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1

Ceramic injection moulding process of alumina

Matula G., Krzysteczko J., Lipowska B.

Journal of Achievements in Materials and Manufacturing Engineering

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2014

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Vol. 67, nr 1

32--38

EN

Purpose: The aim of this research is presented ceramic injection moulding process of alumina parts. Firstly alumina parts was performed by using binder system. The binder consisted of a mixture of a polypropylene (PP), paraffin wax (PW) and stearic acid (SA). Design/methodology/approach: The volume fractions of powder in the feedstocks were changed from 40-50%vol and the volume of polypropylene were changed from 20-34%vol The concentrations of SA were kept at 6%vol. Secondly the feedstock was heated to melt the binder and injected into a mould. Thirdly the polymeric and wax binder was debinding by using solvent and thermal debinding. The thermal cycle was performed based on the results of the thermogravimetric analysis. Previously samples were sintered in one cycle with debinding of the binder during 23 h at 1400°C using heating rates of 0.5°C/min. Findings: Thermogravimetric analysis (TGA) was performed to determine decomposition temperatures of polypropylene, paraffin and stearic acid. Morphology of alumina powder by scanning electron microscopy (SEM) was disclosed. Originality/value: The paper presents ceramic injection moulding process of alumina parts for selected samples.

2

Application of powder injection moulding for manufacturing of tool composite materials

Matula G., Jędrzejewska-Anioł A., Niespodziański J.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 59, nr 2

80--85

EN

Purpose: The goal of this work is development of the tool composites on the basis of T15 HSS contained 10% of carbides. This tool material were manufactured by Powder Injection Moulding method and sintered. Design/methodology/approach: Torque-load test, rheological tests, thermal debinding, sintering, hardness test and microstructure examinations. Findings: Examination of the effect of the binder type and portion on structure and properties of the experimental tool materials revealed that using the stearic acid for covering the carbides surface reduces viscosity, thus improving technological properties of the feedstock. Employment of polypropylene instead of the high density polyethylene reduces viscosity and torque-load of the investigated feedstocks. Therefore, there is a possibility to increase the portion of the metallic and ceramic powder. Practical implications: Stearic acid significantly reduces the viscosity of tested polymer-powder mixtures, so its use is justified. The share of the binder in materials, injection molded or extruded should be minimal and allows only the formation of the slurry. Too high proportion of binder creates difficulties during the degradation and causes greater shrinkage and possibility of a distortion during sintering. Employment of polyethylene instead of the high density polypropylene reduces viscosity and torque-load of the investigated feedstocks. Therefore, there is a possibility to increase the portion of the metallic or ceramic powder. This results in a lower deformation probability and in a lower sinter shrinkage. Originality/value: In the paper the using extruding of the polymer-powder mix gives the possibility to fabricate cermets which, with their structure and mechanical properties, fill the gap in tool materials between the high-speed steels and cemented carbides.

3

Simulation of powder injection moulding conditions using cadmould program

Matula G., Dobrzański L. A., Ambroziak M.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 55, nr 2

556--560

EN

Purpose: Development of a new generation tool materials on the basis of high speed-steel manufactured by Powder Injection Moulding. To investigate formability of the polymer-powder slurry in which the HS12-1-5-5 (T15) high-speed steel powder was used, as well as the HD-PE polyethylene and paraffin, the „Cadmould” commercial software was employed, developed mostly for simulation of the powder injection moulding of the thermoplastic and composites. Design/methodology/approach: Powder metallurgy, powder injection moulding, sintering, microstructure examination, symulation of injection moulding. Findings: Simulation of powder injection moulding was preceded by the rheological tests, which made obtaining possible of the data indispensable for modelling, pertaining to the polymer-powder slurry viscosity. The portion of particles reinforcing the composite is usually lower than powder portion in mixtures used for forming and next binding agent degradation and sintering. The big powder portion is often the reason for the high viscosity of the mixture and problems with its forming. However, simulation results revealed that the fabricated polymer-powder mixture may be injected, which was confirmed by carrying out powder injection moulding on a typical Arburg injection moulding machine using in the industry. Practical implications: Application of powder injection moulding to manufacturing of high speed steel matrix composites gives the possibility to obtain tool materials with the relative high ductility characteristic of steel and high hardness and wear resistance typical for cemented carbides. Originality/value: Application of symulation of powder injection moulding conditions using cadmould program gives the possibility to reduce cost of expensive injection mould and control the injection conditions.

4

Carbon effect in the sintered high-speed steels matrix composites - HSSMC

Matula G.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 55, nr 1

90--107

EN

Goal: The goal of this monograph is development of the tool materials being the outcome of the concept of merging the surface engineering as the domain of knowledge with technology which is the powder metallurgy. The result are the fabricated materials with the gradient, high-speed steels matrix composites (HSSMC) surface layers on steel substrate, combining the mutually exclusive mechanical properties like the high surface hardness and ductility of a tool. Project/methodology/approach: Modern powder forming technologies were used for fabrication of the developed tool materials, e.g., powder injection moulding, pressureless forming, and classic compacting. Sintering was carried out in the vacuum or protective atmosphere conditions, which makes direct material hardening possible from the sintering temperature. Testing of mechanical properties encompassed hardness testing, bending strength testing, and determining the abrasion wear resistance. Detailed structural examinations were carried out to determine the effect of temperature and atmosphere during sintering on type and size of the carbide- and carbonitride precipitations. Moreover, retained austenite portion was determined after hardening and tempering. Achievements: The original achievement is development of the method of the polymer-powder slurry moulding for fabrication of coatings which, because of the binding agent degradation and sintering, form the homogeneous or gradient HSSMC surface layers on the steel substrate - completed or fabricated in the same technological process. Tool materials fabricated with this method are characteristic of high ductility of the steel core and high hardness of the surface layer. Limitations of research/applications: The assumption of the powder injection moulding technique is forming of the small elements with complex shapes and, therefore, this technology is not designed for fabrication of tools with the big overall dimensions. In case of the pressureless forming of the surface layers from HSSMC on the steel core or in case of regeneration of the tool worn out, the limitations come only from the heating device chamber size and the necessity to heat up the entire treated element. Practical applications: It is anticipated that the worked out and fabricated tool materials of the new generation will fill a gap in respect of the mechanical properties between the relatively ductile high-speed steels and the brittle sintered carbides. The newly developed method may be used in the mass- or piece production conditions making, e.g., regeneration possible of the costly tools’ surfaces. Originality/value: Employment of the modern powders forming techniques, and especially of the pressureless forming and sintering in the flowing nitrogen-hydrogen mixture atmosphere, makes it possible to fabricate tool materials with the layered or gradient structure with the multidirectional growing portion of the hard carbide- or carbonitride phases.

5

Application of polymer-powder slurry for fabrication of abrasion resistant coatings on tool materials

Matula G.

Archives of Materials Science and Engineering

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2011

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Vol. 48, nr 1

49-55

EN

Development of a new generation tool materials on the basis of M2 high speed-steel or 41Cr4 steel covered with the carbides. Application of pressureless forming of powder as a manufacturing method of anti-wear coatings gives the possibility to produce this materials with relative low cost of production.

6

Carbide alloyed composite manufactured with the Powder Injection Moulding method and sinterhardened

Matula G.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 42, nr 1-2

164-171

EN

Purpose: Development of a new generation tool materials on the basis of M2 high speed-steel reinforced with the mixture of carbides and with their structure and mechanical properties, fill the gap in tool materials between the high-speed steels and cemented carbides. Design/methodology/approach: Powder metallurgy, powder injection moulding, sintering, sinter hardening, heat treatment, microstructure and porosity examination, X-ray analysis, TEM, bending test, hardness test. Findings: Powder injection moulding processes were used to fabricate the proposed carbide alloyed composite materials. The addition of hard particles increase hardness after heat treatment and slightly reduces the ductility of these materials. Compared with M2 high-speed steel the bending strength of carbide alloyed composite decrease. The main advantage of the presented experimental tool materials is application of powder injection moulding to produce tool materials in a mass scale with relative low cost of production. Moreover the cost of production reduce application of sinterhardening. Practical implications: Application of heat treatment and especially sinterhardening to improve the mechanical properties of presented experimental tool materials gives the possibility to obtain tool materials with the relative high ductility and high hardness typical for cemented carbides. Originality/value: The essential advantage of the investigated injection moulded material and sintered is the broad range of the optimum sintering temperatures and the relatively small effect of the sintering temperature growth on the carbides growth makes using the industrial heating equipment possible.

7

Carbide alloyed composite manufactured with the PIM method

Matula G.

Archives of Materials Science and Engineering

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2010

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Vol. 43, nr 2

117-124

EN

Purpose: Development of a new generation tool materials on the basis of M2 high speed-steel reinforced with the carbides. Application of powder injection moulding as a manufacturing method gives the possibility to produce these materials in a mass scale with relative low cost of production. Design/methodology/approach: Powder Injection Moulding, solvent debinding, sintering, thermogravimetric analysis, microstructure examination, porosity examination, Findings: To manufacture the proposed new tool materials was used powder injection moulding processes. It was found out based on the investigations carried out that the powder injection moulding method is suitable for fabrication of M2 high speed-steel reinforced with the carbides. The main advantage of the presented experimental tool materials is the wide sintering window being only about 5°C oftentimes in case of the high-speed steels; whereas, it is about 40°C for the investigated material. Practical implications: Application of powder metallurgy and especially powder injection moulding to manufacturing of high speed-steel reinforced with the carbides gives the possibility to obtain tool materials with the relative high ductility characteristic of steel and high hardness and wear resistance typical for cemented carbides. Originality/value: The powder injection moulding gives the possibility to fabricate carbide alloyed composite which, with their structure and mechanical properties, fill the gap in tool materials between the high-speed steels and cemented carbides.

8

Finite Element Method application for structure determining of powder injection moulding samples

Śliwa A., Matula M., Dobrzański L.A.

Archives of Computational Materials Science and Surface Engineering

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2010

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Vol. 2, nr 3

157-164

EN

Purpose: To improve the understanding of the rheology of a metal-loaded polymer, a computer program which simulates the powder injection molding (PIM) process has been developed and its output has been compared to actual laboratory experiments. Design/methodology/approach: The polymer-powder feedstock was injection moulded using Arburg injection moulding machine. Feedstock of M2 HSS reinforced with carbides and mixed with stearic acid, paraffin wax and polypropylene as a binder was made by twin-screw extruder. Feedstock viscosity examination was made by capillary rheometer HAAKE RheoCap. Computer simulation results were compared with experimental results. Findings: Computer aided numerical analysis gives the possibility to select the optimal parameters of injection moulding without necessitate of preparation different feedstocks and manufacturing injected samples in different conditions of injection. Moreover application of ANSYS allows to apply initial process of injection moulding simulations without the necessity of purchasing expensive programs applied to material modeling injection. Research limitations/implications: It was confirmed that using of finite element method in powder injection moulding process can be a way for reducing the investigation costs Results reached in this way are satisfying and in slight degree differ from results reached by experimental method. However for achieving better calculation accuracy in further researches it should be developed given model which was presented in this paper. Originality/value: Nowadays the computer simulation is very popular and it is based on the finite element method, which allows to better understand the interdependence between parameters of process and choosing optimal solution. The possibility of application faster and faster calculation machines and coming into being many software make possible the creation of more precise models and more adequate ones to reality.

9

Stan powierzchni mikroelementów z proszków formowanych wtryskowo

Biało D., Skalski A., Pakuła A.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Nauki Techniczne

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2009

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Z. 13

29--35

PL

Artykuł dotyczy problemów jakości powierzchni mikroelementów otrzymywanych przez formowanie wtryskowe proszków. Do wytwarzania mikroelementów zastosowano proszki żelaza i stali kwasoodpornej. Przedstawiono wpływy ziarnistości proszków i napełnienia masy proszkiem na chropowatość powierzchni oraz wpływ rodzaju materiału na skurcz elementów po spiekaniu.

EN

This article presents the problems of surface microelements obtained by powder injection moulding. Iron powders and stainless steel powders for the manufacture of microelements were used. The influence of powder granularity and powder volume fraction in the mass on surface roughness and sintering shrinkage is also presented in this paper.

10

Finite Element Method application during powder injection moulding

Śliwa A., Matula M., Dobrzański L. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 37, nr 2

584-591

EN

Purpose: The general topic of this paper is problem of model ling of a polymer-powder mix flow during filling, in which the high-speed steel was used along with paraffin and polypropylene as a binding agent. Design/methodology/approach: Modelling of the polymer-powder mix flow process during filling was performed using the finite element method in Cadmould environment; polymer-powder mix was injection moulded using Arburg injection moulder. Computer simulation results were compared with experimental results. Findings: The presented model meets the initial criteria, which gives ground to the assumption about its usability for injection moulding of polymer-powder slurry process, employing the finite element method using the Cadmould software. The computer simulation results correlate with the experimental results. Research limitations/implications: It was confirmed that using of finite element method in powder injection moulding process can be a way for reducing the investigation costs Results reached in this way are satisfying and in slight degree differ from results reached by experimental method. However for achieving better calculation accuracy in further researches it should be developed given model which was presented in this paper. Originality/value: Nowadays the computer simulation is very popular and it is based on the finite element method, which allows to better understand the interdependence between parameters of process and choosing optimal solution. The possibility of application faster and faster calculation machines and coming into being many software make possible the creation of more precise models and more adequate ones to reality

11

Struktura i własności spiekanej stali szybkotnącej HS6-5-2 formowanej wtryskowo

Dobrzański L. A., Matula G.

Hutnik, Wiadomości Hutnicze

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2005

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Vol. 72, nr 3

187--194

PL

Na podstawie porównania struktury i własności stali szybkotnących HS6-5-2 wytwarzanych metodą formowania wtryskowego proszku, formowania niskociśnieniowego, prasowania i spiekania oraz stali komercyjnych wytwarzanych metodą ASEA-STORA stwierdzono, że w strukturze wszystkich badanych stali szybkotnących w stanie spiekanym występują drobne węgliki równomiernie rozmieszczone w osnowie stali. Zastosowanie atmosfery zawierającej azot podczas spiekania, powoduje formowanie się drobnych, sferycznych węglikoazotków typu MX, trwałych w wysokiej temperaturze spiekania i austenityzowania. Wspólną zaletą stali formowanych wtryskowo oraz niskociśnieniowo jest szerszy zakres temperatury spiekania w stosunku do stali wytwarzanych przez tradycyjne prasowanie i spiekanie, dla których wynosi zaledwie 5 °C. Stale formowane niskociśnieniowo charakteryzują się najniższą temperaturą spiekania oraz najwyższą gęstością, wynikającą z wysokiego stężenia węgla pochodzącego z procesu degradacji lepiszcza. Dodatkowo wyższe stężenie węgla powoduje zwiększenie udziału austenitu szczątkowego i niższą twardość po hartowaniu i odpuszczaniu. Stal formowana wtryskowo w stanie obrobionym cieplnie osiąga twardość porównywalną do twardości stali komercyjnej typu ASP 23, wskazując na zasadność stosowania metody formowania wtryskowego proszku do wytwarzania stali szybkotnących. Formowanie wtryskowe proszku umożliwia wytwarzanie narzędzi na gotowo, tj. z pominięciem obróbki plastycznej i ubytkowej, koniecznej w przypadku stali typu ASP 23. Ponadto czas procesu degradacji i spiekania stali formowanych wtryskowo jest o ok. 10h krótszy niż stali formowanych niskociśnieniowo, co jest spowodowane zastosowaniem lepiszcza dwuskładnikowego.

EN

On the basis of comparison of structure and properties of high-speed steels HS6-5-2 manufactured by Powder Injection Moulding, Pressureless Forming, compacted and sintered andproduced by comercial ASEA-STORA method it has been shown that the structure of all examined high-speed steels in sintered state are small and spherical carbides uniformly distributed inferrite matrix. The use ofatmosphere with nitride during sintering process cause formation of the small and spherical carbonitrides MX type stable in high temperaturę of sintering and austenitizing in steel matrix. The common feature of steel formed by Powder Injection Moulding and Pressureless Forming is broaden range of sintering temperaturę in relation to steels produced by conventional compacting and sintering which equals only 5°C. Steels formed by Pressureless Forming are characterized by the lowest sintering temperature and the highest density resulting from high carbon content coming from thermal debinding process of a binder. Moreover, higher carbon concentration causes increase of the retained austenite portion and lower hardness after quenching and tempering. The steel formed by Powder Injection Moulding and heat treated obtain comparable hardness to hardness of commercial ASP 23 steel showing the reason of high speed steel manufacturing by Powder Injection Moulding. The Powder Injection Moulding makespossible production of final shape tools without plastic working and machining which is necessary in case of ASP 23 type steel. Moreover time of thermal debinding and sintering process of steels formed by Powder Injection Moulding is about 10 h shorter than steels formed by Pressureless Forming because two-component binder application.