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End Milling of Stainless Steel Using Vegetable Oil Cutting Fluid
Denni Kurniawan(대니쿠니아완),Safian Sharif,Muhammad Azrul Hisyam,Lim Joong Yeon(임중연) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
Vegetable oil can be alternative cutting fluid with its positive impact to both machine shop workers’ health and environmental friendliness. Its use as cutting fluid is investigated by performing end milling of hardened stainless steel using coated carbide tool with minimum quantity lubrication technique. Comparisons were made by other cooling techniques, i.e. dry, flood cooling using emulsion, and minimum quantity lubrication using fatty alcohol in terms of tool life and surface roughness. Results showed that minimum quantity lubrication using vegetable oil outperformed other cooling techniques, thus provided positive evaluation on its particular experimental use.
Periimplant bone biomechanics : Finite element analysis for partial osseointegration
Denni Kurniawan,Fethma M. Nor,Ho Yong Lee(이호용),Joong Yeon Lim(임중연) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
Finite element analysis on periimplant bones often assumes perfect osseointegration to occur. However, bone never integrates completely to implants. This paper implements a technique to represent partial osseointegration, by featuring transition regions assigned with a fraction of bone’s elastic properties. Further refinement is through the use of transversely isotropic properties of bones. For a case study, an occlusal-loaded dental implant is generated and the associated mandible having properties of type Ⅲ bone is modeled. Perfect and 50% osseointegration is assigned to the periimplant bone. Stress-strain conditions are resulted and further analysis based on a bone overload criterion is performed. Degree of osseointegration affects maximum stress and stress distribution on the induced stress on periimplant bones.
Kurniawan, Denni,Kim, Byung Sun,Lee, Ho Yong,Lim, Joong Yeon Elsevier 2012 Composites Part B, Engineering Vol.43 No.3
<P><B>Abstract</B></P> <P>This study evaluates the effects of atmospheric pressure glow discharge plasma polymerization on basalt fiber to the properties of basalt fiber/polylactic acid composite. Plasma exposure time was the object of interest so the basalt fiber was exposed to the glow for 0.5, 1.5, 3, 4.5, and 6min, respectively. Characterization was conducted on the plasma polymerized fibers by identifying the molecular bonds and surface morphology. Properties (mechanical and thermal) and water absorption behavior of the fabricated composites were tested. Plasma exposure time on BF affected mechanical properties of its BF/PLA composite, showing a decline in mechanical properties until the BF was plasma polymerized beyond 1.5min. Optimum plasma polymerization on BF was for 4.5min of plasma exposure time where the composite’s strength and modulus were 45% and 18% higher, respectively, compared to those of untreated one.</P>
Finite element analysis of acupuncture needle insertion : Skin’s elastic response
Fethma M. Nor,Denni Kurniawan,Ho Yong Lee(이호용),Joong Yeon Lim(임중연) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
This study on acupuncture needle insertion offers preliminary finite element analysis on skin’s elastic response when acupuncture needle is inserted. Models are developed to be capable of simulating insertion force and stress distribution resulted from needle insertion. A three layer skin model and three designs of needle tip are generated. Needle insertions technique by skin stretching is also simulated and analyzed. The models resulted stress and stress distribution induced on skin which is further used to indicate effectiveness of a needle design and to show effects of skin stretching needle insertion techniques.
Wen-Chin Chen,Denni Kurniawan 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.
This paper presents a two stage optimization system to find optimal process parameters of multiple quality characteristics in plasticinjection molding. Taguchi method, Back-Propagation Neural Network (BPNN), Genetic Algorithm (GA), and combination of ParticleSwarm Optimization and Genetic Algorithm (PSO-GA) are used in this study to find optimum parameter settings. Melt temperature,injection velocity, packing pressure, packing time, and cooling time are selected as initial process parameters in the experiment. First,experimental work is conducted using Taguchi orthogonal array. According to the result from the Taguchi experiment, S/N ratio iscalculated to find the best combination settings for product quality. Then, ANOVA is used to determine significant factors of the controlparameters. Moreover, the S/N ratio predictor and quality predictor are constructed using BPNN. In the first stage optimization, S/Nratio predictor and GA are used to reduce variance of quality characteristic. In the second stage optimization, the S/N ratio predictorand quality predictor with hybrid PSO-GA are used to find optimal parameter settings for quality characteristic and stability ofthe process. Finally, three confirmation experiments are conducted to assess the effectiveness of the proposed system. Uponoptimization, it is seen that the proposed system not only improves the quality of plastic parts, but also reduces variability of theprocess effectively.