Sızdırmazlık profillerindeki kalıp şişmesi fenomeninin gerçek üretim koşulları altında ticari bir ekstrüzyon hattında incelenmesi

The weather-strip manufacturers aim to reduce one of their main costs, trial scrap, to be competitive and to have a lower carbon foot. Annual scrap rates of sealing systems are mainly caused by the extrusion dies and process-related issues. Roughly 70% of scraps resulted from the extrusion die fine tunings. We can categorize the defects as flow-related and process-related which are caused by the extrusion die again. Dead zones, over pressurizing a location in fluid channels, miss calculating an exit, etc. are flow-related defects. Over-curing, under-curing, heating issues, etc. are process-related defects. Die-swelling-related defects can be categorized as both flow-related and process-related. Many works in the literature on the die-swelling phenomenon have basically approached the phenomenon without implementing complex extrusion process parameters which are influencing even the simplest extrusion products. Even the smaller extrusion speed arrangements drastically change the behavior of die-swelling outputs. To reach the high number of needs of the global market, weather-strips are produced by the extrusion method. Extrusion is a continuous production method in which raw material is fed on the extruder side and the extrudate is pulled downstream of the extruder. Both extruder rate and puller speed affect the die-swelling ratios. Die-swelling can be positive or negative(shrinkage) at the end of the line after the extrudate is cured. Positive results are caused when the extruder speed dominates over the puller speed and vice versa. The innovative aspect of this thesis, we have developed a measurement method by dividing extruder speed (ES) over puller speed (PS) in order to predict swelling ratios two-dimensionally and directly related to extrusion process conditions. To understand die-swelling we have developed an indicator based on ES/PS value with the help of extrusion process trials. Then a dimensionless Extrudate Speed Number (ESN) established to understand the effects of process conditions on die-swelling. To compare die-swelling values over process conditions we have used dimensionless ESN results instead of ES/PS. Besides the physical effects, the compound type is also important for the swelling ratio. The filler percentage for the rubber compounds has an important role in the die-swelling occurrences. Filler-rich sponge-like compounds have a more swelling tendency than the relatively lower-filled solid compounds. This difference can be observed in pro and post-cured phases.