• Journal of the Korean Society for Precision Engineering
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• v.17 no.6
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• pp.96-102
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• 2000

The finishing process for dies and molds is an important process because it has influence on final quality of products. And it is difficult to automatize finishing process so that the process has depended on expert's skill until now. However, recently a study on development of die automatic finishing machine has been progressed, and actually this machine is applied to fabrication of die. But the research about tooling system is not enough and finishing tool must have high machining efficiency and adaptability of curved surface. So, this study investigated the application of conductive elastic tool which is composed of metal-resin bonded pellet and elastic backing material. The metal-resin bonded pellet is used to finish the surface by conventional mechanical grinding or electro-chemial grinding method. And elastic backing material is used to follow the curved surface. So conductive elastic tool has long lifetime, uniform removal rate and adaptability of curved surface.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.5
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• pp.514-520
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• 2009

In configuring an automated polishing system, a monitoring scheme to estimate the surface roughness is necessary. In this study, a precision polishing process, magnetic abrasive finishing (MAF), along with an in-process monitoring setup was investigated. A magnetic tooling is connected to a CNC machining to polish the surface of stavax(S136) die steel workpieces. During finishing experiments, both AE signals and force signals were sampled and analysed. The finishing results show that MAF has nano scale finishing capability (upto 8nm in surface roughness) and the sensor signals have strong correlations with the parameters such as gap between the tool and workpiece, feed rate and abrasive size. In addition, the signals were utilized as the input parameters of artificial neural networks to predict generated surface roughness. Among the three networks constructed -AE rms input, force input, AE+force input- the ANN with sensor fusion (AE+force) produced most stable results. From above, it has been shown that the proposed sensor fusion scheme is appropriate for the monitoring and prediction of the nano scale precision finishing process.

• Transactions of the Society of Information Storage Systems
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• v.3 no.2
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• pp.66-72
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• 2007

Surface finishing using magnetorheological (MR) fluid is useful to finish small but not too small workpieces such as those in a few millimeter scale. However, due to the high surface hardness, this finishing process does not seem to be suit for applying to a hard disk slider. In this work, a preliminary study is performed on the finishing of the hard disk slider surface with a mixture of an MR fluid and diamond powder. During a wheel type MR finishing process, centrifugal force is found to be a major factor to cause a reduction in material remove rate (MRR), which is supported by a theoretical model. To facilitate this founding, the rotational speed of tool is confined to 500rpm while a rectilinear alternating motion with the mean speed, which is equivalent to the rotational speed, is additionally applied to the workpieces. As a consequence, MRR of about 2 times of the sole rotational case is obtained. This paper shows that MR finishing process can be used to polish a hard material in millimeter scale efficiently by controlling the speeds of the tool and the workpiece.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.12
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• pp.37-43
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• 2004

The performance of magnetic abrasive finishing fur surface is evaluated by the characteristic curve. The characteristic curve is generated by experiment in surface finishing. For experiment, new magnetic inductor is designed and manufactured. 15 kinds of powders are provided to find the relationship between powder characteristic and finishing performance. As powder, Fe-TiC. Polymer-TiC and Fe-NbC are used with different size. The size of abrasives and location are also important factor for the performance. From characteristic curve, two index are obtained, which specify the initial finishing performance and endurance of finishing performance. It is proved that the performance index can be applied to select proper powder for efficient deburring. It is shown that the characteristic curve can be used as good tools for evaluating powder performance in surface finishing and deburring.

• Journal of Technologic Dentistry
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• v.43 no.4
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• pp.145-152
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• 2021

Purpose: This study aimed to produce resin prosthetics using a dental barrel finishing machine. For dental resin grinding, the ingredients of the barrel finishing media were analyzed, and surface residues of the resin were observed. Methods: Two types of barrel finishing media for dental resin grinding were tested. Specimens were made from thermal polymerized, auto polymerized, and photopolymerized resins. Finishing media were analyzed through energy-dispersive X-ray spectroscopy (EDS) component analysis and inductively coupled plasma-optical emission spectrometry (ICP-OES) component analysis. Then, the prepared specimen was barrel finished for 25 minutes using two types of barrel finishing media, and scanning electron microscope was photographed to observe the surface residues. Results: As a result of EDS component analysis, both types of finishing media were analyzed for the components of C, O, Zr and Al elements, and industry media (IM) was further analyzed for the components of Si and Mg elements. In the ICP-OES component analysis, Cd and As, which are harmful elements, were detected in IM, and no harmful elements were detected in manufacturing media (MM). Because of observation of surface residues, no residues were observed in the three types of resin specimens that were barrel finished with two types of finishing media. Conclusion: Surface residue wasn't observed on the specimens polished using two types of finishing media. However, in IM, Cd and As, which are harmful elements, were detected, making it inappropriate for clinical use. In MM, harmful elements were not detected; therefore, clinical use will be possible.

• The Journal of Advanced Prosthodontics
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• v.8 no.1
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• pp.16-20
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• 2016

PURPOSE. Polymer infiltrated ceramic network (PICN) materials, also called hybrid ceramics, are new materials in dental market. The manufacturer of the PICN material VITA Enamic suggests 3 different finishing procedures for this new material. In the present study, surface roughness and color differences caused from different finishing procedures of VITA Enamic were investigated. MATERIALS AND METHODS. 120 specimens were prepared in dimensions $2{\times}10{\times}12mm$ from VITA Enamic hybrid ceramic blocks with 'high translucency' and 'translucency 2M2' shades. The specimens were divided into 8 groups. For each group, different finishing procedures suggested by the manufacturer were performed. Surface roughness values were determined by a tactile portable profilometer. Color changes were evaluated using a clinical spectrophotometer. The data were analyzed using one-way ANOVA and Tukey's post-hoc comparison. The significance level was set at ${\alpha}=0.05$. RESULTS. The roughest surfaces were observed in Glaze Groups. Their surface roughness values were similar to that of the control group. Clinical Kit and Technical Kit groups did not show a statistically significant difference regarding surface roughness (P>.05). The largest color difference regarding ${\Delta}E_{00}$ was observed in Clinical Kit finishing groups. There were also statistically significant color changes between the groups (P<.05). However, all the groups showed clinically acceptable color change (${\Delta}E_{00}$<2.25) except Clinical Kit Groups (${\Delta}E_{00}$>2.25). CONCLUSION. Within the limitations of the present study, it may be suggested that finishing the VITA Enamic restorations by Technical Kit instead of Glaze and Clinical Kit gives better clinical performance in regard to surface roughness and shade matching.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.1
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• pp.47-53
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• 2001

Results ar presented of a new process for internal precision finishing of slender fine ceramic pipes using a magnetic field generated by a permanent magnets. For finishing the interior surface of a long pipe, a new type of finishing equipment was developed which can be very easily used in an industrial surrounding. In general, the pipe is so slender that a conventional finishing tool is hardly inserted into the pipe deeply, being impossible to finish. Therefore, a new technology has been considered to finish inside of a slender ceramic pipe by a simple technique. In this experimental, Magnetic Abrasive Machining is applied for the inner surface of silicon nitride fine ceramic pipe using ferromagnetic particles mixed with chromium-oxide powder. It is shown the initial roughness of 2.6㎛ Ry(0.42㎛ Ra) in the inside surface can be precisely finished to the roughness of 0.1㎛ Ry(0.01㎛ Ra). This paper discusses the outline of the processing by the application of magnetic abrasive machining and a few finishing characteristics.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1995.10a
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• pp.24-29
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• 1995

A recently developed finishing process using rotating magnetic field is known to be very efficient for the finishing of parts such as vacuum tube, sanitary tube, etc., which are difficult to be finished by the conventional finishing methods as they are generally curbed tubes. But, the finishing system using rotating magnetic field have the defect that is the cross section of workpiece only circle because of internal rotating tool. Therefore, new finishing process of the workpieces which cross section are not circle is important and required. magnetic abrasive jet machining is a new concept finishing process. It is the precision internal finishing method using working fluid mixed with magnetic abrasives, which is jetted into the internal surface of tube. And magnetic poles are equipped on external surface of tube. In this study new concept finishing process or, magnetic abrasive jet machining system was developed. machining condition was predicted using simulation and some characteristics of the finishing process was analyzed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.2
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• pp.23-30
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• 2022

After drilling, reaming is required to process a workpiece for obtaining an excellent surface quality. In general, a cermet is defined as a "composite of a ceramic hard phase and metal-bonded phase." Cermets have excellent abrasion resistance, thermal resistance, and performance in finishing operations that require surface roughness and processing precision. However, although cermets have significant advantages, research on them is insufficient. In this study, workpiece SM45C was machined using drills and cermet reamers. The cermet reamer was processed for drag finishing for 0, 4, and 6 min. The experimental results showed the effects of drag finishing on surface roughness and dimensional accuracy.

• Journal of Technologic Dentistry
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• v.43 no.2
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• pp.56-61
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• 2021

Purpose: This study aimed to produce resin prosthetics using a dental automatic barrel finishing. Surface roughness and surface topography of resins were observed according to the grinding time of the dental automatic barrel finishing. Methods: This study was performed with thermopolymer, autopolymer, and photopolymer resins. The dimensions of the specimen were 10×10×2 mm. Each specimen was polymerized according to the manufacturer's instructions. The polymerized resin was honed for 30 minutes at 5-min intervals in a dental automatic barrel finishing. The specimen was observed using a three-dimensional (3D) optical microscope, and the surface roughness was measured. Results: After the polishing with the dental automatic barrel finishing, the heat-cured (HC) specimen showed the highest and lowest values of Ra after 10 and 15 minutes, respectively. The self-cured (SC) specimen showed the highest and lowest values of Ra after 10 and 25 minutes, respectively. Finally, the 3D specimen showed the highest and lowest values of Ra after 5 and 20 minutes, respectively. Conclusion: After measuring the surface roughness of the three types of resins according to the grinding time of the dental automatic barrel finishing, the lowest Ra values for the HC, SC, and 3D specimens were measured after 15, 25, and 20 minutes, respectively. Therefore, we concluded that a limit on the grinding time of the resin using a dental automatic barrel finishing is needed.