Micro-ECM of the Aerodynamic Surface Understating

2021 ◽  
Vol 316 ◽  
pp. 214-220
Author(s):  
Yuriy A. Morgunov ◽  
S.L. Petukhov ◽  
B.P. Saushkin
Keyword(s):  
Alignment Error ◽  
Profile Error ◽  
Flat Bottom ◽  
Surface Alignment ◽  
Deep Surface ◽  
Micro Ecm ◽  
Development Analysis ◽  
Size Tolerance

This paper demonstrates that 18 μm deep surface understating with a tolerance of 4.5 μm and a roughness Ra=0.4 μm can be produced to the required accuracy by electrochemical die-sinking if configured appropriately.Theoretical analysis shows that the bottom profile error can be presented as a superposition of the errors of surface alignment (non-parallel bottom) and shape (non-flat bottom). In this case, the alignment error accounts for a greater part of the size tolerance (3 μm out of 4.5 μm). This is why the attainment of desired accuracy revolves around the development, analysis, and assessment of ways to reduce this error.

Controlling Profile Error for Spherical Surface Micro-Lens in Precision Grinding

2011 ◽  
Vol 215 ◽  
pp. 361-365
Author(s):  
Wei Ren ◽  
Zhi Hui Xia ◽  
C.Q. Han
Keyword(s):  
Mathematical Model ◽  
Measurement Error ◽  
Spherical Surface ◽  
Alignment Error ◽  
Shape Error ◽  
Profile Error ◽  
Machined Surface ◽  
Ultra Precision ◽  
Profile Accuracy ◽  
Micro Lens

As the consumer market in the optics, electronics and aerospace industries grows, the profile accuracy demand for ultra-precision flat, spherical and aspheric optical surface micro-lens increases. Previous studies have found that machine system accuracy, tool alignment error and tool radius measurement error impact greatly on the profile accuracy of the machined surface. In this paper, we developed a grinding system based on the ultra-precision diamond lathe, presented a unified mathematical model of effects of all the geometric errors to the shape error by using the multi-body system theory. Aiming at the main source of profile error, the practical mathematical model is derived, and their propagation coefficients to profile error are calculated. By means of simulation analysis and grinding experiments of spherical part of tugnsten carbide, we conclude that the radial tool alignment error is the main influencing factor for the profile error of spherical surface; while tool radius measurement error influence the radius of sphere only.

UJI TARIK HIDRODINAMIKMODEL KAPAL BERSAYAP WiSE DENGAN LAMBUNG DASAR BERSTEP

2013 ◽  
Vol 12 (3) ◽  
Author(s):  
Iskendar Iskendar ◽  
Andi Jamaludin ◽  
Paulus Indiyono
Keyword(s):  
Comparative Study ◽  
Model Test ◽  
Hydrodynamic Model ◽  
Surface Effect ◽  
Center Of Gravity ◽  
Test Results ◽  
Flat Bottom ◽  
Towing Tank ◽  
Test Models ◽  
Wetted Surface Area

This paper describes hydrodynamic model tests of Wing in Surface Effect (WiSE) Craft. These craft  was fitted with  stephull  form in different location on longitudinal flat bottom (stepedhull planning craft) to determine the influences of sticking and porpoising motion performances. These motions are usually occured when the craft start to take-off from water surfaces. The test models with scale of 1 : 7 were comprised of 4 (four) stephull models and 1 (one) non-stephull model  as a comparative study. The hydrodynamic  tests were performed with craft speed of 16 – 32 knots (prototype values) in Towing Tank at UPT. Balai Pengkajian dan Penelitian Hidrodinamika (BPPH), BPPT, Surabaya. The resistance (drag) was measured by dynamo meter and the trim of model (draft changing at fore and aft  of model due to model speed) was measured by trim meter. By knowing the value of model trim, the wetted surface area can be determined. Then, the lift forces were calculated based on these measured values. The model test results were presented on tables and curves.  Test results show that models  with step located far away from center of gravity of the WiSE craft tend to porpoising and sticking condition, except if the step location on the below of these center of gravity. While model without step tends to sticking conditions.

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