Plastic injection molding continues to advance as new technology emerges, and with its growth comes new opportunities for using parts made with this method in automotive manufacturing. The global industry continues to work a higher percentage of plastic injection molding parts into each new round of vehicle designs, and plastic injection molding is capable of keeping up with demand.

1. Plastic Injection Molding
In Automotive Sector
Presentation by: Prathamesh Sanjay
Sawarkar

2. • Definition
• Why Plastic Injection Molded Parts?
• How it Works ?
• Materials with Applications and properties.
• Advantages
• Limitations
Contents

3.  A manufacturing process for producing parts by injecting
molten material into a Mold, or mold.
 Injection Molding can be performed with a host of
materials mainly including metals (for which the process
is called die-casting), glasses, elastomers, confections,
and most
commonly thermoplastic and thermosetting polymers.
Injection Molding
What is injection Molding ?

4. Injection molding is one of the most commonly used
production processes for plastics, as it offers a viable
solution for mass producing high quality and consistent
parts from a broad range of polymers.
Why Plastic Injection Moulded Parts?

5. Core : The core makes the internal shape of the product
Cavity : Cavity is the external shape of the mould
Injection Molding
What is Core and Cavity?
Core (Bumper) Cavity (Bumper)

6. Process Flowchart
Feeding
Material
Plasticization
(Melting)
Mold Closed
Injection
Filling
Holding
Pressure
Mold
Release
(Ejecting)
Cooling
Down
Mold Open

7. INJECTION MOLDING PROCESS (FOR SIMPLE OBJECTS)

8. MOLD FOR AUTOMOTIVE COMPONENT

9. MATERIALS USED FOR
INJECTION MOLDING

10. Material
name
Abbreviation Trade
names
Description Applications
Acetal POM Celcon,
Delrin,
Hostaform,
Lucel
Strong, rigid, excellent fatigue resistance, excellent creep
resistance, chemical resistance, moisture resistance, naturally
opaque white, low/medium cost
Bearings, cams, gears, handles, plumbing
components, rollers, rotors, slide guides,
valves
Acrylic PMMA Diakon,
Oroglas,
Lucite,
Plexiglas
Rigid, brittle, scratch resistant, transparent, optical clarity,
low/medium cost
Display stands, knobs, lenses, light
housings, panels, reflectors, signs,
shelves, trays
Acrylonitrile
Butadiene
Styrene
ABS Cycolac,
Magnum,
Novodur,
Terluran
Strong, flexible, low mold shrinkage (tight tolerances), chemical
resistance, electroplating capability, naturally opaque,
low/medium cost
Automotive (consoles, panels, trim,
vents), boxes, gauges, housings, inhalors,
toys
Cellulose
Acetate
CA Dexel,
Cellidor,
Setilithe
Tough, transparent, high cost Handles, eyeglass frames
Polyamide 6
(Nylon)
PA6 Akulon,
Ultramid,
Grilon
High strength, fatigue resistance, chemical resistance, low
creep, low friction, almost opaque/white, medium/high cost
Bearings, bushings, gears, rollers, wheels
Polyamide 6/6
(Nylon)
PA6/6 Kopa, Zytel,
Radilon
High strength, fatigue resistance, chemical resistance, low
creep, low friction, almost opaque/white, medium/high cost
Handles, levers, small housings, zip ties
Polyamide
11+12 (Nylon)
PA11+12 Rilsan,
Grilamid
High strength, fatigue resistance, chemical resistance, low
creep, low friction, almost opaque to clear, very high cost
Air filters, eyeglass frames, safety masks
Polycarbonate PC Calibre,
Lexan,
Makrolon
Very tough, temperature resistance, dimensional stability,
transparent, high cost
Automotive (panels, lenses, consoles),
bottles, containers, housings, light covers,
reflectors, safety helmets and shields
Polyester -
Thermoplastic
PBT, PET Celanex,
Crastin,
Rigid, heat resistance, chemical resistance, medium/high cost Automotive (filters, handles, pumps),
bearings, cams, electrical components

11. Polyetherimide PEI Ultem Heat resistance, flame resistance, transparent (amber color) Electrical components (connectors,
boards, switches), covers, sheilds,
surgical tools
Polyethylene -
Low Density
LDPE Alkathene,
Escorene,
Novex
Lightweight, tough and flexible, excellent chemical resistance,
natural waxy appearance, low cost
Kitchenware, housings, covers, and
containers
Polyethylene -
High Density
HDPE Eraclene,
Hostalen,
Stamylan
Tough and stiff, excellent chemical resistance, natural waxy
appearance, low cost
Chair seats, housings, covers, and
containers
Polyphenylene
Oxide
PPO Noryl,
Thermocomp,
Vamporan
Tough, heat resistance, flame resistance, dimensional stability,
low water absorption, electroplating capability, high cost
Automotive (housings, panels), electrical
components, housings, plumbing
components
Polyphenylene
Sulphide
PPS Ryton, Fortron Very high strength, heat resistance, brown, very high cost Bearings, covers, fuel system
components, guides, switches, and
shields
Polypropylene PP Novolen, Appryl,
Escorene
Lightweight, heat resistance, high chemical resistance, scratch
resistance, natural waxy appearance, tough and stiff, low cost.
Automotive (bumpers, covers, trim),
bottles, caps, crates, handles, housings
Polystyrene -
General
purpose
GPPS Lacqrene,
Styron,
Solarene
Brittle, transparent, low cost Cosmetics packaging, pens
Polystyrene -
High impact
HIPS Polystyrol,
Kostil, Polystar
Impact strength, rigidity, toughness, dimensional stability,
naturally translucent, low cost
Electronic housings, food containers, toys

12. Polyvinyl
Chloride -
Plasticised
PVC Welvic, Varlan Tough, flexible, flame resistance, transparent or opaque, low
cost
Electrical insulation, housewares, medical
tubing, shoe soles, toys
Polyvinyl
Chloride - Rigid
UPVC Polycol,
Trosiplast
Tough, flexible, flame resistance, transparent or opaque, low
cost
Outdoor applications (drains, fittings,
gutters)
Styrene
Acrylonitrile
SAN Luran, Arpylene,
Starex
Stiff, brittle, chemical resistance, heat resistance, hydrolytically
stable, transparent, low cost
Housewares, knobs, syringes
Thermoplastic
Elastomer/Rubb
er
TPE/R Hytrel,
Santoprene,
Sarlink
Tough, flexible, high cost Bushings, electrical components, seals,
washers
Polyether
Sulphone
PES Victrex, Udel Tough, very high chemical resistance, clear, very high cost Valves
Polyetheretherk
etone
PEEKEEK Strong, thermal stability, chemical resistance, abrasion
resistance, low moisture absorption
Aircraft components, electrical
connectors, pump impellers, seals
Polyester -
Thermoplastic
PBT, PET Celanex,
Crastin, Lupox,
Rynite, Valox
Rigid, heat resistance, chemical resistance, medium/high cost Automotive (filters, handles, pumps),
bearings, cams, electrical components
(connectors, sensors), gears, housings,
rollers, switches, valves

13. PLASTIC DEFFECTS & REMEDIES
Defect Cause Countermeasure
1.Strength poverty
1.Lack of drying 1.Preliminary dry the pellet well enough
2.High resin temperature 2.Drop the cylinder temperature
3.Too much cushion volume 3.Reduce the cushion volume
4.Shear heat generation at the runner
and the gate
4.Make the runner and the gate bigger,
and shorten the gate land.
5.Use the molding machine with
appropriate injection volume(about 1.5 to
3 times more than the cavity volume)
5.Residence time too long
6.If resin remains inside the cylinder by
some kind of trouble, resume molding
after purging it.
2.Warpage
1.Inappropriate gate location
1.Change the gate location, Add the
gates.
2.Un even molded product thickness
2.Try to make the molded product
thickness even.
3.Design of undercut, rib, and boss is
inappropriate
3.Change the design, thinking about
warpage.
4.Lack of cooling
4.Drop the mold temperature, and make
the cooling time longer.

14. PLASTIC DEFFECTS
3.Appearance defect 1.Slow injection speed
1.Make the injection speed faster.
2.Make the injection pressure stronger.
3.Make the runner and the gate bigger.
4.Make it thinner.
5.Raise the cylinder temperature.
6.Raise the mold temperature.
7.Preliminary dry well enough under an
appropriate condition.
8.Place a vent, clear the clog.
9.Refrain to use mold lubricant.
10.Use good liquidity grade.
4.Burnt deposit
1.Fast injection speed 1.Make the injection speed slower.
2.High resin temperature 2.Drop the cylinder temperature.
3.Long residence time
3.Shorten the mold cycle, Use the
molding machine of appropriate size.
4.Poorly ventilated 4.Place a vent,Clear the clog.
5.Nozzle clogged up 1.Low nozzle temperature 1.Raise the nozzle temperature

15. Advantages
 Repeatability:
In the automotive industry, repeatability—or the ability to consistently produce identical parts—is crucial.
Because injection molding typically relies on robust metal molds, the final plastic parts produced using the
mold are practically identical. There are factors that come into play with injection molding, but if the mold
is well designed and made, injection molding is a highly repeatable process.
 Scale and cost:
Though the injection mold-making process is expensive (as well as the cost of the mold), injection
molding is a highly scalable process whose overall cost decreases the more parts are made. For mass
production applications, injection molding is thus beneficial to the manufacturer. For anything less than
mass production, however, injection molding tooling costs may curb the cost efficiency of the process.
plastic materials also influence the final surface finish.

16. Advantages
 Material availability:
A significant benefit of using injection molding for automotive production is the wide range of rigid, flexible
and rubber plastics the process is compatible with. In the automotive industry, a range of different
polymers are used for various applications, including ABS, polypropylene, acrylic, acetal, nylon,
polycarbonate and more.
 High precision and surface finish:
Injection molding is ideal for producing plastic parts with relatively simple geometries and results in parts
with high surface finish quality. Manufacturers have many finish options when producing parts, including
various surface textures—such as glossy, rough or matte—which are applied directly to the mold rather
than the molded part. Different plastic materials also influence the final surface finish.

17. Limitations
 High tooling costs.
 Making tool for mass production takes time.
 Critical Design Considerations.
 Plastic Defect studies are required to avoid Warpage, Sink marks, Weak tool conditions.
 Analysis for constant wall thickness and flowlines, proper mold flow are required.
 Needs analysis for Once the tool is made the modification in the design is costly.

18. Automotive Applications Parts (Injection Molding)
 Under-the-hood:
For the past two decades or so, many under the hood components that were once made from metal
have been transitioned to plastic. For these applications, robust polymers such as ABS, Nylon and PET
are common. Parts such as cylinder head covers and oil pans are produced using injection molding and
offer lower weights and costs compared to metal parts.
 Exterior:
Injection molding is an established process for many exterior automotive components, including
fenders, grilles, bumpers, door panels, floor rails, light housings and more. Splash guards are a fine
example for demonstrating the durability of injection molded parts. The components, which protect the
car from road debris and minimize splashing, are often made from rubber or other durable and flexible
materials.
 Interior:
Many automotive interior parts are also produced using injection molding. They include instrumentation
components, interior surfaces, dashboard faceplates, door handles, glove compartments, air vents and
more. Decorative plastic elements can also be produced using injection molding.

19. Automotive Applications Parts (Injection Molding)
Part Core Cavity
Bumper (FRONT)