Week Fourteen 'Final Design & Materials'

Final Design Form #

Sketches show that the final design has been finalised. The bottom left hand sketch shows a wrist band, this will now be incorporated into the final design. The image is to represent possible add-ons that may be incorporated in future development of a product range.

Solid works model

The solid works model was created by Kiu as he wanted to generate the model well in advance to be printed at the workshop facilities. In regards to the Final models they will be posted in my next weeks blog as this is when they will be 3D printed. The final Solid works model however turned out great! The Design clearly came across as a gun designed ergonomically for the hand and inspired by the plasma pistol.

These where the final form models which where used in our video to explain the contextual and environment interactions with the product. The video can be viewed via this link

https://drive.google.com/?tab=wo&authuser=0#folders/0Bwskb6a0NubdN0FBYVdMdXJQS2s

Materials

The two materials making the housing for our product are Silicone rubber and Polypropylene.

Polypropylene

Polypropylene is a light density (.91-.92 gm/cm3) thermoplastic. It can be stabilized to enhance prolonged use at elevated temperatures, prolonged life in exposure to ultra-violet light and improved flame retardancy.

Polypropylene fabricates with standard woodworking tooling. It can be butt welded, extrusion welded, fusion welded, and spun welded. It can be machined with ordinary wood or metalworking equipment.
Polypropylene offers a good balance of thermal, chemical and electrical properties with moderate strength. It is a good strength to weight ratio. Because it has such a hard, high gloss surface, polypropylene is ideally suited to environments where there is concern for bacteria build up or build up that can interfere with flow.
Polypropylene has good insulating properties, but dielectric strength shows some degree of change at elevated temperatures. Excellent track, arc resistance and dielectric strength allows polypropylene to be used extensively in electrical applications. It can also be modified to be conductive or antistatic. (COPE PLASTICS, 2008)

Why Polypropylene was chosen

As mentioned polypropylene is a great plastic in terms of its strength to weight ratio, the plastic has a high resistance to breakdown and is perfect for housing electrical components. The defining element as to why this was chosen was the aesthetic polypropylene gives. The transparent visual will be perfect for the glow aesthetic within the products communication of the reload on the top of the Steam Tagger.

Silicone Rubber - Advantages/Characteristics  

 

Economic Use

As the most stable polymer available, silicones offer superior reliability, excellent service life and reduced production costs.  The compounds are simple to mix and do not contain flammable or toxic solvents.  Silicone will cure at room temperature, eliminating heating costs associated with oven-cured polymers.  Cure rates can be adjusted, allowing flexibility in production line use.

Versatile Application

Silicones offer excellent release characteristics, ideal for casting epoxy, polyester, polyurethane and other plastic parts.  The compounds will bond to primed surfaces.  Silicone rubbers cure in deep sections as needed for electrical potting and encapsulating, casting rubber parts and flexible prototype tooling.

Environmental Resistance

Silicone polymers offer the best long term resistance to environmental extremes.  .   Silicones have a low flammability rating ...they do not support or promote flame and do not produce toxic combustion by-products.

Physiologically Inert

Used extensively in medical applications, silicone rubbers have caused no adverse health reactions in clinical testing or field application.

Chemical Resistance

Silicones resist acids, bases, solvents, chemicals, oils and water. (Silicones, nd)

 

Why Silicone Rubber was chosen

The positives mentioned above are much alike the criteria used for the Polypropylene, durability and chemical resistance where heavily emphasised as the product will be held in the hand. The silicone rubber was selected as a material for the stress release element incorporated into the design. The rubber acts much alike a stress ball due to the high anxiety of the user.