• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.1
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• pp.120-126
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• 2002

The near net shape forging of gears offers significant technical and economic advantages ever other forms of manufacture. These potential benefits can however only be realized by careful die design. This paper describes a computer-based methodology fur achieving this. A Visual-BASIC program has been developed on a rule based system that enables optimal design of the dies taking into account the elastic deflections generated in shrink-fitting the die inserts and that caused by the stresses generated in the forging process. The method also enables the profile of the spark erosion electrode to be determined. An example of the application to forging spur gears is given.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.5
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• pp.91-97
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• 2020

A split-die design for the cold forging of symmetric parts such as those having a hexagonal cross-section is presented in this paper. Parts with a hexagonal cross-section, such as bolt heads and nuts, should be forged with a die that has a hexagonal-shaped hole. A split type die is required to mitigate the buildup of stress concentrations located at the corners of the hexagonal hole. Generally, the insert of a hexagonal die is made by cutting each corner of a cylinder using a hexagonal hole and then combined with the die and shrink-fitted. However, split dies face problems when extruding material at the corners of the hexagonal split die. To address this problem, two types of split dies were evaluated: rounded hexagonal dies and angular hexagonal dies. The effects of the pre-stress ring on the dies were compared and analyzed and results show that using the angular split hexagonal die can extend the lifetime of forging dies.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.170-175
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• 2005

Generally, Aluminum is superior to durability, light, and characteristics of the material are embossed luminant. So, these characteristics of aluminum will be used automobile interior parts by aluminum injection moulding. Especially, The external of Aluminum plate is engraved differing pattern by roller working. This working can use any longer and be seen gracefully. This is the reason why aluminum insert moulding is used. This feature of research can be characterized by simple process to customize aluminum sheet of blanking and forming process with internal parts of configuration if products are injected by aluminum sheet. Besides, to analysis completed Automobile interior parts to be concerned volumetric shrinkage, best gate location, fill time analysis and so on through the mold-flow before the aluminum insert moulding is worked.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.119-123
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• 2009

In this paper, effects of major design parameters of cold forging dies on die mechanics are quantitatively investigated with emphasis on shrink fit using a thermoelastic finite element method. A ball-stud cold forging process found in a cold forging company is selected as a test process and the effects of die insert material, shrink fit, dimension of ring, partition of die inert and clamping force on effective stress and circumferential stress are analyzed.

• Transactions of Materials Processing
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• v.7 no.4
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• pp.347-353
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• 1998

A new approach of elastic finite element to die stress analysis in forging is presented in this paper. The die set analysis problem is formulated by considering contact problems under both mechanical and thermal loads. In the approach, amount of shrink fit is controlled by thermal load i.e., temperature difference between die insert and shrink fits. The loading conditions are extracted automatically from a forging simulator. The predicted solution is compared with analytical one and it has been shown that the predicted results are in excellent agreement with the analytical ones. An application example is given, which was found in a cold forging company.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.1
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• pp.29-37
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• 1995

In many metal forming processes, it is common to use stress rings for reducing elastic deformation and failures of forming dies. But, shrink fit of dies inner diameter of die insert, machining is reuqired after shrink fit processes. The reduction of inner diameter can be predicted by the analysis of elastic-plastic finite element method. The dimension of dies before shrink fit can be determined to minimize or remove machining after shrink fit processes by deformation analysis of die. The computation of contacting stresses along die surface was analyzied by rigid plasitic finite element method, and data were interpolated by the contact search algorithm. In this paper, we propose the analysis method of forging dies after shrink fit and forming to improve dimensional accuracy of final products.

• Transactions of Materials Processing
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• v.19 no.8
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• pp.460-467
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• 2010

It was studied that two plates of aluminum can be welded by extru-riveting experiments with extru-rivet welding dies, and that the welding strength and metal flow on the welding section were analyzed by computer simulation according to the welding variable such as the diameter of extrusion insert dies. It was known by computer simulation that welding strength on the welding section of plates could be influenced by the diameter of extrusion insert dies. And it was known by experiments that two plates of aluminum can be welded on a spot point on aluminum plate by extru-rivet welding process, and that welding strength is higher and higher if the diameter of extrusion insert die is smaller and smaller, and that welding strength is the highest when diameter of extrusion insert dies is ${\emptyset}4.2$mm in the case that the diameter of rivet is 5 mm, when aluminum 5052 two plates with 1.5 mm thickness and one plate with 3mm thickness for rivet plate are used as welding material.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.9
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• pp.1364-1372
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• 1997

In this paper, the forging of helical gears has been investigated. Punch is tooth-shaped as is the die insert. The punch compresses a cylindrical billet placed in a die insert. As a consequence the material of billet flows into the tooth region. The forging has been analysed by using the upper-bound method. A kinematically admissible velocity field has been developed, wherein, an involute curve has been introduced to represent tooth profile of the gear. Numerical calculations have been carried out to investigate the effects of various parameters, such as module, number of teeth, helix angle and friction factor on the forging of helical gears. Some forging experimentswere carried out with aluminum alloy to show the validity of the analysis. Good agreement was found between the predicted values of the forging load and obtained from the experimental results.

• Design & Manufacturing
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• v.11 no.1
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• pp.30-33
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• 2017

In this study, the mold technology for manufacturing of porous implant was investigated. Firstly, we considered the concept of insert molding technology with 3D printing of porous inert part. The part on implant was designed in the end region of the implant. And then main implant bodies were manufactured using conventional machining method. The other porous parts were designed and optimized with molding simulation. As the feature size of porous implant was so small that perfect feature of it using 3D printing technology could not be obtained. So, we proposed another scheme for manufacturing of the porous implant in the replace of the former approach. Polymer mold cores with 3D printing technology were considered. The effects of addictive manufacturing process parameters on the properties of mechanical and dimensional accuracy were investigated. Direct 3D printed polymer mold cores were designed and manufactured under the simulation of thermal and molding analysis. It was shown that 3D printed mold core with polymer could be adapted to the injection molding for porous implant.

• Transactions of Materials Processing
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• v.23 no.5
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• pp.282-288
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• 2014

It is difficult to control welding variables during spot welding of non-ferrous metals like aluminum because of the low electrical resistance of the material. It has been suggested that a solid state welding process such as friction stir spot welding or extru-spot welding can be used to spot weld aluminum plates. In the extru-spot welding, there is a need to increase the weld strength by improving the shape of the welding die. The current study shows that the weld strength for an extru-spot welding can be increased by using a pin placed on the inside of the upper electrode in the welding die. In the current study, the deformed shape of the insert rivet and the stress distribution in the welding zone were analyzed by simulation. Extru-rivet spot welding experiments were performed by changing the height of pin on the inside of the upper electrode. From the experimental result, it is shown that the weld strength for an extru-rivet spot welding can be increased by adjusting the height of the pin. The optimal shape of the deformed rivet after the extru-rivet spot welding can be observed from the simulation results. The deformed shape of the insert rivet can also be controlled by the height of pin.