Plastic gears are a popular choice for industrial applications. They are lightweight, non-rusting and quiet. They are also cost-effective. They can be manufactured using the molding process and CNC machining.
Most experts agree that the best way to reduce wear is by keeping contact ratios above one. To do this, molded teeth have to be designed with careful consideration.
Strength
Plastic gears can be manufactured to a high level of accuracy, especially when injection molded. A tooth-to-tooth composite error of 0.075 – 0.125 mm is easily achievable with proper design, tooling and quality control.
Popular plastic materials include acetal and nylon resins. They vary in physical and mechanical properties such as strength, rigidity, dimensional stability, fabrication requirements and moisture absorption. Standardized tabular data is available from various manufacturers’ catalogs.
A key benefit of plastic gears is that they can be molded into shapes not possible in metal, and this can reduce drive size and cost. They also resist shrinkage, temperature and chemical exposure well. This makes them a good choice for industrial settings where equipment is subject to constant, heavy load. They are easy to lubricate with a hard, non-polar oil.
Durability
Plastic gears can be made to high accuracy, especially when injection molded. Injection molded gears with a total composite error of less than 0.075 – 0.125 mm and a corresponding tooth-to-tooth composite error of 0.025 – 0.050 mm can easily be achieved with good mold design, quality control and filled materials.
Moulded plastic gears have long provided alternatives to metal gears in lightly loaded applications. However, a lack of polymer-specific calculations and material data sheets that explain how the resins respond to temperature, chemicals and moisture has prevented them from reaching their full potential.
Due to their low levels of density, plastics don’t resonate as much as harder materials such as metal would and are often used in factories and industries to help make work spaces quieter. In addition, they are also self-lubricating.
Lightweight
Plastic gears are often used in drone technology to drive the wings. They are lightweight and help reduce noise vibrations. They are also self-lubricating and do not require lubrication.
Engineers are experimenting with different polymer formulations to find optimal combinations for specific applications. Some popular plastics include acetal resins (POM), nylon resins, and TPEE. These materials are easy to injection mold with good dimensional stability, strength, wear resistance and corrosion-resistance properties. However, their physical and mechanical properties differ with varying temperatures, fabrication conditions and moisture absorption.
While injection molding provides good initial accuracy, CNC machining can provide lasting precision within.005 inches of your design specifications. However, machining is more expensive than injection molding. It is important to optimize the structure of the plastic gear so it can withstand the desired loads.
Environmentally friendly
Plastic gears have started to displace metal ones in many applications. They are quiet, inexpensive and easy to mold. They are used in food production machines, consumer electronics and chemical equipment. They also have many positive attributes: they don’t rust, can operate without lubrication and can accommodate more complex geometries than metal gears.
However, they are prone to dimensional creep and have lower strength and modulus than metals. The creep is accelerated by temperature and the operating load. It is important to take this into account during design.
Injection-molded gears require good material selection to avoid shrinkage. Various polymer resins have different shrink characteristics, coefficients of thermal expansion and moisture absorption rates. It is essential to choose the right resin for the intended application.
Economical
Plastic gears have a wide range of applications. They can be used in automobiles, drones, medical equipment and more. They are more cost effective than metal gears, run lubrication free, and can be easily made to be chemical resistant. They also withstand high temperatures and vibrations.
The key to using plastic gears is proper design. This requires a thorough understanding of the different characteristics of the gear materials being used. In addition, the gears must be properly sized for the load they will carry. This should be done by taking into account the stress concentration in corners and the reduction in material flow where walls meet.
Properly sized plastic gears achieve higher levels of accuracy than their machined counterparts. These features help to save money and reduce mechanical failures.