Aysun Ekinci

The fabrication of thin-walled plastic parts has potential in the automotive industry in terms of sustainability and circular economy targets to decrease any harmful effects on the ecosystems, cost and performance. Injection molding of thin-walled automotive parts is more complex in terms of processing defects compared to traditional plastic parts. Optimization of processing parameters is of critical importance to solving problems and defects in the production of thin-walled parts. In this study, the flow length and weight of thin-walled spiral parts (with wall thicknesses of 0.50, 1.50, 2.70 and 3.00 mm) were investigated with theoretical and experimental studies. The theoretical flow length and weight of the thin-walled spiral parts were determined by Moldflow analysis according to the pressure and wall thickness. The correlation graph between theoretical results and experimental measurements was obtained. When the wall thickness of the thin-walled spiral parts increased, the flow length of the thin-walled spiral parts increased. As a result, it was found that the thin-walled spiral part mold could not be filled for wall thicknesses of 0.50 and 1.50 mm at maximum pressure due to decreasing temperature at the flow front. In addition, the thin-walled spiral part mold can be filled for a wall thickness of 2.70 and 3.00 mm. In the correlation study conducted for these values, an agreement of approximately 90% was achieved. However, it was also observed that as the pressure increases, the deviation between the experimental and theoretical results becomes more pronounced.

Kauçuk ve plastik ürün imalat sektörü dünya genelinde hızla büyümeye devam etmektedir. Ülkemizde 2022 yılı itibari ile 15.771 işletme kauçuk ve plastik ürün imalat sektöründe faaliyet göstermektedir. Bu çalışmada, 2014-2022 yılları arasındaki Sosyal Güvenlik Kurumu (SGK) istatistiklerine göre Türkiye’de kauçuk ve plastik sektöründe meydana gelen iş kazası oranları analiz edilmiştir. SGK istatistikleri veri kaynağı olarak kullanıldığı için sadece resmi kayıt altına alınan iş kazaları değerlendirilmiştir. Türkiye’de kauçuk ve plastik ürün imalatında 2014-2022 yılları arasında iş kazalarından dolayı toplam 163 kişi hayatını kaybetmiştir. 2022 yılında meydana gelen toplam 18.000 iş kazası sonucunda 21’i erkek çalışan ve 1’i kadın çalışan olmak üzere toplam 22 kişi hayatını kaybetmiştir. Bu veriler, Türkiye’de faaliyet gösteren kauçuk ve plastik ürün imalat sektöründe meydana gelen iş kazalarının diğer imalat sektörlerinde olduğu gibi önemli bir sorun olduğunu göstermektedir. Türkiye’de kauçuk ve plastik ürün imalatında yaşanan iş kazaları verileri olası kaza durumlarının önlenebilmesi adına iş güvenliği ve sağlığı açısından yeni tedbirler alınması gerektiğini göstermektedir. Sonuç olarak, kauçuk ve plastik ürün imalatındaki iş sağlığı ve güvenliği gereklilikleri göz önünde bulundurularak iş kazalarının önlenmesi için önerilere yer verilmiştir.

In recent years, plastic decorative materials have been used in the automotive industry due to their advantages such as being environmentally friendly, aesthetic, light and economically affordable. Plastic decorative materials can exhibit high strength and metallic reflection with metal coatings. Chrome plating is generally preferred in the production of decorative plastic parts in the automotive industry. In this study, the effect of injection molding processing parameters on the metal–polymer adhesion of chrome-plated acrylonitrile butadiene styrene (ABS) was investigated. The ABS-based front grille frames are fabricated by means of using an industrial-scale injection molding machine. Then, the fabricated ABS-based front grille frame was plated with chrome by means of the electroplating method. The metal–polymer adhesion was investigated as a function of the injection molding processing parameters by means of a cross-cut test and scanning electron microscope (SEM). As a result, it was determined that the optimal injection process parameters, a cooling time of 18 s, a mold temperature of 70 °C, injection rates of 45-22-22-20-15-10 mm/s, and packing pressures of 110-100-100 bar, were effective in enhancing polymer–metal adhesion for the ABS-based front grille frame.

The additive manufacturing sector is rapidly developing, providing alternatives for mass production in the polymer composite industry. Due to the direction-dependent mechanical properties and high cost of fiber-reinforced polymeric materials, it is necessary to take advantage of alternative multi-materials and production technologies. In this study, a special geometric-shaped knitting technique was investigated using two different materials. The main material was polyamide 6 (PA6), and the inner or second material was PA6 with a 30 wt.% glass fiber addition by weight (PA6GF30). The special geometric shape, layer thickness, nozzle temperature, and post-heat treatment time were measured as process parameters in the production of the PA6/PA6GF30 composites with the fused deposition modeling (FDM) technique. The Taguchi design method and L9 fractional experiment were used in the experimental study. The mechanical behaviors of the PA6/PA6GF30 samples were obtained using tensile and impact tests. In addition, scanning electron microscopy (SEM) analyses were performed on the fracture lines of the PA6/PA6GF30 samples, and damage analyses were carried out in more detail. The experimental results were sorted using grey relational analysis (GRA). Moreover, the optimal experimental conditions and their related plots were obtained. As a result, the highest tensile strength of the PA6GF30 composite was 89.89 MPa with the addition of a special geometric shape. In addition, the maximum impact resistance value of the PA6/PA6GF30 composite was 83 kJ/m². Hence, the developed knitting method presented many advantages when using the FDM technique, and both were successfully used to produce the PA6/PA6GF30 composites.

To develop novel materials through the recycling of waste polymers and to enhance their mechanical and thermal properties, composites were synthesized using chain extenders (CEs), compatibilizers (PP-g-MA), and short carbon fiber (CF) reinforcements within recycled polyamide 6 (rPA6) and polypropylene (rPP) blends. The recycling of waste polymers holds paramount importance in the context of environmental sustainability. This study investigates the role of additives in effectively improving the properties of recycled polymers. The composites were fabricated using the twin-screw extrusion method and subjected to a comprehensive range of characterizations, including Fourier Transform Infrared Spectroscopy (FTIR), differential scanning calorimetry (DSC), molecular weight analysis, melt flow index (MFI), heat deflection temperature (HDT), tensile testing, impact testing, and Scanning Electron Microscopy (SEM). Additionally, ANOVA statistical methods were applied to analyze HDT, tensile, and impact test results. The findings of this research demonstrate that chain extenders and compatibilizers significantly enhance the mechanical properties of rPA6/rPP blends, while carbon fiber reinforcements markedly improve both tensile strength and impact resistance. Furthermore, the incorporation of rPP led to an approximately 4% reduction in hardness values; however, this loss was effectively compensated by the addition of chain extenders and CF reinforcements, resulting in an overall increase in hardness. It was observed that chain extenders enhanced the elastic modulus and tensile strength by reinforcing interphase bonding, whereas CF reinforcements strengthened the polymer matrix, leading to improved impact resistance. These findings emphasize the synergistic role of chain extenders, compatibilizers, and CF reinforcements in enhancing the mechanical properties of rPA6/rPP blends. The study underscores recycling as both an environmentally beneficial and effective strategy for developing durable, high-performance composites for industrial use. Consequently, the utilization of recycled polymers contributes substantially to the circular and sustainable materials economy, demonstrating the potential for the widespread industrial adoption of such composites.