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On the development of technological properties of ferrite powder
Soviš, Jan ; Dvořák, Jaromír (referee) ; Píška, Miroslav (advisor)
This master’s thesis deals with production of ferrite cores by the powder metallurgy technology in EPCOS s.r.o. Šumperk. Special importance is given to powder compaction process through uniaxial cold pressing in a rigid die. The production company is introduced in the first part and is followed by a study of pressure propagation in a powder bed during uniaxial pressing, then the analysis of critical phases of compaction process in terms of green cracks and compact’s defects follows. Main test methods of compact’s green strength are also presented. Significant part of the master’s thesis deals with an analysis of a powder technological properties’ testing method. For that purpose, an instrumented compaction device called Powder Testing Center (PTC, KZK Powder Tech Corp.) is used. A new pressing tool of smaller diameter was made and mounted to the experimental press; also the testing technique, procedure and certificate of powder’s properties was slightly changed. Technological property called advanced compactibility of powder is introduced. Decision about suitability of powder for uniaxial pressing process is made upon the value of newly introduced coefficient of advanced compactibility . Compact’s green strength is evaluated by a proposed contract bend test method, which uses cylindrical-shaped testing pieces with high height-to-diameter ratio. The results from both testing methods show the impact of additional granulate adjustment on green strength and heterogeneity of density distribution along axial direction. Implementation of gained knowledge to production process led to more than 40 % cost savings in term 2/2016 – 4/2016 in comparison with term 8/2015 – 11/2015, because of lowering the number of scrap parts from KLY material due to crack reduction.
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Tack of textile coated with rubber blend
Mahel, Jindřich ; Petrůj, Jaroslav (referee) ; Kučera, František (advisor)
The theoretical part of the diploma thesis describes basic composition of the rubber stock and the methods used for its processing. It summarizes current knowledge about building tack. The experimental part of the thesis deals with the methods of accelerated aging proposal, which have been used for testing UV radiation, ozone, temperature and humidity effect on tack. After bringing two samples together by defined pressure, the tack was determined by T-peel test. Surfaces of the samples were characterized by scanning electron microscopy and infrared spectroscopy. The aditivation of the rubber stock was done in order to compare the effects of tackifiers on accelerated aging.
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On the development of technological properties of ferrite powder
Soviš, Jan ; Dvořák, Jaromír (referee) ; Píška, Miroslav (advisor)
This master’s thesis deals with production of ferrite cores by the powder metallurgy technology in EPCOS s.r.o. Šumperk. Special importance is given to powder compaction process through uniaxial cold pressing in a rigid die. The production company is introduced in the first part and is followed by a study of pressure propagation in a powder bed during uniaxial pressing, then the analysis of critical phases of compaction process in terms of green cracks and compact’s defects follows. Main test methods of compact’s green strength are also presented. Significant part of the master’s thesis deals with an analysis of a powder technological properties’ testing method. For that purpose, an instrumented compaction device called Powder Testing Center (PTC, KZK Powder Tech Corp.) is used. A new pressing tool of smaller diameter was made and mounted to the experimental press; also the testing technique, procedure and certificate of powder’s properties was slightly changed. Technological property called advanced compactibility of powder is introduced. Decision about suitability of powder for uniaxial pressing process is made upon the value of newly introduced coefficient of advanced compactibility . Compact’s green strength is evaluated by a proposed contract bend test method, which uses cylindrical-shaped testing pieces with high height-to-diameter ratio. The results from both testing methods show the impact of additional granulate adjustment on green strength and heterogeneity of density distribution along axial direction. Implementation of gained knowledge to production process led to more than 40 % cost savings in term 2/2016 – 4/2016 in comparison with term 8/2015 – 11/2015, because of lowering the number of scrap parts from KLY material due to crack reduction.
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|
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Tack of textile coated with rubber blend
Mahel, Jindřich ; Petrůj, Jaroslav (referee) ; Kučera, František (advisor)
The theoretical part of the diploma thesis describes basic composition of the rubber stock and the methods used for its processing. It summarizes current knowledge about building tack. The experimental part of the thesis deals with the methods of accelerated aging proposal, which have been used for testing UV radiation, ozone, temperature and humidity effect on tack. After bringing two samples together by defined pressure, the tack was determined by T-peel test. Surfaces of the samples were characterized by scanning electron microscopy and infrared spectroscopy. The aditivation of the rubber stock was done in order to compare the effects of tackifiers on accelerated aging.
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