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Statistical Process Control at the Compound plant of DSM Engineering Plastics B.V. Emmen A Theoretical and Practical Feasibility Study (Public version)

Hoek, R.E. van den (2008) Statistical Process Control at the Compound plant of DSM Engineering Plastics B.V. Emmen A Theoretical and Practical Feasibility Study (Public version).

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Abstract:process variability. The use of SPC can yield a more reproducible production process and thus a more consistent product quality. DSM Engineering Plastics B.V. Emmen has to use SPC in its Compound plant. First, SPC is regarded as a ‘best practice’ by DSM; its use is a corporate requirement. Second, currently, in the Compound plant, the most important process characteristics are not used to control quality; processes are mainly controlled based on outputs and product characteristics. Therefore, the following research problem was posed: To what extent can Statistical Process Control be implemented to change from product quality control to process control in the Compound plant at DSM Engineering Plastics B.V. Emmen? The main conclusion from the research is that, from the viewpoint of the technical conditions of SPC (process knowledge, measuring systems, control charts, decision rules & OCAPs), the extrusion and packaging operations are ready to implement and use SPC as a tool for the continuous monitoring and control of the processes. At drying, the needed technical improvements to become ‘ready for SPC’ are known by DEP Emmen. It can thus be said that the technical conditions for SPC will not be the limiting factor in SPC efforts. It are the organizational conditions (education, commitment, teamwork) that will be problematic; if both operators and staff personnel are fully committed to the efforts and a sense of urgency is present, it should be possible to implement and use SPC in all parts of the Compound plant. In time, when the SPC project is properly started and the organization is prepared for its use, the focus will more and more shift from the organizational aspects to the technical side concerning the implementation and use of sophisticated control tools. It became clear, based upon pilot projects, that the applicability of SPC is not the same for the three production stages at DEP Emmen. At extrusion, for the investigated products, the quality of the process was increased when increasing control of the most important KOP. This eventually resulted in a higher viscosity quality. It seems reasonable to expect that increased process (and as a result increased product) quality can also be achieved for other products, when increasing the level of control of their most important process parameter. These results can be achieved using the current equipment. However, for products of which the most determining KOP is the polymer melt temperature, a system for continuous monitoring of this KOP has to be installed first. The following can be concluded for the future course of the extruder pilot: · The extruder pilot can be successfully continued and upgraded when considering the seven points of attention discussed in section 6.7.1 of the original report; · After a period of successful SPC use on extruder E12, similar SPC concepts can be used for all extruders and eventually, other KOPs can also be added to the SPC efforts. At drying, SPC cannot be successfully applied given the current state of the equipment and the process. The executed pilots did not prove to contribute to the process insight of operators and no possibilities were found to put them in charge. Therefore, it is advised to not continue the SPC pilots at drying at the moment. Furthermore, operator resistance was encountered on a large scale. If the improvements suggested in the memo of Van de Rijt (2007) are applied possible. At packaging, an offline SPC tool can be used to study problem like e.g. contamination. However, the level of education / training and commitment of employees is an inhibiting factor. If the operators can be clearly instructed and perform their SPC duty, offline SPC can be successfully used at packaging. Results can be expected on the long run, after recording on contamination and cleaning procedures for several months. The following advises are given: · Use the ideas of the existing format and integrate the SPC chart into the shift report. The current tool can be used as a ‘transition tool’; · Check on the completeness of the SPC charts on a daily basis, as operators tend to forget their SPC activities. This is of essential importance to keep the efforts going; · The Chief P&S should do the data collection for packaging and ‘pull’ the integration process. The Plant Performance Team of packaging is an ideal team for evaluating the efforts and proposing improvements; · It is advised to use the first month(s) to familiarize operators with the concept, with only line 2 as subject. After that, full-scale SPC can be launched for all lines. The pilot projects make use of relatively simple tools and did not require the operators to continuously monitor the processes. However, it was addressed that a situation of continuous monitoring of the process is desirable. The following points of attention should be taken into account or actions have to be conducted to prepare DEP Emmen for this more sophisticated form of SPC. A more detailed description can be found in table 6.2 of the original report: · SPC efforts should be perceivably beneficial for the operator, which is currently not the case for all production stages. A performance indicator is needed to stimulate commitment and clearly visualize this benefit; · An initial meeting with the SPC project team should be conducted to enhance the fundament of SPC and to create a sense of urgency for the team members; · SPC has to become a part of the regular jobs, e.g. by putting it on the daily agenda of the ‘morning club’; · The team structure has to be altered by creating a difference between control room and field operators and as a consequence a central control room at extrusion is needed; · AspenTech training is needed for all operators and introductory courses in SPC and process control. Currently, there is too much uncertainty to be able to state the benefits that SPC will yield in the specific case of DEP Emmen. It could nevertheless be stated that the decision to introduce SPC in the Compound can be the initiation of large improvements concerning e.g. process stability, equipment and documentation. In time, SPC can probably yield benefits, like scrap and rework reduction. An additional benefit of SPC might be concerned with the workforce. DEP Emmen has a problem with attaining qualified and young personnel: the average age of operators in the plant is 48 years. According to Rungthusanatham (1999), use of SPC is expected to improve the attitudes of employees towards their jobs, motivating them and increasing job satisfaction. As Smith (2001) also states, SPC can let people perceive that they contribute to the quality of the product. Perhaps, the concept of SPC can be used to promote DEP Emmen as a company where employees have freedom and responsibility for the successful continuation of the production processes. SPC can then thus be seen as a ‘marketing instrument’ to attract ambitious personnel. Future research is needed to study 5 this and other beneficial effects that SPC might have for the company. Other future research by DEP Emmen was already mentioned in this report. The extrusion KOPs should be determined and for all essential parameters at all production stages, the operating windows should be evaluated and determined. Within the DSM research department, models on this topic already exist. This study also yields interesting possibilities for future research on SPC in theory. Literature on the ‘implementation of SPC’ merely concentrates on the development of statistical tools like control charts. However, implementation of the methodology SPC in an organization and its implications are hardly discussed in detail. Aspects concerning ‘organizational change’ and ‘SPC’ and were not found in theory. Thus, the organizational aspects of SPC should be studied in more detail in literature as these proved to be critical during this research.
Item Type:Essay (Master)
DSM Engineering Plastics B.V., Emmen
Faculty:BMS: Behavioural, Management and Social Sciences
Subject:85 business administration, organizational science
Programme:Industrial Engineering and Management MSc (60029)
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