YRG Inc. Product Setup & Demos
A common misconception in industrial automation is that a new robot runs flawlessly forever without routine care. Neglecting simple preventative maintenance (PM) often leads to mechanical binding, low battery warnings, or lost origin data after two to three years of operation. In this lesson, Tim Wilborne and Chris Elston from YRG Inc. walk through the simple, two-step PM schedule for Yamaha Scara robots.
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Direct-Drive Advantage: Zero Belt Maintenance
Unlike traditional robots that use internal timing belts to drive joints, Yamaha Scara arms feature a direct-drive design across all primary axes:
Direct Drive Construction: Servo motors couple directly to harmonic drive units on the X, Y, and R axes.
Maintenance Benefit: There are no internal drive belts to inspect, tension, adjust, or replace over the life of the machine.
Greasing the Ball Spline and Ball Screw
The primary physical maintenance required on a Yamaha Scara robot is lubricating the vertical shaft every 6 months.
Shaft Lubrication Procedure:
Remove the top robot cover to expose the full length of the central shaft.
Identify the dual-function shaft:
Ball Screw Portion: Controls vertical movement for the Z-axis.
Ball Spline Portion: Controls rotation for the R-axis through the hollow-shaft motor.
Apply a thin layer of AFL gel lubricant along the length of the spline and screw shaft using a gloved finger.
Cycle the Z and R axes to evenly distribute grease across the recirculating ball bearings.
Routing User I/O and Pneumatic Lines
Yamaha Scaras feature integrated internal wiring and air lines to keep end-of-arm tooling connections clean and reliable.
Pre-Routed Lines: User I/O wiring and pneumatic tubing pass internally through the articulated joint covers.
Hollow-Shaft Routing: Connections emerge at the top of the arm and route down through the center of the hollow ball spline shaft directly to the end-of-arm tooling—preventing external cable snagging and flex fatigue.
Controller Battery Replacement Schedule
To prevent losing axis origin points during system power-downs, the RCX340 controller utilizes individual absolute encoder backup batteries.
Battery PM Guidelines:
Replacement Interval: Recommended annually as part of a formal PM schedule (though batteries may last 2–3 years under normal conditions).
Live Replacement Option: To preserve origin calibration, battery replacement can be performed while main controller power remains ON.
Low Battery Diagnostics: The RCX340 firmware monitors battery voltage levels and sets a diagnostic bit when voltage drops. This status bit passes directly to Studio 5000 via Ethernet/IP AOIs to trigger an HMI maintenance warning before position data is lost.
Knowledge Check Quiz
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Why does the Yamaha Scara robot design require no internal timing belt maintenance?
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It utilizes a direct-drive design where the servo motors couple directly to the harmonic drive units on the axes, eliminating belts entirely.
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What is the recommended preventative maintenance interval for greasing the robot's ball spline and ball screw shaft?
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Every 6 months using AFL gel lubricant.
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How can absolute encoder backup batteries be replaced without losing the robot's origin (homing) calibration?
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By replacing the batteries while the main system power to the controller remains turned ON.
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What is the recommended replacement schedule for the absolute encoder batteries in the controller?
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Every 1 year as part of a routine preventative maintenance (PM) schedule.
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How can a technician detect that an encoder backup battery is running low before absolute position data is lost?
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The RCX340 firmware sets an internal low-battery diagnostic bit, which passes through Ethernet/IP fieldbus communication to trigger an alarm in the PLC and HMI.