setup:
Fig. 34: mold along with base table and cylinder

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Fig 35: different views of mold setup

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CHAPTER 3
MANUFACTURING PHASE
Material Required
Pre Machining Process
Machining Process
Surface Finishing Process
Table Fabrication Process
Components Used

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3.1: material required
Sr. No. Part name material
1 Bottom al plate Aluminium
2 Bottom steel plate Steel
3 Side block Aluminium
4 Tapper block Aluminium
5 Top steel plate steel
6 Top al plate Aluminium
7 Lever Steel
8 Clamp Steel
Table 3: material requirement list
3.2 Pre machining process:
Shaping:
A shaper is a type of machine tool that uses linear relative motion between the work piece
and a single-point tool machine a linear tool path. Its cut is analogous to that of a lathe,
except that it is linear instead of helical.. (Adding axes of motion can yield helical tool paths,
as also done in helical planning.) A shaper is analogous to a planer, but smaller, and with the
cutter riding a ram that moves above a stationary work piece, rather than the entire work
piece moving beneath the cutter. The ram is moved back and forth typically by a crank inside
the column; hydraulically actuated shapers also exist.
Grinding machine:
A grinding machine, often shortened to grinder, is a machine tool used for grinding, which is
a type of machining using an abrasive wheel as the cutting tool. Each grain of abrasive on the
wheel's surface cuts a small chip from the workpiece via shear deformation.

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Grinding is used to finish workpieces that must show high surface quality (e.g., low surface
roughness) and high accuracy of shape and dimension. As the accuracy in dimensions in
grinding is on the order of 0.000025 mm, in most applications it tends to be a finishing
operation and removes comparatively little metal, about 0.25 to 0.50 mm depth. However,
there are some roughing applications in which grinding removes high volumes of metal quite
rapidly. Thus, grinding is a diverse field.
3.3 Machining process:
3.3.1About Milling Machine:
Milling is the machining process which uses rotary cutters to remove material from a work
piece advancing (or feeding) in a direction at an angle with the axis of the tool.It covers a
wide variety of different operations and machines, on scales from small individual parts to
large, heavy-duty gang milling operations. It is one of the most commonly used processes in
industry and machine shops today for machining parts to precise sizes and shapes.
3.3.2. Drilling Machine:
A drill is a tool fitted with a cutting tool attachment or driving tool attachment, usually a drill
bit or driver bit, used for boring holes in various materials or fastening various materials
together with the use of fasteners. The attachment is gripped by a chuck at one end of the drill
and rotated while pressed against the target material. The tip, and sometimes edges, of the
cutting tool does the work of cutting into the target material. This may be slicing off thin
shavings (twist drills or auger bits), grinding off small particles (oil drilling), crushing and
removing pieces of the workpiece (SDS masonry drill), countersinking, counterboring, or
other operations.
3.4 Surface finishing process:
3.4.1: polishing process:
Polishing and buffing are finishing processes for smoothing a work piece’s surface
using an abrasive and a work wheel or a leather strop. Technically polishing refers to
processes that use an abrasive that is glued to the work wheel, while uses a loose
abrasive applied to the work wheel. Polishing is a more aggressive process while

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buffing is less harsh, which leads to a smoother, brighter finish. A common
misconception is that a polished surface has a mirror bright finish, however most
mirror bright finishes are actually buffed.
3.5. Table fabrication process:
Table is made up of the L- section of the cast iron.
These L-sectoins are cut into required length and welded together to from the table.
Fig 36: fabricated table
3.6: Components used:
Heater used:
The heater used in seat cushion molding process is a ceramic heater 400mm*400mm.
About Ceramic heater:
Ceramic heaters are space heaters that generate heat by passing electricity through heating
wires embedded in ceramic plates. The plates heat aluminium baffles, and a fan blowing
across the baffles heats the air. Ceramic heaters are usually portable and typically used for
heating a room or small office, and are similar to metal-coil fan heaters.

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It is shown in the image below
Fig 37: Ceramic heater
Thermocouple:
A thermocouple is a temperature-measuring device consisting of two dissimilar conductors
that contact each other at one or more spots. It produces a voltage when the temperature of
one of the spots differs from the reference temperature at other parts of the circuit.
Thermocouples are a widely used type of temperature sensor for measurement and control,
and can also convert a temperature gradient into electricity. Commercial thermocouples are
inexpensive, interchangeable, are supplied with standard connectors, and can measure a wide
range of temperatures. In contrast to most other methods of temperature measurement,
thermocouples are self powered and require no external form of excitation. The main
limitation with thermocouples is accuracy; system errors of less than one degree Celsius (°C)
can be difficult to achieve.

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Heater cutoff circuit:
The thermal cutoffs (TCO) are non resetting, thermally sensitive, single pole, normally closed
devices and are intended to be used in various appliances. A temperature sensitive thermal
fuse melts and opens electrical contacts when temperatures exceed the rating of the thermal
fuse.
Thermal cutoffs are providing protection against potentially hazardous overheating
conditions in billions of products around the world.
Standard product offerings include:
Thermal Fuse
* Metallic Case type (Axial, Spring Action, Current: 10A, 15A) - USW-1 Series
* Low melting alloy type (Axial, Surface tension type, Current: 2A, 5A) - USW-2 Series
Note that the TCO shall be connected at the readily detectable location when abnormal
conditions such as thermostat failure, fan failure, locked rotor, dry operation, etc. might occur
in the appliance.
TCO is designed to lessen the heat created from TCO itself, but there may be a difference
between the ambient temperature and operating temperature of TCO due to wrong connection
method.
Pneumatic cylinder:
Like hydraulic cylinders, something forces a piston to move in the desired direction. The
piston is a disc or cylinder, and the piston rod transfers the force it develops to the object to
be moved..Engineers sometimes prefer to use pneumatics because they are quieter, cleaner,
and do not require large amounts of space for fluid storage.
Because the operating fluid is a gas, leakage from a pneumatic cylinder will not drip out and
contaminate the surroundings, making pneumatics more desirable where cleanliness is a
requirement. For example, in the mechanical puppets of the DisneyTikI Room, pneumatics
are used to prevent fluid from dripping onto people below the puppets.
The pneumatic cylinder provides the required pressure for closing and opening of the mould.
It is shown in figure as follows:

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Fig 38: pneumatic cylinder
3.7. Molding process:
Step 1). The polyethylene solution is used to make the cushion. For which the polyethylene
solution is poured into the mold.
Step 2). The solution is manually poured into the mold & then the mold is closed by pnumetic
cylinder, and the clamp makes it sure that mold remains closed during the entire process.
Step 3). The heater is then on and the heating starts.
Step4) care should be taken that the solution shuld not be heated above 60 degree C.
Step 5)the solution needs to be heated for about 30 minutes.
Step 6) after the heating is done the mold is kept for about 15-20minutes for cooling at room
temperature.
Step 7) the product is then manually removed from the mold..

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CHAPTER 4
CONCLUSION & REFERENCES

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4.1 CONCLUSION
Thus for making seat cushion its design phase: product design,
mold component design and assembly design has been completed
and its machining process is initiated

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4.2 References:
 Journal of Rehabilitation Research and Development Vol. 27 No. 3, 1990
 “Superior Processing New all-MDI Solutions for Automotive Seating
with Low emission of Volatile Organic Compounds (VOC)”
 http://www.us-electronics.com/datasheets/thermalcutoffs.pdf to
understand the working and use of heater cutoff circuits.
 http://www.moldmakingtechnology.com/articles/six-best-practices-for-
mold-design to understand the important aspects of designing.
 http://en.wikipedia.org/wiki/Ceramic_heater for detailed knowledge
about the ceramic heater.

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