• 한국정밀공학회지
• /
• 제18권1호
• /
• pp.117-122
• /
• 2001

Many kinds of channels are used in industrial equipment and production machinery. Although mechanical saw has been used to cut many sorts of channels, there is cost rise problem because of low productivity. Shearing of channel has a special place because it helps to cut expected shape and size easily. A channel cutting die set which can be mounted and used on a hydraulic press is developed to improve the productivity of channel cutting process. Mode for the channel cutting is divided into single cut and double cut method. This study use double cut method, and the developed channel cutting die set is composed of upper and lower die set. Shearing time can be reduced from 40 minutes to 20 seconds using the developed channel cutting die set. The productivity of channel cutting process can be increased with shearing time reduction as well as cost reduction.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2004년도 추계학술대회 논문집
• /
• pp.1440-1443
• /
• 2004

Shearing including punching, blanking, trimming, slitting, etc is one of the most frequently used processes in sheet metal manufacturing. It has been widely used for manufacturing autobody, electronic components, aircraftbody, etc. In this paper, it has been researched by the experiment to examine the effect of burr height corresponding to die clearance, cutting angle, tool sharpness, etc. This paper presents the experimental results with using Al alloy sheet.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 1999년도 춘계학술대회논문집
• /
• pp.140-143
• /
• 1999

The major objective of the present paper is to develop a channel cutting machine and to establish an analytical technique for actual shearing process. Isothermal finite element(FE)-simulation of the shearing process are carried out using FE software DEFORM. The element-kill method has enabled the achievement of FE-simulation from the initial stage to the final stage of the shearing process. The effects of the punch-die clearance on the shearing process are investigated.

• 반도체디스플레이기술학회지
• /
• 제18권2호
• /
• pp.6-10
• /
• 2019

In the presence of $\mu-tip$ for narrow stripe coating, there appears lateral capillary flow along the hydrophilic head lip because the $\mu-tip$ has some resistance to flow. It was known to be suppressed by increasing the contact angle of the head lip. In this paper, we have demonstrated by computational fluid dynamics(CFD) simulations that it can also be suppressed by the formation of micro-patterns on the shim and meniscus guide embedded into the slot-die head. To optimize the micro-patterned structure, we have performed simulations by varying the groove width, depth, and clearance. In the absence of micro-patterns, it is shown by experiment and simulation that the solution spreads to a distance of $1,300{\mu}m$ from the ${\mu}-tip$. In the presence of micro-patterns with the groove width and clearance of $50{\mu}m$, the distance the solution spreads is reduced to $260{\mu}m$. However, no further suppression in the capillary flow is observed with micro-patterns with the groove width of $40{\mu}m$ or less. It is also observed that the capillary flow is not affected by the groove depth if it is larger than $10{\mu}m$. We have shown that the distance the solution spreads can be reduced further to $204{\mu}m$ by coating a hydrophobic material (contact angle of $104^{\circ}$) on the surface of micro-patterns having the groove width and clearance of $50{\mu}m$.

• Design & Manufacturing
• /
• 제2권1호
• /
• pp.11-14
• /
• 2008

we can save a development cost and time as computer was used in tool and die design of car fields in die manufacture process. Dimension accuracy errors such as springback, springgo, overcrown and twist were reduced product accuracy and caused trouble to assembly each parts of car. In this paper, CADCEUS was used to modify and optimize results of deflection for a tail gate panel of car parts in order to reduce dimension accuracy errors by springback in sheet metal forming. As CADCEUS was used to apply for a tail gate panel, the time for quality to improve was reduced to 30%.

• Design & Manufacturing
• /
• 제15권1호
• /
• pp.41-47
• /
• 2021

The Fine Blanking process is an effective precision shearing process that can obtain a smooth cutting surface and high product precision through a single blanking process. It is widely used in various manufacturing fields. However, shearing through this fine blanking process is only intended to minimize burrs, die rolls and fracture surfaces and does not completely remove them. Therefore, it is necessary to study the minimization of burrs, die rolls and fracture surfaces in the fine blanking process. In this study, a study was conducted on the relationship between the fracture surface and process conditions that occurred during product production using the fine blanking process. For this purpose, the shape of the V-ring indenter, the distance to the punch, and the pressure force, clearance, shear rate, and physical properties of the material were selected as process and design variables, and the relationship with the fracture surface according to each process and design condition was tested. It was analyzed through the Experimental Design Method.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2001년도 춘계학술대회 논문집
• /
• pp.679-682
• /
• 2001

An experiment is carried out to investigate the influences of shearing characteristic factors for the process design of lead frame blanking in copper alloy C194(t=0.205mm). 3 process parameters, e.g., clearance between die and punch, strip holding pressure, and bridge allowance are selected for this study. From the basis condition 6% clearance, 20N/$mm^2$, and 1.5t bridge allowance the seven times of experiment are done by varying the each factor. The square shape specimen is used to study the characteristics of shearing factors. The ratios of roll over, burnish, fracture zone are measured after blanking. The experimental analysis shows that the burnish ratio is decreased as the clearance increases. And the larger strip holding pressure is shown that the roll over and burnish ratio are both decreased. It is found that an optimal strip holding pressure is need for large burnish zone. Finally it is shown that the bridge allowance is less affected than clearance and strip holding pressure.

• 한국공작기계학회논문집
• /
• 제13권6호
• /
• pp.87-93
• /
• 2004

An experimental is carried out to investigate the characteristics of blanking for nickel alloy Alloy42 (t=0.203mm), a kind of IC lead frame material. By varying clearance between die and punch the shapes of shear profile are examined. Finite element analysis with element deletion algorithm for ductile fracture mode is also carried out to study the effect of clearance theoretically and to compare with experimental results. The rectangular shape specimen with four different comer radius is used to study the characteristics of blanking for straight side and comer region simultaneously. As the result the ratios measured k(m experiment of roll over, burnish and fracture zone based on initial blank thickness are compared with those of FE analysis. Both experiment and FE analysis show that the amount of mil over and fracture is increased as the clearance increases. When the radius of comer is less than thickness of blank it has been found that larger clearance is required than that of straight region in order to maintain same quality of shear profile at the comer region.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2003년도 추계학술대회논문집
• /
• pp.21-24
• /
• 2003

In hot forming process of the backward end-bulkhead of a pressure hull, the blank diameter and the tool clearance are the critical factors which influence wrinkling defect, forming load and shape completeness of the product. Two F.E.A softwares with the elasto-plastic material model and rigid plastic model were utilized to predict the occurrence of wrinkling defect. Tool clearance was determined by considering the increase of blank thickness, die strength and the stretching effect. Heat treatment condition after the hot forming to recover the original properties of the material was estabilished by specimen-based heat treating experiment.

• BMB Reports
• /
• 제50권10호
• /
• pp.496-503
• /
• 2017

The human body loses several billions of cells daily. When cells die in vivo, the corpse of each dead cell is immediately cleared. Specifically, dead cells are efficiently recognized and cleared by multiple types of neighboring phagocytes. Early research on cell death focused more on molecular mechanisms of cell death regulation while the cellular corpses were merely considered cellular debris. However, it has come to light that various biological stimuli following cell death are important for immune regulation. Clearance of normal dead cells occurs silently in immune tolerance. Exogenous or mutated antigens of malignant or infected cells can initiate adaptive immunity, thereby inducing immunogenicity by adjuvant signals. Several pathogens and cancer cells have strategies to limit the adjuvant signals and escape immune surveillance. In this review, we present an overview of the mechanisms of dead cell clearance and its immune regulations.