• Title/Summary/Keyword: die wear

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Tribological Properties of DLC for Die Applications

  • Lee, Kyu-Yong;Liu, Zhen-Hua
    • Design & Manufacturing
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    • v.6 no.1
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    • pp.24-28
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    • 2012
  • Friction and wear affect all processes involved in the extraction of materials and their conversion into finished products in the die applications such as drawing, extrusion etc. Originating phenomenon from the contact surface between the tool and workpiece, they are usually a hindrance to materials process operations which usually result in damaging the tools, increasing energy consumption, the contamination of processed material by wear particles and also some problems associated with technologies to control friction and wear. The most well established method to control friction and wear is by the application of lubricant such as fluorocarbon. Besides, a surface technique so-called surface modification can be applied to solve the tribology problems of the die applications for both the economical and ecological reasons. In this article, we applied DLC(diamond-like carbon) thin film on alumina ceramic for HT test using the PIID(plasma ion immersion deposition), 4 groups of test specimens were tested up to $200^{\circ}C$ which is a little higher than the normal working temperature of die application. Pin-on-disc tribo-tester was used to test the friction and surfaces were characterized by SEM and EDS and else, the morphology changes of DLC coatings were studied. The present work indicated that the DLC had a great potential to reduce the friction and wear in the alumina die application without lubricants.

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A Study on Die Wear Model considering Thermal Softening(II) -Application of Suggested Wear Model (열연화를 고려한 금형마멸모델에 관한 연구(II) -마멸모델의 적용)

  • Kang, Jong-Hun;Park, In-Woo;Jae, Jin-Soo;Kang, Seong-Soo
    • Transactions of Materials Processing
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    • v.7 no.3
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    • pp.282-290
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    • 1998
  • In bulk metal forming processes prediction of tool life is very important for saving production cost and achieving good material properties. Generally the service life of tools in metal forming process is limited to a large extent by wear, fracture and plastic deformation of tools. In case of hot and warm forging processes tool life depends on wear over 70%. In this study finite element analyses are con-ducted to warm and hot forging by adopting suggested wear model. By comparison of simulation and eal profile of die suggested wear model. By comparison of simulation and real profile of die suggested model is verified.

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Application of High Speed Tool Steel in Warm Forging (온간단조용 금형에 있어서 고속도 공구강의 적용)

  • 김동진
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2000.04a
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    • pp.75-78
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    • 2000
  • There are several effective factors to influence die life in the warm forging process. For instance process design die design and die materials etc This study presented heat treatment method which could improve toughness and wear resistance simultaneously in high temperature to apply high speed tool steels like SKH51 to die material for warm forging process. To verify the feasibility of application of heat treatment method mentioned above wear test was performed under the condition of constant time in 40$0^{\circ}C$ Wear coefficient was examined to search a relation between wear amount and time for each material and heat treatment method in 30, 60, and 130 minutes. To quantify the toughness-behavior between room and high temperature impact test was performed and heat fatigue test also fulfilled to compare with the resistance of heat check in room, 200, 400, and $600^{\circ}C$ temperature. On the basis of experimental results mentioned above high speed tool steel was applied to verify appropriateness of newly proposed heat treatment method for die of rotor pole used in automobile alternator. As a result die life of high speed tool steel applied newly proposed heat treatment is longer than that of STD61.

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Indirect Prediction of Surface Damage for a Press Die with Wear Characteristics and Finite Element Stamping Analysis (마모특성 및 유한요소해석을 이용한 프레스금형 손상 간접예측)

  • Jeon, Y.J.;Kim, S.H.;Yoon, K.T.;Heo, Y.M.;Lee, T.G.
    • Transactions of Materials Processing
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    • v.23 no.1
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    • pp.29-34
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    • 2014
  • The damage level of the die surface was predicted by estimating the surface roughness with a finite element analysis and the wear characteristics. Wear and friction tests were conducted to compare the wear characteristics for three kinds of surface treatments - CrN, TiAlN and AlCrN coatings. A prediction model was derived from the surface roughness results with respect to contact pressure and sliding speed which were obtained from the wear test. Surface roughness values for the damage regions of the die surface were compared between the experiments and the prediction model, which shows fairly good agreement with each other.

A Study on Predictin of Die Life of Warm Forging by Wear(II) -Application of Suggested Die Wear Model- (마멸에 의한 온간단조의 금형수명 예측에 관한 연구(II) -금형 마멸 모델의 적용-)

  • 강종훈;박은우;제진수;강성우
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1998.03a
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    • pp.94-99
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    • 1998
  • In bulk metal forming processes prediction of tool life is very important for saving production cost and achieving good material properties. Generally the service life of tools in metal forming process is limited to a large extent by wear, fracture and plastic deformation of tools. In case of hot and warm forging processes, tool life depends on wear over 70%. In this study finite element analyses are applied to warm forging and hot forging by adopting suggested wear model. By comparision of simulation and real profile of die, suggested model is verified

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Design of punch shape for reducing the punch wear in the backward extrusion (후방 압출 펀치의 마멸 저감을 위한 금형 형상 설계)

  • 박태준;이동주;김동진;김병민
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.575-578
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    • 2000
  • Die design to minimize the die wear in the cold forging process is very important as it reduce the production cost and the increase of the production rate. The quantitative estimation for the die wear is too hard because the prediction of the die wear is determined with many process variables. So, in this paper, the optimal shape of the backward extrusion punch is newly designed through the FE-analysis considering the surface expansion and Archard's wear model in order to reduce the rapid wear rate that is generated for the backward extrusion product exceeding the forming limit. The main shape variables of the backward extrusion punch are the flat, angle, and round of the punch nose part. As the flat and angle of the punch nose are larger, the surface expansion is reduced. and, the wear rate is decreased according to the reduction of the punch round. These results obtained through this study are applied to the real manufacturing process, it is implemented the reduction of the wear rate.

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Minimization of Die Wear Rate by Using Multi-Objective Optimization in Three-Dimensional Extrusion Processes (3차원 압출 공정에서 다목적 최적화 기법을 이용한 금형 마모율의 최소화)

  • Lee S. R.;Yang D. Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.05a
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    • pp.262-265
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    • 2005
  • A shape optimization of flow guide is accomplished to minimize the wear rate of die in three-dimensional flat-die extrusion processes. In order to achieve the balanced flow and the uniformed distribution of the effective strain during the extrusion, a multi-objective optimization is implemented. During the process of optimization formulation, the flow balance and the deviation of strain is considered as constrained conditions. The proposed approach is applied to an extrusion of H section. Through the optimization, it has been confirmed that the wear rate of die can be minimized satisfying the constraint.

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A Study on the Sliding Wear Characteristicsn of the Die Steel for the Cold Molding (냉간성형용 Die 강의 미끄럼 마멸특성에 관한 연구)

  • 전태옥;박흥식;류경곤
    • Tribology and Lubricants
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    • v.9 no.1
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    • pp.38-44
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    • 1993
  • The present study was undertaken to investigate the dry wear characteristics of die steel STD 11 for cold molding. The wear test was experimentally carried out under different conditions using a wear device, which was made in laboratory, and in which annular surfaces of wear testing specimens wear rubbed in dry sliding condition with varying the sliding speed, contact pressure, and sliding distance. The wear loss by variation of sliding speed was much in 0.3 m/sec and less in higher speed range above its sliding speed according to formation of the boundary lubrication film. The critical sliding speed with maximum value of the specific wear rate switched over to lower speed side according. as contact pressure increased. The critical sliding distance was increased with decrease in oxidation reaction velocity. The depth below subsurface showing maximum hardness (Hv) came out at the position, $60 \mu m$, of the maximum shear stress due to strain hardening.

Life Estimation of Hot Forging Die by Plastic Deformation and Wear (소성변형 밀 마멸에 대한 열간 단조 금형의 수명 평가)

  • 이현철;김병민;김광호
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.2
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    • pp.66-75
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    • 2003
  • This paper describes about the estimation method of die lift by wear and plastic deformation in hot forging process. The thermal load and the thermal softening are happened by the high temperature in hot forging process. Tool lift decreases considerably due to the softening of the surface layer of a tool caused by high thermal load and long contact time between tool and billet. Also, tool life is to a large extent limited by wear, heat crack and plastic deformation in hot forging process. Above all, the main factors which affects die accuracy and tool lift are wear and the plastic deformation of a die. The new developed technique for predicting tool life applied to estimate the production quantity for a spindle component and these techniques assist to improve the tool life in hot forging process.

A Study on the Prediction of Die Wear Based on Piezobolt Sensor Measurement Data in the Trimming Process of an Automobile Part (피에조 볼트 측정 데이터에 기반한 자동차 부품 트리밍 공정에서의 금형 마모 예측 연구)

  • Kwon, O.D.;Moon, H.B.;Kang, G.P.;Lee, K.;Hur, M.C.
    • Transactions of Materials Processing
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    • v.31 no.2
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    • pp.103-108
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    • 2022
  • Systematic quality control based on real time data is required for modern factories. This study introduced a method of predicting punch wear in the trimming process of automobile parts. Based on monitoring data of the mass production process using a bolt-type piezo sensor, it was shown that precursor symptoms of die wear could be predicted from the change in load pattern with respect to production volume. The load pattern that changed according to the wear of the die was verified by numerical analysis.