• 소성∙가공
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• 제29권5호
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• pp.265-271
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• 2020

The purpose of this paper is to analyze the numerical simulation accuracy according to the CFRP modeling method in the CFRP-Al alloy SPR (Self-Piercing Rivet) joint process. The mechanical properties of the CFRP, aluminum sheet are precisely obtained from the tensile test according to the loading direction. Additionally, the hardening curve of rivet was calculated from the inverse analysis of the machined rivet-ring compression test. For the CFRP-Al alloy SPR simulation, two kinds of the CFRP modeling methods were established based on the continuum and layer-by-layer approaches. The simulation results showed that the CFRP layer-by-layer modeling method can provide more reliable prediction shape of the fractured sheets and deformed rivet. This simulation technique can be used in evaluating the CFRP-Metal SPR performance and designing the SPR process conditions.

• Design & Manufacturing
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• 제2권3호
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• pp.40-44
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• 2008

Shaving in sheet metal forming is defined as a finish process to make the sheared surface clean which was blanked or pierced in the previous shearing stage. In this study the new shaving technique is applied to the progressive operation. The specimen is automatically fed by continuous movement of the strip. Which improve the positioning accuracy higher. For this study a square part which consist of blanking and piercing is selected for investigation and the progressive die which includes pre-piercing, pierce-shaving, half-blanking and blank-shaving etc is prepared for specimens of steel sheet(SPCC) and aluminum alloy sheet(AL5052). Experiments are carried out for several working variables such as shaving allowance, pre-shearing clearance and relative half-blanking depth. Consequently it was confirmed that the shaving by progressive die can be successfully employed to produce the clean parts requiring shaving process and optimum working conditions for shaving SPCC and AL5052 sheet metal are shaving allowance of 0.2mm(1.3% of thickness) and pre-shearing clearance of 5%.

• 한국정밀공학회지
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• 제15권3호
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• pp.18-23
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• 1998

This paper describes a research work of developing a computer-aided design of blanking and piercing for irregular-shaped sheet metal products. An approach to the CAD system is based on the knowledge-based rules. Knowledge for the CAD system is formulated from plasticity theories, experimental results and the empirical knowledge of field experts. The system has been written in AutoLISP on the AutoCAD with a personal computer and is composed of four main modules, which are input and shape treatment, flat pattern layout, production feasibility check, and strip layout module. Based on knowledge-based rules, the system is designed by considering several factors, such as radius and angle of bend. material and thickness of product, complexities of blank geometry and punch profile, and availability of press. This system is capable of unfolding a formed sheet metal part to give flat pattern and automatically account for the adjustment of bend allowances to match tooling requirements by checking the dimensions and relationships of parts of the folded product. Also this system can carry out a process planning which is obtained from results of irregular shape of product that was successful in production feasibility check module according to flat pattern layout and generate strip layout drawing in graphic forms. The developed system provides its efficiency for flat pattern layout, and strip layout for the irregularly shaped sheet metal products.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 추계학술대회 논문집
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• pp.409-410
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• 2009

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1996년도 춘계학술대회논문집
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• pp.121-129
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• 1996

This study aimsdetecting defects for the forming precesses of X2 spline, which is designed by an industry expert. The exist process consists of 3 runs and 7 operations with 3 heat treatments. The rigid-plastic FEM analysis was carried out to design a new process and some defects were found. Thus the design was modified to get better results. it is ocnfirmed that the industry expert agree the possibility of defects derived from the FEM results.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.735-739
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• 2001

This paper describes a research work of developing computer-aided design of a product with bending and piercing for progressive working. An approach to the system for progressive working os based on the knowledge-based rules. Knowledge for the system is formulated from plasticity theorise, experimental results and the empirical knowledge of field experts. the system has been written in AutoLISP on the AutoCAD with a personal computer and is composed of three main modules, which are input and shape treatment, flat pattern layout and strip layout modules. Strip layout of the system is designed by using fuzzy set theory. Process planning is determinated by fuzzy value according to several rules. Strip layout drawing generated in strip layout module is presented in 3-D graphic forms, including bending sequences and piercing processes with punch profiles divided into for external area. Results obtained using the modules enable the manufacturer for progressive working of electric products to be more efficient in this field.

• 한국정밀공학회지
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• 제17권8호
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• pp.198-206
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• 2000

This paper describes a research work of developing automated progressive process planning system for working electric products. An approach to the CAD system in based on the knowledge-based rules. Knowledge for the CAD system is formulated from plasticity theories experimental results and the empirical knowledge of field experts. The system has been written in AutoLISP on the AutoCAD with a personal computer and is composed of three main modules which are input and shape treatment flat pattern layout and strip layout module. Based on knowledge-based rules the system is design by considering several factors such as radius and angle of bend material and thickness of product complexities of blank geometry and punch profile bending sequence and availability of press. Strip layout drawing automatically generated by piercing with punch profiles divided into for external area is simulated in 3-D graphic forms including bending sequences for the product with piercing and bending. Results obtained using the modules enable the manufacture of electronic products to be more efficient in this field.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 춘계학술대회논문집
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• pp.96-100
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• 2000

It is difficult to predict material behavior of forming process because the plastic instable flow phenomenon happens in practical forming process I. e. upsetting backward extrusion piercing indentation. In view of the direct relationship between instable material flow and quality defects of the products we should find out their phenomena, In this study we introduced the plastic spin and the kinematic hardening considering the kinematic hardening constitutive equation for rate-dependent material. Also analysis of upset forging is carried out using the rigid plastic FEM with Al7075

• 한국정밀공학회지
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• 제15권2호
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• pp.124-133
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• 1998

This paper describes a research work of developing a computer-aided design of blanking and piercing for irregular-shaped sheet metal products. An approach to the development of compact and practical CAB system is based on the knowledge-based rules. Knowledge for the CAD system is formulated from plasticity theories, experimental results and the empirical knowledge of field experts. The system has been written in AutoLISP on the AutoCAD with a personal computer. Based on knowledge-based rules, the system, STRT-DES, is designed by considering several factors, such as complexities of blank geometry and punch profile, availability of press equipment and standard parts, utilization ratio which minimizes the scrap in a single or a pairwise operation, bridge width, grain orientation and design requirements which maximize the strength of the part when subsequent bending is involved. This system checks a forming feasibility with both internal and external features, a dimension of blanked hole, and a corner and a fillet radius for irregualrly shaped sheet metal products. Therefore this system can carry out a die design for each process which is obtained from results of an automated blank layout drawing with a best utilization ratio for irregular shape of product that was successful in production feasibility check module and those of an automated strip layout drawing and generate part drawings and the assembly drawing of die set in graphic forms.

• 대한기계학회논문집
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• 제10권6호
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• pp.876-888
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• 1986

본 논문에서는 자유 표면과 강체부분이 많은 피어싱 공정의 해석에서 발생하 는 해의 수렴성 저하를 방지하기 위하여 비정상 상태의 가공경화 효과와 강체 연속처리 리방법을 프로그램 개발에 적용하고 프로그램 개발에 적용하고 프로그램 범용성을 높 이기 위해 초기 속도장 발생 프로그램을 개발하여 본 공정 해석에 적용하여 보려고 한 다. 또한 재료를 가공 경화를 고려한 강소성체(rigid-plastic material)로 가정해서 시편에 크랙이 발생하여 파괴될때까지 컴퓨터 시뮬레이션을 수행한 후 냉간 피어싱 공 정에 있어서 표면 크랙의 발생과 성장 그리고 파괴에 가장 많은 영향을 미치는 인자들 을 계산결과를 토대로 실험과 비교조사하고, 실험 시편의 지름과 높이 그리고 마찰상 태를 다르게 조합해서, 실험과 계산을 시하여 시편 모양에 따른 변형 모우드(mode)와 파괴 모우드의 차이를 규명해 보기로 한다.