[1] breakage resistance. · The geometrical accuracy is

 

1 http://www.bpf.co.uk/plastipedia/polymers/hdpe.aspx

References: –

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Injection moulding is the most
common method for mass manufacturing plastic products.

Manufacturing process of trigger of toy gun: –

 

Moreover, in terms of sustainability,
HDPE is environment-friendly material as they have high recoverability and
recyclability.  

For the given part, HDPE is very good
choice because it is rugged, durable and flexible. Due to these properties, it
is very easy to be machining and easily injection moulded. Furthermore, it
provides excellent chemical and environmental crack resistance. In addition to
this, HDPE is light weight and has high strength to weight ratio. Hence, the
material is suitable, children can play with the trigger without becoming
fatigued. The most important characteristic of HDPE is its high mouldability
and malleability. The HDPE is UV stable, corrosion and wear resistant. It also
provides longer service life as compared to any other plastics.

                       Table
1: – properties of HDPE (High density polyethylene) 1

Properties

                
Value

                 
Units

Tensile
strength

                0.20-0.40

                  N/mm2

Notched
impact strength

                0.5-20

                  j/m

Thermal
coefficient of expansion

                100-220

                  1/°C

Maximum
continuous operating temperature

                60-65

                    °C

Density

                0.944-0.965

                  g/cm3

 Injection moulding melt temperature

                204-220

                    °C

Injection
pressure

                800-1500

                   psi

Dissipation
factor at 1kHz

                0.0003

 

Elongation

                20-1000

                    %

Specific
Gravity

                0.941-0.965

 

Specific
volume

                29.4-28.7

                    in3/lb.

Hardness,
Rockwell R

                 65

 

 

 Material
and its properties: – The material which is used in manufacturing of trigger is
HDPE (High density polyethylene). HDPE is a good choice because of its low cost
and strong breakage resistance.

 

·        
The geometrical accuracy is the closeness of
measurement to its true value. Trigger has 0.5mm thickness and at the flanges,
it has 0.9mm thickness and there is a critical surface between trigger and the
pin holding it in a place, a running fit is required. H9d10 fit is suitable to
reduce friction and easy to pull trigger.

Geometrical properties: –

·        
The lower part of the trigger (hall sensor
trigger magnet) should have excellent surface finish because the user will touch
that part for firing purpose.

·        
The trigger will need good surface finish on the
both sides which slide between the case with low friction to compress the
spring that striker and firing pin. For this application, an average roughness
of trigger is around 0.4?m as it may be hand polished or ground into the mould.

Surface finish: –

·        
With a notched impact strength of about 0.5-20
j/m, the material is also strong enough to withstand impact fall.

·        
The trigger of the toy gun is constructed out of
HDPE (high density polyethylene) material. This is a type of brittle
thermoplastic material having high tensile strength (0.20-0.40 N/mm2)
to withstand a smooth and easy to pull the trigger.

Structural properties: –

Part analysis and functionality: – The given part is trigger of the
toy gun. As its obvious from the name, the main function of trigger is used to
compress the spring that drives the hammer, striker and firing pin. In
addition, it is used for rotating the cylinder to next chamber as precursor to
firing.

 

 Figure 1: – trigger of the toy gun                                           
Figure 2: – case of the toy gun

Introduction: – A manufacturability analysis was carried out on
trigger of the toy gun. Analysis conducted on the part analysis and its
functionality related to structure properties, surface finish and geometrical
accuracy, the materials used in the trigger, the manufacturing process to
generate the part and estimation on the critical surfaces of the trigger and
how the process are adjusted to cope with them.

Manufacturability
analysis – Individual

                                                                                                         
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