When a paper machine suddenly began manufacturing products with excessive moisture variations, ABB was able to quickly detect the cause and help the mill improve productivity and increase production.
Increase in moisture variations
A Scandinavian paper mill relies on ABB products and services to keep its product quality and runnability high. When company personnel discovered that moisture variations had suddenly increased in the paper produced by the mill’s new machine, they turned to ABB to discover why. With the help of ABB Advanced Services, the mill was able to find the root cause of the variation problem. By identifying the source of the moisture variation increases, ABB helped the mill get production back on track by significantly decreasing product rejects, improving runnability, and reducing costs.
Challenges:
- Identify source of unexpected moisture variations
- Get production back on track
- Maintain high paper quality
- Reduce product rejects
- Improve runnability
Identify and resolve issues
ABB provided the Scandinavian paper mill with the Advanced Services needed to correctly diagnose the moisture variation problem that was negatively impacting production. By investing in ABB Service, the mill was able to draw on the experience and specialized knowledge of an ABB engineer who correctly identified the problem source using Variance Partition Analysis (VPA).
To provide customers with continuous improvement for automation and processes, ABB uses a systematic approach to problem-solving and proactive service. ABB’s strategy helps minimize problems while increasing return on investment.
ABB identifies the source of issues that interfere with performance in automation and processes. ABB also provides recommendations to resolve issues quickly, and prioritizes them based on the actions that can deliver the greatest economic return.
At the Scandinavian paper mill, moisture variations decreased significantly after a new ABB System QCS 800xA was installed to replace the previous ABB 1180M System. However, seven months after the System 800xA was in place, moisture variations suddenly increased. Puzzled by this unexpected and unwanted turnaround, mill managers asked ABB to try to determine the cause so it could be corrected.
An ABB engineer evaluated the paper machine control tuning, noted the extent of the moisture variations, and then went one step further to identify the cause. The ABB engineer knew that production data collected at the reel contained extremely valuable information on moisture variations for those who understand how to analyze it. The engineer had the expertise, and he used VPA to troubleshoot the root cause behind the elevated variations. VPA provides an overview of process variances, grouping them according to grade, time periods and/or weight range, and then analyzing each area.
The ABB engineer found that tuning parameters had been changed by a consultant around the time that the moisture variation problems began to increase. He used VPA to analyze nine months of reel report production data. The engineer focused on machine-direction long-term variability (MDL), machine-direction short-term variability (MDS) and cross-direction variability (CD). He also noted variability increases in the three weight groups defined by the VPA data.
By using VPA, the ABB engineer concluded that disturbances in the machine direction were causing the largest moisture variations.
Results
After the ABB engineer correctly identified the source of the moisture variation problem, the mill had the information needed to correct it. With the adjustments made, the mill was able to get production back on track and reduce costs by lowering product rejects and improving runnability.
Remote-enabled Variance Partition Analysis
Variance Partition Analysis is an important and popular service delivered by ABB Advanced Services experts. Due to high customer demand for this and other ABB Advanced Services, ABB now offers remote facilitation of many Advanced Services through the ServicePort Service Delivery Platform.
ServicePort is a secure, remote-enabled platform that automatically gathers and analyzes data from customer control systems to expedite the identification, categorization and prioritization of issues that will improve equipment and process performance. Many Advanced Services for Quality Control Systems are facilitated through ServicePort, including:
- Control Utilization
- Product Transitions
- Sensor Stability
- Variance Partition Analysis
These ServicePort-enabled Advanced Services analyze specific Key Performance Indicators (KPIs) to accelerate problem-solving. For example, the VPA service examines reel report information for each grade produced to monitor total variation, cross-direction variation and machine-direction variation against industry standards. Through continuous, automatic monitoring and analysis of these KPIs, customer and ABB personnel can be informed and alerted to KPIs exceeding pre-set thresholds, so actions can be taken immediately to improve QCS and process performance.
Other Advanced Services powered by ServicePort include: