scholarly journals Dynamic Generation of Machined Surfaces, Part 1: Description of a Random Excitation System

1991 ◽  
Vol 113 (2) ◽  
pp. 137-144 ◽  
Author(s):  
G. M. Zhang ◽  
S. G. Kapoor
Keyword(s):  
Surface Finish ◽  
Mathematical Formulation ◽  
Three Dimensional ◽  
Surface Profile ◽  
Random Excitation ◽  
Work Piece ◽  
Excitation System ◽  
Machining Conditions ◽  
Dynamic Generation ◽  
Machined Surfaces

With increasing emphasis on the adaptive control for the purpose of quality and productivity improvement, it becomes necessary to develop models which can correlate the surface finish parameters with the machining conditions as well as work-piece material characteristics. This paper presents a study that leads to the development of a model for the dynamic generation of three-dimensional texture of machined surfaces. In Part 1, the mathematical formulation of the random excitation system which is responsible for the random portion of a surface profile is developed. It is assumed that the random excitation system originates from the nonhomogeneous distribution of microhardness of workpiece material. Machining tests are also performed to verify the validity of such a model development. In Part 2, a procedure for the construction of three-dimensional topography will be developed and the relationship between the machining conditions and the surface finish parameters will be established.

Development of an Ultra-Precision Annular Polishing Machine Tool with Full Gas Static Pressure

2020 ◽  
Vol 837 ◽  
pp. 183-190
Author(s):  
Heng Xing Tang ◽  
Chu Peng Zhang ◽  
Lin Lin
Keyword(s):  
Machine Tool ◽  
Static Pressure ◽  
Three Dimensional ◽  
Surface Profile ◽  
Numerical Control ◽  
Work Piece ◽  
Guide Rail ◽  
Processing Efficiency ◽  
Contour Map ◽  
Ultra Precision

In order to improve chemical mechanical polishing (CMP) efficiency and accuracy in the fabrication of planar optics, CMP models and machine tools have been developed. A three-dimensional contour map of the surface of the polishing plate was established by measuring the runout error of several circles on the polishing plate. Based on the Preston equation and the three-dimensional contour map, a CMP model that simulates material removal at any point on the work piece is proposed. This model shows that higher motion accuracy can improve efficiency and accuracy. Then, based on this point of view, a new CMP machine tool was designed, and the ultra-precision gas static pressure guide rail and turntable and Siemens 840Dsl numerical control system were applied to the new CMP machine tool. In order to validate the new machine, a series of testing and processing experiments were carried out. The straightness error of the gas static pressure guide rail can be less than 1.1 μm. The axial runout error of the gas turntable can be less than ±0.4 μm. The surface profile of the experimental workpiece can be less than 0.01λ, and the processing efficiency of the new CMP machine can reach 4 times of the processing efficiency of the conventional CMP machine. In addition, the repeatability and stability of the CMP process is improved on new machines.

scholarly journals Extrusion Based 3D Printing of Sustainable Biocomposites from Biocarbon and Poly(trimethylene terephthalate)

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4164
Author(s):  
Elizabeth Diederichs ◽  
Maisyn Picard ◽  
Boon Peng Chang ◽  
Manjusri Misra ◽  
Amar Mohanty
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Surface Finish ◽  
Three Dimensional ◽  
Morphological Properties ◽  
Great Promise ◽  
Structural Components ◽  
Computer Aided ◽  
Trimethylene Terephthalate ◽  
Optimal Quantity

Three-dimensional (3D) printing manufactures intricate computer aided designs without time and resource spent for mold creation. The rapid growth of this industry has led to its extensive use in the automotive, biomedical, and electrical industries. In this work, biobased poly(trimethylene terephthalate) (PTT) blends were combined with pyrolyzed biomass to create sustainable and novel printing materials. The Miscanthus biocarbon (BC), generated from pyrolysis at 650 °C, was combined with an optimized PTT blend at 5 and 10 wt % to generate filaments for extrusion 3D printing. Samples were printed and analyzed according to their thermal, mechanical, and morphological properties. Although there were no significant differences seen in the mechanical properties between the two BC composites, the optimal quantity of BC was 5 wt % based upon dimensional stability, ease of printing, and surface finish. These printable materials show great promise for implementation into customizable, non-structural components in the electrical and automotive industries.

The Use of Photogrammetry in Piping Design

1983 ◽  
Vol 197 (2) ◽  
pp. 125-138 ◽  
Author(s):  
P A Bracewell ◽  
U R Klement
Keyword(s):  
Information Retrieval ◽  
Mathematical Formulation ◽  
Three Dimensional ◽  
Cost Effective ◽  
Process Industry ◽  
Process Plant ◽  
Definition Of ◽  
High Degree ◽  
Positional Data

Piping design for ‘revamp’ projects in the process industry requires the retrieval of large amounts of ‘as-built’ data from existing process plant installations. Positional data with a high degree of accuracy are required. Photogrammetry, the science of measurement from photographs, was identified in Imperial Chemical Industries plc (ICI) as a suitable tool for information retrieval. The mathematical formulation enabling the definition of three-dimensional positions from photographic information is described. The process of using ICI's photogrammetric system for the definition of complete objects such as structures and pipes is illustrated. The need for specialized photogrammetric software for design purposes is explained. A case study describing how the photogrammetric system has been applied is described and graphical outputs from this exercise are shown. It is concluded that this particular photogrammetric system has proved to be a cost effective and accurate tool for the retrieval of ‘as-built’ information.

scholarly journals Dynamic Generation of Machined Surfaces, Part 2: Construction of Surface Topography

1991 ◽  
Vol 113 (2) ◽  
pp. 145-153 ◽  
Author(s):  
G. M. Zhang ◽  
S. G. Kapoor
Keyword(s):  
Surface Topography ◽  
Random Excitation ◽  
Surface Generation ◽  
Distribution Model ◽  
Excitation System ◽  
Machined Surface ◽  
Spiral Trajectory ◽  
Vibratory Motion ◽  
Texture Generation ◽  
Simulation Results

In Part 1 of these two-part papers, a normal distribution model has been formulated to describe the random excitation system present during machining. Part 2 presents a methodology to dynamically generate the surface topography under the random excitation environment through computer simulation. The proposed methodology uses the tool vibratory motion along with the tool geometrical motion to construct the topography of a machined surface. Both experimental and simulation results confirm that when a small feed is used, the influence of the spiral trajectory of tool geometrical motion on the surface generation decays dramatically and the random excitation system, on the opposite, is strengthened playing a significant role in surface texture generation.

scholarly journals Fringe projection profilometry for recovering 2.5D shape of ancient coins

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 142
Author(s):  
Giuseppe Schirripa Spagnolo ◽  
Lorenzo Cozzella ◽  
Fabio Leccese
Keyword(s):  
Cultural Heritage ◽  
Good Accuracy ◽  
Three Dimensional ◽  
Surface Profile ◽  
Fringe Projection ◽  
Profile Measurement ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Cultural Heritage Objects ◽  
Physical Access

<p class="Abstract">The relief of form is undoubtedly one of the most topical topics in the field of cultural heritage. Physical access to historic and artistic manufactures can be limited by a lot of factors. For example, the access to the collection of the ancient coins is difficult, especially for students. Indeed, for coins digital archive of high-quality three-dimensional model and remote fruition is of great interest. The use of projected fringes for the measurement of surface profile is a well-developed technique. In this paper, we present a surface profile measurement system for small objects of cultural heritage where it is important not only to detect the shape with good accuracy but also to capture and archive the signs due to ageing. The illustrated equipment is simple, reliable, and cheap. Furthermore, some examples of acquisitions are presented to demonstrate the potentiality of the proposed scheme for recovering 2.5D shape of cultural heritage objects.</p>

Online quality evaluation of tissue paper structure on new generation tissue machines

2018 ◽  
Vol 33 (1) ◽  
pp. 133-141 ◽  
Author(s):  
Jukka-Pekka Raunio ◽  
Tommi Löyttyniemi ◽  
Risto Ritala
Keyword(s):  
3D Structure ◽  
Three Dimensional ◽  
Surface Profile ◽  
Absorption Capacity ◽  
Tissue Paper ◽  
Paper Manufacturing ◽  
Residual Variation ◽  
Residual Variances ◽  
New Generation

Abstract At present, the tissue paper manufacturing is mostly based on the dry crepe technology. During the last decade, the manufacturers have introduced new tissue machines concepts that increase the softness, bulk, and absorption capacity. Such machines produce a strong regular three-dimensional (3D) structure to the sheet before the Yankee cylinder. At present, the quality of the 3D structure is not evaluated, or it is evaluated only subjectively at the mill. This is mostly because of the difficulties to separate reliably the regular 3D pattern from other variations. This paper introduces a frequency analysis based method which separates the surface profile variances in tissue paper to the creping, to the regular 3D pattern and to the residual variation. The 3D surface profiles and their variances were determined online with the photometric stereo method. We show that the introduced analysis method evaluates the variance portions reliably and the results are consistent with the visual perception of the 3D surfaces. In one particular product, the regular 3D pattern explains 74 % of total surface variance; the creping explains 10 % and residual variations 16 %. Furthermore, the creping and residual variances are quite stable over time whereas the variance of the regular 3D pattern fluctuates significantly.

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