Papers by Author: Wesley Huang

Abstract: This paper presents the optimal chromium nitride (CrN) deposited performance by tuning magnetic systems on die steel in PVD. The strength of magnetic fields was controlled by adjusting the gap distance between magnet sets and target surfaces of the unbalanced magnetic field of sputtering systems. In L18 orthogonal experiments, the effect of control factors were explored such as gap distance between magnet set and target surface (GDMT), target current, argon and nitrogen flow rate, DC pulse frequency, and work distance. Hardness and wear behavior of the CrN films were analyzed using a statistical method. The wear rate was estimated by Pappus’s theorem. Among the results, the Cr2N phase with the mixture crystallographic orientations of (111) and (002) exhibited better wear resistance than CrN(200) with a single preferential orientation. In addition, variance analysis exhibited the largest percentage contribution to friction coefficient in comparison with the other two properties of friction coefficient and GDMT, which showed that GDMT is extremely sensitive to friction coefficient.

Abstract: The paper reported using a mathematical model that simulated the wear volume in comparison to measurement by a ball-on-disc for deposited CrN films on tool steel (JIS SKD11). Three dimensional profile instruments were used to measure the wear scar trace for variations of numerical data of two dimensional profiles. By using numerical algorithms, the wear volume measurements of wear profiles are to save considerable time and economical. A new mathematical method is issued for determining wear volumes in this study. The estimated results were precisely fitted as compared with other calculations for three dimensional estimations of wear volumes.

Abstract: Sticking problems in injection molds are a significant challenge in product quality control. Molds are usually coated with a surface ceramic layer to prevent sticking problems. This study presents two films deposited on light-guide plate microinjection molds using an unbalanced magnetron sputtering process to investigate the anti-sticking property of molds. The deposited film materials include chromium nitride (Cr-N) and zirconium containing diamond-like carbon (Zr-DLC). The anti-stick film properties examined here include water contact angles, the coefficients of friction, as well as product flatness for the practical injection process. The results show that the performance of Cr-N films involve water contact angles at 111.4 degrees and a coefficient of friction at 0.742, respectively. The performances of Zr-DLC films involve water contact angles at 86.2 degrees and a coefficient of friction at 0.106, respectively. For the practical injection process, the deposited Cr-N films have better anti-sticking property than do the deposited Zr-DLC films.