• Journal of the Architectural Institute of Korea Structure & Construction
• /
• v.35 no.2
• /
• pp.37-44
• /
• 2019

The primary objective of this study is to develop a prototype of all-in-one attachment-based PHC pile head cutting robot that improves the conventional work in safety, productivity, and quality. For this, the following research works are conducted sequentially; 1)literature review, 2)development of an all-in-one attachment-based PHC pile head cutting robot prototype, 3)performance evaluation of each device, 4)economic analysis of an automated method. As a result, PHC pile cutting level sensing device, PHC pile cutting device, PHC pile handling device are developed. Futhermore, working process of an automated method is developed based on result of performance evaluation. According to the economic analysis result, the cost of the automated method was 21.37% less than that of the conventional method, and the economic efficiency was also superior(ROR 215.44%, Break-even Point 5.52month). It is expected that conclusions for future improvements are used in the development of the all-in-one attachment-based PHC pile head cutting robot to practical use.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.34 no.3
• /
• pp.35-40
• /
• 2011

5-axis laser cutting has great advantages when it is applied to three dimensional machining requiring high cutting quality. For developing 5-axis CNC laser cutting systems, however, many problems such as rotating a laser head or a working table, 5-axis servo-control mechanism, tool path generation and post-processing, and collision avoidance between a laser head and a work-piece should be solved. In this paper, we deal with developing a motion simulator for 5-axis laser cutting machine with a nutating cutting head whose rotational axis is in an inclined plane. Two essential modules such as post-processor and cutting motion simulator was developed based on a commercial 3D CAD of UG-NX. The developed system was applied to three dimensional cutting products and showed the validity of the developed methods.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2023.05a
• /
• pp.387-388
• /
• 2023

PHC pile head cutting is an essential work in pile foundation construction. However, since the work has labor-intensive characteristics, there are problems such as productivity and safety. So in previous study PHC pile one-cutting head cutting automation equipment was developed to solve this problem. However, it has been investigated as a limitation that checking the cutting position of the PHC pile can be challenging in place where a rotary laser leveler cannot irradiate cutting position, as the sensing unit of the developed automated equipment utilizes an optical method. Therefore, the objective of this study is to delvelop a GNSS-based methodology for sensing the cutting position of PHC piles to overcome the limitations of the optical method and to examine its feasibility for field application. If the proposed methodology is applied to the construction site, it is expected that the convenience and productivity of the PHC pile cutting position sensing work will be improved.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.7 no.2
• /
• pp.161-167
• /
• 1983

In this study the phenomenon of cutting stress which arises on cutting tools and work pieces in cutting process is investigated by rake angle of cutting tools and feed for this measurement, P$_{s}$-1 (high modulus, photolastic Inc.) was used as a cutting tool, P$_{s}$-3 (medium modulus, photolastic Inc.) was used as work piece and reduction apparatus was attached to the head stock, and orthogonal cutting was adapted as a cutting method and transparent glass was used to block the strain in the orientation of thickness. The followings are the results of this study. (1) Photoelastic experimental equipments have made it possible to make dynamic measurement and analyze stress distribution in cutting tool and work piece surface which has hitherto been conducted only in static measurement and analyzing method. (2) The maximum stress arising at tools and work pieces in cutting process is on the tool edge tip, and the maximum stress arising on the tip of cutting tools is equal to that on the contacting area of work pieces in values. (3) The distributions of maximum shear stress on certain parts of the cutting tools and work pieces are as follows; for cutting tools, .alpha.=12.deg., .alpha.=0.deg., .alpha.=-12.deg. in order, and for work pieces, .alpha.=-12.deg., .alpha.=0.deg., .alpha.=12.deg. in opposite order.der.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.8 no.4
• /
• pp.7-13
• /
• 2009

Five-axis laser cutting has great advantages when it is applied to 3-dimensional machining requiring high cutting quality. For developing 5-axis CNC laser cutting systems, however, many problems such as rotating a laser head or a working table, 5-axis servo-control mechanism, tool path generation and post processing, and collision avoidance between a laser head and a work-piece should be solved. In this paper, we deal with developing a dedicated CAM system based on UG-NX3 for 5-axis laser cutting machine. Two essential modules such as post-processor and cutting motion simulation was developed. The developed system was applied to cutting curve defined on 3-D workpiece in order to show the validity of the proposed methods.

• Journal of the Architectural Institute of Korea Structure & Construction
• /
• v.34 no.11
• /
• pp.45-54
• /
• 2018

The primary objective of this study is to develop a conceptual design of all-in-one attachment based steel pipe pile cutting robot that improves the conventional work in safety, quality, convenience and productivity. For this, the following research works are conducted sequentially; 1)literature review, 2)field investigation, 3)selection of element technology for conceptual design, 4)deduction of conceptual design and its work process, 5)technical feasibility analysis of the conceptual design and its work process. As a result, leveling laser and laser detector, plasma cutter, rotary grapple are selected as core technologies. Futhermore, a conceptual design and work process of an all-in-one attachment based steel pipe pile cutting robot are developed based on the core technologies. According to the technical feasibility analysis result, at least 76.8% of the respondents are selected positive answer about each device of the all-in-one attachment based steel pipe cutting robot. It is expected that the application range and impact on the construction industry will be enormous due to the increasing trend of the steel pipe pile market.

• Korean Journal of Construction Engineering and Management
• /
• v.6 no.4 s.26
• /
• pp.142-151
• /
• 2005

Several advanced countries have been continually developed PHC pile cutting automation machines for improving productivity, safety and quality of the conventional PHC pile cutting work. However, the target work of the previously developed PHC pile cutting automation machines is only crushing the head of PHC pile. Dangerous grinding work is still performed by workers with seven inch hand grinder. In domestic construction industry, the PHC pile cutting work is usually performed by a crusher and three to four skilled workers. Recent analysis results of the PHC pile cutting work reveal that it frequently makes a lot of cracks which significantly reduce the strength of the pile and is labor-intensive work. The primary objective of this study is to propose the end-effector which can effectively break PHC pile without any longitudinal cracks and to develop an automated pile cutting machine having unified grinder and crusher parts through a wide variety of laboratory and field tests. It is anticipated that the development of the automated pile cutting machine would be able to bring improvements in safety, productivity, quality as well as cost saving.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
• /
• v.3 no.1
• /
• pp.40-48
• /
• 2000

The term "deep holes" is used to describe the machining of holes with a relatively large length to diameter ratio. The main feature of BTA deep hole drilling is the stabilization of cutting force necessary for the self guidance of the drill head. An additional feature is the cutting tool edges that are unsymmetrically placed on the drill head. There is an increasing necessity to predict the hole geometry and other dynamic stability behavior of deep hole drilling guidance. In this study, the effects of BTA deep hole drilling conditions on the hole profile machined piece are analyzed using domain analysis technique. The profile of deep hole drilled work piece is related to cutting speed, feed rate, chip flow, tool wear, and so on. This study deals with the experimental results obtained during the BTA drilling on SM45C, SM55C carbon steels and SCM440 steels under various cutting conditions, and these results are compared with analytical evaluations.aluations.

• Journal of Welding and Joining
• /
• v.30 no.1
• /
• pp.51-58
• /
• 2012

To assess hydraulic connections between sub-components of the International Thermonuclear Experimental Reactor (ITER) diagnostic port plug, the laser welding and ablation cutting process were investigated in order to be applied the remote handling maintenance. In this study, laser ablation cutting, which vaporizes a small amount of solid material directly into gas by focusing a laser beam of high density energy, is adopted in order to overcome the limitation of the normal laser cutting technology that the head should be placed as close to the work piece as possible to blow out melt metal at a distance. Complete cutting of a work piece is obtained by repetitive multi-passes of the laser beam. The welding and cutting process were tested on the sample work pieces and finally on a prototype of a hydraulic connection module for remote handling. The results showed that this process can be a promising candidate for hydraulic connections by remote handling.

• Korean Journal of Construction Engineering and Management
• /
• v.21 no.2
• /
• pp.98-106
• /
• 2020

Conventional method of PHC pile head cutting work has several challenges with regard to safety, convenience, productivity, and quality. To address such problems, a prototype of the all-in-one attachment-based PHC pile cutting robot is developed(Yeom, 2018). The Primary objective of this study are to develop a final prototype of all-in-one attachment-based PHC pile cutting robot and to analyze technical feasibility and field applicability of final prototype. According to the technical feasibility and field applicability analysis result, at least 74.2% of the respondents are selected positive answer about technical feasibility of the final prototype, at least 66.6% of the respondents are selected positive answer about field applicability of the final prototype. It is expected that when deployed onsite, the final prototype can not only increase the practical use but also improvement the work safety and productivity of work at the PHC pile head cutting job site.