3. • Plastics component are prevalent in consumer and industrial segments for its strength
to weight ratio, low cost and ease of manufacturability.
• They have a clean surface finish, water and UV resistance, chemical resistance and
corrosion resistance.
• From bumpers in automotive, Computer Peripherals-Mice, keyboards, Medical equipment
for its sterility, mobile components, packaging products – plastic component has its
footprint.
Introduction
4. Introduction
For a given component, there are many ways to manufacture. Some of the manufacturing
processes for plastic parts are
• Casting
• Extrusion
• Compression Moulding
• Forming
• Injection moulding
• Rotational Moulding
• Blow Moulding
• Thermoforming
• 3D Printing
5. Material Selection:
• Polymer selection is always a tedious part in the product development phase.
Mostly, product engineers rely on the vendors to advise a suitable variant of
polymer for the product.
• Based on the objectives and requirements pledged by the product’s operation
and working environment – polymers are selected based on the level of
Chemical and UV resistance, Temperature, Heat resistance, Flammability,
Electrical and Mechanical capabilities, required surface finish and assembly
ease suitable material are chosen.
• Due to the day by day developments in polymer resins, the feasibility of
manufacturing process for the material, its availability and cost are taken into
account on selection.
7. Radius:
• Internal sharp edges have to be avoided while designing the component.
• All corners and edges are to be filleted and provided with the radius based on
the thickness considered and the strength parameters required near the
corners.
• As a general thumb rule, the corners and edges are filleted with a radius of 0.9
to 1.2 times the nominal thickness
8. Wall Thickness :
• Wall thickness is a primary element for the strength of the component and is
also in the prospect of manufacturability.
• Wall thickness has to be consistent to avoid most of the defects occurring during
the manufacturing processes. In-consistent thicknesses affect mould flow, part
formation and cooling.
• Higher thickness may affect the flow and cooling of the flow. Radius and
Rounded corners in the edges help proper filling in the mould.
9. Draft Angle:
• Taper in the vertical walls of the component is called the draft angle.
• Positive draft angle enables proper ejection of the component from the die
without damage.
• As a general thumb rule, the draft angle of 1 to 2 degrees is applied to the inner
vertical walls.
10. Gate Location
• Gates ensures proper resin flow and filling of the cavity in the mould.
• Gates are positioned to effectively fill the cavity in the mould before the resin
cools down.
• Type of gate and its position varies based on the geometric complexity and has a
high impact over the feasibility of producing the component without any
defects.
11. Ribs
• Plastic components with small wall thickness and requires mechanical strength
– Ribs are provided to reinforce the walls and to reduce shrinking.
• To eliminate white marks, 50 to 70 per cent of the wall thickness is considered
for ribs.
12. Mould Shrinkage:
• Generally, 20 per cent of the volume gets reduced from the cavity due to
shrinkage while cooling.
• Amorphous material shrinks lesser over crystalline polymers. Some of the
parameters to consider to avoid shrinkage are – Polymer formulation, mould
design, process temperature, melting temperature, cooling temperature,
injection speed, time and pressure.
13. Conclusion :
• Graphler Technology providing services like 3D to 2D Conversion Services,
• CAD Conversion Services etc.
• We have engineering experts specialized in CAD, FEA Services, Plastic Design,
Plastic Part design, Pressure Vessel Analysis Services, Surface modelling and on 3D
Modelling Services in India etc.
