Challenge/Solution Case Study: Resolving Ongoing Equipment Failure in Chill Rolls through Root Cause Analysis

Nestor Rentas Challenge/Solution Case Studies

Result

EFI Group’s timely and cost-effective solution to ongoing equipment failure enabled the client to engage the OEM with specific evidence, as well as take action to prevent recurrence of this failure.

Challenge

The client was faced with the failure of two chill (cooling) rolls on one of their printing presses. The on-site engineer was not able to devote the attention necessary to reach a final resolution, and the OEM was not responsive to our client’s requests for resolution. The client asked EFI Group to identify the cause of the roll failure so that they could engage in substantive discussions with the OEM. EFI Group was also tasked with developing recommendations for specific actions to prevent recurrence.

Solution

EFI Group was provided with the failed parts for use in evaluation and subsequent laboratory analysis. After inspection, EFI Group embarked on a Root Cause Analysis effort (using Fault Tree techniques) to identify potential failure modes. This approach was chosen as it allows for an organized approach to understanding the failure, guides the team to the most likely causes and uncovers a path for effective investigation.

The fault tree analysis showed that the most likely cause was corrosion of a specific component, resulting in the cooling water leaking from the roll.

EFI Group engaged the supplier of the cooling water treatment chemicals, performed testing in the supplier’s laboratory and collaborated with their experts. This was a cost-effective method of obtaining outside experts at limited cost. As a result of this work, EFI Group concluded that the corrosion was galvanic in nature.

Based on laboratory results of the cooling water, a metallurgical evaluation of the failed parts and an understanding of the process variables, EFI Group was able to assist the client in establishing both short- and long-term actions to resolve the problem.

Deliverables

  • Fault tree analysis.
  • Laboratory analysis.
  • Metallurgical report.
  • Specific methods to modify the roll system to prevent galvanic corrosion.
  • Recommended action plan to guide the client through the complete resolution of the failure.

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