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1

Density Distribution and Resin Migration Investigations in Samples of Sand Core Made by Blowing Method

Dańko R., Jamrozowicz Ł.

Journal of Casting & Materials Engineering

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2017

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Vol. 1, no. 3

70--73

EN

Resin migration in a core can occur during the core production process performed by blowing methods in which the core sand is transported into the core box as a two-phase sand-air flux characterized by various working parameters (working pressure, shooting time, volumetric concentration). This migration is the result of the resin being blown off from the matrix grain surfaces by compressed air. The methodology of the investigation of this effect developed at AGH University of Science and Technology is presented in this paper. The results of the resin migration tests obtained for cores made with cold-box technology at various working parameters of the shooting process are also shown.

2

Examinations of parameters influencing the outflow of two phase air-sand stream from machine chamber and core box filling in shooting process

Fedoryszyn A., Dańko R.

Archives of Metallurgy and Materials

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2013

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Vol. 58, iss. 3

903--906

EN

The study investigates the key aspects involved in the flow of the air-sand stream from the machine chamber and in the core box filling in the core shooting and core blowing processes. The prevailing tendency to manufacture thin-walled castings with intricate channel structures has become the major determinant of castings quality and production rates. An important parameter of most core sand used in the shooting processes is the ability to eject from the machine chamber and the core-box filling capability. These properties are the key factors determining the feasibility of manufacturing intricate cores and the process efficiency. The research work outlined in this study focuses on establishing the performance criteria of core sand ejection from the machine chamber and of core box filling and sand compaction. The results given below were obtained for several new-generation core sand types, containing organic and inorganic binders, and designed to be used in hot-box, warm box and warm air processes.

PL

W publikacji przedstawiono zagadnienia związane z wypływem strumienia piaskowo-powietrznego z komory nabojowej i zapełnianiem rdzennicy metodami dmuchowymi z wykorzystaniem strzelarek i nadmuchiwarek. Tendencja do konstrukcji odlewów o coraz cieńszych ściankach i skomplikowanych kanałach, sprawia, że produkcja wysokiej jakości rdzeni jest nadal czynnikiem determinujacym jakość oraz wydajność produkcji odlewów. Ważnymi właściwościami ogółu mas rdzeniowych stosowanych w procesach dmuchowych jest ewakuacja masy z komory nabojowej maszyny dmuchowej oraz zdolność do zapełniania i zagęszczania masy w rdzennicy. Właściwości te, decydują często o możliwosci wykonania skomplikowanych rdzeni oraz o efektywności procesu technologicznego. Przedstawione badania dotyczą ustalenia kryteriów oceny ewakuacji masy z komory nabojowej oraz zdolność do wypełniania rdzennicy i zagęszczania kilku nowoczesnych mas formierskich, zarówno organicznych jak i nieorganicznych, pochodzących technologii hot box, warm box, warm air.

3

Effective cross-section area of a shooting valve in core shooting machines

Dańko J., Dańko R.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 1 spec.

243--246

4

Assessment of core sands suitability for filling the core box and for compaction - by blowing methods

Dańko J., Dańko R.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 1

37-40

EN

The obtained effects of filling the core box cavity and moulding sand compaction in processes of core production by blowing methods (blowing, shooting) depend on several factors. The most important are: geometrical parameters of cavity and complexity of its shape, number, distribution and shape of holes feeding sands as well as the way of deaeration of a technological cavity. Values of individual parameters are selected according to various criteria, but first of all, they should be adjusted to properties of the applied core sand. One of the ways of a preliminary estimation of suitability of a core sand for filling the core box and for compaction by means of blowing methods is the determination of its fluidity and assessment how this parameter is changing when core sand is awaiting to be shot. Another criterion of suitability of core sands for the blowing process is their apparent density obtained at filling the testing core box of a complicated shape (Boenisch test). Various methods developed by several researchers, including the authors, allow to assess the tested property on the basis of special technological tests projecting the process into a laboratory scale. The developed criteria defining a degree or a filling ability factor provide a better possibility of assessing the core sand behaviour during flowing and core box filling, which indicate the value and structure of the obtained compacting decisive - after hardening - for strength and permeability. The mentioned above aspects were analysed - on the basis of authors' own examinations - in the hereby paper.