The reason that they are the more cost effective gear is that nylon gears are far more economical to produce that a metal gear, which in turn results in a lower cost for the customer. In addition to the initial cost savings, nylon gears also have to lubricated far less than a metal gear might require, meaning further savings to the customer long term.
However, in order to ensure that a nylon gear is the right investment for your application we encourage you to seek out a trusted and experience nylon gear manufacturer and discuss your requirements with them before making a purchase. Before manufacturing a nylon gear, a manufacturer must consider a number of factors, perhaps the most important factor being the load that the nylon gear must be able to withstand. If the load is too much, a nylon gear is far more likely to break than a metal gear counterpart.
Nylon gears have more advantages than just being cheaper than the sturdier metal gears, nylon gears also operate at a much lower noise level. This makes them ideal for the applications we discussed earlier in an office setting. Often times these machines are made from similar materials which means that nylon gears are a must as a metal gear would eventually grind away at the plastic tracks they must operate on. On top of all of these, nylon gears also offer an advantage when it comes to maintenance as they absorb dirt and other particles rather than grinding them down, as frequent grinding can cause damage over time to a metal gear.
So if you are unsure if a Nylon gear is right for your application or you need a custom built gear, consult a knowledgeable, trusted and experienced nylon gear manufacturer in order to receive the right solution for your unique application.