• Industries

Six Years On, Zero Bearing Replacements: How COC Bearings Transformed a Cement Plant’s Limestone Conveyor

A case study from a cement plant in Japan shows how switching to COC CX2SN20-090L bearings cut operating temperatures by more than 60% and eliminated a recurring maintenance cycle that had been costing the plant a bearing replacement every three months.

For maintenance teams at a cement plant in Japan, the drive shaft of a limestone conveyor had become a predictable source of downtime. Every three months, like clockwork, the bearing units needed replacing. More than six years after that cycle was broken, the plant has yet to replace a single bearing.

The Problem

The conveyor in question runs at 1,480 RPM, typically operating three to four times a week for around eight hours per session — a demanding but not unusual duty cycle for limestone handling in cement production.

Before COC bearings were introduced, the units installed on the drive shaft were running at approximately 70°C. That figure mattered because the plant’s internal safety standard requires bearing temperature to stay within 40°C of ambient — a threshold these bearings were consistently pushing against. To stay within that limit, the maintenance team was replacing the bearings roughly every three months. On top of the replacement cycle, the application was also experiencing repeated shutdowns under heavy load, disrupting production and adding further strain on the maintenance schedule.

	Previous bearings	COC CX2SN20-090L
Operating temperature	~70°C (158°F)	~26°C (79°F)
Replacement interval	Every ~3 months	Zero replacements in 6+ years
Load-related shutdowns	Recurring	Eliminated
Speed	1,480 RPM	1,480 RPM
Installed	—	June 2020

The COC Solution

In June 2020, the plant installed two COC CX2SN20-090L units on the conveyor’s drive shaft. The change in operating temperature was immediate and significant: where the previous bearings ran at around 70°C (158°F), the COC units settled at approximately 26°C (79°F) — a drop of roughly 44°C.

That reduction in operating temperature did more than bring the application comfortably within the plant’s safety threshold. The heavy-load shutdowns that had plagued the conveyor stopped occurring entirely, allowing the line to run smoothly through its duty cycles without the interruptions the previous bearings had caused.

More Than Six Years Later

A site inspection carried out in August 2026 — more than six years after installation — found both COC units still operating normally, with no abnormal temperature rise, no unusual noise, and no unplanned shutdowns recorded.

Over that period, routine maintenance has consisted of little more than monthly greasing and temperature monitoring. According to the plant’s maintenance team, both bearings remain in good condition and are expected to continue running.

Runs Cooler, Lasts Longer

The case illustrates a straightforward but often underappreciated point in industrial maintenance: a bearing running dramatically cooler doesn’t just avoid a single failure, it changes the entire maintenance economics of an application. What had been a quarterly replacement task — with associated labour, parts costs, and shutdown risk — became, in this case, a non-event for more than six years running.

For plant operators managing similarly demanding conveyor or drive-shaft applications, the results point to a broader lesson: addressing the root cause of elevated bearing temperature can do more for uptime and total cost of ownership than managing around it.

COC will be exhibiting at bauma CHINA 2026 in Shanghai, November 24–27.

Come visit and see COC bearing solutions in person.