scholarly journals Optimizing Sampling Parameters of CMM Data Acquisition for Machining Error Correction of Freeform Surfaces

2018 ◽  
Vol 12 (4) ◽  
pp. 265-269
Author(s):  
Małgorzata Poniatowska

Abstract An optimization study using the design of experiment technique is described, in which the surface profile height of a freeform surface, determined in coordinate measurements, is the response variable. The control factors are coordinate sampling parameters, i.e. the sampling grid size and the measuring tip diameter. As a result of the research, an optimal combination of these parameters was found for surface mapping with acceptable measurement uncertainty. The presented study is the first stage of optimization of machining error correction for the freeform surface and was intended to take into account mechanical-geometric filtration of surface irregularities caused by these geometrical parameters. The tests were carried out on a freeform workpiece milled with specific machining parameters, Ra of the surface roughness was 1.62 μm. The search for the optimal combination of parameters was conducted using Statistica software.

Author(s):  
Menderes Kam ◽  
Mustafa Demirtaş

This study analyzed the tool vibration (Vib) and surface roughness (Ra) during turning of AISI 4340 (34CrNiMo6) tempered steel samples using Taguchi Method. In this context, Taguchi design L18 (21 × 32) was used to analyze the experimental results. The vibration amplitude values from cutting tools were recorded for different machining parameters, control factors; two different sample hardness (46 and 53 HRc), three different cutting speeds (180, 220, 260 m.min−1), and feed rates (0.08, 0.14, 0.20 mm.rev−1) were selected. The machining parameters giving optimum Vib and Ra values were determined. Regression analysis is applied to predict values of Vib and Ra. Analysis of variance was used to determine the effects of machining parameters on the Vib and Ra values. The most important machining parameters were found to be the feed rate, sample hardness, and cutting speed for Vib and Ra, respectively. The lowest Vib and Ra values were obtained in 46 HRc sample as 0.0022 gRMS and 0.255 µm, respectively. The surface quality can be improved by reducing the sources of vibration by using appropriate machining parameters. As a result, there is a significant relationship between Ra and Vib. The lower Ra values were found during turning process of tempered steel samples according to the literature studies. It is suggested that the process can be preferred as an alternative process to grinding process due to lower cost and machining time. In application of the turning of experiment samples by ceramic cutting tool, a substantial technological and economical benefit has been observed.


2018 ◽  
Vol 12 (2) ◽  
pp. 104-108 ◽  
Author(s):  
Yusuf Fedai ◽  
Hediye Kirli Akin

In this research, the effect of machining parameters on the various surface roughness characteristics (arithmetic average roughness (Ra), root mean square average roughness (Rq) and average maximum height of the profile (Rz)) in the milling of AISI 4140 steel were experimentally investigated. Depth of cut, feed rate, cutting speed and the number of insert were considered as control factors; Ra, Rz and Rq were considered as response factors. Experiments were designed considering Taguchi L9 orthogonal array. Multi signal-to-noise ratio was calculated for the response variables simultaneously. Analysis of variance was conducted to detect the significance of control factors on responses. Moreover, the percent contributions of the control factors on the surface roughness were obtained to be the number of insert (71.89 %), feed (19.74 %), cutting speed (5.08%) and depth of cut (3.29 %). Minimum surface roughness values for Ra, Rz and Rq were obtained at 325 m/min cutting speed, 0.08 mm/rev feed rate, 1 number of insert and 1 mm depth of cut by using multi-objective Taguchi technique.


Author(s):  
Vaibhav Shukla ◽  
Syed Nadeem Akhtar ◽  
S. Kanmani Subbu ◽  
J. Ramkumar

Micro electric discharge milling (μ-ED milling) is an effective and economic process for the fabrication of micro channels. In the present work, the bulk approach of μ-ED milling is being attempted to make complex shaped micro channels. For a straight channel the bulk approach of μ-ED milling was found to be a successful approach. A tungsten tool of diameter 500 μm was used to fabricate semi-circular micro channels on EN-24 steel. Important machining parameters had earlier been optimized to make straight channels on EN-24 steel by the same method. The effect of geometrical parameters such as radius of curved channel and aspect ratio on MRR and TWR were studied by full factorial experimental design for single pass at optimized machining parameters. Finally complex shapes like T-type and serpentine channels were made by using optimized conditions of straight and curved channels by bulk approach with multiple passes of μ-ED milling.


Wear ◽  
1982 ◽  
Vol 83 (1) ◽  
pp. 91-108 ◽  
Author(s):  
T.G. King ◽  
T.A. Spedding

2010 ◽  
Vol 09 (04) ◽  
pp. 359-363
Author(s):  
HUSEN KARTASASMITA KANG ◽  
CHEE CHEONG WONG ◽  
FILIPPO ROMANATO

Surface plasmon polariton is surface electromagnetic waves that propagate parallel along a metal/dielectric interface through a 1D or 2D periodic structures. Since the polaritons wave is confined at interface, the surface plasma polariton (SPP) is very sensitive to any changes on this boundary that directly change the effective refractive index of the system. This enables us to do some variations to control the SPP, i.e., modifying the metallic nanostructure of the plasmonic crystal (PCL) to vary the effective refractive index. Interference lithography has been widely used to produce different orders of periodic/array of nanostructures. It also has been used as the most economist and efficient way to provide 1D and 2D plasmonic crystals over large area. However, this method suffers from nonlinear processes involved in the manufacture of nominally sinusoidal surface relief diffraction gratings that can introduce distortions. Such distortions may dramatically affect both the specular reflectivity and diffracted efficiencies from plasmonic crystals. Therefore, the quality of surface profile and some geometrical parameters need to be controlled in order to optimize the coupling condition. This will lead us to the understanding of the fundamental geometrical contribution to obtain the field enhancement and variety of profile qualities.


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