• Journal of the Korean Society of Safety
• /
• v.9 no.4
• /
• pp.17-28
• /
• 1994

Chip breaking is important in lathe work for maintaining good surface of the products and safety of operator. The purpose of this study is to investigate the performance of chip breaking and chip shape resulted from the carbide inserts with grooved type and obstruction type chip breaker. Experiments have been performed under the following cutting conditions, (1) constant cutting speed with variable depth of cut and feed rate, (2) constant depth of cut with variable cutting speed and feed rate. Also, the flying distance of chip and it's distribution have been investigated. As a results, good performance of chip breaking can be obtained for small radius of curvature and land width of grooved type chip breaker. And the thickness of chip increase with the increase of feed rate and decrease of cutting speed, and the chip breaking becomes easier with the increase of chip thickness due to the large deformation rate. Obstraction type chip breaker shows better performance of surface roughness than the grooved type. The flying distance of the chips over 90% are less than 1 meter, and the distance decreases as the feed rate decreases.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.04a
• /
• pp.993-997
• /
• 1997

The continuous chip depresses the accuracy of workpieces and promotes the wear of machine tools and hunts operators. So chip control os a major problem in turning process. In this paper, a method of chip identification is develope by pyrometer. The identifier is applied in real-time control of chip pattern with adjusting feedrate.

• Journal of the Korean Society for Heat Treatment
• /
• v.25 no.1
• /
• pp.14-21
• /
• 2012

The effects of cutting condition and tempering temperature for the shape of cutting chip were investigated. For this purpose, a lead-free brass containing 1wt.% of Bi extruded at $750^{\circ}C$ in straight turning was used in this study. The cutting chip preferred was mainly found to be loose form of arc chips with curling discontinuity, and these were formed by shear fracture. However, some of fragmental element chip were found to be mixed when tempering temperature was as high as $500^{\circ}C$. The form and size of chip was more affected by feed rate than by tempering temperature and cutting rate. In addition, the cutting surface was observed to be formed more rough in the case of high feed rate and low cutting rate compared to low feed rate and high cutting rate.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.10 no.3
• /
• pp.327-334
• /
• 2022

In this study, in order to evaluate the characteristics of mortar and concrete using wood chip cogeneration plant flooring as fine aggregate, mortar characteristics according to wood chip aggregate replacement rate and water-cement ratio as a substitute for crushed sand, and concrete characteristics according to wood chip aggregate replacement rate were compared and evaluated. The cement mortar flow according to the wood chip aggregate replacement rate showed a tendency to increase as the wood chip aggregate replacement rate increased, and the compressive strength and flexural strength increased as the wood chip aggregate replacement rate increased. The slump and air content of concrete increased as the aggregate replacement rate increased, and the compressive strength and tensile splitting strength of concrete tended to increase as the wood chip aggregate replacement rate increased. Accordingly, the possibility of using the flooring by the cogeneration plant as a fine aggregate for concrete was confirmed.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.4 no.2
• /
• pp.3-9
• /
• 2005

In this study, the chip breaking characteristics of S, PbS and BiS free machining steels have been assessed. PbS free machining steel shows the lowest value of chip thickness ($t_c$) under the same cutting conditions. SM10C steel has the largest value of the chip cross-section area ratio ($R_{CA}$). As the feed rate becomes larger the chip breaking cycle time ($T_B$) decreases and the chip breaking index ($C_B$) increases. The properly controlled-C type chip has been obtained with the value of $C_B$ between 0.05 and 0.2. Free machining steel, PbS produces the properly controlled-C type chip in a wider feed rate range than other steels.

• Journal of Korea Foundry Society
• /
• v.29 no.1
• /
• pp.38-44
• /
• 2009

Magnetic separation of Fe contaminated Al-Si cutting chip scraps was performed for the recyclability assessment. It was also aimed to investigate the casting and solidification characteristics of the cutting chip scraps. The magnetically separated cutting chip scraps were adequately treated for the casting procedure and test specimens were made into a stepped mold inducing different cooling rates. The test specimens were evaluated by the combined analysis of ICP, Spectroscopy, OM-image analyzer, SEM/EDS, etc. Solidification characteristics of cutting chip scraps were examined as functions of Fe content and cooling rate. It is concluded that the magnetic separation process can be utilized to recycle the Fe contaminated Al-Si cutting chip scraps in the high cooling rate foundry process.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.2A
• /
• pp.128-133
• /
• 2010

We investigate the optimal chip rate of power or rate adapted direct-sequence code division multiple access (DS/CDMA) communication systems in Nakagami fading channels. We find that the optimal chip rate that maximizes the spectral efficiency depends upon both the channel parameters, such as multipath intensity profile (MIP) and line-of-sight (LOS) component, and the adaptation scheme itself. With the rate adaptation, the optimal chip rate is less than $1/T_m$, irrespective of the channel parameters, where $1/T_m$ is multipath delay spread. This indicates that with the rate adaptation, correlation receiver achieves higher spectral efficiency than RAKE receiver. With the power adaptation, however, the optimal chip rate and the corresponding number of tabs in RAKE receiver are sensitive to MIP and LOS component.

• Proceedings of the KWS Conference
• /
• 2005.06a
• /
• pp.19-21
• /
• 2005

The ball shea. tests for ball grid array (BGA) and flip chip packages were carried out with different displacement rates to find out the optimum condition of the displacement rate for this test. The BGA packages consisted of two different kinds of solder balls (eutectic Sn-37wt.%Pb and Sn-3.5wt.%Ag) and electroplated Au/Ni/Cu substrate, whereas the flip chip package consisted of electroplated Sn-37Pb solder and Cu UBM. The packages were reflowed up to 10 times, or aged at 443 K up to 21 days. The variation of the displacement rate resulted in the variations of the shear properties such as shear force, displacement rate at break, fracture mode and strain rate sensitivity. The increase in the displacement rate led to the increase of the shear force and brittleness of solder joints.

• Biomedical Science Letters
• /
• v.21 no.1
• /
• pp.32-39
• /
• 2015

High-risk (HR) human papillomavirus (HPV) genotypes are strongly associated with cervical cancer, whereas other HPV genotypes are not. To identify the various HPV genotypes in clinical samples, we conducted HPV genotyping using a DNA chip test and reverse blot hybridization assay (REBA) in normal cytology samples and atypical squamous cells of undetermined significance (ASCUS) cytology samples. We also investigated the HPV infection rate and HPV genotype prevalence in women with normal cytology and ASCUS cytology. Liquid-based cytology preparations were used for the initial screening of 205 subjects with normal cytology and ASCUS cytology. The HPV infection rate was 49.8% when using the DNA chip assay and 61.0% when using the REBA test. In patients with normal cytology, the HR-HPV positive rate was 21.9% with the DNA chip assay and 43.9% with the REBA test. In contrast, 8.3% of patients with ASCUS were HR-HPV positive when using the DNA chip assay, and 13.6% were positive when tested with the REBA test. The infection rate of HR-HPV in the 40~50-year age group was significantly higher than that of the other age groups. Based on the cytological analysis of the normal and ASCUS samples, the five most prominent HPV genotypes were HPV 16, 18, 68, 33, and 58 using the DNA chip test, and they were HPV 16, 18, 53, 33, and 66 when using the REBA test. In conclusion, the findings show that the results of the REBA test are comparable to those of the DNA chip test. Most strikingly, the REBA test detected the HR-HPV genotype associated with cervical carcinoma similar to that detected with the DNA chip method. Therefore, the REBA test is a useful method to detect clinically important HR-HPV genotypes.

• Journal of the Korean Society of Industry Convergence
• /
• v.2 no.2
• /
• pp.131-137
• /
• 1999

Package crack caused by the soldering process in the surface mounting plastic package is evaluated by applying the energy release rate criterion. The package crack formation depend on various parameters such as chip set, chip size, package thickness, package width, material properties and the moisture content etc. The effects of chip set and the other parameters were estimated during the analysis of package cracks which were located in the edge of the upper interface of the chip and the lower interlace of the die pad. From the results, it could be obtained that the more significant parameters to effect the chip set are chip width.