How to select grease for key components of industrial robots

October 14, 2022

In recent years, industrial robot technology has developed rapidly and has been widely used in industrial production and people's daily life. Good lubrication is one of the key factors for the normal operation of industrial robots. Among the grease products used by industrial robots, the proportion of fully synthetic and semi-synthetic grease products has gradually increased. With the increasing emphasis on lubrication work by the production and use enterprises of industrial robots, fully synthetic and semi-synthetic grease products with better performance, longer service life and longer maintenance period are more and more popular.

Industrial Robot Classification
According to the geometric structure and motion form of industrial robots, industrial robots can be divided into Cartesian coordinate robots, cylindrical/spherical coordinate robots and articulated robots.

Cartesian coordinate robot

Cylindrical spherical coordinate robot

Cylindrical/spherical coordinate robot

Articulated robot

Usually, the service period of a robot is 10 to 20 years, which is closely related to the lubrication and maintenance of the robot. Selecting appropriate lubricating grease and doing relevant daily maintenance can ensure and prolong the service life of industrial robots.

1. Selection of drive motor bearing grease
The drive motor is the power source of the robot. At present, most industrial robots use electric servo drive systems. The grease used for servo motor bearings is generally lithium-based or polyurea grease of fully Synthetic Base Oil type. The base oils used for lubricating greases are mostly PAO and polyol ester oils. These two base oils have excellent lubricating properties and low-temperature flow properties, and can effectively lubricate and protect bearings in harsh working environments. Require.

Servo motor bearing specific requirements for grease
✅Mechanical stability, no grease loss after long-term use
✅Oxidative stability, no obvious oxidative deterioration occurs when the grease is used for a long time
✅Abrasion reduction and fretting resistance
✅Low temperature, can still start and run normally at lower temperature
✅Vibration damping, can reduce the noise generated when the bearing is running
✅Anti-rust, can effectively avoid bearing rust in humid environment

2. Selection of reducer grease
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The reducer is the power transmission mechanism of the industrial robot and one of the core components of the robot. It is located between the servo motor and the actuator of the robot. It uses its own speed converter to decelerate the number of revolutions of the servo motor to the required number of revolutions. and get a larger torque. Because the operating temperature is generally not high, most industrial robot reducer greases use lithium-based thickeners. In order to ensure a longer oil change interval, the Base Oil is generally selected from synthetic base oil or semi-synthetic base oil.

The specific requirements of the reducer for grease
✅Oxidative stability, no obvious oxidative deterioration occurs when the grease is used for a long time
✅Anti-fretting wear, the robot reducer needs to be started and stopped frequently and reciprocates frequently, which is prone to fretting wear. For this reason, the grease is required to have excellent anti-fretting wear performance
✅Extreme pressure and anti-wear performance, the torque on the reducer is large, and it is easy to cause wear, so the grease is required to have excellent extreme pressure and anti-wear performance
✅Low temperature, can still start and run normally at lower temperature

3. Selection of guide rail and ball screw grease
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For a Cartesian coordinate industrial robot, or when an industrial robot needs a long stroke in a certain direction, a guide rail and a ball screw are generally used to realize the movement of the robot. Depending on the operating conditions, the formulations of the robot rail and ball screw grease are quite different. The thickener used in the robot guide rail and ball screw grease is generally lithium-based or polyurea, and the base oil can be mineral oil or synthetic oil.

Specific Grease Requirements for Guideways and Ball Screws
✅ Lubricity and adhesion, can form a stable oil film on the surface of the guide rail and ball screw
✅Mechanical stability, no obvious softening loss after long-term use
✅Oxidative stability, which can effectively prevent the oxidative deterioration of grease
✅Appropriate viscosity and good low temperature, the equipment can start and run normally at lower temperatures
✅Anti-rust, can effectively prevent the rust of guide rails and ball screws
✅ Greases used in high temperature environments must have good high temperature resistance to prevent the grease from softening and losing at high temperatures.

Author:

Mr. James

E-mail:

sales@cn-lubricantadditive.com

Phone/WhatsApp:

+86 13783582233