표면 연마 방법에 따른 니티놀 잔류응력 분석

정지선,홍광표,김운용,조명우,Jeong, Ji-Seon,Hong, Kwang-Pyo,Kim, Woon-yong,Cho, Myeong-Woo 한국금형공학회 2017 한국금형공학회지 Vol.11 No.2

Nitinol, a shape memory alloy (SMA), is manufactured from titanium and nickel and it used in various fields such as electrical applications, micro sensors. It is also recommended as a material in medical for implant because it has excellent organic compatibility. Nitinol is intended to be inserted into the human body, products require a high-quality surface and low residual stress. To overcome this problems, explore electrolyte polishing (EP) is being explored that may be appropriate for use with nitinol. EP is a particularly useful machining method because, as a non contact machining method, it produces neither machining heat nor internal stress in the machined materials. Sandpaper polishing is also useful machining method because, as a contact machining method, it can easily good surface roughness in the machined materials. The electrolyte polishing (EP) process has an effect of improving the surface roughness as well as the film polishing process, but has a characteristic that the residual stress is hardly generated because the work hardened layer is not formed on the processed surface. The sandpaper polishing process has the effect of improving the surface roughness but the residual stress remains in the surface. We experimented with three conditions of polishing process. First condition is the conventional polishing. Second condition is the electrochemical polishing(EP). And Last condition is a mixing process with the conventional polishing and the EP. Surface roughness and residual stress of the nitinol before a polishing process were $0.474{\mu}mRa$, -45.38MPa. Surface roughness and residual stress of the nitinol after mixing process of the conventional polishing and the EP were $1.071{\mu}mRa$, -143.157MPa. Surface roughness and residual stress of the nitinol after conventional polishing were $0.385{\mu}mRa$ and -205.15MPa. Surface roughness and residual stress of sandpaper and EP nitinol were $1.071{\mu}mRa$, -143.157MPa. The result shows that the EP process is a residual stress free process that eliminates the residual stress on the surface while eliminating the deformed layer remaining on the surface through composite surface machining rather than single surface machining. The EP process can be used for biomaterials such as nitinol and be applied to polishing of wafers and various fields.

복합레진 표면의 연마방법에 따른 표면조도

민정범,조공철,조영곤 대한치과보존학회 2007 Restorative Dentistry & Endodontics Vol.32 No.2

본 연구는 복합레진의 종류와 연마방법, 복합레진 연마 후 레진전색제의 적용이 복합레진의 표면조도에 미치는 영향을 알아보기 위하여 복합레진의 표면조도 측정과 FE-SEM 관찰을 통하여 상호 비교하였다. 미세입자형과 nanofill 복합레진을 이용하여 8×3×2 mm의 시편을 각각 100개씩 제작하였고, 연마방법과 레진전색제의 적용 유무에 따라 20개의 군으로 분류하였다. 복합레진의 종류에 따라 Micronew를 사용한 군은 M군, Filtek Supreme을 사용한 군은 S군으로 분류한 후, 연마방법에 따라 M1군과 S1군은 polyester strip만을 사용한 군, M2군 와 S2군은 Sof-Lex disc를 사용한 군, M3군과 S3군은 Enhance disc와 polishing paste를 사용한 군, M4군과 S4군은 Astropol disc를 사용한 군, M5군과 S5군은 carbide finishing bur를 사용한 군으로 다시 분류하였다. 또한 연마 후 Biscover 레진전색제를 적용한 군은 연마방법에 따른 각 군에 B를 추가하여 M1B군-M5B군 및 S1B군-S5B군으로 분류하였다. 제작된 모든 시편은 표면조도의 측정과 주사전자 현미경 관찰을 시행하기 전에 실온의 증류수에서 24시간 동안 보관 하였다. 표면조도측정기를 사용하여 각 시편의 상면과 하면 모두에서 각각 5회씩 측정하여 평균 표면조도 값을 산출하여 통계적으로 분석하였으며, 각 군에서 대표적인 시편 1개를 선택하여 FE-SEM에서 관찰하여 다음과 같은 결과를 얻었다. 1. 복합레진의 표면조도 값은 polyester strip에 의해 형성된 모든 군에서 가장 낮게 나타났고, 레진전색제를 적용한 S군을 제외한 다른 모든 군에서 finishing bur로 연마한 군이 가장 높게 나타났다 (p < 0.05). FE-SEM 관찰에서 레진전색제를 적용하기 전의 표면은 polyester strip을 사용한 M1군과 S1군이 가장 평활한 표면을 나타냈고, finishing bur를 사용한 M5군과 S5군은 필러의 탈락에 의해 형성된 여러 개의 기포와 함께 울퉁불퉁한 표면을 보였다. 2. 복합레진의 종류에 따른 표면조도는 레진전색제를 적용하기 전에는 통계학적으로 차이를 나타내지 않았으나, 레진전색제를 적용한 후에는 Micronew가 Filtek Supreme보다 평활한 표면을 나타내었다 (p < 0.05). 3. 레진전색제를 적용하기 전에는 복합레진의 종류와 연마방법에 따른 표면조도 간에 상호 연관성이 있었으나, 레진전색제를 적용한 후에는 복합레진의 종류와 연마방법 간에 상호 연관성이 없었다. FE-SEM 관찰에서 레진전색제를 적용한 후의 표면은 모든 군에서 대체적으로 평활한 표면을 나타내었다. 4. 동일한 복합레진과 연마방법으로 처리된 군에서 레진전색제 적용 전과 후의 표면조도 값은 M1B군이 M1군보다, S1B군이 S1군보다 통계학적으로 높게 나타났으며, M4B군과 M5B군은 각각 M4군과 M5군 보다, 그리고 S5B군은 S5군 보다 통계학적으로 낮게 나타났다 (p < 0.05). 본 연구를 종합하여 보면, 복합레진의 종류에 따라 표면조도의 순서는 다르게 나타났고, polyester strip 하에서 복합레진이 중합된 경우 가장 낮은 표면조도 값과 평활한 표면을 제공하였으며 전반적으로 finishing bur는 가장 높은 Ra 값과 거친 표면을 제공하였다. Enhance, Astropol, carbide finishing bur로 연마한 표면은 레진전색제의 사용으로 평활한 표면을 얻을 수 있었지만, polyester strip과 Sof-Lex disc로 얻어진 표면은 레진전색제의 사용으로 표면조도의 개선이 이루어지지 않았다. The purpose of this study was to evaluate the difference of surface roughness of composite resin according to composite resin type, polishing methods, and use of resin sealant. Two hundred rectangular specimens, sized 8 × 3 × 2 mm, were made of Micro-new (Bisco, Inc., Schaumburg, IL, U.S.A) and Filtek Supreme (3M ESPE Dental Products, St. Paul, MN, U.S.A.), and divided into two groups; Micronew-M group, Filtek Supreme-S group. Specimens for each composite group were subdivided into five groups by finishing and polishing instruments used; M1 & S1 (polyester strip), M2 & S2 (Sof-Lex disc), M3 & S3 (Enhance disc and polishing paste), M4 & S4 (Astropol), and M5 & S5 (finishing bur). Polished groups were added letter B after the application of resin surface sealant (Biscover), eg, M1B and S1B. After specimens were stored with distilled water for 24 hr, average surface roughness (Ra) was taken using a surface roughness tester. Representative specimens of each group were examined by FE-SEM (S-4700: Hitachi High Technologies Co., Tokyo, Japan). The data were analysed using paired t-test, ANOVA and Duncan's tests at the 0.05 probability level. The results of this study were as follows; 1. The lowest Ra was achieved in all groups using polyester strip and the highest Ra was achieved in M5, S5 and M5B groups using finishing bur. On FE-SEM, M1 and S1 groups provided the smoothest surfaces, M5 and S5 groups were presented the roughest surfaces and voids by debonding of filler on the polished specimens. 2. There was no significant difference in Ra between Micronew and Filtek Supreme before the application of resin sealant, but Micronew was smoother than Filek Supreme after the application of resin sealant. 3. There was significant corelation between Ra of type of composite resin and polishing methods before the application of resin sealant (p = 0.000), but no significant interaction between them after the application of resin sealant. On FE-SEM, most of composite resin surfaces were smooth after the application of resin sealant on the polished specimens. 4. Compared with before and after the application of resin sealant in group treated in the same composite and polishing methods, Ra of M4B and M5B was statistically lower than that of M4 and M5, and S5B was lower than that of S5, respectively (p < 0.05). In conclusion, surface roughness by polishing instruments was different according to type of composite resin. Overall, polyester strip produced the smoothest surface, but finishing bur produced the roughest surface. Application of resin sealant provided the smooth surfaces in specimens polished with Enhance, Astropol and finishing bur, but not provided them in specimens polished with Sof-Lex disc.

Surface changes of metal alloys and high-strength ceramics after ultrasonic scaling and intraoral polishing

Hyung-In Yoon,Hyo-Mi Noh,Eun-Jin Park 대한치과보철학회 2017 The Journal of Advanced Prosthodontics Vol.9 No.3

PURPOSE. This study was to evaluate the effect of repeated ultrasonic scaling and surface polishing with intraoral polishing kits on the surface roughness of three different restorative materials. MATERIALS AND METHODS. A total of 15 identical discs were fabricated with three different materials. The ultrasonic scaling was conducted for 20 seconds on the test surfaces. Subsequently, a multi-step polishing with recommended intraoral polishing kit was performed for 30 seconds. The 3D profiler and scanning electron microscopy were used to investigate surface integrity before scaling (pristine), after scaling, and after surface polishing for each material. Non-parametric Friedman and Wilcoxon signed rank sum tests were employed to statistically evaluate surface roughness changes of the pristine, scaled, and polished specimens. The level of significance was set at 0.05. RESULTS. Surface roughness values before scaling (pristine), after scaling, and polishing of the metal alloys were 3.02±0.34 μm,2.44±0.72 μm, and 3.49±0.72 μm, respectively. Surface roughness of lithium disilicate increased from 2.35±1.05 μm (pristine) to 28.54±9.64 μm (scaling), and further increased after polishing (56.66±9.12 μm, P<.05). The zirconia showed the most increase in roughness after scaling (from 1.65±0.42 μm to 101.37±18.75 μm), while its surface roughness decreased after polishing (29.57±18.86 μm, P<.05). CONCLUSION. Ultrasonic scaling significantly changed the surface integrities of lithium disilicate and zirconia. Surface polishing with multi-step intraoral kit after repeated scaling was only effective for the zirconia, while it was not for lithium disilicate.

Surface changes of metal alloys and high-strength ceramics after ultrasonic scaling and intraoral polishing

윤형인,노효미,박은진 대한치과보철학회 2017 The Journal of Advanced Prosthodontics Vol.9 No.3

PURPOSE. This study was to evaluate the effect of repeated ultrasonic scaling and surface polishing with intraoral polishing kits on the surface roughness of three different restorative materials. MATERIALS AND METHODS. A total of 15 identical discs were fabricated with three different materials. The ultrasonic scaling was conducted for 20 seconds on the test surfaces. Subsequently, a multi-step polishing with recommended intraoral polishing kit was performed for 30 seconds. The 3D profiler and scanning electron microscopy were used to investigate surface integrity before scaling (pristine), after scaling, and after surface polishing for each material. Non-parametric Friedman and Wilcoxon signed rank sum tests were employed to statistically evaluate surface roughness changes of the pristine, scaled, and polished specimens. The level of significance was set at 0.05. RESULTS. Surface roughness values before scaling (pristine), after scaling, and polishing of the metal alloys were 3.02±0.34 μm,2.44±0.72 μm, and 3.49±0.72 μm, respectively. Surface roughness of lithium disilicate increased from 2.35±1.05 μm (pristine) to 28.54±9.64 μm (scaling), and further increased after polishing (56.66±9.12 μm, P<.05). The zirconia showed the most increase in roughness after scaling (from 1.65±0.42 μm to 101.37±18.75 μm), while its surface roughness decreased after polishing (29.57±18.86 μm, P<.05). CONCLUSION. Ultrasonic scaling significantly changed the surface integrities of lithium disilicate and zirconia. Surface polishing with multi-step intraoral kit after repeated scaling was only effective for the zirconia, while it was not for lithium disilicate.

연마 과정에 따른 열중합 의치상 레진의 표면 거칠기 평가

황성식,임용운,김시철,한민수 대한치과기공학회 2015 대한치과기공학회지 Vol.37 No.4

Purpose: The objective of this study was to compare the surface roughness according to polishing process in conventional laboratory techniques used for polishing three different acrylic denture base resins. Materials and methods: Specimen preparation and surface polishing procedures were conducted to manufacturer’s recommendation with three heat-polymerized denture base resins. Surface roughness and gloss were measured by a contact type tester and a LED gloss checker using thickness 2 mm and diameter 10 mm. There were five specimens for each acrylic resin material and polishing procedures. Mean average surface roughness (Ra) values of each specimen group were analyzed using a one-way ANOVA analysis of variance and Scheffe’s post hoc test. Surfaces after surface roughness and gloss testing according to each polishing process were evaluated under a stereoscopic microscope. Results: The highest mean average surface roughness was measured (Ra=2.43± 0.47) for surfaces finished with a denture tungsten carbide bur in Triplex. The lowest surface roughness values (Ra=0.11 ±0.07) were determined in Vertex polished with a lathe. In addition, all materials revealed that surface roughness determined highly in HP1 and HP2 than other procedures. All correlation between surface roughness and gloss showed highly with three heat-polymerized resins. Specially, topmost correlation revealed than other material in Triplex. Significant differences in mean average surface roughness were found between polishing process used high speed lathe and low speed hand-piece. Conclusions: Laboratory polishing used to high speed was found to produce the smoothest surface of heat-polymerized denture base acrylic resin. Therefore, we recommended that high polishing process need to get smooth surface.

Surface changes of metal alloys and high-strength ceramics after ultrasonic scaling and intraoral polishing

Yoon, Hyung-In,Noh, Hyo-Mi,Park, Eun-Jin The Korean Academy of Prosthodonitics 2017 The Journal of Advanced Prosthodontics Vol.9 No.3

PURPOSE. This study was to evaluate the effect of repeated ultrasonic scaling and surface polishing with intraoral polishing kits on the surface roughness of three different restorative materials. MATERIALS AND METHODS. A total of 15 identical discs were fabricated with three different materials. The ultrasonic scaling was conducted for 20 seconds on the test surfaces. Subsequently, a multi-step polishing with recommended intraoral polishing kit was performed for 30 seconds. The 3D profiler and scanning electron microscopy were used to investigate surface integrity before scaling (pristine), after scaling, and after surface polishing for each material. Non-parametric Friedman and Wilcoxon signed rank sum tests were employed to statistically evaluate surface roughness changes of the pristine, scaled, and polished specimens. The level of significance was set at 0.05. RESULTS. Surface roughness values before scaling (pristine), after scaling, and polishing of the metal alloys were $3.02{\pm}0.34{\mu}m$, $2.44{\pm}0.72{\mu}m$, and $3.49{\pm}0.72{\mu}m$, respectively. Surface roughness of lithium disilicate increased from $2.35{\pm}1.05{\mu}m$ (pristine) to $28.54{\pm}9.64{\mu}m$ (scaling), and further increased after polishing ($56.66{\pm}9.12{\mu}m$, P<.05). The zirconia showed the most increase in roughness after scaling (from $1.65{\pm}0.42{\mu}m$ to $101.37{\pm}18.75{\mu}m$), while its surface roughness decreased after polishing ($29.57{\pm}18.86{\mu}m$, P<.05). CONCLUSION. Ultrasonic scaling significantly changed the surface integrities of lithium disilicate and zirconia. Surface polishing with multi-step intraoral kit after repeated scaling was only effective for the zirconia, while it was not for lithium disilicate.

연마방법에 따른 탄성의치의 표면거칠기와 Candida albicans의 부착율 변화

오주원,서재민,안승근,박주미,강철균,송광엽 대한치과보철학회 2012 대한치과보철학회지 Vol.50 No.2

연구 목적: 본 연구는 탄성의치 제작 시 주로 사용되는 polyamide를 수종의 연마방법을 사용하여 처리 후 Candida albicans의 부착정도와 표면거칠기를 비교하고자 하였다. 연구 재료 및 방법: 25×15×2 mm 크기의 polyamide 시편을 4군으로 나누어 연마재를 사용하여 기공용 lathe 연마하는 방법(기공실내 연마방법)과 각기 다른 2종의 실리콘 포인트로 진료실내 연마하는 방법, 그리고 실리콘포인트 연마 후 pumice로 연마하는 방법으로 처리하였다. C. albicans의 부착성을 평가하기 위해 5×106 CFU/ml의 C. albicans 현탁액에 시편을 2시간 동안 침적하였고 5회 수세처리 후 한천배지에서 배양하였다. 그리고 주사전자 현미경(JSM-5900, JEOL LTd., Tokyo, Japan) 촬영을 시행하였다. Profilometer (Surf-pak; Kawasaki, Japan)를 이용하여 표면거칠기를 측정하였고 통계처리를 위하여 SPSS 18.0 프로그램을 사용하였다. 일원변량분석으로 비교 분석하였고 사후검증은 C. albicans의 부착성 검증을 위해 Scheffe test를 시행하였으며 표면조도검증을 위해 Tamhane’s T2 test를 시행하였다(α=.01). 결과: 최대 거칠기 값을 보인 군은 2단계의 연마용 버를 사용한 것으로 0.32 ㎛±0.10 값을 나타냈으며, 가장 낮은 거칠기 값을 보인 것은 tungsten carbide를 사용하지 않고 기공용 lathe로만 연마를 한 군으로 0.02 ㎛±0.00의 거칠기 값을 나타냈다. C. albicans 부착 실험에서는 기공용 lathe만을 이용한 연마방법이 가장 적은 부착수를 보였으며 다른 세 군과 유의한 차이가 발견되었다(P<.01). 결론: 표면거칠기 및 미생물 부착능 실험 결과 기공실 연마만을 시행한 경우 유의하게 낮은 거칠기 값과 부착율을 보였다. Pumice로 추가 연마한 군은 진료실연마를 시행한 군에 비해 낮은 거칠기 값을 보였으나 C. albicans 부착에 있어서는 유의한 차이를 보이지 않았다(P>.01). Purpose: The purpose of this study was to compare the effect of 3 chairside polishing methods and laboratory polishing methods on surface roughness and C. albicans adhesion of polyamide denture base. Materials and methods: Using contact profilometer, the surface of polyamide specimens (25×15×2 mm) was studied after conventional polishing without finishing and after chiarside polishing with 2 chiarside polishing kits and chairside-pumice polishing following finishing with tungsten carbide bur. To evaluate the adhesion of C. albicans, C. albicans suspension was overlayed on the test specimen. And the specimens were incubated for 2 hours. Imprint culture method was achieved and counted the colony on the agar plate. Polished polyamide were evaluated using a scanning electron microscope. The statistics were conducted using one-way ANOVA and in case of difference, Scheffe test and Tamhane’s T2 test were used. Results: Surface roughness (Ra) of surfaces polished with 2 chairside polishing kits had higher than conventional polishing and pumice polishing. The highest roughness value was 0.32 ± 0.10 ㎛, and the lowest was 0.02 ± 0.00 ㎛. The adhesion of C. albicans on the specimens polished with chairside polishing group and pumice polishing group were increased than conventional polishing group (P<.01). Conclusion: Conventional laboratory polishing was found to produce the smoothest surface and the lowest adhesion of C. albicans. Two groups polished with Chairside polishing kits were similar with respect to surface roughness. Surface of the specimen polished with pumice is significantly smoother than 2 chairside polishing groups, but the result of C. albicans adhesion is that group polished with pumice was similar with 2 chairside polishing groups (P>.01).

3차원 자유곡면의 정밀연마기술에 관한 연구

조종래,정윤교 한국공작기계학회 2006 한국공작기계학회 추계학술대회논문집 Vol.2006 No.-

In the current environment, the mold industry should response to the human's need more quickly. However, in the manufacturing of molds, the most time consuming process is on the final stage-the polishing process. The polishing process of the mold not only affects the final appearance and the quality of the mold, it also occupies the total production time and cost up to 30 ∼ 50%. Almost all the polishing process in the mold industry are conducted manually. The dust and noise producted by the polishing process are not good for human health. the monotonic nature of polishing process even lends itself to bo rejected by workers. Beside, the polishing process needs exceptional skill that can only be taught by experienced master. For mass production of molds, automatic polishing of the mold is a necessary. For the automation of the polishing process, that is classified the sculptured surface as 3 parts according to the surface characteristic. it classified the case which the structure inside is the sculptured surface, the case which a structure outside is the sculptured surface, the case which the one sided of the structure consists of complex surface. According to each picture characteristic, it is applied MAGIC polishing technique, Hydrostatic polishing technique and Magnetic fluid polishing technique and is polished precisely. And it is evaluated each about the sculptured surface polishing characteristic.

Study on surface shape control of pure Ti fabricated by electron beam melting using electrolytic polishing

Jung, Jae-Hyun,Park, Hyung-Ki,Lee, Byoung Soo,Choi, Jaeho,Seo, Bosung,Kim, Hyo Kyu,Kim, Gun Hee,Kim, Hyung Giun Elsevier 2017 Surface & Coatings Technology Vol.324 No.-

<P><B>Abstract</B></P> <P>Titanium parts in special industries such as vacuum, catalyst and medical application require a variety of surface properties with a unique structure for high efficiency. In this study, the unique surface of commercially pure titanium (CP Ti) parts fabricated using Electron Beam Melting (EBM) in the process of additive manufacturing is post-treated by the electrolytic polishing process under conditions ranging from 10 to 30V and 10–600s in order to study the surface characteristics. The possibility of controlling microstructural surface shape according to electrolytic polishing process conditions is presented from the increase of surface area through the formation of micro-dimples on protruding residual powder on the surface to the flattening of entire surface.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Microstructural study on the surface of additive manufactured pure Ti part after electrolytic polishing. </LI> <LI> It is possible to maximize surface area by forming micro dimpling at the initial stage of electrolytic polishing. </LI> <LI> Identification of surface flattening mechanism of additive manufactured Ti part using electron beam melting. </LI> </UL> </P>

연마방법에 따른 복합레진의 표면특성 평가

백민경,김종철,장기택 大韓小兒齒科學會 2016 大韓小兒齒科學會誌 Vol.43 No.3

The aim of this study was to evaluate the surface characteristics of composite resins polished with two different polishing methods. 30 disk-shaped specimens were prepared with microhybrid (FiltekTM Z250) and nanofilled (FiltekTM Z350) resins respectively, and classified into three groups: not polished as controls, polished by an abrasive disk (Soflex), and polished by a polishing brush (Occlubrush). Surface roughness was increased after polishing. In terms of micro-roughness, there were no significant differences between the two polishing methods. But macro-roughness values were markedly increased in the Occlubrush group (p < 0.05). In the Sof-lex group, the matrix and fillers were polished together, resulting into a smoother and homogeneous surface. However, in the Occlubrush group, the matrix layer was torn off, with more heterogeneous surfaces and large scratches. In regards to micro-hardness, no significant differences were observed between the two polishing systems (p > 0.05). And the hardness value increased about 25% after polishing. In conclusion, the method of polishing should be chosen deliberately in view of the hardness characteristics of composite resins. Sof-lex is recommended to improve the surface characteristics of polished resins. 본 연구는 복합레진의 연마방법에 따른 표면특성을 평가하기 위해, microhybrid 레진(FiltekTM Z250)과 nanofill 레진(FiltekTM Z350)을 연마 전, abrasive disk(Sof-lex) 연마 후, polishing brush(Occlubrush) 연마 후로 나누어 분석하였다. 그 결과 레진 표면조도는 연마 후 증가하였는데, 미세조도는 연마방법에 따른 차이가 없었으나 거시조도는 Occlubrush를이용한 경우 현저하게 커졌다(p < 0.05). Sof-lex 연마의 경우 레진의 filler까지 연마되어 표면이 보다 균일한 형상을 보였으나 Occlubrush 연마시편은 기질층이 뜯겨져 나간 불균일한 형상을 보였다. 두 연마방법 간의 미세경도 유의차는 없었으며(p > 0.05), 연마 후 경도 값이 약 25% 상승하였다. 결론적으로, 복합레진의 표면경도 향상을 위하여 적합한 연마가 필요하며, Sof-lex를 이용한 연마가 더 우수한 것으로 사료된다.