This study investigates the warpage problem observed in dishwasher bottom cover manufactured via plastic injection molding, considering primary recycled material characteristics, key processing parameters (injection set temperature and in-cycle cooling time), and real-time in-mold sensor data. The material used was a polypropylene homopolymer filled with 40 wt% calcium carbonate (CaCO₃) (I1TPC40), which was mechanically reprocessed (ground) and subsequently reintroduced into injection molding. The effects of material properties, injection set temperature, and cooling time on warpage behavior were systematically evaluated. Material characterization was performed using melt flow index (MFI), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). The DSC results indicated no statistically significant differences in thermal behavior between the recycled I1TPC40 and the original PURPC40. MFI analysis showed increased flowability of the recycled material, while FTIR spectra confirmed the absence of noticeable chemical degradation. These findings demonstrate that the material retains its integrity and can be safely reused in further production processes. Samples were molded using three injection temperatures (200, 210, and 225 °C) and six cooling times (23–40 s). Warpage was quantified based on dimensional and mass measurements, and in-mold temperature profiles were monitored using embedded sensors. The results revealed that cooling time and the in-mold temperature distribution play a decisive role in warpage formation. To predict warpage, multiple linear regression (MLR) and classification and regression trees (CART) were employed, and both models achieved prediction accuracies exceeding 90%. Overall, the findings indicate that combining primary recycled materials with appropriately selected processing conditions and sensor-driven data-based models offers substantial potential for reducing warpage and enabling more sustainable injection molding practices.

Polipropilen blok kopolimer (PPB) kompozit malzemeler, polipropilen ve mikro tane boyutlu mineral dolgulu malzemelerinden, yani kalsiyum karbonattan (CC) oluşur. Testlerde kullanılacak numuneler, üç farklı tane boyutunda kalsiyum karbonat (CC) mineralinin eklenmesiyle oluşturulmuştur. Farklı ticari CC minerallerinin ortalama tane boyutları 1.65 um, 2.15 um, 5 um'dir. PPB kompozit malzemeler, hacim oranının % 17.5'i (veya ağırlıkça % 38.89) içeriğinde sabit miktarda CC ile hazırlandı. Bu çalışmada, hacimce %17,5 olan ve farklı boyutlarda CC katkılı PPB kompozit malzemelerin kısa süreli çekme tip sürünme özellikleri farklı gerilme seviyeleri için incelenmiştir. Gerilme seviyeleri, akma dayanımının altındaki gerilmelerden seçilmiştir. Gerilme seviyeleri 8 MPa ve 16 MPa'dır. Sonuç olarak, katkısız PPB malzemeye göre CC katkılı PPB malzemelerde, sürünme uzaması veya uzama düşüşü (∆ε) değerleri azaldığı tespit edilmiştir. Ayrıca, tane büyüklüğü arttıkça depolanan enerji seviyelerinin azaldığı da bulunmuştur.

In this study, 5% and 10% by weight of anhydrous borax (AHB) was added to the iron (Fe) matrix material by powder metallurgy method and the effects of the additive ratio on the Vickers hardness (HV), Brinell hardness (HB) and Indentation modulus (EIT) values of the composites (Fe/AHB) were investigated. In the productions carried out using Taguchi experimental design method, AHB additive ratio, and sintering temperature parameters were selected as control parameters that were thought to affect the physical and/or mechanical properties of the Fe/AHB composite materials. The productions were carried out according to the Taguchi L4 orthogonal array, which was created depending on the control parameters and levels. Vickers hardness and indentation modulus measurements of pure iron and Fe/AHB composite materials were performed in accordance with BS EN ISO 14577-1 standard and Brinell hardness measurement was performed in accordance with TS EN ISO 6506-1 standard. According to the signal-to-noise ratio (S/N) analysis performed with the experimental data, it was determined that the 10% AHB additive ratio and 950oC sintering temperature optimized all the investigated properties of the Fe/AHB composite material. It was determined that the values for Vickers hardness, Brinell hardness and indentation modulus increased by 142.03%, 69.32% and 144.11%, respectively, in the levels where the properties of the composite material were optimized compared to pure Fe material. As a result of the qualitative examination of all samples after storage in a comfortable environment without daylight, it was also observed that the anhydrous borax additive delayed the corrosion time of pure iron material.