How is Nylon made?

- Oct 11, 2017-

            Nylon, like other plastics, typically starts with the distillation of hydrocarbon fuels into lighter groups called “fractions” some of which are combined with other catalysts to produce plastics (typically via polymerization or polycondensation). Nylon can also be produced from biomass which generally results in a more biodegradable material. The actual process for Nylon production falls into one of two methodologies. The first involves the reaction of monomers with amine (NH2) groups reacting with carboxylic acid (COOH). The second involves the reaction of diamine (a molecule with 2 x NH2 groups) with dicarboxylic acid (a molecule with 2 x COOH groups).

        Nylon for Prototype Development on CNC Machines, 3D Printers, & Injection Molding Machines:

        Nylon can be easily melted into filaments (useful for 3D printing), fibers (useful for fabrics), films (useful for packaging), sheet stock (useful for CNC machine manufacturing). It is also an easily injection moldable material.  Natural nylon stock is most commonly an off-white color and it is also commonly available in white and black. That said, nylon can be dyed into virtually any color. The material is readily available in filament form for 3D printing where it is heated and the melted filament is manufactured into the desired 3D shape.

         When we prototype nylon parts, we CNC machine them. Just recently, we have been prototyping a number of plastic hooks for use with bungee cords. We start with an ABS FDM prototype to confirm size/shape/aesthetics/function. Then we CNC machine the hook in Nylon in order to test strength. The final step is injection molding the production parts.

         With injection molding, nylon is sometimes filled with a certain percentage of glass fibers in order to increase its tensile strength. The percentage of glass is typically between 10% and 40%. The hooks we are injection molding are actually above 40%. The glass fibers do increase strength, but they also impact the way a part fails. With no glass fill, nylon will bend and yield before it breaks. With the addition of the glass fibers (especially at higher percentages), the failure becomes an instantaneous brittle break with very little bending. When nylon has a glass fiber fill it is referred to as, for example, 30% GF Nylon. (GF stands for “glass filled”).