• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.14 no.5
• /
• pp.1-7
• /
• 2015

Cleaning by injecting dry ice and water is a generally adopted trend these days to clean molds (injection, diecasting foundry, press, rubber mold, etc). This cleaning method is performed manually, or by installing multiple high pressure spray nozzles. We have manufactured a turbine cleaning module device that is able to clean diecasting modules at any position and angle in the space by mounting an articulated robot instead of the existing pipe type injection nozzle, to minimize lead time and enhance working yield of the cleaning process. In this paper, we analyzed process factors that are required to design the turbine module by reviewing number of revolution, and results according to different blade angles and thicknesses of the mold release injection turbine module, using computational fiuid dynamics (CFD).

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.9 no.4
• /
• pp.14-25
• /
• 2010

Small cracks or chips of a product appear very frequently in the course of continuous production of an automatic press process system. These phenomena became the cause of not only defective product but also damage of a press mold. In order to solve this problem AE(Acoustic emission) system was introduced. AE system was expected to be very effective to real time detection of the defective product and for the prevention of the damage in the press molds In this study, for the pick and analysis of AE signals generated from the press process, AE sensors/pre-amplifier/analysis and processing board were used as frequently found in the other similar cases. For the analysis and processing the AE signals picked in real time from the normal or the detective products, specialized software called AE-win(software for processing AE signal from Physical Acoustics Corporation) was used. As a result of this work it was conformed that intensity and shape of the various AE signals differ depending on the weight of the press and thickness of sheet and process type.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.13 no.1
• /
• pp.107-114
• /
• 2014

A friction hinge system which moves without power was designed and developed using the principle of friction force, which is caused by interference between the inner diameter of a silicon cap and the outer diameter of a cylindrical roller bearing with one-way rotation in a counterclockwise direction. The system was applied to the lid of buffet ware, which moved up by external force and moved down by gravitational force. However, design conditions which included a rotation angle of the hinge of more than 80 degrees and a closing time of more than 20 seconds were required when the lid of the buffet ware closed due to gravitational force. The design safety of the friction hinge body connected to the lid of the buffet ware from the hinge system was checked on the basis of structural, fatigue and thermal analyses. The material of the shaft, cap and flange among the hinge elements was changed to polyethylene from steel to reduce the weight of the friction hinge system. An injection molding simulation was performed and injection molds of the shaft, cap and flange were created. The weight of the hinge system was decreased from 805g to 219g.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.16 no.3
• /
• pp.131-137
• /
• 2017

In this study, we evaluated the surface roughness of mold and injected parts manufactured by polycarbonate (PC) injection molding. The mold surface was polished to produce six differentiated roughnesses with 12 areas using stones (#800, #1200), sandpapers (#800, #1200), and diamond compounds (#8000, #14000). Injected parts were created using 20mm/s injection speed, 80 bar holding pressure for 5 seconds, and $70^{\circ}C$ cooling water. Injected parts surface roughness (Sa) was measured randomly in 10 of 30 using an interferometer (NewView8000, zygo, USA). In the same way, mold surface was measured randomly 10 times on 12 polished areas. Surface roughness of molds and injected parts were compared, and a regression equation to predict mold surface roughness was proposed for specific injection molding parameters.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.1
• /
• pp.34-39
• /
• 2011

Temperature control of a rubber injection mold is important for the dimensional accuracy of product. The main objective of this paper is to optimize the arrangement of heaters by FEM and optimal design method. Firstly, 3-dimensional transient heat transfer analysis was carried out for a square specimen mold. Results of FE analysis are a good agreement with the experimental results, showing about 1.22~7.22% error in temperature distribution. Secondly, we suggested the optimal method about an arrangement of heaters of rubber injection mold by using the optimal design technique. Distances between heater's center and the contact surface of mold, distances between heater's center and symmetric surface were considered as design variables. And the variances between the temperatures of cavity surfaces and their average temperature were used as the objective functions. Applying the optimal solution, the temperature variation was improved about 52.9~88.1 % compared to the existing mold. As a result of sensitivity analysis for design variables, design variables parallel to the direction of the split plane in mold affect the largest on the surface temperature variation in mold cavity.

• Journal of the Korea Society for Simulation
• /
• v.23 no.4
• /
• pp.131-142
• /
• 2014

Phone camera lens module is assembled with a barrel, multiple lenses, multiple spacers and a shield. The major processes of manufacturing system are injection molding, coating and assembly processes, and each process has multiple machines. In this paper, we introduce a scheduler based on simulation model which can be used for frequent rescheduling problem caused by urgent orders, breaking down of molds and failures of machines. The scheduling algorithm uses heuristic Backward-Forward method, and the objective is to minimize the number of tardy orders.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.24 no.1
• /
• pp.56-62
• /
• 2015

Using an optical 3D scanning device to collect data from a diffused reflection surface is very difficult. To solve this problem, there are many applications including a spray-type developer and silicon molds. However, using a developer can cause chemical reactions between objects and particles of the developer and uneven surfaces on the object. To overcome these problems, we suggest an electrostatic powder coating method for even coating of particles onto surfaces for collecting 3D shape data. We have developed an automatic, electrostatic powder-coating machine and performed three different experiments to compare this system with a laser interferometer and a T-scan 3D scanner. As a result, we could ascertain the various characteristics of this new method, including good sensitivity for the various surface states of the bare surface, developer, and electrostatic powder coating. Finally, we verified the outstanding scanning performance and were able to demonstrate that this method achieves quality than traditional methods.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.19 no.6
• /
• pp.847-851
• /
• 2010

It was attempted to develop an auto part by over molding injection mold that produces precision products in high productivity with use of an eco-friendly TPE substitute material for NBR. NBR is currently used in motor gear cover, one of the key parts in motor module for auto doors. Gear cover is composed of plastics and rubber mostly today, which requires a two (2) step process for production using two presses of different types. A hot press is used at this time for forming the rubber, which has drawback of requiring a rather long forming time of 400 seconds for one forming process. Even though this difficulty is overcome by reducing production time through employment of multi-cavity molds, time for forming process must be shortened for improvement of the productivity eventually, and the existing method of insert injection for products that have been formed with plastic material must be outgrown. In this point of view, over molding injection using TPE has a big advantage. Forming time is shortened to 54 seconds, and working the two (2) processes in series by one (1) press could solve the durability problem caused by deflection of the plastics, not to mention shortening the process time. Enhancement of productivity by almost 80% and improvement in the accuracy of the product could thus be achieved.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.17 no.4
• /
• pp.160-168
• /
• 2018

Among the components of rotary hooks, a core component of an embroidery sewing system, a study was conducted to apply metal injection molding to the manufacture of a hook body and a housing that was very difficult to mechanical working. The correlation of feedstock, a mixture of binder and SCM 415 metal powder, and properties of the pressure-volume-temperature interrelationship, viscosity, specific heat, and thermal conductivity were measured. Injection molds for the hook body and the housing were developed through injection molding analysis using these properties and conducted injection tests. Optimal injection gate position and number, injection pressure, and injection time were obtained through a comparison of analysis results with the experiment results.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.21 no.6
• /
• pp.1008-1012
• /
• 2012

Injection molds are fabricated by assembling a number of plates in which mold core and cavity components are inserted. The assembled structure causes a number of contact interfaces between each component where the heat transfer is affected by the thermal contact resistance. However, the mold assembly has been treated as a one body in numerical analyses of injection molding, which has a limitation in predicting the mold temperature distribution during the molding cycle. In this study, a numerical approach that considers the thermal contact effect is proposed to predict the heat transfer characteristics of an injection mold assembly. To find the thermal contact conductance between the mold core and plate, a number of finite element (FE) simulations were performed with the design of experiment (DOE) and statistical analysis. Thus, the heat transfer analyses using the obtained conductance values can provide more reliable results than conventional one-body simulations.