• International Journal of Precision Engineering and Manufacturing
• /
• 제9권4호
• /
• pp.16-21
• /
• 2008

The demand for three-dimensional (3D) shape measurements is increasing in a variety of fields, including the manufacture of molds and dies. The most popular technology for 3D shape measurement is the coordinate measuring machine (CMM) with a contact trigger probe. Although a CMM provides a high degree of accuracy, it is inefficient due to its long measuring time. It also has difficulty measuring soft objects that can be deformed by the touch of the contact probe. In addition, a CMM cannot digitize areas that are difficult to reach, and cannot capture very minute details on the surface of complex parts. For these reasons, optical non-contact measurement techniques are receiving more attention since they eliminate most of the problems associated with contact methods. Laser scanning is emerging as one of the more promising non-contact measurement techniques. This paper describes various acquisition considerations for laser scanning, including the accuracy of the 3D scan data, which depends on the charge-coupled device (CCD) gain and noise. The CCD gain and noise of a 3D laser scanner are varied while keeping the other conditions constant, and the measurement results are compared to the dimensions of a standard model. The experimental results show that a considerable time savings and an optimum degree of accuracy are possible by selecting the proper CCD gain and noise.

• International Journal of Precision Engineering and Manufacturing
• /
• 제8권2호
• /
• pp.26-31
• /
• 2007

A novel scanning probe measurement system was developed to enable precise profile measurements of microaspheric surfaces. An air-bearing stylus with a microprobe was used to perform the surface profile scanning. The new system worked in a contact mode and had the capability of measuring micro-aspheric surfaces with large tilt angles and complex profiles. Due to limitations resulting from the contact mode, such as possible damage caused by the contact force and lateral resolution restrictions from the curvature of the probe tip, several system improvements were implemented. An air bearing was used to suspend the shaft of the probe to reduce the contact force, enabling fine adjustments of the contact force by changing the air pressure. The movement of the shaft was measured by a linear encoder with a scale attached to the actual shaft to avoid Abbe errors. A $50-{\mu}m-diameter$ glass sphere was bonded to the tip of the probe to improve the lateral resolution of the system. The maximum contact force of the probe was 10 mN. The shaft was capable of holding the probe continuously if the contact force was less than 40 mN, and the resolution of the probe could be as high as 10 nm, The performance of the new scanning probe measurement system was verified by experimental data.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2010년도 추계 학술발표회 3차
• /
• pp.24-30
• /
• 2010

The void ratio and elastic moduli are design parameters used in geotechnical engineering to understand soil behavior. Elastic and electromagnetic waves have been used to evaluate the various soil characteristics due to high resolution. The objective of this study is to evaluate the void ratio and elastic moduli based on elastic wave velocities and electrical resistivity. The Field Velocity Resistivity Probe (FVRP) is developed to obtain the elastic and electromagnetic wave profiles of soil during penetration. The Piezoelectric Disk Elements (PDE) and Bender Elements (BE) are used as transducers for measuring the elastic wave velocities such as compressional and shear wave velocities. The Electrical Resistivity Probe (ERP) is also installed for capturing the electrical resistivity profile. The application test is carried out on the southern coast of the Korean peninsula. The field tests are performed at a depth of 6~20 m, at 10 cm intervals for measuring elastic wave velocities and at 0.5cm intervals for measuring electrical resistivity. The elastic moduli such as constraint and shear moduli are calculated by using measured elastic wave velocities. The void ratios are also evaluated based on the elastic wave velocities and the electrical resistivity. Furthermore, the converted void ratios by using FVRP are compared with the volumetric void ratio obtained by a standard consolidation test. The comparison shows that the void ratios based on the FVPR match the volume based void ratio well. This study suggests that the FVRP may be a useful device to effectively determine the elastic moduli and void ratio in the field.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 1999년도 춘계학술대회 논문집
• /
• pp.63-68
• /
• 1999

A 2$\frac{1}{2}$ dimensional measurement and inspection system realized on the machine tool using a touch trigger probe and measuring G codes is synthesized in this paper. Measuring G codes have been constructed according to geometric farms, precision attributes, relationships between two parts, datum hierarchies, and relevant technological data by using measuring arguments. Algorithms far calibration and compensation of measuring errors are proposed to ensure the measuring accuracy by using a laser interferometer and ring gauges. Classification of feed rates according to the objectives of movement makes it possible to reduce measuring time and also implement collision-free measurement. Experiments are conducted to verify the validity and effectiveness of proposed methods.

• 한국기계가공학회지
• /
• 제19권9호
• /
• pp.40-46
• /
• 2020

Inspection of vehicle systems is regularly performed by the state to ensure the emission status and the safety of vehicles. Thereby, the safety and quality of life can be improved by reducing green-house gases and fine dust, which are the main causes of vehicle defects and air pollution. This study analyzed the soot measuring probes used in the free acceleration mode method, at no-load condition, looking at the efficiency of a probe to measure soot emissions from diesel vehicles. In this study, a technique that can improve the inhalation efficiency of the probe over the (a) probes and the improved (b) probes was applied to probes (c). Probe (c) involves a structure designed close to the center of the circumference of the exhaust pipe. Results showed that the suction efficiency was improved by adding a variable center unit.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 26-27 Oct. 1990
• /
• pp.1184-1189
• /
• 1990

In order to investigate liquid fuel filming over the intake manifold wall, an electrode-type probe has been developed by lines of authors and this probe was employed in a single cylinder two and four-stroke cycle engine and in a four cylinder four-stroke engine operated by neat methanol fuel. The performance of the probe was dependent upon several parameters including the liquid fuel layer thickness, temperature, additive in the fuel, and electric power source (i.e., AC and voltage level) and was independent of other variables such as direction of liquid flow with respect to the probe arrangement. Several new findings from this study may be in order. The flow velocity of the fuel layer in the intake manifold of engine was about (if the air velocity in the steady state operation, the layer thickness of liquid fuel varied in both the circumferential and longitydinal directions. In the transient operation of the engine, the temporal variation of fuel thickness was determined, which clearly suggests that there was difference between fuel/air ratio in the intake manifold and that in the cylinder. The variation was greatly affected by the engine speed, fuel/air ratio and throttle opening. And the variation was also very significant from cylinder to cylinder and it was particularly strong different engine speeds and throttle opening.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회B
• /
• pp.2381-2384
• /
• 2008

The heat exchange between the Borehole Heat Exchanger(BHE) and the surrounding ground depends directly on ground thermal conductivity k at the certain site. The k is thus a key parameter in designing BHE and coupled geothermal heat pump systems. Currently, although a thermal hydraulic Response Test(TRT) is mostly used in practice, the thermal hydraulic TRT needs additional power and is generally time-consuming. A new, simple wireless probe for hi-speed k determination was introduced in this paper. This technique using a wireless probe is less time-consuming and requires no external source of energy for measurement and predicts local thermal properties by measuring soil temperatures along the depth. Measured temperature data along the depth was analyzed. As a result, the electronic wireless probe can replace the conventional hydraulic TRT method after carrying out the additional research on a lot of local heat flow, etc.

• 대한기계학회논문집A
• /
• 제36권2호
• /
• pp.195-201
• /
• 2012

다양한 소비자의 요구에 따라 가공된 제품을 좀더 신속하고 정확하게 측정할 수 있는 공작기계 내 자동계측장치를 적용하는 사례가 급격히 증가하고 있다. 자동 계측으로 가장 많이 활용되는 접촉식 측정 프로브는 주로 공작물의 가공 원점을 설정하고, 정확한 치수 검사를 통한 불량유무 판정 및 보상가공에 많이 활용된다. 따라서 본 연구에서는 기기상 자동계측장치인 접촉식 측정 프로브를 활용하여 가공된 형상을 신속하고 정확하게 측정하는 방법을 연구하였으며 이를 위하여 가장 많이 활용되는 홀 측정 사이클에 대한 매크로 프로그램을 개발하였다. 또한 측정 시 홀의 진원도 오차에 따라 발생할 수 있는 편심량을 시뮬레이션하여 분석하였으며 본 연구의 신뢰성을 높이기 위하여 기기상에서 개발된 홀 측정 매크로 프로그램을 이용하여 홀플레이트에 대한 측정이 이루어졌으며, 진원도 오차에 따른 편심량을 검증하였다.

• 한국정밀공학회지
• /
• 제17권5호
• /
• pp.124-130
• /
• 2000

For measuring out the submicron order straightness, a precision measuring device is developed in this paper. The device is constructed with a hydrostatic feed table and a capacitive type sensor which is mounted to the feed table. Straightness is acquired as substracting the motion error of feed table from the measured profile with probe. Motion error of feed table is simultaneously compensated upto 0.120${\mu}{\textrm}{m}$ of linear motion error and 0.20arcsec of angular motion error using the active controlled capillary. Reversal method and strai호t-edge is used fur estimating the measuring accuracy and from the experimental result, it is verified that the device has the measuring accuracy 0.030m. Also, through the practical application on the measurement of ground surface, it is confirmed that the device is very effective to measure the submicron order straightness.

• 산업공학
• /
• 제12권2호
• /
• pp.180-192
• /
• 1999

A coordinate measuring machine (CMM) is a computer-controlled measuring device that uses a probe to obtain measurements on a manufactured part's surface. CMM's have been very popular over traditional hard gauges due to their flexibility, accuracy, and ease of automated inspection. This paper considers the use of a CMM for the inspection of gears. We compare the inspection capability of a CMM and that of a gear-specific measuring machine. The result of this paper may benefit gear manufacturing companies in their dimensional quality assurance activities, especially for special type gears and for large-scale gears which are not measurable by gear-specific measuring machines.