• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2000년도 추계학술대회 논문집
• /
• pp.120-123
• /
• 2000

It is well known, for many years, that deep drawability can be improved by applying variable blank holding force. To apply variable blank holding force during cup during, we set up pressure controlling system on experimental hydraulic press, and the pressure control system is often called NC(Numerically Controlled) cushion system Using the NC cushion system we compared the drawability of square steel cups with NC cushion and that with conventional cushion. The results show drawability is greatly improved when the pressure control curve is designed in a S-shaped curve. This paper includes design details of the NC cushion system and experimental analysis of drawability with experimental NC cushion system.

• 소성∙가공
• /
• 제10권2호
• /
• pp.115-122
• /
• 2001

It is well known, for many years, that deep drawability can be improved by applying variable blank holding force. To apply variable blank holding force during cup drawing, we set up cushion pressure control system on the hydraulic press, and the pressure control system is often called NC(Numerically Controlled) cushion system. A cushion pressure control experiment was carried out using the NC cushion and it was shown that the proposed system produced good performance. The comparison of drawability of square cups with and without NC cushion showed that the drawability could be greatly improved when S-shaped pressure curve was applied. This paper includes design details of the NC cushion system and experimental analysis of drawability with NC cushion system.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 1995년도 제2회 단조심포지엄 단조기술의 진보
• /
• pp.180-187
• /
• 1995

Helical gears are machined from blanks, which are usually prepared by forging cylindrical billets at high temperatures through buster, blocker and finisher processes. As dimensions of the blank are closer to those of the machined part, machining cost can be more reduced. Therefore, there are a lot of efforts being made to optimize the forging processes in order to produce near-net shaped blanks. In the present investigation, a rigid viscoplastic finite element technique was used to analyze a helical gear blank hot forging processes and deformation, strain and temperature distributions, forging load variations during forging were obtained. In the paper, it is discussed how these results can be utilized to optimize die design, billet dimensions and press usage.

• 대한기계학회논문집
• /
• 제17권12호
• /
• pp.3094-3104
• /
• 1993

The five punch and die sets are selected as the examples of arbitrary cross sections which have two opposite inclined sides. Two kinds of blank shapes are designed for all cross sections. One(h-b1.) is determined by slip-line theory and the other (G-b1.) is determined conventionally as the similar shapes with the cross sections which were used by Gopinathan. As a result of the experimental procedures, the superiority of the blank shapes designed by slip-line theory is verified in the limiting drawing ratio, the uniformity of cup height and the thickness distributions.

• 한국기계가공학회지
• /
• 제13권6호
• /
• pp.54-60
• /
• 2014

In industry, several casting process are widely used to manufacture complex and accurate blank part of hard materials such as aluminum, casting steels, bronze and magnesium alloys which are difficult to manufacture in a blank shape. Even if the casting process does not high accuracy superior surface characteristics other machining process, the casting process is widely used in manufacturing blank part. Furthermore, it is difficult to select appropriate casting process a part among several casting process. for effective selection different process, a careful decision given casting application is necessary. An appropriate casting for a given material and shape condition must be selected for novice engineers in industry. In this paper, an expert system based on an analytic network process(ANP) is suggested for best selection of casting considering a prior interdependency effect among various factors such as material, geometry, process capability, economy and equipment.

• Advances in aircraft and spacecraft science
• /
• 제3권1호
• /
• pp.29-43
• /
• 2016

Composite materials are rapidly gaining popularity as an alternative to metals for structural and load bearing applications in the aerospace, automotive, alternate energy and consumer industries. With the advent of thermoplastic composites and advances in recycling technologies, fully recyclable composites are gaining ground over traditional thermoset composites. Stamp forming as an alternative processing technique for sheet products has proven to be effective in allowing the fast manufacturing rates required for mass production of components. This study investigates the feasibility of using the stamp forming technique for the processing of thermoplastic, recyclable composite materials. The material system used in this study is a self-reinforced polypropylene composite material (Curv$^{(R)}$). The investigation includes a detailed experimental study based on strain measurements using a non-contact optical measurement system in conjunction with stamping equipment to record and measure the formability of the thermoplastic composites in real time. A Design of Experiments (DOE) methodology was adopted to elucidate the effect of process parameters that included blank holder force, pre heat temperature and feed rate on stamp forming. DOE analyses indicate that feed rate had negligible influence on the strain evolution during stamp forming and blank holder force and preheat temperature had significant effect on strain evolution during forming.

• 한국정밀공학회지
• /
• 제14권11호
• /
• pp.171-179
• /
• 1997

This paper describes a nesting system of a computer-aided design of blanking and piercing for irregularly shaped sheet metal products. An approach to the system is based on knowledge-based rules. A nesting system is designed by considering several factors, such as utilization ratio which minimises the scrab for single or pairwise operation, bridge width, grain orientation and design requirements which maximise the strength of the part when subsequent bending is involve. Therefore this system which was implemented blank layout and strip layout module can carry out a nesting with a best utilization and a process planning for irregular shaped sheet metal products in single or pairwise operation and generate the blank layout and strip layout in graphic forms. Knowledges for a nesting and a process planning are extracted from plasticity theories, relevant references and empirical know-hows of experts in blanking industries. This provides its efficiency and effectiveness for nesting irregularly shaped sheet metal products.

• 한국산학기술학회논문지
• /
• 제9권5호
• /
• pp.1113-1118
• /
• 2008

프로그레시브금형에 있어서 스트립 레이아웃석계는 제품 양산을 결정하는 중요 요인이다. 본 논문에서는 자동차에 사용되는 브라켓의 스트립 레이아웃설계를 하였다. 3D모델링이 아닌 자동화 모듈인 씨마트론 다이 디자인을 활용하여 3D로 스트립 레이아웃설계를 하였다. 광폭 2열 2개 뽑기의 내측캐리어를 단 배열로 블랭크 레이아웃을 최적화하였다. 사용된 3D CAD/CAM 소프트웨어는 Cimatron Die Design이며 10개 공정으로 스트립 레이아웃설계를 완성하였다.

• 대한기계학회논문집A
• /
• 제20권6호
• /
• pp.1810-1818
• /
• 1996

A new finite elemetn approach is introduced for direct prediction of bland shapes and strain distributions from desired final shapes in sheet metal forming. The approach deals with the geometric compatibility of finite elements, plastic deformation theory, minimization of plastic work with constraints, and a proper initial guess. The algorithm developed is applied to cylindrical cup drawing, square cup drawing, and fron fender forming to confirm its validity by demonstratin reasonable accurate numerical results of each problems. Rapid calculation with this algorithm enables easy determination of various process variables for design of sheet metal forming process.

• 소성∙가공
• /
• 제9권5호
• /
• pp.478-485
• /
• 2000

This study aims to Improve the productivity in forming of flanged thrust engine bearings from two kinds of laminated sheet materials by integrating the forming processes or by reducing the number of the subsequent sizing and machining processes or by modifying the forming tools used. For steel-Al rolled blank, a design scheme for the one-step forming operation and the geometry of the tool set required is suggested and is verified its usefulness by the finite element simulation. And for steel-Cu sintered blank, the results of experiment and finite element analysis show that it is possible to improve the dimensional accuracy of formed products and to reduce the number of sizing processes just by modifying the shape and dimensions of initial blanks and flange forming dies, and by controlling the spring force.