Capable of lights-out operation, robots are virtual workhorses designed to remain in service for at least 10 to 15 years, and in many cases beyond. However, to maintain their top performance potential, manufacturers may want to consider adopting a DIY approach to routine robot maintenance. Not only will this help prevent major malfunctions that can cause unnecessary downtime and unexpected costs, but also, ROI is maximized.
To achieve the best outcome for any task, clear-cut guidelines should be followed. Robot maintenance is no different. From designating a leader to spearhead the planning, budgeting and execution of the maintenance plan to following best practices consistent with current manufacturing regulations, companies need to have a clear plan with achievable action steps for the work to be completed. Along with this, communication is key. Each worker responsible for a task should be provided step-by-step instructions on how to perform the required maintenance duties, and the expected outcomes should also be relayed.
Most importantly, a smart inventory strategy should be followed. Working closely with the robot OEM or appropriate supplier well in advance can help solidify a strategic maintenance plan, as well as help determine what parts should be kept on hand in the event they are needed. Collecting data from an extensive device monitoring tool and talking to internal experts in charge of key equipment can also go a long way toward deciding what items to keep in stock. If parts are not going to be stored onsite, decision makers should be mindful of lead times and order any necessary items in advance.
Basic troubleshooting checks
Typically measured by its overall performance where repeatability, part quality and path accuracy are concerned, robot “health” is also determined by its internal functionality, as well as subsequent controller and pendant performance. Regarding internal functionality, following a comprehensive and strict maintenance schedule is suggested. While much of the information needed can be found in the instruction manual for the specific model in question, it never hurts to gain clarification from the robot OEM or system integrator when in doubt. That said, common inquiries for robot life-cycle management are often centered around these topics:
Filter cleaning. Like a home furnace, consistent air filter replacement on the robot controller is essential. This filter should be replaced annually at a minimum, which goes a long way toward maintaining top equipment performance.
Cable management. Frequent inspection of cables and rerouting, when necessary, is highly recommended, as they can costs thousands of dollars to repair. Cables should be free from rubbing against the outside of the robot arm, and base cables should be clear from human interaction or heavily placed objects. Any damage increases the risk for an electrical short that has the potential to take out a motor or circuit board.
Grease analysis. This is one of the most common maintenance tests to monitor the condition of the gear reducers. This procedure checks the level of iron in the grease for each robot axis. While minimal buildup over time is normal, a spike in iron content in one or more axes can indicate a potential problem with the drive. Intervals for this preventive maintenance step are based on servo hours (approximately every 6,000) and all specs (e.g., type of grease to be used) and procedures to be followed can be found in the robot manual.
Note that it is vital to remove exhaust plugs before grease replenishment as this prevents the robot arm seals from blowout. Other gear reducer checks that can be used, when needed, include torque analysis, manual tests and backlash testing.
Teach pendant check. Often overlooked, frequently inspecting the teach pendant for damage is advised. Cracks can allow dirt and other debris to get inside, risking damage to internal parts and potential downtime due to replacement. To help prevent serious issues, teach pendant covers should always be used and replaced, as needed.
Other items. Robot gaskets, as well as the controller fan unit and CPU battery, should be replaced every three years. Gear oil should be replaced every other year and items such as connectors and seals should be replaced when necessary.
Life-cycle management
Previously mentioned, integrated device monitoring platforms that can track, accumulate and visually deliver equipment data (e.g., robots, spot guns, etc.) in real time can prove useful in predictive and preventive maintenance situations. Proven edge server solutions are ideal as they use an OPC-UA interface that enables an integrated, intelligent and innovative approach to data analytics.
Likewise, hands-on maintenance training for any team members responsible for servicing the robot is suggested. Comprehensive training that adheres to American National Standards Institute (ANSI) and International Accreditors for Continuing Education and Training (IACET) standards is best. This training is typically offered through the robot OEM.
Web-based robot maintenance platforms with easy-to-use graphical interfaces can also help technicians quickly troubleshoot and tackle repairs with minimal training and zero guesswork. Extremely convenient, troubleshooting tools like this offer an interactive approach, and they provide step-by-step instructions tailored to specific robot and controller models.
Real-world results
The growing demand for mass product customization requires more accuracy, capacity, efficiency and quality than ever, prompting manufacturers to sustain operational equipment efficiency for a competitive edge. A detailed DIY maintenance program that suits a company’s specific goals along with the integration of life-cycle management tools can help achieve this. If a comprehensive maintenance check of the robotic system fails to reveal a cause for an ongoing issue, manufacturers should look at the bigger picture – as the part, fixture or programming may be at fault.
As always, fostering a solid working relationship with the robot OEM or system integrator is advised, especially in the event quick assistance is needed. Companies that do not have the workforce capacity or know-how to deal with maintenance issues on their own should opt for an annual service plan through the robot OEM or system integrator. Regardless of the maintenance plan put in place, any steps taken to bolster robot performance will help ensure long-term success.
