• Journal of the Korean Society for Precision Engineering
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• v.16 no.3 s.96
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• pp.38-46
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• 1999

Spindle motor current is used to estimate the cutting force indirectly and control the feed rate for the cutting force regulation. The proposed algorithm is implemented to a DSP board based hardware for the industrial application. The software to make POP terminal communicate with the DSP board and POP server is coded under Windows 95 environment. Experiments under varying cutting conditions show that the DSP board recognizes the information of installed cutting tool and cutting conditions delivered from the POP server to use them for the proper control of the feed rate. The cutting force is regulated well during machining of tapered or stepped workpiece and circular shaped workpiece as well.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.10
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• pp.15-27
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• 1997

Quasti-static cutting force variations in milling process are measured indirectly using spindle motor current. Quasi-static sensitivity of the spindle motor current is higher than that of the feed motor current. Magnitude of the spindle motor current is independent of cutting direction. The linear relationship between the cutting force and the spimdle motor RMS current at various spindle rotational speed is obtained. Frequency/ Voltage(F/V) converter voltage is measured to identify the spindle speed and to determine the cutting force at various spindle speeds. Overload on the tool during milling process can be detected using the proposed indirect cutting force measurement. Based on these measurements, cutting force is regulated at a constant level by feedrate control.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.240-245
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• 2000

This paper presents the experimental study of drilling for duralumin A2024 with intermittently decelerated feed rate. It is achieved through a programmed periodic increase and decrease in the feed rate using a machining center. The following experimental result were performed with the objective of solving chip to disposal problems. In conventional drilling of aluminum, long continuous chips are produced that wind around the drill causing difficulties in eliminating chips from the cutting zone. In order to acquire the basic data necessary to regulate the chip profile, the relationship between cutting variables and chip shape was investigated. The following conclusions are established from the experimental results. At a suitable feed fluctuation ratio, intermittently decelerated feed drilling proved successful in breaking chips to appropriate lengths while maintaining stable cutting. Thus, it is an effective method for improving chip disposal. The amplitude of the dynamic component of cutting force in intermittent feed frilling is influenced by the feed fluctuation ratio.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.2 s.233
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• pp.333-340
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• 2005

Feedrate is one of the factors that have the significant effects on the productivity, qualify and tool life in the cutting mechanism as well as cutting velocity, depth of cut and width of cut. In this study, in order to realize the high-efficient machining, a new feedrate optimization method is proposed based on the concept that the optimum feedrate can be derived from the allowable cutting power since the cutting power can be predicted from the cutting parameters as feedrate, depth of cut, width of cut, chip thickness, engagement angle, rake angle, specific cutting force and so on. Tool paths are extracted from the original NC program via the reverse post-processing process and converted into the infinitesimal tool paths via the interpolation process. And the novel NC program is reconstructed by optimizing the feedrate of infinitesimal tool paths. Especially, the fast feedrate optimization is realized by using the Boolean operation based on the Goldfeather CSG rendering algorithm, and the simulation results reveal the availability of the proposed optimization method dramatically reducing the cutting time and/or the optimization time. As a result, the proposed optimization method will go far toward improving the productivity and qualify.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.5
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• pp.377-383
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• 2016

Recently, research on bone fracture and osteoplasty using ultrasonic bone surgery unit has been ongoing in the fields of dentistry, plastic surgery, and otorhinolaryngology. However, detailed data evaluation with ultrasonic bone surgery unit has not been conducted to date. In this study, we developed handpiece moving system (HMS) for cutting performance evaluation. In the experimental setup of HMS, a handpiece was immobilized, and bone samples from cortical bone of bovine leg were prepared. Also, the experimental process was described in detail, and a basic experiment was carried out to evaluate the cutting performance. Future study is required on all experimental process conditions by HMS.

• Explosives and Blasting
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• v.19 no.3
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• pp.105-113
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• 2001

채석, 굴착, 가공과 같은 워터젯 응용분야에서 대상재료에 깊은 홈(kerf)을 절단할 수 있는 실험실용 회전식 슬로터(slotter)를 제작하여 암석을 대상으로 워터젯 시스템의 절단효율을 시험하였다. 고압펌프는 유율 7.5 l/min, 압력 379 MPa, 용량 75 kW급의 JETPAC을 주로 사용하였고, 암석시료는 화강석인 제천석, 거창석을 사용하였다. 시험과정에서는 물과 연마재 투입에 의한 절단 및 진동식 슬로터에 의한 슬롯절단 기초시험을 먼저 수행하고, 그 결과를 토대로 회전식 슬로터에 의한 절단시험을 실시하였다. 순수한 물에 의한 시험의 결과 고압수류의 토출압력은 절단심도에 정비례하였고, 노즐의 이송속도는 이차함수 형태의 반비례 관계를 보였다. 연마재 투입시험에서는 순수한 물에 의한 경우에 비해 연마재로 인한 충격력의 증가로 절단심도가 크게 증가하였는데, 유사한 조건하에서 3~5배 이상의 절단심도의 증가를 보였다. 진동식 슬로터에 의한 슬롯절삭에서는 생성된 슬롯의 내벽면이 바닥으로 갈수록 좁아짐으로써 넓은 폭의 슬롯형성은 가능하나 절삭심도가 제한되었다. 회전식 슬로터에 의한 시험에서 생성된 슬롯들은 평균 22 mm의 폭으로 내벽면이 바닥까지 서로 평행하여 깊은 심도까지 비트진입이 가능하였다. 절단율은 16~32 mm/sec의 속도범위에서 $40~160{\;}\textrm{mm}^2/sec$로 나타났다. 한편, 최대유율 24 l/min의 HUSKY S-200 펌프에 의한 시험결과 JETPAC 펌프에 비해 1.13~3.47 배의 절단심도를 보였다

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.1
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• pp.73-79
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• 2013

In this study, NIMAX material has been processed using the three-dimensional measuring instrument and white light interferometer. they were tested to roundness and surface roughness and results are as follows: As for a cutting characteristic, it indicated that F4 showed a lower result than 2F showed due to the high hardness of the material and showed a good result when spindle rotation speed and tool feed were low. As for the measurement of roundness through 3-Dimensional measuring machine, it indicated that 4F showed a good result like the condition of cutting component and that roundness showed a good result when spindle rotation speed of 1,700 rpm and tool feed speed of 85 mm/min were applied. As for the surface roughness of processing surface, Surface roughness showed better 4F than 2F and conditions of spindle rotation speed 1,700 rpm, tool feed rate 55 mm/min showed good results in the Ra $0.4025{\mu}m$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.2
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• pp.471-477
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• 2012

SCM420 steel tempered after performing gear hove PACVD carbide coating on the surface after the cutting surface hardness was high. Difficult-to-cut, without coating is classified as mild as large, including materials like mild, high strength that improves tool life and productivity have limited availability. Drive to improve it in the TiCN-coated carbide call for war to the finish coating on cutting a hob skiving good workability, tool wear less, 2.5-fold increase in tool life results were obtained. Experiments using CNC Skiving hobbing machine with wet cutting conditions, cutting speed and feed rate to apply a variety of the tool wear and surface roughness data were obtained. Results from condition 2 (V = 200m/min F = 0.7mm/rev) cutting speed feed mark the cutting surface microstructure and surface roughness Rmax $4.7{\mu}m$(Ra $1.19{\mu}m$) of the data was obtained.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.1
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• pp.120-130
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• 1993

Generally, the machinability of materials that have a good mechanical properties is poor. For materials having a high strength, high toughness, high strength in high temperature and wear resistance, it is difficult to remove a chip from work materials. These properties are well shown in a Nickel, so this metal is used in machine materials, semi-conductor industry, metal mold and optical fields etc. But it is limitted in use because of high cost and poor machinability. In this study, the cutting of pure Nickel was conducted to examine wear of CBN, poly crystal diamond (PCD) and single crystal diamond (SCD) tools. From the result, the CBN tool is superior to poly crystal diamond tools or single crystal diamond tools in terms of tool wear and tool wear is predictable from experimental data base.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.59-64
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• 1997

This paper investigates the relationship between cutting conditions and Acoustic Emission(AE) signals; AEavg, AErms, AEmode, as the base working to monitor the tool wear with in-process. For this purpose, cutting tests were conducted on a CNC lathe with comprehensive cutting conditions.. It is known that AEavg and AErms are proportionaly increased as the increasing of cutting velocity and depth of cut respectively. It is also known that AEmode among three kinds of AE signals may be applied for in-process monitoring to make the self diagnosis system because of its stability to the variation of cutting condition.