• Design & Manufacturing
• /
• v.17 no.1
• /
• pp.56-63
• /
• 2023

In this study, the vibration signal of the mold was measured and analyzed to monitor the process information and characteristics during the press molding process. A necklace-type picture frame mold was used for press molding, and the vibration signal was measured by GY-61 acceleration sensor module attached to the surface of the upper (movable) mold base. The change of the vibration signal of the mold according to press speed was analyzed. As a result, the vibration signal had a large change at five sections: "Holder contact", "Punch contact and start of pressing", "End of pressing", "Mold open", and "Demolding". The time difference between "Punch contact and start of pressing" and "End of pressing" means the pressing time which is the actual time the material is molded under pressing pressure. The time intervals for each section, represented by the time interval between "Holder contact" and "Punch contact and start of pressing", can be used to compare and evaluate the press speed applied to the process. By comparing the vibration signals at 60 rpm and 90 rpm, the amplitude at the section of "Punch contact and start of pressing" increased as the press speed increased. This result means that as the press speed increases, more force and pressure is applied to the material. Also, the peak values of the other sections were found to increase as the press speed increased. It was found that the pressing time, the time interval between "Punch contact and start of pressing" and "End of pressing", decreases as the pressing speed increases. Similarly, press speed factor, the time interval between "Holder contact", and "Punch contact and start of pressing", is found to be shorter. Therefore, based on the result of this study, the pressing time, press speed, pressing(punching) pressure of each cycle can be monitored by measuring the vibration signal of the mold. Also, it was confirmed that the level and trend of process information and characterization can be evaluated as the change of the mold vibration during press molding.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.44 no.1
• /
• pp.12-20
• /
• 2022

In this research, the silk web was hot-pressed for various times, the effect of press time on the structure and mechanical properties of silk non-woven fabric was also investigated. The yellowing appeared in the silk non-woven fabric and became more apparent as press time was increased. The crystallinity of silk was decreased by the hot press treatment and it did not change significantly with an increase of hot press time. The porosity of silk non-woven fabric was constantly decreased until 120 s and it did not change much after that. The thickness of silk non-woven fabric was significantly decreased by a press time of 10 s and slightly decreased with a further increase of hot press time. The hot press treatment increased the maximum stress and elongation of silk non-woven fabrics. The press time had a significant impact on the mechanical properties of silk non-woven fabric, with 90 s being the optimum condition for the best work of rupture of silk non-woven fabric.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.9 no.3
• /
• pp.76-82
• /
• 2010

A laborer always watched a process of production carefully but defective manufactures were inspected after press process. These inspections made a waste of human power and defective manufactures could make a serious damage of press mold. Therefore, AE(Acoustic Emission) system was introduced to prevention of the damage of the press molds, to a real time detection of defective manufactures and to save human power. AE system was introduced to solve this problem which is a detecting defective manufacture on real time and to prevent the damage of the press mold. In this research we get acoustic emission signal in accordance with weight and processing method of press by using AE sensor, Preamplifier, AE board signal board which occurs press processing and it analyzed various signal through using CMD8 software on the time. From the result, we found that the intensity and shape of the signal were changed according to the weight and processing type of the press. By using this special algorithm, it can judge the acoustic signal which occurs from press on real time.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.252-252
• /
• 2000

The Resistance Spot Welding (RSW) has been considered as an inherently safe and reliable method far joining metals, and has been widely employed, especially in automobile body assembly shops, as a manufacturing process. In recent years, the requirement for more sophisticated quality control procedures has considerably grown in the mass production industries. The object of the application of servo control to spot welding gun is the improvement of quality control in the spot welding, one of conventional industrial areas. The important factors affecting welding qualities (shear strength, nuggest size, indentation depth) are welding current, welding time, and gun press force. Welding current and welding time are controlled by welding timer. But, the conventional welding guns using compressed air are out of control in changing gun press forces in welding process. In this paper, a servo gun welding system having a AC servo motor and a PC control system is presented. The main object of this paper is to estimate the influence of gun press force changes in the welding process (press time -> welding time -> hold time) to welding qualities, and to evaluate welding qualities in real time, by recognizing the patterns of gun press forces changed in the welding process and comparing with the standard patterns.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.7 no.2
• /
• pp.66-71
• /
• 2008

The data of the deformation and the stress according to time are studied at upper model of press and lower model of the blanking plate applied by press with the width, length and height of 0.4 m and 0.6 m respectively. The press is pushing downward on the plate fixed at the lower floor. These data are compared and investigated through this study. By using these results, there is the maximum deformation at 4 corners in the lower plate model of aluminium alloy fixed at lower floor. This deformation incase of elapsed time of 0.6 second becomes 4 times as much as in case of elapsed time of 0.2 second. The quantity of deformation at the lower plate model becomes more than at the upper press model to the extent of 10%. At the lower plate model of aluminium alloy, there is the maximum Von-Mises equivalent stress at 4 corners and both sides of middle area on the lower plate model of aluminium alloy. This stress in case of elapsed time of 0.6 second becomes 6 times as much as in case of elapsed time of 0.2 second. The Von-Mises equivalent stress of lower plate model becomes 2 times as much as that of upper press mode.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1994.06a
• /
• pp.69-78
• /
• 1994

A rotating disk is introduced to be applied to the deep drawing press. Several characteristics are summarized to see the basics of deep drawing of sheet metal in terms of load-stroke relationship and formability. Many conventional drawing presses, which are mostly link-type presses, are also shown to be compared with the rotating disk-type press. Performances of the new press are kinematically analyzed it terms of load-main gear angle relationship, stroke-gear angle relationship, and slide velocity-gear angle relationship and they are compared with those of conventional types', e. g. crank press and so on. The comparison show kinematically better performance of rotating disk-type press than that of conventional ones. Also, the new press are proven to be one of the best press for mass production in terms of cycle time. Applicability of the rotating disk press to deep drawing and cold forging work is introduced. The new press is described in terms of economy such that the cost of new press would be much lower than those of conventional types'.

• Korean Journal of Computational Design and Engineering
• /
• v.14 no.5
• /
• pp.314-322
• /
• 2009

In these days, automotive companies are trying to develop new manufacturing technologies and paradigms for rapid product development and production. The press die development process account for 40% of entire vehicle development process, and tryout process usually takes 3 to 4 months, and it is the biggest time portion out of dies manufacturing. Therefore, the effective tryout management system is essential to reduce time and cost of automotive press die production. This paper suggests improved process and practical application of tryout management using ubiquitous technology, and shows the results such as shorten time, improved quality and supporting of lifecycle engineering of press die.

• Design & Manufacturing
• /
• v.10 no.2
• /
• pp.39-43
• /
• 2016

Most of automobile parts manufactured through sheet metal forming are mass-produced by using press mold. In recent years, automation and speeding up of press lines have been expanding to maximize product productivity using a press die. The proportion of the moving time in the press line is high, and therefore requires high-speed and automated equipment for the moving process. In this paper, to provide the double-moving system can be the moving time reduction and increased productivity. Developed transport system consists of the material supply, the material feeding device and the PLC controller and the devices are positioned between each of the pressing process. In this paper, the double-moving system including developed units using a multi-axial single-acting through this reduced the C/T(cycle time) and improved the productivity.

• Journal of the Korean Wood Science and Technology
• /
• v.33 no.5 s.133
• /
• pp.66-75
• /
• 2005

Soybean-based adhesives have recently been reconsidered as alternatives to petroleum-based adhesives due to the uncertainty of availability of petrochemical products and the increased demand for wood adhesives. This study was conducted to investigate the adhesive properties of alkaline phenolic soy (APS) resin for hybrid poplar flakeboard. The APS resin was formulated by crosslinking an alkaline soy flour hydrolyzate with lab-prepared PF resin in the soy hydrolyzate to PF resin weight ratios of 70/30, 60/40, and 50/50. The APS resins were used to fabricate homogeneous hybrid poplar flakeboards with different resin solid levels (5%, 7%, and 9%), press temperatures (175 and $200^{\circ}C$), and press times of 8 and 10 minutes. The IB, wet MOR, and dimensional stability properties of board improved with increasing press time, press temperature, and PF level in APS resins. Increasing press time can be used to offset poor IB strength associated with a 9% resin solid level and the excessive moisture content in the mat. The following conditions were concluded to meet the requirements of the CSA standard for exterior-grade flakeboard: a 50% PF level, a 5% resin content, a $200^{\circ}C$ press temperature, and an 8 minute press time.

• Journal of Korea Foresty Energy
• /
• v.21 no.2
• /
• pp.10-16
• /
• 2002

In this study, sawdust boards with a density 0.6g／$cm^2$, powder phenol resin containing 10% were made from thinned logs of Pinus densiflora, Larix leptolepis and Pinus koraiensis. Four levels of the pressure and press time were designed to investigate the effect on the properties of sawdust boards. Thickness swelling and water absorption were increased as press time was decreased. The condition of 3-stage pressure for lower thickness swelling and water absorption of board was 40$\rightarrow$30$\rightarrow$20kgf／$cm^2$. Bending strength and brinell hardness were decreased as press time was decreased. But there have no change with pressing pressure. These results indicated that properties of sawdust board were affected by press time.