Optimization of 5-axis milling processes using process models

Productivity and part quality are extremely important for all machining operations, but particularly for 5-axis milling where the machine tool cost is relatively higher, and most parts have complex geometries and high quality requirements with tight tolerances. 5- axis milling, presents additional challenges in modeling due to more complex tool and workpiece interface geometry, and process mechanics. In this paper, modeling and optimization of 5-axis processes with cutting strategy selection are presented. The developed process models are used for cutting force predictions using a part-tool interface identification method which is also presented. Based on the model predictions and simulations, best cutting conditions are identified. Also, for finish process of a complex surface, machining time is estimated using three machining strategy alternatives. Results are demonstrated by example applications, and verified by experiments

Investigation of lead and tilt angle effects in 5-axis ball-end milling processes

5-axis milling is widely used in aerospace, die-mold and automotive industries, where complex surfaces and geometries are machined. Being special parameters of 5-axis milling, lead and tilt angles have significant effects on the process mechanics and dynamics which have been studied very little up to now. In this paper, first of all, effects of tool tip contact on the surface finish quality is presented, and conditions to avoid tip contact in terms of lead and tilt angles and depth of cut are stated. The effects of lead and tilt angles on cutting forces, torque, form errors and stability are investigated through, modelling and verified by experimental results. It is shown that the cutting geometry, mechanics and dynamics vary drastically and nonlinearly with these angles. For the same material removal rate, forces and stability limits can be quite different for various combinations of lead and tilt angles. The results presented in the paper are expected to help understanding of complex 5-axis milling process mechanics and dynamics in a better way. The results should also help selection of 5-axis milling conditions for higher productivity and machined part quality

Machining strategy development in 5-axis milling operations using process models

Increased productivity and part quality can be achieved by selecting machining strategies and conditions properly. At one extreme very high speed and feed rate with small depth of cut can be used for high productivity whereas deep cuts accompanied with slow speeds and feeds may also provide increased material removal rates in some cases. In this study, it is shown that process models are useful tools to simulate and compare alternative strategies for machining of a part. 5-axis milling of turbine engine compressors made out of titanium alloys is used as the case study where strategies such as flank milling (deep cuts), point milling (light cuts) and stripe milling (medium depths) are compared in terms of process time by considering chatter stability, surface finish and tool deflections

Modeling and simulation of 5-axis milling processes

5-axis milling is widely used in machining of complex surfaces. Part quality and productivity are extremely important due to the high cost of machine tools and parts involved. Process models can be used for the selection of proper process parameters. Although extensive research has been conducted on milling process modeling, very few are on 5-axis milling. This paper presents models for 5-axis milling process geometry, cutting force and stability. The application of the models in selection of important parameters is also demonstrated. A practical method, developed for the extraction of cutting geometry, is used in simulation of a complete 5-axis cycle

The clinical, cytogenetics and molecular characterization of inverted duplication/deletion of chromosome 8p in a boy with mental and motor retardation: Genotype-phenotype correlation in a case report

Background: Rearrangements that occur mainly through the non-allelic homologous recombination (NAHR) during maternal meiosis in short arms of chromosome 8 is relatively associated with various clinical spectrum.Aim: The objective of this study was to report cytogenetics and molecular characterization of a mental and motor retarded boy with short arm of chromosome 8 rearrangements [invdupdel(8p)] in this current case report. Subjects and methods: We report an 11-year-old boy with scoliosis, intellectual disability, mental-motor retardation and characteristic facial features. Agenesis of corpus callosum was detected with brain Magnetic Resonance Imaging (MRI) analysis. Derivative chromosome 8 structure was identified after conventional cytogenetics – karyotype analysis, Multiplex Ligation-Dependent Probe Amplification (MLPA) and Microarray-based Comparative Genomic Hybridization (aCGH) techniques. Genotype-phenotype correlation in the current proband case will be discussed.Results: Case was diagnosed as 46, XY, der (8), del (8) (p23.1) invdup (8) (p11.1-p23.1) by using advanced comparable techniques. Subtelomeric MLPA analysis showed deletion of FBXO25 gene which is located at 8p23.3 locus and FISH with subtelomeric probes for 8p shows also only deleted region. The microarray- CGH profilling showed 7,9 mb deletion for 8p23.1 and 31 mb duplication for 8p11.1 locuses.Conclusion: Results from the current case emphasized that the cases with clinical manifestations of such disorders extremely need to be examined by combined comparable genetics techniques such as; karyotyping, FISH, MLPA and chromosomal microarray for the accurate phenotype – genotype correlation.Keywords: Chromosomal rearrangement, Corpus callosum, Invdupdel(8p)Array-CGH, MLP

Development of an optimum proliferation medium via the graph kernel statistical analysis method for genetically stable in vitro propagation of endemic Thymus cilicicus (Turkey)

Thymus cilicicus is an endemic Eastern Mediterranean element that has aromatic-medicinal properties. Its natural population spreads across gravelly ground and open rocky areas of South and Southwest Anatolia. The current study on in vitro propagation of T. cilicicus focused deeply on environmental applications such as the development of an optimum medium composition for efficient and genetically stable micropropagation and improved preservation procedures for long-time conservation of elite germplasms for further studies. For this purpose, MS and OM media were used individually and in combination with cytokinins, charcoal, AgNO3, Fe-EDDHA, and H3BO3. The raw data were statistically analyzed via the graph kernel method to optimize the nonlinear relationship between all parameters. The optimal proliferation medium for T. cilicicus was OM supplemented with a combination of 10 g L-1 charcoal and 1 mg L-1 KIN and the calculated averages of the best regeneration rate, the best shoot number and the best shoot length were 96.89%, 3 and 1.24 respectively on this medium. The determination of genetic stability of in vitro grown plants on the optimum medium compositions obtained by the graph kernel method was carried out with the use of the ISSR-PCR technique. All the ISSR primers produced a total of 192 reproductive band profiles, none of which were polymorphic. Furthermore, the micropropagated plants were successfully rooted and acclimatized to greenhouse conditions. In this study, we present a graph kernel multiple propagation index which considers all the possible parameters needing to be analyzed. Such an index is used for the first time for the determination of the optimum proliferation medium

The genetic architecture of membranous nephropathy and its potential to improve non-invasive diagnosis

Membranous Nephropathy (MN) is a rare autoimmune cause of kidney failure. Here we report a genome-wide association study (GWAS) for primary MN in 3,782 cases and 9,038 controls of East Asian and European ancestries. We discover two previously unreported loci, NFKB1 (rs230540, OR = 1.25, P = 3.4 × 10-12) and IRF4 (rs9405192, OR = 1.29, P = 1.4 × 10-14), fine-map the PLA2R1 locus (rs17831251, OR = 2.25, P = 4.7 × 10-103) and report ancestry-specific effects of three classical HLA alleles: DRB1*1501 in East Asians (OR = 3.81, P = 2.0 × 10-49), DQA1*0501 in Europeans (OR = 2.88, P = 5.7 × 10-93), and DRB1*0301 in both ethnicities (OR = 3.50, P = 9.2 × 10-23 and OR = 3.39, P = 5.2 × 10-82, respectively). GWAS loci explain 32% of disease risk in East Asians and 25% in Europeans, and correctly re-classify 20-37% of the cases in validation cohorts that are antibody-negative by the serum anti-PLA2R ELISA diagnostic test. Our findings highlight an unusual genetic architecture of MN, with four loci and their interactions accounting for nearly one-third of the disease risk

Robots in machining

Robotic machining centers offer diverse advantages: large operation reach with large reorientation capability, and a low cost, to name a few. Many challenges have slowed down the adoption or sometimes inhibited the use of robots for machining tasks. This paper deals with the current usage and status of robots in machining, as well as the necessary modelling and identification for enabling optimization, process planning and process control. Recent research addressing deburring, milling, incremental forming, polishing or thin wall machining is presented. We discuss various processes in which robots need to deal with significant process forces while fulfilling their machining task

Multidisciplinary treatment from infancy to adolescence of a patient with a unilateral cleft lip and palate: a 16-year follow-up case report

Cleft lip and palate (CLP) are conditions that require long-term management and review from infancy to adolescence. Surgical procedures become easier when nasoalveolar moulding (NAM) measures are applied during the neonatal period. Orthodontic treatment provided for these patients during the progressive dentition developmental periods can achieve positive aesthetic and functional results. In patients affected by a CLP, the lateral incisor in the cleft region is usually missing and multidisciplinary prosthodontic rehabilitation of the edentulous space is often required. In the present case report, positive results of NAM, coupled with orthodontic and prosthodontic treatment are presented for a CLP patient who began management during the neonatal period. In addition, a minimally invasive aesthetic restoration is presented as a solution for the prosthodontic rehabilitation of a missing lateral incisor.</p

Covering ISIS in the British media: Exploring agenda-setting in The Guardian newspaper

Taner Dogan - ORCID: 0000-0003-0727-1455 https://orcid.org/0000-0003-0727-1455Item not available in this repository.Self-proclaimed ‘Islamic State’ (ISIS) hit the news headlines across the globe in the post-Arab Uprisings period. Its main aim was to replace the ‘colonialist borders’ of the Middle East created with the Sykes–Picot agreement in 1916. One of the atrocities of this terror network was against a minority in Iraq, the Yazidis. Whereas other victims of ISIS, such as Alawites, Druze, Ismailis and Turkmen, have not been covered thoroughly in the British and US media, Yazidis – in particular Yazidi women – dominated the titles. Notwithstanding, the framing of the Yazidis has been influential in the engagement of the Obama administration against ISIS’ move in the Levant; the Kurdish minority is still under threat today because of their ethnic and religious identity. This article discusses how agenda-setting effects the news media’s power to shape individual attitudes and public opinion. The Guardian’s agenda-setting is discussed in this article as a credible, ‘most liberal’ and ‘most trusted’ news brand in the United Kingdom. A content analysis of news articles regarding the plight of Yazidi population in Iraq and its continuous coverage mostly focusing on Yazidi women was conducted, with the articles published at the time when the crisis broke out. The authors of this article apply the notions of an ‘East–West’ divide and ‘Othering’ to frame ISIS’ move in Mount Sinjar, Iraq. The study emphasizes that The Guardian not only set the agenda by prioritizing the circumstances of the Yazidi population, but also deployed frameworks of ‘orientalist’ depictions of Yazidi women as slaves of ISIS.https://doi.org/10.1386/jammr_00019_113pubpub