injection moulding ppt
TRANSCRIPT
INJECTION MOULDING
ABHISHEK DOBHAL
Me 8th Semester
Roll No. :- FEJB13ME13
JBKP,FARIDABAD
Email :- [email protected]
What Is Injection Moulding?
Injection moulding is a manufacturing
process for producing parts by injecting
material into a mould. Injection moulding can
be performed with a host of materials mainly
including metals, glasses, elastomers,
confections, and most commonly thermoplastic
and thermosetting polymers. Material for the
part is fed into a heated barrel, mixed, and
forced into a mould cavity, where it cools and
hardens to the configuration of the cavity.
Injection Moulding Machine
Main Components Of Injection
Moulding Machine
Clamping unit
Injection unit
Drive unit
Mould
Hydraulic system
Control system
Hopper
Heaters
Cooling channels
Injection Moulding Process -
Resources
Material
Machine
Mould
Manpower
Most Commonly Used Materials
PVC
ABS(Acrylonitrile Butadiene Styrene)
Polypropylene
Polystyrene
HDPE( High density poly ethylene)
LDPE(Low density poly ethylene)
Rubber Thermoplastic
Epoxy
Injection Moulding Process
Material preparation
Feeding into hopper
Injection
Mould holding and cooling
Ejection
Injection Moulding Machine
Process
Material granules are fed into hopper then
melted down in barrel which is surrounded by
the heaters.
Injection Moulding Machine
Process
Melted material is injected into mould cavity
and mold is held under pressure until the
material cools and hardens.
Injection Moulding Machine
Process
Once the material hardens, the mold is opened
and the component is ejected by runner plate.
Injection Moulding Machine
Process
And the process can be repeated.
Injection Moulding Machine
Process
Mould
Moulds are the common terms used to describe
the tool used to produce components in moulding.
Moulds are constructed from hardened steel, pre-
hardened steel, aluminium, beryllium-copper alloy.
In general, steel moulds cost more to construct,
but their longer lifespan will offset the higher initial
cost over a higher number of parts made before
wearing out.
The moulds can be manufactured either by CNC
machining or by using electrical discharge
machining processes.
Mould Design
The mould consists of two primary
components, the injection mould (A plate) and
the ejector mould (B plate).
Mould Design Consideration
Shrinkage allowance: Depends on shrinkage property of material core and cavity size.
Cooling circuit: In order to reduce the cycle time, water circulates through holes drilled in both the core and cavity plates.
Ejection gap: The gap between the ejector plate face and core back plate face should hold dimension within the core. It must allow component to be fully removed from the mold.
Mould Design Consideration
Mold polishing : The core, cavity, runner and
sprue should have good surface finish and
should be polished along material flow
direction.
Mold filling : The gate should be placed such
that the component is filled from the thicker
section to thinner section.
Draft: Required in both the core and cavity for
easy ejection of the finished component.
Mould Storage
Manufacturers go to great lengths to protect
custom moulds due to their high average
costs.
The perfect temperature and humidity level is
maintained to ensure the longest possible
lifespan for each custom mould.
Custom moulds such as those used for rubber
injection moulding are stored in temperature
and humidity controlled enviornments to
prevent warping.
Mould Cooling
Constant mold temperature for uniform quality
Reduced cycle time for productivity
Improved surface finish without defects
Long mold life
Avoiding warpage by uniform mold surface
temperature (warpage caused by nonuniform
cooling)
Mould Cooling
Moulding Defects
Blister
Flash
Burn marks
Warping
Weld lines
Colour streaks
Voids
Manpower
To set up process
To monitor process and troubleshoot
To operate machine
Injection Moulding Used For
Plastic Injection Moulding
Rubber injection Moulding
Metal Injection Moulding
Plastic Injection Moulding
It is a manufacturing process for producing
components by injecting polymer material into
a mould.
Thermoplastic and Thermosetting plastic
material are used.
Thermoplastic materials are reusable.
Plastic Injection Moulding
Plastic Injection Moulding
Applications
Writing instruments components ( pen barrel,
cap, bush etc)
Computer Electronics
Automative Components
Aerospace Components
Electronic Components
Toys etc.
Rubber Injection Moulding
Injection molds can make many rubber
components. It makes valve steam seals, oil
seals for engines, telecommunication items
etc.
Metal injection moulding
• Injection molds can stamp out small to large
items. It can stamp out automobile parts from
spark plugs and floor pans to ball bearings. It
also can stamp out items like TV hangers and
knitting needles.
Advantages Of Injection
Moulding
Fast production.
Low labour costs.
Design flexibility.
High-output production.
Multiple materials can be used at the same time.
Can be used to produce very small parts.
Leaves little post-production scrap.
Ability to include inserts.
Good colour control.
Good product consistency.
Reduced requirements for finishing.
Good dimensional control.
Disadvantages Of Injection
Moulding
High initial tooling and machinery cost.
Part design restrictions.
Small runs of parts can be costly
Applications Of Injection
Moulding
Injection moulding is used to create many
things such as Cups, Containers, tools,
Mechanical parts (Including gears).
Injection moulding is the most common
modern method of manufacturing parts. It is
ideal for producing high volumes of the same
object.
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