FEASIBILITY STUDY: THE REDUCTION OF DEFECTIVE HOLES IN PLASTIC FLOORING MANUFACTURING

Abstract: Defects are a common phenomenon related to the manufacturing of products in industries and unavoidable to a full degree. Companies can manage or mitigate risks relating to manufacturing through standardization in processes, methods, and quality checks. The quality requirements ensure that a product lives up to the expectation set by the customer to satisfy their needs. Tarkett needs to be flexible to utilize all its capacity efficiently and at the same time decrease the risk of wastes during manufacturing. Many products are manufactured on the same line with various products tied to different material properties. Tarkett has several defects attracted to their products and improved with time through World Class Manufacturing, which means continuous improvements to decrease the number of losses and derives from Lean production. This thesis investigates and analyzes data related to defective “holes” related to a manufacturing aggregate called 219 at Tarkett’s factory in Ronneby. The purpose is an attempt to learn and suggest possible reasons for the occurrence of holes in their homogeneous PVC-flooring. Methods used to facilitate the investigation are gathered from interviews with personnel, observation, the scientific framework, quality tools, and lab-scale tests linked to chosen products of interest. The framework of this thesis tries to be consistent in how the results are presented and how they tie up between cause and effect. The results show that the main root-cause seems to be packing density between product granulates that increase the risk of hole formation because of porosity, implying air entrapment in the granulate bed during manufacturing through the feeder (dosage process). This granulate bed transports into a double belt press (DBP) that is a closed system and allows for minimum air escape some meters inside the DBP. The problem is either managed through DBP-parameters depending on the product that follows some set standards. But parameters do often require some configuration after the start of a work order of a product because the product needs can vary. The conclusion is that the problem should be mitigated because there seems to be hard to implement a straightforward solution to the root cause. Suggested improvements or assessments are to continue to study granulate size and geometry related to the specific granulate extruder die that determines the granulate design set by various product standards. The dosage process and DBP are of most importance together with the recipe and product specifications.