Choosing the right gear material is the key to achieving the best performance and lifespan of gear motors. This article delves into the key factors that influence gearboxes, including mechanical properties, cost considerations, and specific application requirements, providing valuable insights for engineers and purchasers. The price of the gear motor is determined by the gearbox material, manufacturing process, and DC motor type, and the gear material is a key factor affecting the unit cost.

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How Does The Material of Gearbox Affect the Gear Motor?

The performance of the gear reducer is affected by many factors, of which the choice of material is a very critical factor. Different materials have different characteristics and advantages, and the correct material can improve the performance and lifetime of the gear reducer.

What are the main factors that affect the performance of the gear reducer?

The main factors include transmission ratio, gear size, mesh angle, number of teeth, gear hardness, and material. The material is one of the most important factors in the gear reducer, which directly affects the strength, hardness, wear resistance, corrosion resistance, and lifetime of the gear reducer.

The common gear reducer materials and their characteristics

The common materials for gear reducers include carbon steel, alloy steel, cast iron, stainless steel, plastic, and so on. Each material has its characteristics and suitable applications.

Carbon steel: it has high strength and hardness, is low cost, suitable for general medium and low-speed gear reducers.

Alloy steel: It has higher strength and hardness, better wear and corrosion resistance, but is more expensive. Suitable for high load, high speed, or high-precision gear reducer.

Cast iron: It has good shock absorption and noise reduction effect, a moderate price, suitable for low-speed, heavy-load, high-precision gear reducers.

Stainless steel: with excellent corrosion resistance, suitable for the reducer working in wet and corrosive environments.

Copper: It has a certain toughness and noise reduction effect. Plastic: It has good self-lubrication and noise reduction effect, low cost, suitable for low load, low precision gear reducer.

How select the right material to improve the performance of the gear reducer?

Selecting suitable materials can improve the gear reducer’s performance and economic benefits. When selecting materials, various factors should be considered comprehensively, including conditions of use, working environment, required performance indicators, manufacturing costs, and maintenance costs.

In general, the working conditions and requirements should be determined first, and then the appropriate materials should be selected according to the needs. For example, the gear reducer with high load, high speed, and high precision requirements can choose alloy steel or other high-strength and high-hardness materials, while the gear reducer with low load and low precision requirements can choose carbon steel or plastic and other materials. In addition, factors such as manufacturing costs and maintenance expenses need to be considered to ensure that the material selection does not add too much manufacturing costs and maintenance expenses.

Ultra-high precision: Precision level:2-3. Gears for c, high-speed gears, or gears requiring special safety and reliability under heavy loads need to be manufactured using special machining methods.

High precision: Precision level:4-5. It is mainly used for turbine gears, aviation gears, high-precision transmission chains, and industrial gears working under certain dangerous conditions. They need grinding.

High precision: Precision level:6-7. It is mainly used for medium-speed industrial gears and vehicle gears that require safe and reliable operation. Generally use grinding or hobbing technology processing, or with high-precision gear hobbing machine processing.

Medium precision: Precision level:8-9. Gears for general transport equipment and low-speed gears for the motor industry. It is usually processed using hobbing, hobbing or shaving techniques.

Low precision: Grade 10-11. For low-speed power transmission gear. Manufactured using general hobbing or hobbing techniques, or machined on relatively old machine tools with lower operating requirements.

Low precision: Precision level:12. Used for some unimportant low-speed gear, low hardness power gear, accessory gear, and toy gear. Generally cast gears or small forged gears.

The precision level of the general gear is 7, and the accuracy level of the precision gear is 5-6, and the high-frequency quenching of the tooth surface is often required in the heat treatment.

Introduction 4 kinds of gear processing process

The different materials have different processing processes. Several different gear machining processes are introduced here:

a. Mechanical processing: Higher precision

Mechanical processing gears are manufactured by shaping and shaping raw materials into the desired gear shape and size through processes such as cutting and grinding.

The advantage of mechanical processing

Machined gears offer powerful versatility as they can be applied to a variety of raw materials, making them suitable for a wide range of applications. They have strong customization capabilities that allow gear shapes and sizes to suit customer requirements, providing greater flexibility. They are suitable for products with high torque density and high lifespan requirements. Mechanical processing gears are superior to powder metallurgy gear in precision, gear root safety factor, tooth surface safety factor, wear safety factor, and so on. Therefore, they are suitable for medical devices, military, and aerospace, among other fields.

One of our customers used CNC machining gears on one of their medical devices. This 16mm planetary gear motor meets customer requirements for high precision, high torque, low noise, and long lifetime.

The disadvantages of CNC machining: limited capacity and high price.

CNC machining has limitations in production capacity and is often more expensive. In addition, on the market, reduction gears used in applications such as N20 gear motor, N30 gear motor, 12 Volt 030 gear reduction motor, and 050 motors have been automated for production. Because stainless steel 416 has good performance, high durability, and low cost, stainless steel 416 is generally used. There is a great demand for these gears in the market.

b. Powder metallurgy gear: It is a high-performance, high-efficiency manufacturing method.

Powder metallurgy is a manufacturing forming technique that heats metal powders above the melting point to create shapes with specific properties. Copper-based powder metallurgy is commonly used in motor gears to provide the advantages of metal processing while solving mass production challenges and reducing costs. However, if the helical gear is manufactured, the choice of powder metallurgy as a material will bring difficulties to the processing.

The advantages of powder metallurgy gears

High material utilization rate: powder metallurgy technology makes the material utilization rate reach more than 90%, which greatly reduces the production cost.

High precision: Due to the precise control of temperature and pressure in the powder metallurgy process, the precision of the gear is relatively high, the operation is smooth, and the vibration is small.

Strong ability for complex shapes: The powder metallurgy process can produce gears with complex geometric shapes and functions, which can meet special working needs.

c. The metal injection molding (MIM) process

The metal powder is sintered by an injection molding machine at a high vacuum temperature of 1400 degrees. Metal parts with complex structure, high precision, and mechanical properties close to plate and bar.

The advantages of MIM technology in gear manufacturing:

High precision

MIM technology can produce high-precision gear parts, the size, shape, and surface quality of the complex structure of the gear are very accurate, to improve the performance and service lifetime of the gear to meet the application requirements in different fields.

They are suitable for 6mm, and 8mm metal planetary gear motors.

The only disadvantage of MIM parts is their high unit price.

d. Plastic Injection Molding

Plastic injection molding generally uses POM (Polyformaldehyde), because POM has self-lubricating properties. It should be noted that to prevent the plastic gear from loosening due to thermal expansion at high speed, the 6mm plastic gear motor shaft should be made of knurled or D-shaped. They are only suitable for cheap, suitable for low-load, low-precision gear reducers.

Usually, the economical solution is the gears made of injection-molded engineering plastics such as POM or LCP. To reduce the load on these gears, a small planetary gearbox arrangement is preferred because each gear has more points of engagement.

To learn more, please go to our page on 6mm planetary gear motors.

For gear motors with a diameter of less than 10mm, the metal gears become very expensive.  Through the above analysis, I believe you have understood the reason why the unit price of metal gear motor is higher than that of plastic gear motor.