• Design & Manufacturing
• /
• v.17 no.4
• /
• pp.72-78
• /
• 2023

Injection molding is a process widely used in various industries because of its high production speed and ease of mass production during the plastic manufacturing process, and the product is molded by injecting molten plastic into the mold at high speed and pressure. Since process conditions such as resin and mold temperature mutually affect the process and the quality of the molded product, it is difficult to accurately predict quality through mathematical or statistical methods. Recently, studies to predict the quality of injection molded products by applying artificial neural networks, which are known to be very useful for analyzing nonlinear types of problems, are actively underway. In this study, structural optimization of neural networks was conducted by applying multi-task learning techniques according to the characteristics of the input and output parameters of the artificial neural network. A structure reflecting the characteristics of each process step was applied to the input parameters, and a structure reflecting the quality characteristics of the injection molded part was applied to the output parameters using multi-tasking learning. Building an artificial neural network to predict the three qualities (mass, diameter, height) of injection-molded product under six process conditions (melt temperature, mold temperature, injection speed, packing pressure, pacing time, cooling time) and comparing its performance with the existing neural network, we observed enhancements in prediction accuracy for mass, diameter, and height by approximately 69.38%, 24.87%, and 39.87%, respectively.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.27 no.8
• /
• pp.1371-1379
• /
• 2003

RP&M (Rapid Prototyping and Manufacturing) is the most appropriate technology for the small-lot production system, because the production cycle is getting shorter owing to various needs of the consumer. In this paper, rapid tooling technology is applied to the casting process. The casting process has the ability to reflect complicated shapes in one process. But it has not been widely used to make a die and mold because of the poor surface quality caused by air bubbles on the surface of the casting product. In this study, the porous casting mold is fabricated from a mixture of plaster and water-soluble binder. The porous casting mold can improve the characteristics of casting products with the help of the vacuum sealed casting process. The vacuum sealed casting process is an advanced technology that removes the air bubbles between the porous casting mould and the liquid metal, thus making the surface of the casting product finer. The purpose of this paper is to develop a high quality shoe mold using porous casting mold and to apply the RP&M technology to the shoe industry.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.05a
• /
• pp.199-200
• /
• 2006

It will not be an exaggeration to say that one of the most important features of RT (Rapid Tooling) technology is to easy manufacturing complex shape of cooling channel in injection mold. That is, RT technology is hardly influenced complex shape of tool, Therefore, mold designer can optimize the position and shape of cooling channel whatever they want. In this study, we optimized cooling channel through CAE analysis to solve the problem; prototype-connector-mold applied conventional cooling channel, locally warped by internal stress: The effect of three-dimensional cooling channel was supported by simulation result. But it is impossible to produce injection mold applied three-dimensional cooling channel through machining operation. Therefore, we produced the prototype-connector-mold with three-dimensional cooling channel using Direct Metal Laser Sintering (DMLS) process, and get good-quality prototype-connector without warpage.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2009.05a
• /
• pp.60-63
• /
• 2009

Manufacturing technologies of micro spur gear and micro mold by micro PIM were studied with stainless steel feedstock. For molding of gears, micro mold with gear cavity of 1.2 mm in diameter was produced by wire EDM. The proper injection pressure was selected to 70bar by observation and measuring of shapes and shrinkage of gears before/after sintering. For fabrication of micro mold, a tiny polymer gear was produced by injection into the mold. Then, 316L feedstock was again injected/compressed on the polymer gear and debinded together with polymer gear followed by sintering. As a result, another metal mold with gear cavity reduced to about 20% was fabricated and through repetition of this process chain, micro gear mold with cavity about below 800 um was finally obtained. In reduction of size by injection/compression molding, height of gear tooth was shrunk more and the effort for decrease of roughness of micro cavity were carried out ultrasonic polishing and as a result, the roughness in cavity decreased from 3-4 um to about 200 nm.

• Design & Manufacturing
• /
• v.13 no.3
• /
• pp.19-23
• /
• 2019

In the mold industry, CAM software has been introduced to solve the impossible or time-consuming part of the mold industry because the increase in labor costs, the drop in mold price, and the short delivery time are tasks to be solved not only in the manufacturing industry but also in the mold industry as a whole. In order to reduce the processing time and improve the surface roughness, we have been conducting various researches for efficient machining. This study was carried out to compare the ball end mill and radius end mill tools with the Power mill software and NC brain software under the same conditions and to find out the most efficient method of machining the smooth drafting surface and improving the surface roughness. (1) By machining the smooth drafting surface using radius end mill, the machining time is 23.7% faster than when using ball end mill. (2) Surface roughness when machined with radius end mill is smoother than when using ball end mill. Based on these results, it can not be applied to all shapes, but if it is a relatively wide and simple gradient shape, the raster machining method using radius end mill can be more effective in terms of delivery and quality than machining with ball end mill.

• The monthly packaging world
• /
• s.177
• /
• pp.100-103
• /
• 2008

• Journal of Korea Foundry Society
• /
• v.11 no.5
• /
• pp.382-391
• /
• 1991

• Design & Manufacturing
• /
• v.10 no.2
• /
• pp.24-28
• /
• 2016

In this study, relevant to impact extrusion process of the rectangular batter case for electric vehicles, numerical and experimental analyses were conducted to reduce the earring defects induced in the unevenness of metal flow. Since the earring is caused by the non-uniform metal flow induced in the friction and aspect ratio in the bottom section. As a way to reduce the earring, variable land die concept was applied. In order to analyze numerically the complex metal flow by using commercial finite element package, DEFORM 3D, impact extrusion process was simplified in upsetting mode at bottom section and extrusion mode at land section. The impact extrusion experiments were conducted to verify the assessment of process parameter for impact extrusion. As results, variable land die which has longer longitudinal section makes reduce earring defects. In addition, it was confirmed that the effect that slug shape like dog-bone also can reduce the earring. This study is expected to be able to present the useful design guidelines for manufacturing the battery case.

• Design & Manufacturing
• /
• v.10 no.1
• /
• pp.51-54
• /
• 2016

Metal sheet forming has been commonly used as the core technology in manufacturing parts of automobiles. It guarantees the highest production rate due to the process of mass production employing the press die. For precision of the product, the accuracy of the molds and its mechanic structures are considered as essential factors. One of these is fine blanking, which is utilized for the production of the metal sheet spring, with which clear sheer surfaces can be achieved in one operation from the materials. However, the current designs of press dies perform the forming analysis with the molds of rigid body, so they are focused on weight lightening by a rule of thumb. Therefore, this paper practice structural analysis about developing the semi fine-fine blanking technology. The semi fine-blanking can be run through the combination of the hydraulic cylinders and normal presses, so this paper analyze the amount of deformation according to the oil pressure. In addition, based on the plasticity of 50CrV4, the materials of the mold parts, the structural analysis and life analysis are proceeded, so they are expected to be useful as data for manufacturing the mold.

• Journal of Korea Foundry Society
• /
• v.24 no.4
• /
• pp.225-230
• /
• 2004

Computer simulation of mold filling and solidification has been performed in order to analyze the flow and solidification phenomena for the casting process of cylinder liner. The simulation result of mold filling shows that the molten metal flows into the mold in stable without scattering. The simulation results of solidification indicate that the last solidified area is located in the feeder. The temperature variation in casting is measured in actual casting and the result is compared with calculation result.