The high repeatability of modern industrial robots makes them ideal for precision tasks ranging from welding and painting to assembly and packing. However, if drive components start to wear or overheat, repeatability will quickly deteriorate, degrading both quality and productivity.
Lubrication is the key to the reliable operation of any robotic system. It minimizes friction and wear in the joints and bearings, thereby stopping clearances from growing larger and minimizing heat build-up, which together ensure repeatability is maintained.
The challenge is that robots are complex machines. Their complexity makes lubrication tricky, and that’s why we always recommend starting with your manufacturer’s manual.
Your Manufacturer Knows Best
No one knows your robotic system like the people who built it. While they didn’t manufacture the motion components, they went to great lengths to select the optimal units for your machine. They know how they were assembled and the lubricants they need to obtain the highest performance and durability. This is why the manufacturer’s manuals should always be your primary reference.
The documentation shipped with your robotic system details:
- What needs lubrication
- Where the access points or lubrication fittings are located
- How to perform lubrication (points like warm-up periods and arm positions)
- How often to lubricate
- The specific types of lubricant to use.
This blog is intended as a guide to lubricating your robotic systems; however, as robots vary between manufacturers, always follow the manufacturer’s recommendations.
Joints
In most robotic systems, the joints consist of housings containing gears, bearings, and (often) shafts, which transmit torque. These components are typically lubricated with grease, although some systems may use oil instead.
The lubricants used in robot joints are formulated with very specific viscosities, are stable over wide temperature ranges, and withstand high loads. Robot manufacturers detail the exact type of grease to use in their operating manuals.
Recommendations for greasing frequency typically range from 3,000 to 5,000 hours of running time. In a three-shift operation, this equates to approximately every six months.
Actuators
Actuators generate the rotary motion and torque. Servo motors are the most common type, although stepper motors, direct-drive motors, and even hydraulic motors are used in some systems. Most motors incorporate a reducer or gearbox that lowers speed and increases torque.
Actuators and motors have very specific requirements for the lubricants used. Most use grease with good temperature stability and a particular viscosity. Complicating maintenance, manufacturers often specify different lubricants to those used for the joints.
Bearing Systems
The bearings in robotic motion systems must operate smoothly and with minimal friction. At the same time, they must also minimize runout and vibration. Whether oil- or grease-based, with the latter the most common, bearing lubricants should have low viscosity to minimize friction, along with high load resistance and good thermal stability.
Environment
The environment that the robotic system is placed in has a significant impact on lubrication requirements. Robot manufacturers’ recommendations are geared toward machines placed for light industrial use. With few exceptions, they do not take specific application requirements or unusual operating conditions into account.
Food processing, medical device manufacturing, and some types of electronics production have specific requirements for lubricants. In addition to needing to be rated food and human body-safe, outgassing can be a concern, especially for systems going into vacuum environments.
Other unusual or special conditions can include very high or very low temperatures (as experienced near furnaces or in cold rooms) and high levels of dust or humidity.
Given these complications, whenever there’s any question about the impact of the environment on a robotic system, always review lubrication requirements with the manufacturer.
Get More Tips From DropsA
Given the important role lubricants play in ensuring robot repeatability and life, some operators implement automated lubrication systems rather than relying on human workers. These automated systems range in complexity from straightforward to highly sophisticated.
DropsA helps manufacturers across a wide range of industries optimize equipment performance through effective lubrication. We offer complete lubrication systems, a wide range of lubrication accessories, and advice and support on all aspects of lubrication. Browse our website for more resources, or contact us to speak with one of our experts.
