Key Takeaways
- Manufacturing processes are influenced by a large number of parameters that interact with one another.
- The causes of disturbances and scrap are often only indirectly visible in the process data.
- It is not always immediately clear which process parameters are related to a given problem.
Solution with ENLYZE:
Using the ENLYZE platform, the customer was able to perform a comprehensive process data analysis, enabling the investigation of relevant measured variables and parameters from the production line. Through the digital integration of the machine control system and the provision of an analysis dashboard, anomalies in the measured values were identified quickly. In this case, the discovery of a significant deviation in roller speeds led to the identification of the root cause: slip between the rollers exceeding permissible limits.
Results:
By using ENLYZE, slip was identified and eliminated as the cause of the recurring problem of partial rewinding of the adhesive tape. Since the implementation of vacuum technology on the master roller, the defect has not occurred again. Annual material savings amount to approximately EUR 11,000, while total savings from reduced operating costs, personnel effort, and lost contribution margins are significantly higher.
Conclusion:
The ENLYZE platform demonstrated how substantial cost reductions can be achieved through the digitalization of manufacturing processes. However, decisive for success was not only the availability of process data and analysis tools, but also the targeted and expert use of these resources. This example illustrates that digital solutions, combined with deep process understanding and an innovative mindset, play a key role in solving complex manufacturing problems.
Key Takeaways
- Complex manufacturing processes are influenced by a large number of parameters.
- The causes of disturbances and scrap are often only indirectly detectable in process data.
- It is usually not known in advance which process parameters are associated with a problem.
- From this, requirements for modern process analysis tools can be derived:
- Recording and preprocessing of large volumes of historical process data
- Flexible data visualization, adaptable to a wide range of possible use cases
- Provision of suitable tools for targeted and effective data analyses
- With the capabilities of the ENLYZE platform, one of ENLYZE’s customers was able to reduce scrap for one of its product groups by 30%.
About the Customer
In this case study, it is shown how one of ENLYZE’s customers was able to reduce scrap for a specific product group by 30% using the ENLYZE platform and a data-driven approach, thereby achieving significant annual cost savings on a production line that was digitalized with ENLYZE.
The company, based in North Rhine–Westphalia, has been using ENLYZE for approximately one and a half years, is a manufacturer of single- and double-sided adhesive tape solutions. These products are used worldwide by customers across a wide range of industries, including medical technology, automotive, and construction.
If you are interested in an exchange of experiences with the customer, contact can be established contact with the company.
Compact overview: Production of adhesive tape
In simplified terms, the production of adhesive tape consists of the following steps: First, a double-sided siliconized liner is unwound from a roll and coated with a liquid adhesive. The adhesive is then dried, and the resulting adhesive film is subsequently wound onto another roll. To prevent the individual winding layers of the adhesive tape from sticking to each other during winding at the end of the manufacturing process, the siliconized liner is coated with silicone of different release forces, ensuring that the adhesive always adheres more strongly to the side with the higher release force.
Within the production line, the adhesive tape passes over various rollers. If the rollers run at different surface speeds (speed differential / overdrive), the tape can slip on the rollers. Such a speed differential cannot be completely avoided due to process-related constraints and does not negatively affect product quality as long as it remains within the low single-digit percentage range.
Under normal conditions, the so-called master roller is the point with the highest friction between the production line and the adhesive tape. The speed of the master roller therefore defines the production speed.
Problem Description
During the production of thin transfer films at one of ENLYZE’s customer’s plants, a recurring problem arose. When rewinding the adhesive tape after coating, a phenomenon known as partial rewinding occurred in certain sections. This refers to undesired detachment of the adhesive tape from the liner material, resulting in damage to the adhesive tape. The repeated occurrence of this production defect led to scrap of approximately 11,000 meters per year. In addition, during partial rewinding, the adhesive film partially remains on the reverse side of the liner, contaminating the rewinding unit. This contamination causes machine downtime and requires extensive cleaning efforts.
As the cause of the partial rewinding, the customer was already able to rule out a wide range of potential error sources through extensive investigations, including defects in the siliconization of the liners used or irregularities in the drying of the adhesive. Adjustments to web tension also failed to deliver a lasting improvement.
Why the problem could not be solved without ENLYZE
The production of adhesive tape is a complex manufacturing process that is influenced by a large number of different parameters. This complexity arises not only from the sheer number of process parameters, but also from the fact that many of these parameters are interdependent and interact with one another.
When disturbances occur in such a process, the root causes are often only indirectly reflected in the process parameters. Identifying the causes is further complicated by the fact that it is usually not known in advance which parameters are related to the observed problem.
To identify the cause of the partial rewinding issue in the customer’s production process, it was therefore necessary to be able to analyze as many measured variables and process parameters as possible. The PLC of the production line (commissioned in 2005), which was digitalized using ENLYZE and the ENLYZE edge device (“ENLYZE Spark”), continuously processes approximately 400 actual and setpoint values from various measurements. These parameters therefore constituted the initial pool of potential explanations for the root cause.
However, the challenge was that the PLC and its connected operator terminal did not provide suitable tools for efficiently analyzing these large volumes of data. While the operator terminal offers a user interface for accessing stored process data, it does not support in-depth analyses, nor does it allow users to export the stored data for evaluation with external software tools.
Due to the lack of appropriate analysis tools and the limited availability of usable process data, the adhesive tape manufacturer was unable to resolve the production issue without ENLYZE’s process data analysis. Only the combination of the customer’s expert process knowledge and the analytical tools provided by ENLYZE led to the desired outcome.
How Was the Problem Solved Using ENLYZE?
Since the integration of ENLYZE into the production line, all setpoint and actual values from the machine control system have been processed and made available for targeted analyses in the web-based ENLYZE app. When the fault pattern described above was observed again during the rewinding of a batch from a previous production run, the Head of Development used the analysis dashboard in the ENLYZE app to investigate whether any anomalies could be identified in the control system measurement data during the production period of the defective batch.
When directly comparing some of the many available roller speeds, the Head of Development noticed a discrepancy of approximately 20% between the actual speeds of the laminating station (11 m/min, corresponding to the setpoint value) and the tensioning station (13.6 m/min) during production—significantly higher than would normally be expected.
As displaying all 400 available setpoint and actual values simultaneously on a PLC operator terminal is practically not feasible, the display is usually limited to only a small number of process variables. For this reason, these two roller speeds could not be displayed on the terminal, making the detection of the speed differential impossible without ENLYZE.
Using the ENLYZE app’s analysis dashboard, measured values and parameters from one or multiple production orders can be directly compared over their respective production durations.
The discovery of this significant deviation marked the starting point for conducting manual speed measurements on the individual rollers of the production line. These measurements revealed that the actual speed of the master roller was significantly above its setpoint value.
The root cause of the increased speed was insufficient friction between the master roller and the adhesive tape. In order to maintain the controlled web tension at the master roller at its setpoint despite the reduced friction, the control system increased the speed of the master roller. At the same time, the system controls the line speed at the rewinding unit. Due to this simultaneous control of two process variables, combined with the low friction at the master roller, an impermissibly large speed differential between the rollers inevitably occurred.
The resulting slip caused severe abrasion of the liner’s silicone coating by the structured master roller. This damage, in turn, led to increased adhesion between the reverse side of the liner and the adhesive surface during rewinding, which ultimately caused the observed defect pattern of partial rewinding.
After slip had been identified as the root cause, it was eliminated by activating a vacuum system at the master roller. The vacuum now provides increased contact pressure at this point and, consequently, higher friction.
What Savings Were Achieved by Resolving the Problem?
Since the vacuum system was activated at the master roller, the defect pattern of partial rewinding has no longer occurred during the production of thin transfer tapes. As a result, with the support of the ENLYZE platform, the customer was able to eliminate all costs that would otherwise have continued to arise in connection with this defect had the root cause not been addressed.
The material cost savings alone amount to approximately EUR 11,000 per year since the implementation of this measure. Total cost savings are significantly higher, as operating costs of the production line, personnel expenses, and lost contribution margins incurred during scrap production must also be taken into account.
Text taken over from the original – ENLYZE
