• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.4
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• pp.123-129
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• 2018

A rotational drawing die which can form a long tube with spiral grooves on the surface is presented. The main feature of the proposed die is a rotation insert that is embedded into the die container for the die to freely rotate with respect to the drawing centerline as the materials are drawn. We employed a three-dimensional finite element model to investigate the effects of the rotational die on the material filling of spiral grooves. The material used in the finite element analysis was stainless 304. We also performed a pilot drawing test to verify the usefulness of the proposed rotational drawing die. Results reveal that the material filling of spiral grooves by the proposed rotational drawing die was in good agreement for both the finite element analysis and the drawing test. We found that the underfill in a conventional drawing die was reduced in the proposed rotational drawing die.

• The Journal of Advanced Prosthodontics
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• v.9 no.6
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• pp.463-469
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• 2017

PURPOSE. To evaluate the fit of a three-unit metal framework of fixed dental prostheses made by subtractive and additive manufacturing. MATERIALS AND METHODS. One master model of metal was fabricated. Twenty silicone impressions were made on the master die, working die of 10 poured with Type 4 stone, and working die of 10 made of scannable stone. Ten three-unit wax frameworks were fabricated by wax-up from Type IV working die. Stereolithography files of 10 three-unit frameworks were obtained using a model scanner and three-dimensional design software on a scannable working die. The three-unit wax framework was fabricated using subtractive manufacturing (SM) by applying the prepared stereolithography file, and the resin framework was fabricated by additive manufacturing (AM); both used metal alloy castings for metal frameworks. Marginal and internal gap were measured using silicone replica technique and digital microscope. Measurement data were analyzed by Kruskal-Wallis H test and Mann-Whitney U-test (${\alpha}=.05$). RESULTS. The lowest and highest gaps between premolar and molar margins were in the SM group and the AM group, respectively. There was a statistically significant difference in the marginal gap among the 3 groups (P<.001). In the marginal area where pontic was present, the largest gap was $149.39{\pm}42.30{\mu}m$ in the AM group, and the lowest gap was $24.40{\pm}11.92{\mu}m$ in the SM group. CONCLUSION. Three-unit metal frameworks made by subtractive manufacturing are clinically applicable. However, additive manufacturing requires more research to be applied clinically.

• Journal of the Korean Society for Heat Treatment
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• v.22 no.1
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• pp.16-22
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• 2009

The rolling process is an efficient and economical approach for the manufacturing of plate metals. In the rolling process, the temperature variation is very critical for plate thickness accuracy. The main cause of thickness variation in hot plate mills is the non-uniform temperature distribution along the length of the slab. Also the exit plate thickness is mainly affected by the rolling conditions such as mill modulus, plate thickness and plate width. Hence the thickness variation in top-end is also dependent on these factors. Therefore this study has concentrated on determining the correct amounts of thickness variation due to top-end temperature drop and process parameters.

• IE interfaces
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• v.13 no.4
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• pp.564-571
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• 2000

Manufacturing companies are implementing a so-called customer-centered supply chain management to have a competitive advantage. In these efforts, collaboration not only within a company but also with suppliers, partners and customers is emphasized. The fast delivery, reducing the total lead-time from development to delivery, is pursued more than ever, though the quality and cost are still importantly regarded. Die manufacturing companies are not exception from these trends, because a die is a necessary tool for almost manufacturing industries. The planning and scheduling system plays an important role in supply chain management. In this study, we address a scheduling problem of a die manufacturing company. The problem is very complex due to many reasons including the uncertainty in environment and the complexity of constraints. Considering the importance of due-date satisfaction and human planners' roles, we designed the solution algorithm and the user interface respectively. In the implementation phase, modeling constructs and basic solution algorithms of ILOG solver and ILOG scheduler are used. In the paper, the problem and the algorithm are described with ILOG constructs, and the experience of use is also addressed.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.1
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• pp.33-41
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• 2010

This study was aimed at the design of the dies for the unified pipe joint of the intermediate shaft using the computer simulation to shorten the period of production, on the basis of the process planning which was designed by the field experts. In the computer simulation, 'Deform-3d' and 'eesy-DieOpt' have been used, which are the commercial process analysis and die design program. Through the process analysis, we could know the propriety of the forming process, the inner pressure of the die and the suitable fitting pressure between the insert and the sleeve which was not showing any positive tangential stresses in the insert. Through the simulation of die design, we could know the number of the stress ring, the diameter ratios, the stresses of the die, the shrink fitting tolerance and temperature in the condition of the already determined maximum outer die diameter of the multi-stage former. The validity of the die design using the computer simulation was analyzed by the experiments and the results were satisfactory. As the results of this study, the new and easy die design system for multi-forging has been developed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.2
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• pp.60-68
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• 2009

The objective of this paper is to design stamping die of inner reinforcement panel with DL 950 advanced high strength steel as stamping materials through numerical analyses and experiments. The stamping process was designed as bending dominant process consisting of 1 step of notching and 4 steps of bending processes. In order to obtain a proper design of the stamping die, various three-dimensional elasto-plastic finite element analyses were performed using a commercial code AUTOFORM V4.2. Design parameter of stamping die was chosen as the corner radius of the stamping die for each step. From the results of the FE analysis, feasible corner radii of the stamping die, which can minimize the deviation of corner angle of the stamped part from design data, and forming load for each part were estimated. Stamping experiments were carried out using the manufactured stamping die according to the proposed die design. The results of experiments were shown that the stamping die can successfully manufacture the inner reinforcement panel with DL 950 advanced high strength steel as base stamping material.

• Design & Manufacturing
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• v.6 no.2
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• pp.17-23
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• 2012

In April 2010, the die and mould grand prix for university student was held in Osaka as a special event of Inter Mold Japan. The students from Korea, China, and Japan participated to demonstrate the design and manufacturing skill of die and mould. Based on the given product drawing of Test Work, progressive die should be designed and manufactured. Also, production of Test Work should be carried out. This study had been conducted to participate in the grand prix and to learn practical knowledge and experience from real die design and making. Test Work is made of SPCC and includes piercing, blanking, deep drawing and burring. From the analysis of product drawing, process planning and die design was carried out. Progressive die for Test Work was manufactured using CNC milling, grinding, wire-cutting and polishing. The production was successfully completed using mechanical press and product showed very good accuracy satisfying all dimensional tolerances.

• Transactions of Materials Processing
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• v.24 no.4
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• pp.264-271
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• 2015

In the current study, a method was proposed to quantitatively predict the wear and fatigue life of a shearing die in order to determine an effective replacement period for the die. The shearing die model of a retainer manufacturing process was used for the proposed method of quantitative life prediction. The retainer is produced through shearing steps, such as piercing and notching. The shearing die of the retainer is carefully controlled because the dimensional accuracy of the retainer is critical. The fatigue life for the shearing die was predicted using ANSYS considering S-N curves of STD11 and Gerber’s equation. The wear life for the shearing die was predicted using DEFORM-3D considering the Archard’s wear model. Experimental shearing of the retainer was conducted to verify the effectiveness of the proposed method for predicting die life. The fatigue failure of the shearing die was macroscopically measured. The wear depth was measured using a 3D coordinate measuring machine. The results showed that the wear and fatigue life in the FE analysis agree well with the experimental results.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.4
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• pp.126-133
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• 2015

To enhance the productivity and quality of the compound process of progressive dies and transfer dies, the semi-progressive method is applied in the material supply step to produce blanks, and then the transfer method is applied. Parts are transferred among processes by means of the finger and transfer bar in the transfer die, and the final seat cushion panel is produced. The main challenge in the current study is how to deform a seat cushion panel while meeting the design specifications without any defects. In order to obtain this technology, a sheet metal-forming simulation and die forming of the seat cushion panel were adopted; as a result, a compound die-forming technology for the automotive seat cushion panel, combining both semi-progressive die and transfer die for continuous production, was successfully developed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1761-1765
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• 2005

The plastic injection molding industry is increasing pressure to reduce the cycle time in order to improve the productivity. The time of a cooling die is a large part of the cycle time. The conformal cooling channels can reduce the cooling time effectively as compared with conventional production die. It is hard to make the die with a conformal cooling channel by the conventional method. This paper introduces the method of a conformal cooling channel manufacturing by the DMT (Direct Metal Tooling) that is a new technology.