• Design & Manufacturing
• /
• 제11권1호
• /
• pp.26-29
• /
• 2017

Burrs generated during shear forming such as notching and piercing may cause lifting during product assembly, which may deteriorate the productivity and quality of products. In this study, various shear angles and variable clearances between the punch and the die were applied in experimental notching tests to investigate the shear fracture surface and the burr height due to various conditions. The experimental results show that the clearance has the greatest effect on shear and fracture surfaces. It is considered that the height of the shear section increases slightly as the shear angle increases.

• 한국기계가공학회지
• /
• 제5권1호
• /
• pp.13-18
• /
• 2006

The magnetic abrasive machining has been developed as a new finishing technology to obtain a fine surface of workpiece. In this paper, a static magnetic field method and a magnetic abrasive brush which has many technical advantages, are applied for the magnetic abrasive machining. In the experiment, some items such as finishing time, ratio of the magnetic abrasives to Fe-powder, motor revolutions per minute, and motor ratio revolutions per minute are tested. The results of this study have shown the fact that the burr height is mostly affected by the finishing time and the abrasive ratio. Also, it has been found that the magnetic abrasive machining is a possible new technology for the deburring.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1997년도 추계학술대회 논문집
• /
• pp.523-526
• /
• 1997

Sheanng is one of the most important operating processes in the field of sheet metal manufacturing. Compared with casting, forging and machining, shearing is very economical to obtain the desired shape. In recent years there has been increasing the use of shearing process in the manufacturing of small and light electronic components. In this paper, it has been researched the experimental investigation to examine the mfl uence of shearing process parameters such as clearance and lower holder configuration. Through the experiment results, the more narrow clearance gives the smaller burr height and the removal of lower holder makes the worse sheared surface. And FE simulation of shearing process using DEFORM-2D were camed out and the results compared w~th experimental studies

• 한국공작기계학회논문집
• /
• 제17권1호
• /
• pp.144-149
• /
• 2008

This study presents the selection of cutting conditions in high speed pipe cutting machine for the better quality. A high speed pipe cutting machine which uses a rotary knife can make good quality products in short time. But, the machine is much sensitive by cutting conditions because of the complicated mechanism. In this reason, many experiments for cutting condition selection are necessary to improve quality of production. This study carried out cutting experiments with the three factors that are cutting RPM, cutting force and pooling force. 2-dimensional profile measuring instrument is used to measure which is represented by ${\Delta}h$, a sum of burr and collapse height. The effects of factors are analyzed by using MINITAB, the commercial software.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1994년도 추계학술대회 논문집
• /
• pp.553-558
• /
• 1994

In this paper, we present a new approach for the automation of deburring process. An algorithm for teaching skills of a human expert to a robot manipulator is developed. This approach makes use of TSK fuzzy model that can express a highly nonlinear functional relation with small number of rules. Burr features such as height, width, area, cutting area are extracted from image processing by use of the vision system. Cutting depth, repeative number and normal cutting force are chosen as control signals representing actions of the human expert. It is verified that our processed fuzzy model can accurately express the skills of human experts for the deburring process.

• Design & Manufacturing
• /
• 제2권2호
• /
• pp.38-42
• /
• 2008

This study is performed for investigating the effects of shearing characteristics in fine blanking, such as camber, burr-height and dimensional accuracy, etc by experiments. Conventional hydraulic press equipped with specially designed hydraulic unit is used for experiments. Cold rolled steel sheet(3.0mm) materials which got properties, 2212.39kgf of maximum, $29.490kgf/mm^2$ of stress and 41.33% of strain were used. it can be concluded that the center distance of vee indenter ring can be obtained 2.0mm in SPCC 3.0t.

• 한국정밀공학회지
• /
• 제13권3호
• /
• pp.102-109
• /
• 1996

In this paper, we present a new approach for the automation of deburring process. An algorithm for teaching skills of a human expert to a robot manipulator is developed. This approach makes use of TSK fuzzy mode that can wxpress a highly nonlinear functional relation with small number of rules. Burr features such as height, width, area, grinding area are extracted from image processing by use of the vision system. Grinding depth, repetitive number and normal grinding force are chosen as control signals representing actions of the human expert. It is verified that our proposed fuzzy model can accurately express the skills of human experts for the deburring process.

• 한국산림과학회지
• /
• 제100권3호
• /
• pp.432-440
• /
• 2011

밤나무의 수고와 근원경은 액비처리구와 화학비료처리구에서 가장 많은 생장량을 나타냈으며 수관폭 생장량은 동-서방향과 남-북방향에서 각각 액비처리구와 화학비료처리구에서 우수하였다. 결과지의 총 길이와 착구부~정단부의 길이생장은 액비처리구에서 가장 우수하였으며 기부~착구부의 길이는 액비처리구와 화학비료처리구에서 동일하게 가장 길게 생장하였다. 결과지의 기부직경과 착구부의 상하부직경은 모두 액비처리구에서 가장 두껍게 생장하였다. 본 연구의 5개의 생장지수(결과지발생지수, 길이생장지수, 착구부상하직경비율, 직경생장지수, 굵기지수)에서 길이생장지수만이 액비처리구에서 가장 높고 나머지 모든 지수는 화학비료처리구에서 가장 높았다. 결과모지당 가지발생수와 소약지 개수는 무처리구와 액비처리구에서 많았으며 처리간 유사한 경향을 보였다. 결과모지당 결과지수는 화학비료처리구와 유기질비료처리구에서 많았으며, 결과지당 착구수는 유기질비료처리구와 액비처리구에서 많았다. 과실의 중량과 수량을 기준으로 한 상품화 비율은 무처리구(87.5%)와 화학비료처리구(84.6%)에서 높았으나 액비처리구의 상품화 비율은 각각 84.3%와 82.7%로 평균 수준이었다. 평균입중과 총착구수는 각각 액비처리구와 화학비료처리구로 가장 우수하였다. 함과수는 처리 간 차이는 없었으며 본당수확량은 화학비료처리구(8.2 kg)와 액비처리구(8.0 kg)에서 다수확성을 보였으나 처리간 통계적으로 유의한 차이는 없었다. 과실의 중량과 수량을 기준으로 등급을 구분한 결과, 액비처리구에서 대립 이상의 비율이 각각 43.5%와 34.3%로 가장 높아 액비처리에서 고부가가치의 고품질 밤이 가장 많이 생산되었다.

• 소성∙가공
• /
• 제26권5호
• /
• pp.271-276
• /
• 2017

A tee is the most common pipefitting used to combine or divide fluid flow. Tees can connect pipes of different diameters or change the direction of a pipe run. To manufacture tee type of stainless steel pipe, combinations of punch piercing and burr forming have been widely used in the industry. However, such method is considerably time consuming with regard to performing empirical work necessary to attain process conditions to prevent upper end tearing of the tee product and meet target tee height. Numerous experiments have shown that the piercing profile is the main cause of defects mentioned above. Furthermore, the mold design is formed through trial and error according to pipe diameters and changes in requirements. Thus, the objective of this study was to perform piercing and burring process analysis via finite element analysis using DYNAFORM to resolve problems mentioned above. An optimization design method was used to determine the piercing punch profile. Three radii of the piercing punch (i.e., large, small, and joined radii) were selected as design variables to minimize thinning of a tee pipe. Based on results of correlation and multiple regression analyses, we developed a predictive approximation model to satisfy requirements for both thickness reduction and target height. The new piercing punch profile was then applied to actual tee forming using the developed prediction equation. Model results were found to be in good agreement with experimental results.

• 한국기계가공학회지
• /
• 제17권3호
• /
• pp.1-6
• /
• 2018

Micro prism pattern is applying in order to get increase of luminance, control the light, and so forth especially in optics and display industry. Most patterns are fabricated by lithography, planning, and EDM, but they have limitations on the productivity or the unit cost of produce. However, ultra precision mold is one of the processes able to replace it, and assure high productivity required by industries. In this investigation, micro prismatic end-milling is suggested in order to fabricate the pattern effectively. Micro prism pattern having $100{\mu}m$ of pitch and height was machined on STD-11. After machining, the flank and boundary wear on micro end mill were measured and analyzed, as well as burr formation and dimensional accuracy of fabricated pattern were evaluated. Thus the optimal cutting conditions were derived.