Plastic Introduction to Automotive Interiors

PLASTIC: INTRODUCTION
(PRELIMINARY STUDY OF
PLASTIC IN AUTOMOTIVE INTERIORS)
CREATED BY:
ADITYA DESHPANDE
14-06-2017PLASTIC INTRO- ADITYA D 1

PRESENTATION CONTENTS
1. Plastic: Introduction
2. Plastic Types
3. Plastic Manufacturing processes
4. Plastic Properties
5. Plastic design considerations
6. Case Studies: Plastic material used in various cars at various places
14-06-2017 2PLASTIC INTRO- ADITYA D

• Plastics are polymers. Polymer is something made of many units as a chain.
Each link of the chain is the "mer" or basic unit that is made of carbon,
hydrogen, oxygen, and/or silicon.
• To make the chain, many links or "mers" are hooked or polymerized together.
• Polymerization can be demonstrated by linking strips of construction paper
together to make paper garlands or hooking together hundreds of paper
clips to form chains.

• Many common classes of polymers are composed of hydrocarbons. These
polymers are specifically made of small units bonded into long chains.
Carbon makes up the backbone of the molecule and hydrogen atoms are
bonded along the backbone. Below is a diagram of polyethylene, the
simplest polymer structure.

PLASTIC: INTRODUCTION: THERMOPLASTIC
• Thermoplastic is a polymer in which the molecules are held together by weak
secondary bonding forces that soften when exposed to heat and return to its
original condition when cooled back down to room temperature.
• When a thermoplastic is softened by heat, it can then be shaped by
extrusion, molding, or pressing.
• Thermoplastics offer versatility and a wide range of applications. They are
commonly used in food packaging because they can be rapidly and
economically formed into any shape needed to full fill the packaging
function. Examples include milk jugs and carbonated soft drink bottles.

PLASTIC: INTRODUCTION: THERMOSETTING
• There are polymers that contain only carbon and hydrogen. Polypropylene,
polybutylene, polystyrene, and polymethylpentene are examples of these.
• Even though the basic makeup of many polymers is carbon and hydrogen, other
elements can also be involved. Oxygen, chlorine, fluorine, nitrogen, silicon,
phosphorous, and sulfur are other elements that are found in the molecular
makeup of polymers. Polyvinyl chloride (PVC) contains chlorine. Nylon contains
nitrogen and oxygen. Teflon contains fluorine. Polyester and polycarbonates
contain oxygen. Vulcanized rubber and thiokol contain sulfur.
• There are also some polymers that, instead of having a carbon backbone, have a
silicon or silicon-oxygen backbone. These are considered inorganic polymers.

AUTOMOTIVE PLASTIC
• The automobile parts which are made of polymeric materials are divided
into four categories
1. Internal parts: inside of car like IP, CC, DP
2. External parts: like bumpers, mudguards, spoilers
3. Parts in the engine compartment: like air supply system, engine lid, oil ducts
4. Bodywork and engine parts: like fuel tanks

COMMONLY USED PLASTIC MATERIALS AND THEIR
SHORT FORMS
1. ABS - acrylonitrile/butadiene/styrene
2. ABS+ PA- thermoplastic alloy acrylonitrile/butadiene/
3. styrene +polyamide
4. ASA- acrylonitrile/styrene/acrylate
5. ASA +PC - thermoplastic alloy acrylonitrile/
6. /styrene/acrylate + pol ycarbonate
7. BMC- bulk moulding compound
8. LFT- long fibre reinforced thermoplastic
9. P A 11 - polyamide 11
10. PA 12 - polyamide 12
11. PA 46 - polyamide 4.6
12. PA 610- polyamide 6.10
13. PA 6-3-T - amorphous polyamide
15. P A6 - polyamide 6
16. PBT - poly(butylene-terephthalate)
17. PBT +PET- thermoplastic alloy
poly(butylene-terephthalate) +poly(
ethylene- -terephthalate)
18. PC - polycarbonate
20. PA 610- polyamide 6.10
21. PA 6-3-T - amorphous polyamide
14-06-2017 8

COMMONLY USED PLASTIC MATERIALS AND THEIR
SHORT FORMS
22. PC+ ABS - thermoplastic alloy
polycarbonate +
acrylonitrile/butadiene/styrene
23. PC+ PBT- thermoplastic alloy
polycarbonate +poly(butylene-
terephthalate)
24. PDAP - poly( diallyl-phthalate) resin
25. PEEK- poly( ether-ether-ketone)
26. PE-HD - high density polyethylene
27. PE-LD- low density polyethylene
28. PET- poly( ethylene-terephthalate)
29. PF - phenol-formaldehyde resin
30. PMMA- poly(methyl-methacrylate)
31. POM- poly(oxymethylene)
32. PP - polypropylene
33. PP GF30 - 30% fibreglass reinforced
polypropylene
34. PPE (PPO) - poly(phenylene-ether)
[poly(phenylene oxide)]
35. PPO + PA- thermoplastic alloy
poly(phenylene oxide)+ polyamide
36. PPS - poly(phenylene-sulfide)
37. PS - polystyrene
38. PTFE- poly(tetrafluoroethylene)
39. PUR - polyurethane
40. PVC- poly(vinyl-chloride)
41. RIM - reaction injection moulding
42. TPE-U- thermoplastic elastomer
43. PES - polyester 14-06-2017 9

PLASTIC CLASSIFICATION BY SPI
• The Society of the Plastics Industry (SPI)
• Manufacturers place an SPI code, or number, on each plastic product, usually
moulded into the bottom

PLASTIC TYPES

PLASTIC TYPES BASED ON PROCESSING
THERMOSETS
• A Thermoset is a polymer that solidifies or “sets” irreversibly when heated or
cured. Similar to the relationship between a raw and a cooked egg, a cooked
egg cannot revert back to its original form once heated, and a thermoset
polymer can’t be softened once “set”.
• Thermosets are valued for their durability and strength and are used extensively
in automobiles and construction including applications such as adhesives, inks,
and coatings. The most common thermoset is the rubber truck and automobile
tire.

THERMOSET PLASTICS EXAMPLES
1. Mattresses
2. Cushions
3. Insulation
4. Unsaturated Polyesters:
5. Boat hulls
6. Bath tubs and shower stalls
7. Furniture
8. Epoxies
9. Adhesive glues
10. Coating for electrical devices
11. Helicopter and jet engine blades
12. Phenol Formaldehyde:
13. Oriented strand board
14. Plywood
15. Electrical appliances
16. Electrical circuit boards and switches

THERMOSET PLASTICS EXAMPLES
Polyethylene:
• Packaging
• Electrical insulation
• Milk and water bottles
• Packaging film
• House wrap
• Agricultural film
Polypropylene:
• Carpet fibers
• Automotive bumpers
• Microwave containers
• External prostheses
Polyvinyl Chloride (PVC):
• Sheathing for electrical cables
• Floor and wall coverings
• Siding Automobile instrument panels
14-06-2017 16

1. POLYCARBONATE (PC)
• often used for the application in automotive industry. They are applied mainly
in non-reinforced condition, and their main application in automobiles is for the
manufacture of various parts of light assemblies, such as lights and lenses of
the front and rear lights. It features the following properties
1. resistant to high temperatures (up to 148°C), whereas high-temperature
polycarbonate (PC- HT) is resistant to temperatures (from 160-220o C)
2. transparent with possibility of being painted into any nuance
3. modulus in tension up to 2300 Mpa, properties of toughness
4. high dimensional stability, precision and good electric insulation properties.
SOME POPULAR TYPES OF PLASTICS IN AUTOMOTIVE
INDUSTRY AND USES

2. ACRYLONITRILE/BUTADIENE/STYRENE (ABS)
• Primarily used for the manufacture of housings, covers and linings, featuring
the following properties
1. very good properties of toughness, strength and rigidity
2. they are opaque, attain high surface polish i. e. have well polished surface
3. good chemical resistance and resistance to temperature of 80-105°C
4. modulus in tension is from 1500-2700 MPa, and when fibre glass
reinforced even up to 5500 MPa

3. POLYAMIDE (PA)
• Most often used are polyamide 66 (PA66) and polyamide 6 (PA6). The main
application of polyamide is the manufacture of parts which are under the engine
hood, mainly using the types of polyamide (PA) reinforced by fibreglass.
Polyamide 66 features the following properties
1. opaque and features good rigidity and hardness
2. high resistance to temperature (in short-term exposure up to 250°C, in long-
term exposure from 80°-150°C), and resistance to many chemicals
3. features very high strength and toughness
4. modulus in tension of 900-15000 MP a (depending on the modifications,
reinforcements and humidity)
5. features good electric insulation properties and very good resistance to wear
and tear 14-06-2017 19

• Polyamide 6 features the following properties
1. opaque, features good rigidity and hardness, it is resistant to many
chemicals, modulus in tension ranges from 450-15000 MPa
2. features good electric insulation properties and very good resistance to
wear and tear
3. features very high dynamic strength and toughness, depending on
modifications, reinforcements and humidity
4. features high resistance to temperature (in short-term exposure up to 200°C,
and in long-term exposure from 80°-150°C)
3. POLYAMIDE (PA)

4. POLYVINYL CHLORIDE (PVC)
• This is a material used in automotive industry for the manufacture of the
protection for the bottom floor in the car, for internal lining and coating of
electric cables in the vehicle, and features the following properties
1. low thermal resistance at high temperatures
2. good absorbent of impacts and vibrations, low flammability
3. diversity of manufacturing procedures, easy to weld, paste, and print

5. URETHANE ELASTOMERE (TPE-U)
• These polymeric materials combine the properties of high-quality
polyurethane with processing efficiency of thermoplastics. The most important
application of urethane elastomeres is for the body parts and steering wheel,
and they feature the following properties
1. good resistance to oils and greases, good resistance to chemicals, resistance
to temperatures from - 40°C - 80°C (in short-term exposure up to l2°C)
2. good at absorbing impacts and vibrations, they feature good recovery
after deformation
3. good resistance to formation and propagation of cracks

6. THERMOPLASTIC ALLOY
• often thermoplastic alloy polycarbonate+acrylonitrile/butadiene/ styrene (PC+ABS) is
used, and the thermoplastic alloy acrylonitrile/butadiene/styrene+polyamide (ABS +
PA). The alloys allow combining of mechanical, thermal and rheological properties of
materials. The thermoplastic alloy of polycarbonate+acrylonitrile/butadiene/styrene
(PC+ ABS) is used to manufacture the internal and external decorative parts and small
bodywork parts, and features the following properties
1. it is opaque, has high surface polish but slight tendency to distortion and humidity
absorption
2. high dimension stability and reaches high precision in the production of small parts,
modulus in tension from 1800-2750 MPa, and fibre glass reinforced 3900-5900
MPa
3. features good electric insulation properties

• Thermoplastic alloy acrylonitrile/butadiene/styrene+ polyamide (ABS+PA) is
used for the manufacture of unpainted parts in the car interior, such as:
housings for radios and navigation systems, sliding roof supports, air nozzles
and air conditioning grates, gear level linings, steering wheels, etc., and also
for the manufacture of painted external parts: hub covers, grilles and fenders.
• Compared to acrylonitrile/butadiene/styrene graft copolymer(ABS) has
enhanced properties of chemical resistance, resistance to crack occurrence due
to the action of residual stresses, greater dynamic load power. Compared to
polyamide (PA), thermoplastic alloy (ABS+PA) features better properties of
machinability, lower tendency to shrinkage and deformation and lower water
absorption. Thermoplastic alloy (ABS+PA) features great flexural and notched
impact strength as well as good chemical resistance. The temperature
resistance is up to 180°C if based on polyamide (PA6), and up to 250°C if
based on polyamide (PA66)
6. THERMOPLASTIC ALLOY

PLASTIC DESIGN CONSIDERATIONS
1. DRAFT ANGLE
2. SHRINKAGE

1. DRAFT ANGLE
1. Reduces the chance of damage to the part due to friction during release
2. Reduces wear and tear and chances of damage to the mold
3. Ensures a uniform, smooth, unscratched finish when required
4. Ensures the integrity and uniformity of other surface finishes and textures
5. Reduces overall cooling time by lessening or eliminating the need for unconventional ejection
setups
6. Most, if not all, of these benefits offer either direct or indirect overall production cost reductions
 A draft angle is calculated as a degree measurement from the vertical axis of a
mold, and it helps account for thermoplastic shrinkage, a practical reality of the
injection molding process for most materials.
 By accounting for thermoplastic shrinkage during the cooling process, draft angles
greatly reduce friction between the finished, cooled part and the side of the mold.
Not only does this create a much easier release process, it offers several other
benefits, depending on the design of the part:
14-06-2017 26

1. DRAFT ANGLE
1. A draft angle of 1½ to 2 degrees is required for most parts
2. Textured parts require more draft — sometimes much more
3. All components of a piece should be drafted
4. Draft may have to be incorporated on two sides of a part.
5. If the parting line for a molded part is in the middle (as with, for
instance, a solid cylindrical part), draft should be incorporated on both
ends of the part. This is because there are essentially not one but two
mold release actions, both of which require draft.
6. At a bare minimum, half a degree of draft should be incorporated
into vertical surfaces
7. Tool matching condition: minimum 7 degrees of draft

1. DRAFT ANGLE
• Large draft angles and a smooth polish are required for parts molded in
strong, brittle, abrasive, and sticky materials. Smaller draft angles can be
used on soft, ductile, and slippery materials.
• In most cases, 1° per side will be adequate, but 2 or 5° per side would be
better. If the design cannot tolerate 1°, then specify 1/2° per side. A minimal
draft angle, such as 1/4° or even .002 inch/inch/side, is better than no draft
angle at all.

2. SHRINKAGE
• Shrinkage is a characteristic of resin which occurs during molding. Different resins
have different mold shrinkages. Crystalline and semi-crystalline materials exhibit
higher shrinkage than amorphous materials. Unreinforced plastics have higher
shrinkage than reinforced grades. It is important that the grade of material be
selected before the mold is constructed and that the proper mold shrinkage be
specified. Basic shrinkage data is obtained from ASTM tests or ISO tests.
• Material shrinkage can vary with part and tool design: thick walls will have higher
shrinkage rates than thin, variation in section thickness can cause differential
shrinkage and warpage; flow direction will effect shrinkage, particularly with
glass fiber-reinforced grades (more when perpendicular to flow and less when
parallel to flow
2914-06-2017PLASTIC INTRO- ADITYA D

2. SHRINKAGE

INJECTION MOLDING DEFECTS
1. Flow Lines
2. Sink Marks
3. Vacuum Voids
4. Surface Delamination
5. Weld Lines
6. Short Shots
7. Warping
8. Burn Marks
9. Jetting
10.Flash 14-06-2017 31

1. FLOW LINES
• streaks, patterns, or lines - commonly off-toned in colour - that show up on the
prototype part as a consequence of the physical path and cooling profile of the
molten plastic as it flows into the injection mold tooling cavity.
• Injection molded plastic begins its journey through the part tooling via an entry
section called a “gate.” then flows through the tool cavity and cools (eventually
hardening into a solid).
• Causes: Flow line defects are caused by the varying speed at which the molten
plastic flows as it changes direction through the contours and bends inside the mold
tool. They also occur when the plastic flows through sections with varying wall
thickness, or when the injection speed is too low causing the plastic to solidify at
different speeds. 14-06-2017 32

1. FLOW LINES
• Remedies:
1. Increase injection speeds and pressure to the optimal
level, which will ensure the cavities are filled properly
(while not allowing the molten plastic time to start cooling
in the wrong spot). The temperature of the molten plastic
or the mold itself can also be elevated to ensure the
plastic does not cool down sufficiently to cause the defect.
2. Round corners and locations where the wall thickness
changes to avoid sudden changes in direction and flow
rate.
3. Locate the gate at a spot in the tool cavity with thin walls.

2. SINK MARKS
• small craters or depressions that develop in thicker areas of the injection
molded prototype when shrinkage occurs in the inner portions of the finished
product.
• The effect is somewhat similar to sinkholes in topography, but caused by
shrinkage rather than erosion.

2. SINK MARKS
• Causes: Sink marks are often caused when the cooling time or the cooling
mechanism is insufficient for the plastic to fully cool and cure while in the mold.
They can also be caused by inadequate pressure in the cavity, or by an
excessive temperature at the gate. All else being equal, thick sections of the
injection molded part take longer to cool than thin ones and so are more likely
to be where sink marks are located.
• Remedies:
1. Mold temperatures should be lowered, holding pressure increased, and
holding time prolonged to allow for more adequate cooling and curing.
2. Reducing the thickness of the thickest wall sections will also ensure faster
cooling and help reduce the likelihood of sink marks.

3. VACUUM VOIDS
• pockets of air trapped within or close to the surface of an injection molded
prototype.
• Causes: by uneven solidification between the surface and the inner sections of
the prototype. This can be aggravated when the holding pressure is
insufficient to condense the molten plastic in the mold (and thereby force out
air that would otherwise get trapped). Voids can also develop from a part
that is cast from a mold with two halves that are not correctly aligned.

3. VACUUM VOIDS
• Remedies:
1. Locate the gate at the thickest part of the molding.
2. Switch to a less viscous plastic. This will ensure that less gas is trapped as
air is able to escape more rapidly.
3. Increase holding pressure as well as holding time.
4. Ensure that mold parts are perfectly aligned.

4. SURFACE DELAMINATION
• condition where thin surface layers appear on the part due to a contaminant
material. These layers appear like coatings and can usually be peeled off
• Causes: Foreign materials that find their way into the molten plastic separate
from the finished product because the contaminant and the plastic cannot
bond. The fact that they cannot bond not only has an affect on the
appearance of the prototype, but also on its strength. The contaminant acts as
a localized fault trapped within the plastic. An over-dependence on mold
release agents can also cause delamination.

4. SURFACE DELAMINATION
• Remedies:
1. Pre-dry the plastic properly before molding.
2. Increase the mold temperature.
3. Smooth out the corners and sharp turns in the mold design to avoid sudden
changes in melt flow.
4. Focus more on the ejection mechanism in the mold design to reduce or
eliminate the dependence on mold release agents.

5. WELD LINES
• Weld lines are actually more like a plane than a line that appears in a part
where molten plastics meet each other as they flow from two different parts
of the mold.

5. WELD LINES
• Causes: Weld lines are caused by the inadequate bonding of two or more flow
fronts when there is partial solidification of the molten plastic.
• Remedies:
1. Raise the temperature of the mold or molten plastic.
2. Increase the injection speed.
3. Adjust the design for the flow pattern to be a single source flow.
4. Switch to a less viscous plastic or one with a lower melting temperature

6. SHORT SHOTS
• situation where a molding shot falls short. This means that the molten plastic for
some reason does not fully occupy the mold cavity or cavities, resulting in a
portion where there is no plastic.
• Causes: Short shots can be caused by a number of things. Incorrect calibration of
the shot or plasticizing capacities can result in the plastic material being
inadequate to fill the cavities. If the plastic is too viscous, it may solidify before
fully occupying all the cavities and result in a short shot. Inadequate degassing or
gas venting techniques can also result in short shots because air is trapped and
has no way to escape; plastic material cannot occupy the space that air or gas is
already occupying.

6. SHORT SHOTS
• Remedies:
1. Select a less viscous plastic with higher flowability. This
plastic will fill the hardest-to-reach cavities.
2. Increase mold or melt temperature so as to increase
flowability.
3. Account for gas generation by designing the mold so that
gas is not trapped within the mold and is properly vented.
4. Increase the material feed in the molding machine or switch
to a machine that has a higher material feed in the event
that the maximum material feed has been reached.

7. WARPAGE
• Warping (or warpage) is the deformation that occurs when there is uneven
shrinkage in the different parts of the molded component. The result is a
twisted, uneven, or bent shape where one was not intended.
• Causes: Warping is usually caused by non-uniform cooling of the mold
material. Different cooling rates in different parts of the mold cause the
plastic to cool differently and thus create internal stresses. These stresses,
when released, lead to warping.

7. WARPAGE
• Remedies:
1. Ensure that the cooling time is sufficiently long and that it is slow enough to
avoid the development of residual stresses being locked into the part.
2. Design the mold with uniform wall thickness and so that the plastic flows in a
single direction.
3. Select plastic materials that are less likely to shrink and deform. Semi-
crystalline materials are generally more prone to warping.

8. BURN MARKS
• Burn marks are discolorations, usually rust coloured, that appear on the
surface of the injection molded prototypes.
• Causes: Burn marks are caused either by the degradation of the plastic
material due to excessive heating or by injection speeds that are too fast.
Burn marks can also be caused by the overheating of trapped air, which
etches the surface of the molded part.

8. BURN MARKS
• Remedies:
1. Reduce injection speeds.
2. Optimize gas venting and degassing.
3. Reduce mold and melt temperatures.

9. JETTING
• Jetting refers to a situation where molten plastic fails to stick to the mold surface
due to the speed of injection. Being fluid, the molten plastic solidifies in a state
that shows the wavy folds of the jet stream on the surface of the injection molded
part.
• Causes: Jetting occurs mostly when the melt temperature is too low and the
viscosity of the molten plastic becomes too high, thereby increasing the resistance
of its flow through the mold. When the plastic comes in contact with the mold
walls, it is rapidly cooled and the viscosity is increased. The material that flows
through behind that viscous plastic pushes the viscous plastic further, leaving
scrape marks on the surface of the finished product.

9. JETTING
• Remedies:
1. Increase mold and melt temperatures.
2. Increase the size of the gate so that the injection speed becomes slower.
3. Optimize gate design to ensure adequate contact between the molten
plastic and the mold.

10. FLASH
• Flash is a molding defect that occurs when some molten plastic escapes from the
mold cavity. Typical routes for escape are through the parting line or ejector pin
locations. This extrusion cools and remains attached to the finished product.
• Causes: Flash can occur when the mold is not clamped together with enough force
(a force strong enough to withstand the opposing forces generated by the molten
plastic flowing through the mold), which allows the plastic to seep through. The use
of molds that have exceeded their lifespan will be worn out and contribute to the
possibility of flash. Additionally, excessive injection pressure may force the plastic
out through the route of least resistance.

10. FLASH
• Remedies:
1. Increase the clamp pressure to ensure that the mold parts remain shut
during shots.
2. Ensure that the mold is properly maintained and cleaned (or replaced when
it has reached the end of its useful lifespan).
3. Adopt optimal molding conditions like injection speed, injection pressure,
mold temperature, and proper gas venting.

COMMON PLASTICS FORMING PROCESSES

EXTRUSION
• Extrusion is a process that can be compared to squeezing toothpaste out of a
tube. Thermoplastic granules are forced through a heated barrel and the
fused polymer is then squeezed through a die that is the profile of the
extruded component.
• The extrusion is cooled by water or air as it leaves the die and is finally cut to
the required length. The shape of the die can be varied from a simple hole
with a centrally supported core to produce tubes such as pipes, to very
complex sections for curtain tracks or hollow window frames.

BLOW MOULDING
• is a simple process where compressed air is introduced underneath a warmed
sheet of thermoplastic material forcing the material into a mould cavity, or
allowing it to expand freely into the shape of a hemisphere. It is a good way
of forming large domes, which when made out of clear acrylic sheet are
often used in shop displays.

VACUUM FORMING
• This is a very common manufacturing process used, for example, to make a
range of plastics packaging. Think of the boxes sandwiches come in, or the
inner in a chocolate box, or your acrylic bath.
• Instead of the warmed plastic sheet being forced into a mould by air
pressure, in vacuum forming the air is drawn out from under the softened
plastic sheet, so it is forced over or into a mould by atmospheric pressure.
Vacuum forming is a very common and effective way of producing complex
shapes in thermoplastic sheeting.

EXTRUSION AND BLOW MOULDING
• This is a combination of extrusion and blow moulding and is often used where
the article to be made has a narrow neck, such as a bottle. The plastic
material is first extruded as a tube shape into an open die. The die is then
closed to seal the ends of the tube and air is blown in forcing the plastic tube
to take up the shape of the die cavity. As the material is extruded first and
then blow moulded, the process is known as extrusion blow moulding

INJECTION MOULDING
• This process is one of the most common of all plastics manufacturing processes.
The polymer, in granule form, is heated until fused and forced into a closed
mould. Because of the viscous (thick, syrupy) nature of the fused polymer, very
high pressures are needed to make it flow, which means that the machine and
mould have to be very strong to withstand the forces involved.

INJECTION MOULDING
• A typical industrial injection moulding machine uses a screw to force the
granules along a heated barrel, and when the granules become fused the
screw is used as a plunger to force the polymer into the mould.
• The moulds are usually made from high-grade steel to withstand the forces
involved and must also be highly polished to produce a very good finish on the
product, as any scratches will show up in the moulded plastic surface.
• Because of the ability of the plastic to show even the smallest of marks very
fine detail can be cut into the surface of the mould, for example in the form of
trade marks, lettering or textures.

ROTATIONAL MOULDING
• Rotational moulding is used to produce hollow thermoplastic products such as drums,
storage tanks and litterbins. A carefully calculated amount of plastic is placed in a
closed mould that is heated in an oven and rotated slowly around both a vertical
and horizontal axes.
• The plastic material fuses and sticks to the hot mould surface, building up the
required thickness. The mould is then gradually cooled by air or water while still
rotating.
• The mould is opened, the finished product removed and the mould reloaded and
closed for the next cycle. The time it takes to make one of the product is known as
the product’s cycle time.

CALENDERING
• Calendering is used to produce plastic sheeting and products such as floor
tiles, coated fabrics and coverings for car interiors.
• Fused thermoplastic is extruded on to heated rotating rollers that squeeze the
material into a continuous sheet or film.
• The film is cooled by jets of air or water, before being cut to suitable lengths
or loaded onto rolls.

COMPRESSION MOULDING
• Compression moulding is one of the oldest manufacturing technologies associated with
plastics
• The process is almost always used with thermosetting plastics. A carefully weighed
amount of thermosetting polymer is placed into a preheated lower mould cavity.
• The mould is then closed by the placing of the upper half and subjected to further heat,
and pressure provided by a press, often of several hundred tons capacity. The pressure
and heat causes polymerisation and the flow of the plasticised material within the
mould.

CASE STUDIES: PLASTIC MATERIAL USED IN
VARIOUS CARS AT VARIOUS PLACES

CASE STUDIES: DOOR PANEL
• Mostly door panel has following parts:
1. Carrier
2. Arm rest
3. Map pocket
4. Switches cover
5. Top panel or shoulder
6. Audio speaker grills
7. Grab handle or bezel

CASE STUDIES: DOOR PANEL
• CARRIER: mostly made up of PP material with either leather covering Map
pocket made up of PP
• Switches cover made up of ABS as it is glossy part and needs shining
• Top panel or shoulder made up of PP or PE

CASE STUDIES: CENTER CONSOLE
• Mostly center console has following parts:
1. Top panel
2. Side panels
3. Gear shifter trim cover
4. Arm rest
5. Rear air vent and ducts

CASE STUDIES: INSTRUMENT PANEL (DASH BOARD)
• Mostly instrument panel has following parts:
• Top panel
• Switch bezels
• Defroster grills
• Air vents
• Structure
• Storage areas like

THANK YOU

Plastic Introduction to Automotive Interiors

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