• Title/Summary/Keyword: machining region division

Search Result 5, Processing Time 0.024 seconds

Development of Ultral Clean Machining Technology with Electrolytic Polishing Process

  • Lee, Eun-Sang;Park, Jeong--Woo;Moon, Young-Hun
    • International Journal of Precision Engineering and Manufacturing
    • /
    • v.2 no.1
    • /
    • pp.18-25
    • /
    • 2001
  • Electrolytic polishing is the anodic dissolution process in the transpassive state. It removes non-metallic inclusion and improves mechanical and corrosion resistance of stainless steel. If there is a Bailby layer, it will be removed and the true structure of the surface will be restored. Electrolytic polishing is normally used to remove a very thin layer of material from the surface of metal object. A new electrolyte composed of phosphoric, sulfuric and distilled water has been developed in this study. Two current density, high & low current density regions, have been applied in this study. In this study, In the region of high current density, there is no plateau region but excellent electrolytic polishing effect can be accomplished in short machining time because material removel process and leveling process occur simultaneously. In the low current density region, there can be found plateau region. The material removal process and leveling process occur successively. The aim of this work is to determine electrolytic polishing for stainless steel in terms of high & low current density and workpiece surface roughness.

  • PDF

A Study on Machining of a Compressor Rotor using Formed Tools (총형공구를 이용한 압축기 로터 가공에 관한 연구)

  • Park S.Y.;Lim P.;Lee H.K.;Yang G.E.
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2005.06a
    • /
    • pp.1285-1288
    • /
    • 2005
  • Screw rotors, the key parts of screw compressors, are used in compressing air and refrigerant due to their high productivity, compact size, low noise and maintenance. In general, a screw compressor is composed of a pair of rotors of complex geometric shape. The manufacturing cost of the screw rotors is high because the complicated helical shapes of the screw rotors are manufactured usually by the dedicated machine tools. In this study, rotor profile is divided into three parts for the efficient machining. The formed tools are designed and shared for the respective split region. By cutting the screw rotor using the formed tools, this method is more efficient than the end mill in machining rotor. Experimental results show that 4-axis machining using formed tools needs less time and has the accuracy.

  • PDF

Design of Structure Corners restraining Tribological Failures: Part II - Analysis of Design Parameters and Examples (트라이볼로지 손상을 억제하기 위한 구조물 모서리부 설계: 제2부 - 설계인자 분석 및 예)

  • Kim, Hyung-Kyu
    • Tribology and Lubricants
    • /
    • v.31 no.4
    • /
    • pp.170-176
    • /
    • 2015
  • As a continuation of Part I, which developed a design formula of the minimum corner radius (Rmin) for restraining tribological failures, Part II investigates design parameters such as material properties and contact force. As design examples, Al 7075-T651, SST 304 and HT-9 are chosen for the materials and 1, 10 and 100 kN are used for the forces. The results show that the difference in Rmin decreases as either the elastic modulus increases or the contact force decreases. Given the same material and force, the permissible Rmin decreases as the flat region increases and vice versa. Because the Rmin values obtained from the examples are very small, the dimensions of the corner radius normally designed in engineering structures are regarded acceptable. The von Mises stress evaluated for a typical example, which is far below the yield strength, confirms this interpretation. Nevertheless, the present work can provide a design criterion as well as a guideline for quality control in the manufacturing of, in particular, contact corners, which has not been attempted before to the best of the author’s knowledge. In addition, this paper considers the problem of a step that may be formed in the contact contour by using a similar approach. The result shows that no size of the step is permissible.

Optimal Design of Clearance in Fuel Injection Pump (연료분사펌프의 최적 간극 설계)

  • Hong, Sung-Ho;Lee, Bora;Cho, Yongjoo;Park, Jong Kuk
    • Tribology and Lubricants
    • /
    • v.31 no.4
    • /
    • pp.148-156
    • /
    • 2015
  • In the study, a design process for ensuring optimal clearance in a fuel injection pump(FIP) is suggested. Structure analysis and hydrodynamic lubrication analysis are performed to determine the optimal clearance. The FIP is simulated using Hypermesh, Abaqus 6.12 to evaluate the reduction of clearance when the maximum supply pressure is applied. The reduction in clearance is caused by the difference in the deformations between the barrel and plunger. When the deformation of the plunger is larger than that of the barrel, a reduction in clearance at the head part occurs. On the other hand, the maximum clearance reduction equals the maximum deformation in the stem part, because the deformation of barrel does not occur in this region. The clearance of FIP should be designed to be larger than maximum reduction of clearance in order to avoid contact between the plunger and barrel. In addition, the two-dimensional Reynolds equation is used to evaluate lubrication characteristics with variations of viscosity, clearance and nozzle for a laminar, incompressible, unsteady state flow. The equation is discretized using the finite difference method. The lubrication characteristics of FIP are investigated by comparing film parameter, which is the ratio of the minimum film thickness and surface roughness. The optimal clearance of FIP is to be designed by considering the maximum reduction in clearance, lubrication characteristics, machining limits and tolerance of clearance.