"Materials matter. They are the stuff that constitutes everything around us."
AM technology was originally developed around polymeric materials, waxes and paper laminates. Subsequently there has been introduction of composites, metals and ceramics. CNC machining can be used for soft materials, like medium density fibreboard, machine able forms, machine able waxes and even some polymers (Lipson & Kurman, 2013). Materials have from the beginning of the technology been an important driving force for development. Like traditional manufacturing processes, the initial choice of material was tied to the constraints of the process (Lipson and Kurman, 2013).
Hardness is defined as the resistance of a material to deformation, particularly permanent deformation, indentation, or scratching. Hardness is purely a relative term and should not be confused with wear and abrasion resistance of plastic materials. Since plastic materials vary considerably with respect to hardness, one type of hardness test is not applicable to cover the entire range of hardness properties encountered commonly known as Moh’s scale of hardness, the Rockwell hardness test and the Durometer hardness test (Kutz, 2002). Below a hardness scale of plastics:
In practical the materials that i explore during the course of the year are silver, nylon and resin. As silver being common in both contemporary and commercial jewellery, this dissertation will therefore explore the strengths and weaknesses of both nylon and resin. Nylon/ Polyamide: The generic name for all long-chain fibre-forming polyamides with recurring amide groups. Characteristically polyamides (nylons) are very resistant to wear and abrasion, have good mechanical properties even at elevated temperatures, have low permeability to gases and have good chemical resistance. Advantages such as: Excellent surface finish even when reinforced, Strength, Stiffness and chemical resistance to hydrocarbons. Nylon however has limitations such as high water absorption and poor chemical resistance to strong acids and bases. Nylon has high self-bonding properties that prevent the layers from de-laminating when put under tension. It does not have warping issues, so no heated print bed or cooling fans are needed. Nylon has the ability to be created in any colour as it is very easy to dye. Nylon is also known to be inexpensive as well as most grades of nylon do not emit fumes (Spadaro, 2013).
According to Nerginer (2012) the advantages of resin based-based 3D printers have also presented themselves as follows: For most applications the Ultra Violet or visible light curing method is much faster and far superior to any other rapid modelling methods, it has a better resolution then most 3D materials, it uses minimal moving parts, and prototypes made by this system are strong enough to be machined and can be used as master patterns for injection moulding , thermoforming, blow moulding, and various metal casting processes. Along with the above resin based 3D printers also propose for disadvantages such as although the process can produce a wide variety of shapes, it is often very expensive. The cost of photo-curable resin ranges from $80 to $210 per litre, and the cost of the machines are higher than popular low-level printers. However cost will be reduced as more people adopt the resin-based 3D printing system.
