Material Selection

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Main Characteristic:

Waterproof
Breathable
Durable
Corrosion resistance
Not Biodegradable
High toughness
Easy to find
Toughness in elevated temperature
Affordable
Easy to fabricate

The way I’m gonna use to select material is by ranking:

The excellent choice(5) to The poor choice(1)

(0) means cannot be consider

Material Selection that I’m doing for is for ;

Main cover structure
The mounting of the XDK

For the main cover I want to use something strong structure just to withstand the outdoor environment and light in weight at the same time.

The mechanical properties that I wish to have for the the main cover is:

Low specific gravity(30%)
Low in water absorption(30%)
High modulus of elasticity(10%)
High Toughness(10%)
High temperature resistance(5%)
Affordable(15%)

The mechanical properties that I wish to have for the mounting of the XDK

Waterproof
Breathable
High Stiffness
High specific strength
High specific weight

Material that I’m choosing for the Main cover Structure

ABS
Acrylic
Expanded PVC
HDPE
Polycarbonate
SentryGlas® Interlayer

The definition for the Requirement

The Primary Selection Table:

The following information is from this website:

https://www.curbellplastics.com/Research-Solutions/Plastic-Properties

From this I like to eliminate the Expanded PVC because of the low mark that it’s get from the above six item. I will eliminating SentryGlas@Interlayer because some missing info that make me suspicious about the material.

So the following item will be undergo the secondary selection that is;

Manufacturing Process:

For the following I have here have a lots of manufacturing process like;

blow moulding
casting
compression moulding
extrusion
fabrication
foaming
injection moulding
rotational moulding
thermoforming of sheet

The one that I can use in my lab to manufacture is

Fabrication( workshop process and CNC)
Extrusion ( 3D printer)
Foaming ( Vacuum Press)

So based on my knowledge I will be considering following aspect before I manufacture my prototype;

Cost and availibitlity(50%)
Chances of Failure(20%)
Availability of the machine(10%)
Time Taken(20%)

The Secondary Selection Table

The price I take from www.monotaro.sg

So from here we will eliminate the ABS and HDPE because of the low mark that the material score in the selection and I will like to choose to Acrylic and Polycarbonate as the suitable material to hold my XDK .

Information about material I select;

Acrylic

Most acrylics are polymers of methyl methacrylate (PMMA). Acrylic can be optically clear or cloudy, as in the case of impact modified acrylics.

ADVANTAGES:

Excellent optical clarity
Excellent weatherability and resistance to sunlight
Rigid, with good impact strength
Excellent dimensional stability and low mould shrinkage
Stretch forming increases bi-axial toughness

DISADVANTAGES AND LIMITATIONS:

Poor solvent resistance; attacked especially by ketones, esters, chlorocarbons and aromatic hydrocarbons, freons
Subject to stress cracking
Combustible
Continuous service temperature limited to about 200 F degrees
Flexible grades unavailable

TYPICAL APPLICATIONS:

Transparent items such as lenses, automotive trim, household items, light fixtures, decorator items signage and point of purchase display .

Taken from:http://www.upcinc.com/resources/materials/acrylic.html

PC (Polycarbonate)

Although some structural variations are possible, the most common system is formed by reaction of bispenol A and phosgene. Its applications are almost always those which take advantage of its unique high impact strength. Recently, additional interest has resulted because of its low flammability. Some studies are currently underway to further improve this characteristic.