Investigation of the effects of cryogenic treatment on delamination deformation in carbon fiber reinforced polymer material drilled by abrasive water jet method

The effects of cryogenic treatment applied to carbon fiber reinforced polymer material on the deformations occurring in the holes during drilling with the abrasive water jet method were investigated. At the beginning of the study, CFRP materials were cryogenically processed using nitrogen gas at -180 °C for different waiting times of 6 hours (6Kİ), 12 hours (12Kİ) and 18 hours (18Kİ). Additionally, samples without cryogenic treatment were prepared in order to compare (0Kİ) the deformation occurring in the holes. All samples, whether cryogenically treated or not, were analyzed using the ASJ method; At constant drilling parameters with 3800 bar water pressure, 1 mm nozzle distance, 750 mm/min cutting feed rate, 80 mesh garnet, abrasive flow rate of 350 g/min and a nozzle with 0.76 mm inner diameter; Holes with diameters of 8 mm, 12 mm and 16 mm were drilled. Deformations occurring during drilling operations were detected using CMM device, surface roughness device and microstructure imaging devices. As a result of the measurements and evaluations made; It was determined that the average circularity error for 8 mm diameter holes was improved by 14% in 6KI samples compared to 0KI samples. It was determined that the average circularity error for 12 mm diameter holes was improved by 37% in 6KI and 12KI samples compared to 0KI samples. It was determined that the average circularity error for 16 mm diameter holes was improved by 20% in 18KI samples compared to 0KI samples. It was determined that there was an 8% improvement in the average kerf angle for 8 mm diameter holes in 18KI samples compared to 0KI samples. It was determined that there was a 15% improvement in the average kerf angle for 12 mm diameter holes in 18KI samples compared to 0KI samples. It was determined that the average kerf angle for 16 mm diameter holes was improved by 5% in 12KI samples compared to 0KI samples. For 8 mm diameter holes, the lowest average delamination error was found to be 1.018 in the sample that was cryogenically treated for 18 hours, and the highest was 1.022 in the sample that was cryogenically treated for 12 hours. For 12 mm diameter holes, the lowest average delamination error was found to be 1.012 in the sample that was cryogenically treated for 18 hours, and the highest rate was 1.016 in the samples that were not cryogenically treated. For 16 mm diameter holes, the lowest average delamination error was found to be 1.009 in the samples subjected to 6 hours, 12 hours and 18 hours of cryogenic treatment, and the highest rate was 1.01 in the sample without cryogenic treatment. It was determined that there was a 17% improvement in the average surface roughness value for 8 mm diameter holes in 18KI samples compared to 0KI samples. It was determined that there was a 33% improvement in the average surface roughness value for 12 mm diameter holes in 18KI samples compared to 0KI samples. It was determined that there was a 44% improvement in the average surface roughness value for 16 mm diameter holes in 18KI samples compared to 0KI samples.