scholarly journals Utilization of cluster analysis in the multi-dimensional evaluation of mould surface quality in product correlation

2018 ◽  
Vol 448 ◽  
pp. 012048
Author(s):  
V Pata ◽  
M Kubišová ◽  
L Sýkorová ◽  
O Šuba ◽  
L Hýlová
Keyword(s):  
Cluster Analysis ◽  
Surface Quality ◽  
Mould Surface

Surface Quality Improvement of Aspheric Pressing Mould Using Parallel Grinding Method

2005 ◽  
Vol 291-292 ◽  
pp. 133-138
Author(s):  
Fei Hu Zhang ◽  
L.J. Li ◽  
Shen Dong
Keyword(s):  
Surface Quality ◽  
Optical Glass ◽  
Cost Effective ◽  
Optical Quality ◽  
Grinding Method ◽  
Mould Surface ◽  
Aspheric Optics ◽  
Grinding System ◽  
Parallel Grinding

It is a cost-effective technology to obtain aspheric optics made from optical glass and other brittle materials using pressing mould. The optical quality of molded optics is determined mostly by the surface quality of the mould, which means poor mould surface with lots of cutter marks will result in adhesion phenomena and error replication between the optics and mould. [1] In this article, a chatter model about parallel grinding system was presented, and the reasons of chatter induced by velocity feed back was analyzed and simulated. By using parallel grinding system integrated ELID technology, and wheel with greater cross-section radius in rough grinding and constant grinding velocity in fine grinding, the amplitude of cutter marks in the surface of mould was minimized and the quality of the mould surface was improved.

scholarly journals Innovative fabrication of diffractive surfaces on plastic parts via textures micromilled on NiP injection moulds

2021 ◽  
Author(s):  
Nicola Milan ◽  
Paolo Parenti ◽  
Massimiliano Annoni ◽  
Marco Sorgato ◽  
Giovanni Lucchetta
Keyword(s):  
Surface Quality ◽  
Mass Production ◽  
Low Cost ◽  
Cutting Parameters ◽  
Process Chain ◽  
Grating Pattern ◽  
Mould Surface ◽  
Microstructured Surfaces ◽  
Blaze Grating ◽  
Plastic Parts

AbstractDiffractive microstructured surfaces are nowadays increasingly applied to polymeric parts for aesthetic, security and optical functionalities. However, both the machining of the mould blaze-grating and its replication on plastic are still representing challenging issues, from both the technical and economical points of view. In this work, an innovative process chain based on carbide tools micromilling of mould gratings was developed for mass production of diffractive patterns on injection moulded parts. A micromilling experimental campaign was conducted on a nickel-phosphorus (NiP) thick coating to machine a blaze-grating on the mould surface, evaluating the influence of the cutting parameters on the diffractive surface quality. Subsequently, the microstructures were replicated on ABS, PC and PMMA by injection moulding. The roughness parameters Sk, Spk and Svk were added with the idea that their sum is representative of the polymer replication of regular diffraction grating pattern. Moreover, the effect of the moulded grating surface quality on the optical performance was preliminarily assessed. The obtained results show that the proposed process chain is suitable for low-cost mass production of polymeric parts with diffractive microstructures.

Detection of Laser Melting Bionic Stripe Quality on Mould Surface Based on Acoustic Signal

2011 ◽  
Vol 101-102 ◽  
pp. 926-929
Author(s):  
Li Jun Liu ◽  
Tie Nan Di ◽  
Zhi Xin Jia ◽  
Ji Qiang Li ◽  
Yi Qiang Wang ◽  
...  
Keyword(s):  
Surface Quality ◽  
Acoustic Signal ◽  
Target Surface ◽  
Quantitative Detection ◽  
Signal Characteristic ◽  
Mould Surface ◽  
And Control ◽  
The Relationship

In order to rescue the problems of controlling laser bionic strengthening local stripe of mould surface quality, it is put forward thoughts about the laser bionic local melting stripe of mould surface quality detection based on acoustic signal. Analyzed with the relationship between defocusing distance and acoustic signal characteristic, laser bionic strengthening local stripe quality, the results show that acoustic signal is weakened with the increased absolute value of defocusing distance. As the defocusing distance is 0mm, the role of the laser is primarily ablation and the stripe quality is the worst; the function of laser on the surface materials is too weak to strengthen when the defocusing distance is -4mm; laser on target surface plays its role of strengthening, mainly owing to melting, with defocusing distance of +4mm. Overall tests show that, based on the quantitative detection of acoustic signal characteristic, it could inspect and control the quality of strengthening stripe, and it will realize the overall control of laser bionic strengthening mould surface quality with guiding significance.

scholarly journals The Influence of Surface Quality on Flow Length and Micro-Mechanical Properties of Polycarbonate

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5910
Author(s):  
Martin Ovsik ◽  
Michal Stanek ◽  
Adam Dockal ◽  
Petr Fluxa ◽  
Vlastimil Chalupa
Keyword(s):  
Mechanical Properties ◽  
Surface Quality ◽  
Processing Parameters ◽  
Polished Surface ◽  
Indentation Hardness ◽  
Indentation Modulus ◽  
Polymer Flow ◽  
Significant Variance ◽  
Mould Surface ◽  
Flow Length

This study describes the influence of polymer flow length on mechanical properties of tested polymer, specifically polycarbonate. The flow length was examined in a spiral shaped mould. The mould cavity’s surface was machined by several methods, which led to differing roughness of the surface. The cavity was finished by milling, grinding and polishing. In order to thoroughly understand the influence of the mould surface quality on the flow length, varying processing parameters, specifically the pressure, were used. The polymer part was divided into several segments, in which the micro-mechanical properties, such as hardness and indentation modulus were measured. The results of this study provide interesting data concerning the flow length, which was up to 3% longer for rougher surfaces, but shorter in cavities with polished surface. These results are in disagreement with the commonly practiced theory, which states that better surface quality leads to greater flow length. Furthermore, evaluation of the micro-mechanical properties measured along the flow path demonstrated significant variance in researched properties, which increased by 35% (indentation hardness) and 86% by indentation modulus) in latter segments of the spiral in comparison with the gate.

Cluster analysis for large data sets: applications to individual aerosol particles from the mid-pacific

1992 ◽  
Vol 50 (2) ◽  
pp. 1488-1489
Author(s):  
Thomas W. Shattuck ◽  
James R. Anderson ◽  
Neil W. Tindale ◽  
Peter R. Buseck
Keyword(s):  
Cluster Analysis ◽  
Chemical Reactivity ◽  
Large Data ◽  
Large Data Sets ◽  
Particle Analysis ◽  
Data Sets ◽  
Halogen Chemistry ◽  
Complete Study ◽  
Components Analysis ◽  
Automated Scanning

Individual particle analysis involves the study of tens of thousands of particles using automated scanning electron microscopy and elemental analysis by energy-dispersive, x-ray emission spectroscopy (EDS). EDS produces large data sets that must be analyzed using multi-variate statistical techniques. A complete study uses cluster analysis, discriminant analysis, and factor or principal components analysis (PCA). The three techniques are used in the study of particles sampled during the FeLine cruise to the mid-Pacific ocean in the summer of 1990. The mid-Pacific aerosol provides information on long range particle transport, iron deposition, sea salt ageing, and halogen chemistry.Aerosol particle data sets suffer from a number of difficulties for pattern recognition using cluster analysis. There is a great disparity in the number of observations per cluster and the range of the variables in each cluster. The variables are not normally distributed, they are subject to considerable experimental error, and many values are zero, because of finite detection limits. Many of the clusters show considerable overlap, because of natural variability, agglomeration, and chemical reactivity.

Measuring “Language Access Profiles” in Deaf and Hard-of-Hearing Children With the DHH Language Exposure Assessment Tool

2020 ◽  
pp. 1-25
Author(s):  
Matthew L. Hall ◽  
Stephanie De Anda
Keyword(s):  
Cluster Analysis ◽  
Exposure Assessment ◽  
Hard Of Hearing ◽  
Assessment Tool ◽  
Communication Mode ◽  
Developmental Potential ◽  
Language Access ◽  
Retest Reliability ◽  
Language Exposure ◽  
Test Retest Reliability

Purpose The purposes of this study were (a) to introduce “language access profiles” as a viable alternative construct to “communication mode” for describing experience with language input during early childhood for deaf and hard-of-hearing (DHH) children; (b) to describe the development of a new tool for measuring DHH children's language access profiles during infancy and toddlerhood; and (c) to evaluate the novelty, reliability, and validity of this tool. Method We adapted an existing retrospective parent report measure of early language experience (the Language Exposure Assessment Tool) to make it suitable for use with DHH populations. We administered the adapted instrument (DHH Language Exposure Assessment Tool [D-LEAT]) to the caregivers of 105 DHH children aged 12 years and younger. To measure convergent validity, we also administered another novel instrument: the Language Access Profile Tool. To measure test–retest reliability, half of the participants were interviewed again after 1 month. We identified groups of children with similar language access profiles by using hierarchical cluster analysis. Results The D-LEAT revealed DHH children's diverse experiences with access to language during infancy and toddlerhood. Cluster analysis groupings were markedly different from those derived from more traditional grouping rules (e.g., communication modes). Test–retest reliability was good, especially for the same-interviewer condition. Content, convergent, and face validity were strong. Conclusions To optimize DHH children's developmental potential, stakeholders who work at the individual and population levels would benefit from replacing communication mode with language access profiles. The D-LEAT is the first tool that aims to measure this novel construct. Despite limitations that future work aims to address, the present results demonstrate that the D-LEAT represents progress over the status quo.

Social representations of human rights violations: Further evidence

2001 ◽  
Vol 60 (2) ◽  
pp. 89-98 ◽  
Author(s):  
Alain Clémence ◽  
Thierry Devos ◽  
Willem Doise
Keyword(s):  
Cluster Analysis ◽  
Human Rights ◽  
Costa Rica ◽  
Young People ◽  
Social Representations ◽  
Social Reality ◽  
Questionnaire Study ◽  
Human Rights Violations ◽  
High Tolerance ◽  
Individual Actions

Social representations of human rights violations were investigated in a questionnaire study conducted in five countries (Costa Rica, France, Italy, Romania, and Switzerland) (N = 1239 young people). We were able to show that respondents organize their understanding of human rights violations in similar ways across nations. At the same time, systematic variations characterized opinions about human rights violations, and the structure of these variations was similar across national contexts. Differences in definitions of human rights violations were identified by a cluster analysis. A broader definition was related to critical attitudes toward governmental and institutional abuses of power, whereas a more restricted definition was rooted in a fatalistic conception of social reality, approval of social regulations, and greater tolerance for institutional infringements of privacy. An atypical definition was anchored either in a strong rejection of social regulations or in a strong condemnation of immoral individual actions linked with a high tolerance for governmental interference. These findings support the idea that contrasting definitions of human rights coexist and that these definitions are underpinned by a set of beliefs regarding the relationships between individuals and institutions.

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