Wyniki wyszukiwania - BazTech

1

Modeling of rough rotary milling of crankshaft pins

Cieślar Kacper, Płonka Stanisław

Zeszyty Naukowe. Transport / Politechnika Śląska

|

2023

|

z. 121

45--61

EN

The development of the modern automotive industry requires a quick adaptation of new production methods. This is possible thanks to software capable of simulating manufacturing processes. The paper discusses the modeling of the machining operation of a crankshaft’s crankpins for a diesel engine with the use of the planetary milling method. i.e., modeling of milling operation when a disc milling cutter, having its cutting inserts directed inwards, is performing rotary motion, and at the same time, the axis of this milling cutter circulates around the axis of a machined crankpin. For this purpose, a geometrical model of the machining of the crankshaft’s crankpin has been developed. Based on the design documentation of the crankshaft of the 4C90 type diesel engine and the documentation of the Steyr internal disc milling cutter, their CAD models have been developed, and the both models were linked together with suitable kinematic dependencies. In the next step, the crankpin having a length of 25 mm was divided by planes (in quantity lp=21) into 1.25 mm sections. On the main cutting edge of two cutting inserts of the disc milling cutter, points were marked at intersection locations with these planes. Using the Inventor 2016 system, twelve spline curves have been generated for each plane because each plane intersects 12 cutting inserts mounted in cassettes positioned around the circumference of the body of the disc milling cutter. Next, the spline curves were brought to a common coordinate system, rotating them at an angle resulting from the positioning of the cassettes with cutting inserts in the body of the disc milling cutter. Prepared in such a way, spline curves were written in dwg format, which allowed for trimming of the spline curves at the circle with a radius of rcp = 27.90 mm, corresponding to the radius of the crankpin after milling, considering grinding allowance (ø55h6 + 0.80 mm grinding allowance). As a result, it enabled to leave sections of the arcs tangential to the diameter ø55.80 mm and, in such a way, generate the outline of the shape of the crankpin using the REGION command for 21 cross-sections. The outline of the cylindricity of the crankpin was obtained using the strategy of outlines of the roundness, which were generated earlier; this strategy consisted in the collection of 360 points on the circumference of 21 mutually parallel sections cut by planes perpendicular to the axis of the crankpin. To determine the effects of the circular feed rate of the circulating move of the axis of rotation of the internal disc milling cutter on the accuracy of the machining, simulations of the shape of the crankpin were performed for three values of the feedrate: vf = 1200 mm/min; vf = 2100 mm/min and vf = 3000 mm/min. The spline curves with a determined (depending on the duration of the simulation) number of points: 3500, 2100 and 1409 were obtained for each simulation. The calculated cylindricity deviation for the feedrate vf = 1200 mm/min amounted to CYLrck = 0.2272 mm, for the feedrate vf = 2100 mm/min – CYLrck = 0.2406 mm, while for the feedrate vf = 3000 mm/min – CYLrck = 0.2929 mm.

2

Methodology of Optimum Selection of Material and Semi-Folded Products for Rotors of Open-End Spinning Machine

Płonka Stanisław, Postrożny Jacek, Drobina Robert

Autex Research Journal

|

2021

|

Vol. 21, no. 4

393--402

EN

The article presents the methodology of optimal selection of material and the form of semi-product for the rotors of the spindle-less spinning machine. The multicriteria approach was utilized taking into account versatile criteria. The applied procedure consists of two stages: the optimum method in the Pareto sense and the method of distance function. Based on the analysis of the spinning head work, rotor and availability function, six different materials and three forms of semifinished products (extruded bar, forged element, and cast element) were considered. In consequence, the admissible set consisting of nine elements was obtained. For the evaluation of technological quality of the rotor, the following criteria were proposed: index of functionality of the material σf/ρ, maximum height of the surface peaks, Sp, and maximal hardness on surface of oxide layer μHV0,1. Finally, taking into account the economical criterion (unit cost), the Pareto-optimal set of solutions was determined based on four criteria. Due to the fact that this set contained five variants, the distance function was utilized for choosing the best final variant. The optimal material and the semi-product (because of the assumed criteria) chosen were as follows: alloy AlSi1MgMn and the forged element - because in this case the value of distance function was minimal.

3

The Mechanism of Operational Wear of Spindle-Neck Coating of Spinning Spindles Made of AlCu4Mg1 Alloy Due to Cooperation with a Stream of Yarns

Płonka Stanisław, Postrożny Jacek

Tribologia

|

2020

|

nr 4

37--49

EN

Results of the investigations of wear of spindle-neck coating with a collapse balloon crown of ring spinning frames, resulting from cooperation with stream of yarn within industrial conditions are discussed in the paper. The study have comprised measurements of the wear of spindle-neck coating made of EN AW-2024 (AlCu4Mg1) alloy after performed burnishing treatment in the course of cooperation with blend of 70 – 80% wool fibres with the addition of 30–20% polyester fibers, causing the greatest wear. Before and after the period of the operation, based on produced outlines of the roundness of the cylindrical part of the burnished neck of the coating, outlines of the cylindricity of the neck of the spindle have been drawn. Next, using the shape-meter, performed measurements were made of the wear on the spindle-neck coating having the form of a helical groove in the direction perpendicular to its run. There were also 2D measurements performer of the roughness on the neck of coating of spinning spindle, and photos were taken of side surface of the wear in form of helical groove, and one has an inserted EDS spectrum for the surface in the location of the precipitation (phase of AlCuFeMnSi type – point 2). Assessment of the surface in friction area between the spindle-neck coating and the stream of the fibres and the microphotography of side surface of the helical groove lead to the conclusion that the wear of the spindle-neck coating made of AlCu4Mg1 alloy, outside the deep grove, occurs as the result of abrasion, while inside the groove as the result of abrasion and oxidation.

PL

W artykule zamieszczono wyniki badań zużycia szyjki okładziny wrzecion z nasadką antybalonową przędzarki obrączkowej przy współpracy ze strumieniem włókien w warunkach przemysłowych. Badania objęły pomiary zużycia szyjki okładziny wrzecion wykonanych ze stopu EN AW-2024 (AlCu4Mg1) poddanych obróbce wykończeniowej przez nagniatanie przy współpracy z mieszanką włókien: 70÷80% włókien wełny z dodatkiem 30÷20% włókien poliestrowych powodującą największe zużycie. Wykonano zarysy okrągłości części walcowej szyjki okładziny, na podstawie których sporządzono zarys walcowości szyjki okładziny wrzeciona nagniatanej przed i po czasie eksploatacji. Następnie przeprowadzono pomiary zużycia szyjki okładziny w postaci rowka śrubowego w kierunku prostopadłym do jego przebiegu za pomocą kształtografu. Wykonano również pomiary chropowatości 2D powierzchni szyjki okładziny wrzecion przędzalniczych i zdjęcia powierzchni bocznej zużycia w postaci rowka śrubowego oraz zamieszczono widmo EDS dla powierzchni w miejscu wydzielenia (fazy typu AlCuFeMnSi – punkt 2). Ocena powierzchni obszaru tarcia szyjka okładziny–strumień włókien oraz mikrofotografii powierzchni bocznej rowka śrubowego skłaniają do stwierdzenia, że zużycie szyjki okładzin wrzecion ze stopu AlCu4Mg1, poza głębokim rowkiem, następuje w wyniku ścierania, natomiast w rowku w wyniku ścierania i utleniania.

4

Selection of Optimal Thermochemical Treatment of Steel Guides of Yarn

Płonka Stanisław, Drobina Robert, Jędrzejczyk Dariusz, Postrożny Jacek

Fibres & Textiles in Eastern Europe

|

2019

|

Vol. 27, no. 6 (138)

27--33

EN

This paper presents a method of selection of an optimal (the best possible) thermochemical treatment of a steel guide of yarn for a ring spinning frame with the use of an optimisation procedure based on assumed criteria, and with consideration of their importance. Yarn guides for a ring spinning frame were manufactured from three brands of steel and were subjected to the following types of thermochemical treatment: 50SiCr4 steel (chrome hardening, diffusion boronising, and titanising); 41CrAlMo7 steel (nitrosulfiding and nitrogen case hardening), and C45 steel (diffusion boronizing). Unit manufacturing costs and six criteria of manufacturing quality: four parameters of surface texture (Rq, Rp, RΔq, rw), maximal hardness of the surface layer (HV0,1), and the case depth of the surface layer (gww), were taken as criteria for assessment. Values of the assessment criteria obtained from calculations and measurements were subjected to normalisation. The knowledge of experts and importance matrix B, evaluated with the use of the Saaty method (consisting in pairwise comparison of the successive criteria) were used to determine the importance of the criteria taken for the assessment. Using the Power method, eigenvalues of matrix B were found, as well as corresponding coordinates yt of the eigenvector, which are simultaneously the weights of the corresponding criteria. Normalised decisions were created in the next step by raising each component of the normalised assessments to a power equal to the corresponding weight. In the last step of the procedure, a single optimal lining-up was created comprising the smallest s-th components of the individual decisions d1, d2, ..., dm. The best variant of the thermochemical treatment was recognised as corresponding to the largest component of the optimal lining-up, which in our case is the diffusion boronizing. Key words: optimisation, thermochemical treatment, yarn guide.

PL

W pracy przedstawiono dobór optymalnej (najlepszej) obróbki cieplno-chemicznej stalowego prowadnika przędzy przędzarki obrączkowej z zastosowaniem metody postępowania optymalizacyjnego ze względu na przyjęte kryteria z uwzględnieniem ich ważności. Prowadniki przędzy przędzarki obrączkowej wykonano z trzech rodzajów stali i poddano następującym rodzajom obróbki cieplno-chemicznej: 50SiCr4 (chromowaniu, borowaniu i tytanowaniu dyfuzyjnemu), 41CrAlMo7 (azotonasiarczaniu i azotowaniu) oraz C45 (borowaniu dyfuzyjnemu). Jako kryteria oceny przyjęto jednostkowy koszt wytwarzania oraz sześć kryteriów jakości wytwórczej: cztery parametry struktury geometrycznej powierzchni (Rq, Rp, RΔq, rw) i maksymalną twardość na powierzchni HV0,1 oraz głębokość utwardzenia warstwy wierzchniej gww. Wartości kryteriów ocen uzyskane z obliczeń i pomiarów poddano normalizacji. Do określenia ważności przyjętych do oceny kryteriów wykorzystano wiedzę ekspertów oraz macierz ważności B wyznaczoną metodą Saaty’ego, polegającą na porównaniu kolejnych par kryteriów. Stosując metodę Powera znaleziono wartości własne macierzy B i odpowiadające im współrzędne yt wektora własnego, które są równocześnie wagami odpowiadających kryteriów. Następnie utworzono decyzje unormowane przez podniesienie każdego składnika ocen unormowanych do potęgi równej odpowiedniej wadze. W ostatnim etapie utworzono jedno uszeregowanie optymalne, którego składnikami są najmniejsze s-te składniki poszczególnych decyzji d1, d2, ..., dm. Wariantem najlepszym obróbki cieplno-chemicznej jest ten, któremu odpowiada największy składnik uszeregowania optymalnego, w naszym przypadku jest to borowanie dyfuzyjne.