Reduced dust generation when loading hoppers with powdered material. Part 1. Research methods

Расчетным путем показана целесообразность веерной загрузки бункеров порошкообразным сыпучим материалом. Предложена конструкция кольцевого загрузочного устройства, использующего эффект Коанда, для снижения пылеобразования. Численно и экспериментально определены рациональные конструктивно-технологические параметры разработанного устройства.

Reduced dust generation when loading hoppers with powdered material. Part 2. Results of numerical-experimental studies

On the basis of the obtained analytical dependencies, the expediency of fan loading of bunkers with powdery bulk material has been proved. The design of an annular charging device, which reduces dust formation, using the Coanda effect is proposed. The rational design and technological parameters of the developed device are numerically and experimentally determined.

Hybrid technology for manufacturing lightweight products with a cellular structure made of aluminum alloys

This article is devoted to one of the new directions of creating and obtaining porous materials. The cellular material part is a new element that provides high specific strength of the structure in combination with low density. An urgent task is to develop and obtain a cellular structure with optimal geometric parameters to ensure maximum manufacturability of the structure. The obtained data can be used in the development of technological processes of hybrid casting technologies, as well as for the manufacture of new lightweight parts with increased specific strength characteristics.

Machine Learning for Warpage Prediction of Fused Deposition Modelling Processed Parts

This paper provides a methodology for the application of a machine learning-based framework for fused deposition modelling manufacturing. The approach was developed to take into account the influence of the material, the part geometry, the process parameters on the maximum part warpage defined by the user. The results showed the effectiveness of machine learning for both classification and regression purposes so that the printability of the part is firstly provided, based on the selected warpage threshold, and secondly, the part warpage can be predicted within the problem design space variables, i.e. part material, part height, part length, and layer thickness. The limitations of the use of the analytic equation as a data-points generator are widely discussed, along with the future research based on the obtained preliminary results. In conclusion, the described methodology represents a concrete step towards a first-time-right strategy in the field of manufacturing processes.

The Origins of Women’s Skirt and Shirt Clothing on the Moravian-Slovak Border and Its Central European Context

Over the past one hundred years, folk clothing has been considered one of the most significant elements of cultural heritage and has been perceived in this way not only by experts but, for many decades, by its wearers as well. In the present study, the author seeks to find an answer, based on an analysis of older expert texts, as to what formed the theoretical basis for this process, who were its representatives, at what conclusions they arrived, and how the methods of their work were reflected in the formulation of their conclusions. From the historical perspective, the study summarises the opinions on folk clothing, projected through the idea of Slavic unity, as can be observed in the case of Jan Koula and, through the reception of these opinions, also in the case of Lubor Niederle, Drahomíra Stránská and Viera Nosáľová. This work also offers newer reflections from the studies by Alena Jeřábková on the shaping of folk clothing within the Carpathian culture. Through the example of women’s linen skirts, the material part of the study seeks to point out the pitfalls of these approaches and highlight the need to study the construction of folk clothing from a longer historical perspective. Only in this way is the effect of clothing styles in the form of domestication of the individual pieces of stylish clothing evident, combined with older clothing layers. Even though most parts of folk clothing are not proto-Slavic and do not necessarily relate to the culture of the Carpathian curve, as a whole, they prove well the way the countryside managed to accept the transformations of contemporary fashion over the last four centuries and to incorporate them into a unique clothing complex.

Investigating the Linear Thermal Expansion of Additively Manufactured Multi-Material Joining between Invar and Steel

This work investigated the linear thermal expansion properties of a multi-material specimen fabricated with Invar M93 and A36 steel. A sequence of tests was performed to investigate the viability of additively manufactured Invar M93 for lowering the coefficient of thermal expansion (CTE) in multi-material part tooling. Invar beads were additively manufactured on a steel base plate using a fiber laser system, and samples were taken from the steel, Invar, and the interface between the two materials. The CTE of the samples was measured between 40 °C and 150 °C using a thermomechanical analyzer, and the elemental composition was studied with energy dispersive X-ray spectroscopy. The CTE of samples taken from the steel and the interface remained comparable to that of A36 steel; however, deviations between the thermal expansion values were prevalent due to element diffusion in and around the heat-affected zone. The CTEs measured from the Invar bead were lower than those from the other sections with the largest and smallest thermal expansion values being 10.40 μm/m-K and 2.09 μm/m-K. In each of the sections, the largest CTE was measured from samples taken from the end of the weld beads. An additional test was performed to measure the aggregate expansion of multi-material tools. Invar beads were welded on an A36 steel plate. The invar was machined, and the sample was heated in an oven from 40 °C and 160 °C. Strain gauges were placed on the surface of the part and were used to analyze how the combined thermal expansions of the invar and steel would affect the thermal expansion on the surface of a tool. There were small deviations between the expansion values measured by gauges placed in different orientations, and the elongation of the sample was greatest along the dimension containing a larger percentage of steel. On average, the expansion of the machined Invar surface was 42% less than the expansion of the steel surface. The results of this work demonstrate that additively manufactured Invar can be utilized to decrease the CTE for multi-material part tooling.

PENGARUH PERUBAHAN DIAMETER PERMUKAAN GUN TIP PADA PROSES SPOT WELDING TERHADAP KUALITAS SIFAT MEKANIK NUGGET WELD DI PT. XYZ

Proses spot welding merupakan teknik pengelasan yang banyak digunakan pada manufacture otomotive. Salah atu keutamaannya untuk menghasilkan kualitas produk yang terjamin dan rapih, adapun permasaahan yang diakibatkan dari proses spot welding ialah spot lose atau pengelasan yang tidak menempel.Untuk mengetahui permasalahan spot lose ada beberapa faktor yang berkaitan, diantaranya parameter spot welding, proses pengerjaan, diameter ujung gun tip, material part dan sirkulasi pendinginan. Pengujian dilakukan dengan memvariasikan jumlah pengelasan yang ke 1, 100, 200, 300, 400 dan 500 kali pengelasan. Material yang digunakan low steel JIS S 20C, parameter disesuaikan dengan standar pemakaian. Pengujian dilakukan untuk mengetahui sifat mekanik dari nugget weld diantaranya pengujian tarik dan pengujian kekerasan.Hasil penelitian menunjukkan bahwa variasi jumlah pengelasan berpengaruh pada diameter ujung gun tip, sehingga pembesaran pada ujung diameter gun tip mempengaruhi luas alas diameter nugget weld, pada pengelasan yang ke 1 menghasilkan UTS tegangan geser paling besar yaitu 27,30 kg/mm2 dan kekerasan pada daerah las sebesar 38 HRC, sedangkan pada pengelasan yang ke 500 menghasilkan penurunan UTS tegangan geser hingga 10,67 kg/mm2 dan kekerasan pada daerah las sebesar 39 HRC.