Excessive machine vibration in one mill, critical equipment failures in another and a need for improved mill operations in a third were producing costs ranging from $200,000 to $1.2 million. Three separate solutions from SKF eliminated problems and costs.

Problems at the first mill

      In the first mill, excessive machine vibration was being experienced from a super calendar stack with vibration worsening when the mill ran at speeds above 1,325 feet per minute.

      This excessive vibration was creating roll damage, costing the mill $500,000 in the last year for replacing ruined rolls. Just as important, the vibration kept the mill from running at its design speed. Also, although the mill had been experiencing these problems for several years the root cause was still unknown. Seeking a solution to this ongoing problem, the mill management went to SKF Reliability Systems for help.

      The mill management saw the problem as:

      •High vibration, especially in the lower part of the stack.

      •Roll barring or flat spots on the paper rolls.

      •Broken rolls, both paper and steam.

      •Failed bearings, predominantly from thrust loading.

      •Reduced operating speed in an effort to reduce failures, leading to reduced production.

 

Solution

      The SKF Reliability Systems solution was developed from a Machine Reliability Assessment process to improve calendar stack reliability. The assessment involved:

      •Listing probable causes for symptoms.

      •Using advanced technologies, like Operating Deflection Shape analysis, to gather multi-parameter data and analyze connections to probable root causes.

      •Making improvement recommendations on roll misalignment.

            •Improving alignment with machine enhancements and precision installation procedures....

 

...Continued in the pages of Twin Plant News, Subscribe Today!