Case Study – Precision Lubrication with LUBExpert

 

Author: Ken Mitchell, SDT Ultrasound Solutions

Implementation of an ultrasonic lubrication program in a paper mill to acoustically grease bearings right.

The LUBExpert system has allowed the maintenance team to shift away from unreliable calendar-based lubrication to on-condition lubrication with instant feedback to the technician as each bearing is greased.

Dryer section felt rolls – previously greased on a time-based schedule delivering 40 grams of grease every 4 weeks before the ultrasound program was implemented.

Ultrasonic greasing program started; first dryer felt roll greased from an RMS of 14.1 dBμV down to 12.2 dBμV after delivering only 20 grams of grease.

One month later, ultrasound shows the RMS has increased to 17.2 dBμV, again the bearing is greased, this time delivering 25 grams total quantity to reduce to 11.7 dBμV.

Initial greasing saved over lubrication of 20 grams (50%) and a further 15 grams (37.5%) to the first roll.

The Ultranalysis® Suite 3 software provides trending and initial/base line readings each time the bearing is greased.

An absolute alarm at 15 dBμV was added to indicate whether the bearing needs lubrication (over and the

LUBExpert will prompt for greasing, under it will return a message of “lubrication not needed”).

This eliminates the need to inject any grease if the bearing does not require it.

Additionally, we can see process statics to quickly see how often we successfully lubricate this bearing.

In a different dryer section of the machine, a felt roll was visited for the first time with the LUBExpert, one month had passed since last greasing.

Not knowing the lubrication status of this bearing, an initial injection of 10 grams was delivered and the RMS immediately increased to 27.1 dBμV.

On the onset, it would appear that we have done something bad to this bearing by entering an over lubrication status on the LUBExpert.

However, keeping in mind that we were previously delivering 40 grams to this bearing, we have effectively prevented an additional 30 grams of unnecessary grease being injected into this bearing which would have increased friction levels, heat and wear even further.

As more data is taken on this bearing and how it reacts to greasing, alarms can be set up to inform the operator that lubrication is not needed before injecting any grease, that will be the final setup of the program.

Suction pick-up roll bearings failed one month prior due to improper lubrication resulting in a bearing change at a cost of CAD $16 000 (10 865€), 8 hours of labor and loss production time to change the bearing out.

The bearing was checked upon startup using the LUBExpert and it was discovered that it was not greased properly, resulting in an under greased status which could have led to another premature bearing failure.

A total of 99 grams was effectively delivered to the bearing (total capacity is 271 grams) upon startup, indicating that the bearing was initially filled to only 63% of the required capacity.

The bearing initially showed an RMS of 29 dBμV and was reduced to an RMS of 24.5 dBμV through ultrasonic greasing with the LUBExpert.

The Ultranalysis® Suite 3 trend shows us successfully greasing the bearing down to the optimum level as expected.

This initial check prevented what could have been another catastrophic failure during production, increasing reliability on this roll and ensuring proper lubrication, reduced friction and wear on this bearing.

 


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