Further Investigation of Multifacet Drills (MFD’s)—Mathematical Models, Methods of Grinding, and Computer Plotting

1984 ◽  
Vol 106 (4) ◽  
pp. 313-324 ◽  
Author(s):  
L. H. Chen ◽  
S. M. Wu

The geometric characteristics of nine representative Multifacet Drills (MFD’s) are summarized. Mathematical models of the various component surfaces are derived and analyzed using coordinate transformations. The mathematical models of the geometric elements are used to deduce appropriate grinding methods. Computer plots of MFD’s are also presented to check the mathematical models and to lay a foundation for future work on computer-aided design (CAD) of MFD’s.

Author(s):  
Т. В. Єліна ◽  
Л. Є. Галавська

The purpose of this study is to analyze the ergonomic properties of knitwear, that form sense of thermophysiological comfort of a person and their connection with the geometric characteristics of the knitted structure to study the prospects of comfort predicting using computer-aided design systems. Methodology. During the research methods of theoretical analysis, basics of the theory of knitting, theories of thin elastic shell, basic concepts of mechanics and the basics of hydrodynamics were used. Findings.  In  the  course  of  the  work  a  theoretical  analysis  of  scientific  works  and  normative  and technical documentation on various aspects of the definition and provision at the required level of ergonomic properties of knitwear that characterize the level of its convenience and comfort has been carried out. It was found  that  many  researchers  refer  as  most  influencing  the  sense  of  comfort  such  properties  as:  air permeability, water vapour permeability, thermal resistance, hygroscopicity, electrical resistance, as well as stiffness and stretchability, that most affect the ability of knitwear to keep shape and fit the size of the human body. It was found that all abovementioned knitwear properties depend on the geometric characteristics of the knitted structure, such as yarn diameter; the loop length; wale spacing; course spacing; the thickness of the knit and others. Theoretical models of mechanical and physical properties of knitwear are functions of the geometrical characteristics of its structure, therefore the quality prediction of physical behaviour of knitwear depends on the quality of the 3D geometric model of the yarn, knitted in the knit. Scientific novelty. As a result of an analytical review of scientific publications and normative and technical documentation, the ergonomics of knitwear that form a feeling of thermophysiological comfort were determined, and their connection with the geometric characteristics of the knitwear structure was established. Practical  value.  Theoretical  models  of  air  permeability,  thermal  conductivity  and  stretchability, published  in  scientific  journals,  from  the  point  of  view  of  the  possibility  of  their  use  as  the  basis  for mathematical support of the computer-aided design system of knitted clothing are analyzed.


2011 ◽  
Vol 80-81 ◽  
pp. 1118-1122
Author(s):  
Ai Qin An ◽  
Ming Hua Pang ◽  
Lian Feng Zhang ◽  
Yong Fang Nie

Logix gear is a new gear based on new tooth profile theory. On the primary, the forming principle of the logix gear tooth profile is analysed. Then the tooth profile curve equations of logix gear are derived, and their center coordinate equations of base circle are given. According these equations, their curves are simulated using Matlab, which are corresponded to practical tests. The study lays a foundation of computer aided design of the logix gears. And the study can be used to perfect mathematical models and to optimize manufacturing methods.


Author(s):  
Andrey Istomin ◽  
Maksim Krivov ◽  
Alena Andreevna Istomina

The problems of constructing a software package for computer-aided design of mathematical models of complex chemical and technological processes are considered.


1982 ◽  
Vol 14 (8) ◽  
pp. 1099-1102
Author(s):  
I. V. Dem'yanushko ◽  
V. V. Zhestovskii ◽  
V. Ya. Bratchik

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 302
Author(s):  
Sindhu Vijayan ◽  
Pravien Parthiban ◽  
Michinao Hashimoto

PolyJet™ 3D printers have been widely used for the fabrication of microfluidic molds to replicate castable resins due to the ease to create microstructures with smooth surfaces. However, the microstructures fabricated by PolyJet printers do not accurately match with those defined by the computer-aided design (CAD) drawing. While the reflow and spreading of the resin before photopolymerization are known to increase the lateral dimension (width) of the printed structures, the influence of resin spreading on the vertical dimension (height) has not been fully investigated. In this work, we characterized the deviations in both lateral and vertical dimensions of the microstructures printed by PolyJet printers. The width of the printed structures was always larger than the designed width due to the spreading of resin. Importantly, the microstructures designed with narrow widths failed to reproduce the intended heights of the structures. Our study revealed that there existed a threshold width (wd′) required to achieve the designed height, and the layer thickness (a parameter set by the printer) influenced the threshold width. The thresholds width to achieve the designed height was found to be 300, 300, and 500 μm for the print layer thicknesses of 16, 28, and 36 μm, respectively. We further developed two general mathematical models for the regions above and below this threshold width. Our models represented the experimental data with an accuracy of more than 96% for the two different regions. We validated our models against the experimental data and the maximum deviation was found to be <4.5%. Our experimental findings and model framework should be useful for the design and fabrication of microstructures using PolyJet printers, which can be replicated to form microfluidic devices.


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