• Journal of the Korean Society for Precision Engineering
• /
• v.14 no.10
• /
• pp.58-67
• /
• 1997

Generally, die polishing process occupies about 30 .approx. 50% of the whole die manufacturing time. However, die polshing has not been automated yet, since it needs a great deal of experience and skill. This study aims at development of an expert system for die polishing which gives such optimal parameters as tool and polishing conditions. Through experiments, polishing characteristics such as surface roughness, stock removal and scratch were analyzed quantitatively for each polishing tool, and a knowledge base for the expert system was established. Evaluation tests show that the developed system works well to suggest the optimal polishing conditions and it is very promising.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.14 no.6
• /
• pp.136-141
• /
• 2015

Laser surface polishing is a polishing method for improving surface roughness using an integrated laser beam. Using a laser for surface polishing can improve the surface condition without physical contact or chemical action. Laser polishing has mainly been used to polish the surface of diamond or optical articles, such as lenses and glasses. Recently, diverse studies on laser polishing for metals have been conducted. The analytic study of laser surface polishing has been conducted with experimental trials for comparison, so that the proper conditions for laser polishing can be recommended. In this study, laser surface polishing was simulated in order to predict the heat-affected zone on the die steel depending on the power of the pulsed laser. The simulated results were verified by comparing them to those of the experimental trials. Through this study, therefore, the application of FEM to the selection of appropriate laser conditions could be possible.

• Journal of the Korean Society of Industry Convergence
• /
• v.5 no.4
• /
• pp.367-372
• /
• 2002

Experimental study was conducted for lapping process after WEDMed specimen. In order to decide the lapping depth of the specimen, the number of the grain size was increased from 400, 600 to 800 to obtain the better surface. Observation of scanning electron microscope, hardness test, surface roughness test and energy dispersive spectrum(EDS) analysis were used for this experimental study. From the comparison and analyses of the results of between the wire-cut electrical discharge machining and the lapping, the following results were obtained. The surface roughness after lapping was found to be improved as increasing the number of lapping process like 1st, 2nd, 3rd lapping and the number of grain size such as 400, 600, 800. The surface hardness after increasing the lapping depth of the specimen was slowly increased. It was found that after 3rd lapping process the hardness was reached the hardness of original base material. It was found that the small amount of coating components within 3% was remained after the 1st lapping process, compared to that approximately 16% after WEDM process.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.7 no.1
• /
• pp.34-40
• /
• 1998

Conductive metal matrix composite(MMC) material of 30% silicon carbide particulated based on aluminum matrix was machined by die sinking electrical discharge machining(EDM) process according to different current and duty factor for reverse polarity of electrode. Material removal rate(MRR) was examined by process under various operation conditions. The surface morphology was evaluated by surface roughness parameter and scanning electron microscopy(SEM) research. The MRR was suddenly increased over 11 ampere of current, and it was slightly changed over 0.3 of duty factor. The maximum surface roughness of EDMed surface was affected by the duty factor. The SEM photograghs of EDMed surface showed wide recast distribution region of melting materials as increased of current and duty factor.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.9 no.1
• /
• pp.134-139
• /
• 2005

This paper works on the manufacture and performance evaluation of bi-polar power supplied diesinking electrical discharge machine. The design and implementation of diesinking electrical discharge machine consists of two parts which are a polarity voltage controller design and a servo motor controller design and they are verified and manufactured through simulation. The performance of the implemented machine and conventional one were evaluated by comparing its machining speed and roughness of machined surface. Eventually, the designed machine showed improved performance in the speed and the roughness.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1994.10a
• /
• pp.98-102
• /
• 1994

There are many difficulties in automatic polishing for die & mold surfaces. Even though the process has been studied in the past 15 years, it has not been achieved yet, but by the process of actual hand work of well-skilled workers. A new magentic assisted polishing process, which is one of the potential method for automation of surface finishing has been studied in the past 10 years by colleagues. The process has many merits, but on the other hand also has demerits, one being low efficiency of gridability by comparision with grinding wheel polish. Therefore, some attempts were tried to improve the grindability by adopting electropolishing, ultra-high speed milling, 5-axis controlled machine etc... most recently by collegues. This study also aims to improve the efficiency of polishing by introducing the easily-polished shape surface milling method equalizing the tool feed per tooth to the pick feed. This milling method was experimentally confirmed to have sufficient grindability to polish milled surface (with 10 .mu. mRmax surface roughness) into mirror surface (with 0.4 .mu. mRmax surface roughness).

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.20 no.12
• /
• pp.3899-3908
• /
• 1996

In order to clarify the effects of nonmetallic inclusion contents insteels (SM45C & SCM440) on the tool life, cutting experiment was performed under various cutting conditions. Tool life, cutting force, roughness of machined surface and cutting mechanism are examined on these two kinds of steel. The following conclusions were obtained from the analysis (1) Cutting force of the steels was not affected by chemical component and nonmetallic inclusion. (2) If the rate of amount, Ca/S has a value grater than about 0.2 and addition of less amount of Al, Mn, tool wear of tips decreasesinturning. (3) It is also proved that higher contents of nonmetallic inclusion improve roughness of the surface. (4) Less amount of Ca, higher amount of S, Mn and Al improve the chip breakability.

• Design & Manufacturing
• /
• v.8 no.2
• /
• pp.12-17
• /
• 2014

Currently, injection molding process is a very useful technique that be applied to many field. And injection molding technology has been commercial based on many studies. However, there is no standard of surface roughness because there are few studies about surface technology of injection product. In addition, when designing the mold, changes of the core surface and the injection conditions are not considered. In this paper, change of surface according to the core and the injection conditions was compared with the surface of the injection product. Accumulation of these technologies will propose direction in mold design, manufacturing and injection molding technology.

• Design & Manufacturing
• /
• v.14 no.1
• /
• pp.36-41
• /
• 2020

Recently, due to the development of MEMS technology, researches for the production of effective micro structures and shapes have been actively conducted. However, the process technology based on chemical etching has a number of problems such as environmental pollution and time problems due to multi-process. Various processes to cope with this process are being studied, and one of the mechanical etching processes is the powder blasting process. This process is a method of spraying fine particles, which has the advantage of being an effective process in manufacturing hard brittle materials. However, it is also a process that adversely affects the material surface roughness and material properties due to the impact of the injection of fine particles. In this study, after fabricating micro-channels in fused silica glass with excellent optical properties among the hard brittle materials, we used the nano indentation system to analyze the micro parts using nano-particles as well as machinability and surface roughness analysis of the processed surface. The analysis was performed for the effective processing of powder blasting.

• 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.