plastic gears

Types of plastic gears

A plastic gear is a mechanical component responsible for the meshing of gear teeth to create motion and transmit power. The plastic gear has the same functions as the metal gear, but it has the following advantages: low noise, self-lubrication, dampening properties, and corrosion resistance. The plastic gear is classified into several types:

• Spur gears: These are classic straight-toothed gears that transfer motion between parallel shafts. They are the most common type of gear found in machinery and equipment. Spur gears provide efficient power transmission and can be manufactured in a variety of plastics.
• Helical gears: These are similar to spur gears, but the teeth are angled rather than straight. This angled shape allows helical gears to provide smoother and quieter operation than spur gears. Helical gears are often used in applications that require high precision and low noise.
• Worm gears: These consist of a screw-like gear called a worm that meshes with a toothed wheel. Worm gears are ideal for applications where large gear reductions are needed or where motion must be transmitted at a right angle. They provide excellent mechanical advantage but may require specific materials and lubrication due to their unique design.
• Bevel gears: These are cone-shaped gears used to transmit motion between intersecting shafts. Bevel gears are suitable for applications that require changes in the direction of power transmission. They come in various plastic materials to meet different needs.

Several factors need to be considered when selecting the right plastic gear for an application. These factors include the type of plastic used, the gear ratio, the load capacity, the operating temperature, and the environmental conditions.

Specification and maintenance of plastic gears

The specifications of plastic gears vary depending on the application. Some of the common specifications include the module, pressure angle, dimensions, and plastic material.

• Module and tooth pitch

These are the gear size specifications. The module is the tooth size and is the most commonly used gear size specification. It is the distance between corresponding points on adjacent teeth in millimeters. The module is a whole number. When the number is large, the gear is larger. Gears with different modules cannot mesh. The tooth pitch is the distance between the centers of two adjacent teeth and half the module. The tooth pitch is the same as the module.

• Pressure angle

It signifies the angle between the tooth profile and the gear’s pitch circle. The most common is 20 degrees and 14.5 degrees. The 20-degree pressure angle is for gears with a module of 1.0 or more. The 14.5-degree pressure angle is for gears with a module of 0.5 or 0.8. The pressure angle is different, and its effect on the gear is different.

• Dimensions

Plastic gears come in various dimensions and sizes. They have a certain outer diameter, pitch diameter, and center hole size. The gear's outer diameter is the distance between the outer edge of the gear. The pitch diameter is the size of the gear teeth. Many plastic gears have a round center hole.

• Plastic Material

Plastic gears are made from a wide range of plastic materials. Each type of plastic material is designed to meet specific industry requirements and gear applications. For example, nylon gears are known for their low coefficient of friction, which provides smooth and quiet operation. They are self-lubricating and resistant to wear and abrasion. Some plastic gears are made of acetal plastic. They are strong and rigid plastic material, which is resistant to moisture, chemicals, and solvents. Acetal plastic gears are ideal for use in harsh environmental conditions. Some plastic gears are made of pom. POM is a strong and durable plastic material that provides high resistance to impact and fatigue. POM plastic gears are suitable for high-speed and high-precision applications.

Proper maintenance of plastic gears enhances performance and prolongs lifespan. The maintenance requirements will depend on the gear's application. For instance, plastic gears used in machinery and equipment must be cleaned and lubricated to ensure smooth operation. Cleaning the gear involves removing any debris, dust, and contaminants that may accumulate on the gear. The gear should be cleaned using a non-abrasive and mild cleanser to avoid damaging the plastic. Then, the gear should be dried thoroughly before reapplying lubricant. Lubrication is essential for reducing friction between the gears and preventing premature wear. Plastic-compatible lubricant should be used. Lubricants that are too thick or thin can cause gear malfunction and wear. In applications where the gear is exposed to extreme temperatures and moisture that may cause degradation, protective coatings are recommended. The coating helps to prevent premature failure and ensure long-lasting performance.

Scenarios of plastic gears

Plastic gears are widely used in various industries and fields, including but not limited to the following scenarios.

• Automotive Industry

In the automotive industry, plastic gears are widely used in various vehicle systems, such as the engine, transmission, power seat adjustment, and HVAC systems. With the development of the automotive industry, the demand for advanced plastic gears with high strength and durability is increasing.

• Robotic Manufacturing

In robotic manufacturing, plastic gears are the key components of industrial robots. They are primarily used in the robot arm drive system, conveyor belt system, and other movement control systems. Plastic gears' light weight and high precision significantly improve the flexibility and efficiency of robotic operations.

• Medical Devices

Plastic gears are widely used in various medical devices, including infusion pumps, ventilators, and surgical robots. These gears play a crucial role in controlling the movement and transmission of medical equipment, ensuring the accuracy and reliability of these devices. Moreover, the biocompatibility of certain plastic gears makes them suitable for use in direct contact with the human body.

• Renewable Energy

In the field of renewable energy, plastic gears are essential components of wind turbines and solar tracking systems. They are used to transfer and adjust the power generated by wind or sunlight. Plastic gears' corrosion resistance and durability make them ideal for use in harsh outdoor environments.

• 3D Printing

3D printing technology is an emerging industry that uses plastic gears in the drive system of 3D printers. These gears control the movement of the print head and build platform, achieving precise positioning and printing. Plastic gears are ideal for 3D printing applications due to their affordability and customization.

• Aerospace and Defense

Plastic gears are used in aerospace and defense industries, including satellites, unmanned aerial vehicles, and missile guidance systems. They are mainly used in light-load transmission and adjustment mechanisms, contributing to reducing the weight of equipment and improving operational efficiency.

How to choose plastic gears

• Application requirements:

Consider the specific demands and requirements of the application. This includes factors such as desired performance, speed, torque, noise levels, and environmental conditions.

• Material selection:

Consider the exact requirements of the plastic gear in the application scenario. For example, if high strength and wear resistance are required, consider nylon or POM. If chemical resistance is required, consider PTFE or PVDF.

• Design and customization:

Some applications may require custom-designed or specialized plastic gears to meet unique specifications. Select a supplier or manufacturer with the expertise to collaborate on design and provide customization services.

• Cost and budget:

It is important to balance performance and cost. Consider the overall cost-effectiveness of plastic gears, including durability, maintenance, and operational efficiency, not just the initial purchase cost.

• Supplier selection:

Choose a reputable supplier with a high-quality product offering and good customer service and technical support. In addition, consider the supplier's delivery capabilities and production scale.

Q&A

Q1: What is the difference between metal and plastic gears?

A1: Metal gears are usually more durable and resistant to high-pressure and high-speed operations. Plastic gears, on the other hand, are preferable for applications that require quietness, corrosion resistance, or self-lubricating properties.

Q2: Are plastic gears as strong as metal?

A2: Although plastic gears are not as strong as metal gears, they are available in a variety of materials that offer varying levels of strength. When selecting plastic gears for a specific application, the load, speed, and operating environment should be considered.

Q3: Is it possible to increase the lifespan of plastic gears?

A3: Ensuring regular maintenance and lubrication of plastic gears can help to increase their lifespan. It is important to use lubricants specifically designed for plastic gears and to avoid excessive loads and speeds that can cause premature wear.

Q4: Can plastic gears be repaired?

A4: In some cases, plastic gears can be repaired by filling in worn or damaged areas with plastic resin or using adhesive bonding techniques. However, in most cases, it is more effective to replace the damaged gear with a new one.