Generally made from Sustamid, gears are toothed mechanical components to transmit motion and power. Even though plastic gears can be paired, for the best wear life performance pairing with another non-plastic (general steel) gear is ideal.
Eliminating Lubricants – Due to the low friction and lubricity properties of plastics, it is often possible for plastics gears to operate without lubrication.
Dirty & dusty conditions – plastics tend to be more tolerant to non-ideal conditions, such as dirty and dusty conditions, especially when external lubricants are eliminated.
Low Friction – This reduces energy consumption due to lower driving forces, as well as contributing to longer service life.
Reduced wear – particularly when plastics are paired with steel, the wear on both materials are lower than metal-on-metal and plastic-on-plastic.
Sacrificial – plastics can be used a sacrificial component in a drive system, to protect other more expensive parts being damaged in the event of system failures or jams.
Fatigue – Plastics don’t suffer from fatigue in the same way that metals, but materials such as Sustamid can provide additional resistance.
Dotmar has qualified engineers that can provide direct support with plastic gear material selection and recommendations.
Spur or Straight Cut Gear
The most common style of gear used to transmit motion and power between parallel shafts.
Helical Gear
Teeth are cut at an angle, providing smoother operation due to the gradual engagement and disengagement, resulting in less noise and vibration.
Split Bearing
Segments are used to make a full ring gear, generally for larger gears, for ease of manufacture.
Rack & Pinion
Used to transmit rotational motion to linear motion or visa-versa.
Bevel Gear
Can be both straight cut or spiral, and a designed for transmitting motion via non-parallel shafts
Worm Drive
Particularly used when there is a high reduction ratio required.
Material selection is a critical consideration when choosing a plastic for gears, as it directly impacts the ability to transmit power and durability. Here are some key material selection considerations for plastic gears:
Load or Power
Understanding the power or load that needs to be transmitted allows for the appropriate material selection. If there are impact loads, such as hard starts, then this should also be a consideration when selecting a material.
Temperature
The surrounding temperature (opposed to heat generated from friction) for both short- and long-term exposure is important, as materials can withstand higher temperatures for short term periods compared to long term or constant exposure, which in turn affect their load and power capacity. In the case of extreme temperatures, materials such as Sustatron can be considered.
Wear and Abrasion
Abrasive conditions provide different challenges to clean environments, and therefore the material selection, which can include Sustamid.
Lubrication
Consider whether the application allows for regular lubrication or requires dry-running, and if self-lubricating materials.
Regulatory Requirements
Does the application have regulatory requirements such as food contact, drinking water, anti-static or flame retardant. The food industry may also require materials to be metal detectable, x-ray detectable and/or visually detectable by being coloured blue.
Other considerations
At times there may be other considerations such as chemical resistance, dimensional stability and machinability. Also, the tooth profile can influence the material choice, especially for small moduli gears.
To receive latest news and promotions