• 한국정밀공학회지
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• 제14권7호
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• pp.15-21
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• 1997

This paper presented a linear motion accuracy by using two-dimensional probe with the master block and the square for NC machine tools. This measuring system could be measured motion error due to numerical control system. The results of measurement and simulation for motion error were similar, and so, this system had enough accuracy to measure a linear motion accuracy for NC machine tools. The experimental results are as follows. 1. This measuring system could be measured motion error due to mumerical control system. 2. The results of measurement and simulation for motion error were similar. 3. This measuring system had enough accuracy to measure a linear motion accuracy for NC machine tools.

• 소성∙가공
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• 제27권3호
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• pp.154-159
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• 2018

In the rectangular bar multi-stage drawing process, the cross-section dimensional accuracy of the rectangular bar varies depending on the aspect ratio and process conditions. It is very important to predict the dimensional error of the cross-section occurring in the multi-stage drawing process according to the aspect ratio of the rectangular bar and the half die angle of each pass. In this study, a process map for improving the dimensional accuracy according to the aspect ratio was derived in the drawing process of a rectangular bar. FE-simulation of the multi-stage shape drawing process was carried out with four types of rectangular bar. The results of the FE-simulation were trained to the nonlinear relationship between the shape parameters using an Artificial Neural Network (ANN), and the process maps were derived from them. The optimum half die angles were determined from the process maps on the dimensional accuracy. The validity of the suggested process map for aspect ratios 1.25~2:1 were verified through FE-simulation and experimentation.

• 한국산업융합학회 논문집
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• 제22권6호
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• pp.599-606
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• 2019

In this study, it was aimed to find the optimal cutting conditions by measuring and analyzing the dimensional accuracy of SNCM 616 alloy steel, which is commonly used in industry, by precision hole machining using Ø25 mm and 8-blade reamer in CNC-HBM to be. As a result of the roundness and dimensional accuracy, it was found that the spindle speed had a significant effect on the dimensional tolerance value. Optimum cutting conditions are spindle speed 25 rpm and feed rate 20 mm / min.

• 한국기계가공학회지
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• 제18권9호
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• pp.58-63
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• 2019

In this research, we examine the change of dimensional accuracy in the cutting process while changing cutting conditions such as feed rate and spindle rotational speed with chromium molybdenum steel (SCM415) material and TiCN- and TiAlN-coated end mill tools. According to dimensional accuracy measurement, TiCN-coated tool displays the most accurate dimensional tolerance at ${\varnothing}20mm$ at feed rates of 200 mm/min and 250 mm/min at a spindle rotation speed of 4,000 rpm. The largest dimension of the coating tool was able to make the TiAlN-coated tool suitable when comparing the smallest dimension.

• 대한치과보철학회지
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• 제37권3호
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• pp.301-312
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• 1999

The purpose of this study was to compare the accuracy of currently used elastomeric impression materials for complete arch impression taking. Five elastomers (Impregum, Permlastic, Express, Extrude, Examix) and one Irreversible hydrocolloid (Aroma-fine) were tested. For each material, 5 impressions were made of stainless steel model to which five tapered posts were attached. Custom trays were used for polyether and polysulfide impression materials, and putty/wash two step technique was used for addition polyvinylsiloxane impression materials. Improved stone mod els were poured to all impressions. Accuracy of the materials was assessed by measuring ten distances on stone dies poured from impressions of the master model. All measurements for master and improved stone models were made with three dimensional measuring machine. The results were as follows 1. The dimensional accuracy of polyether, extrude, and examix were significantly superior to poly-sulfide, exress, and alginate in reproducing full arch mode (p<0.05) 2. There were no statistical differences in dimensional accuracy for full arch impression between polyether extrude and examix (p>0.05). 3. there were no statistical differences in dimensional accuracy between polysulfide, express, and alginate(p>0.05). 4. There were no statistical differences between addition polyvinyl siloxane materials (p>0.05) 5. There were no statistical differences between anterior-posterior and lateral dimensional changes of all impression materials (p>0.05).

• 대한기계학회논문집A
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• 제32권6호
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• pp.474-480
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• 2008

Recently, rods having irregular sections more complex than a rectangle or ellipse are necessary to produce mechanical parts. The cold shaped drawing process is used to obtain shaped drawn products with high levels of dimensional accuracy and quality. A cross roller guide, considered in this study, is one of the parts produced by shaped drawing process. A cross roller guide has a linear bearing system that rolls along a guide way. A cross roller guide is one of the most important components in terms of equipment because the quality of the product influences the precision linear motion. Therefore, the final dimensional accuracy of the linear rail in the shaped drawing is very important. The objective of this study is to find the optimized die angles to improve the dimensional accuracy and straightness of the final shaped drawn product. In order to achieve the aim of this study, design of experiment, FE-simulation, and the Taguchi method were used. Based on the analytical results, shaped drawing experiment has been performed to verify the result.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.338-341
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• 2004

The dimension of forged part is different with the die dimension by the various effects, such as, elastic deformation and thermal effect. And, the difference amounts are not same according to the forging conditions, for example, forging mode, flow stress, etc. Therefore, the use of FEA is effective to predict and update the required die dimension. However, the variables for FE simulation are also as many as variables in the experiment. The variables give very much effect to the accuracy of FE results. At first, the material model is very deeply affected to the estimated dimension of forged part. And the considering of loading and ejecting stages is also important to increase the dimensional accuracy. The experiment and FEA are performed to investigate the dimensional changes and accuracy in cold forging. Two types of upsetting are used to survey the effects of forging mode and stages.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1107-1108
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• 2010

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 추계학술대회 논문집
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• pp.537-538
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• 2009

• 구강회복응용과학지
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• 제35권2호
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• pp.55-63
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• 2019

본 논문은 기존에 선행되었던 연구들을 바탕으로 디지털 모형의 정확도를 평가하는 여러 가지 방법에 관하여 정리하였다. 디지털 모형의 정확도 평가 시, 시험자 교육과 인공적 지표의 사용을 통해 오차를 줄일 수 있다. 디지털 치아 모형의 정확도 평가법은 크게 선형 측정법, 2차원 단면 분석법, 3차원 최적합 분석법으로 분류할 수 있다. 스캐너의 기술이 발전함에 따라 디지털 인상 기술과 전통적 인상법의 정확도를 비교하는 많은 연구들이 이루어지고 있다. 다양한 방법을 이용하여 디지털 모형의 정확도를 평가할 수 있으며, 앞으로 스캐너의 기술 향상 및 3차원 모형 분석 소프트웨어의 개발에 따라 디지털 모형의 정확도 평가 방법이 더욱 효과적으로 변화할 것이라 생각된다. 이 논문에서는 디지털 모형의 정확도를 평가하는 방법들에 대해 소개하고, 각각의 상황에 따른 효과적인 정확도 분석법에 대해 알아보고자 한다.