Utjecaj trošenja alata i parametara obrade na raslojavanje pri bušenju kompozitnih materijala

master's thesis

• Title (english): Influence of tool wear and cutting parameters on delamination at drilling of composite materials
• Author: Ivan Bartolin
• Mentor: Toma Udiljak (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2015-07-16, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Kompozitni materijali primjenjuju se u gotovo svim granama industrije, ponajprije zahvaljujući mogućnosti modeliranja njihovih svojstava. Tehnologije proizvodnje dijelova od polimernih kompozita uglavnom omogućuju proizvodnju dijelova na konačan oblik ili na oblik blizak konačnom što smanjuje ili čak eliminira potrebu za obradom odvajanjem čestica (OOČ). Međutim, bušenje je u većini slučajeva još uvijek neophodan postupak OOČ korišten za obradu polimernih kompozita. Bušenje se koristi za izradu provrta koji u pravilu služe za spajanje dijelova, tj. montažu. Kao najveći problem kod bušenja ističe se raslojavanje ili delaminacija. Povećani iznosi raslojavanja značajno narušavaju svojstva materijala u zoni obrade, a napredovanjem duž matrice mogu izrazito nepovoljno djelovati na statička i dinamička svojstva konstrukcije. Do sada provedena ispitivanja pokazuju da najveći utjecaj na iznos raslojavanja u zoni obrade imaju parametri obrade (brzine rezanja i posmična brzina), geometrija svrdla i istrošenost svrdla. Stoga je u ovom radu ispitan utjecaj parametara obrade i istrošenosti svrdla na raslojavanje u zoni obrade. Ispitivanje je provedeno bušenjem kompozitnih uzoraka na način da su određene kombinacije parametara obrade ponavljane više puta pri različitim stupnjevima istrošenosti svrdla. Tijekom izvođenja pokusa, kontinuirano i periodički, snimani su signali koji su kasnije obrađeni i analizirani u cilju pronalaženja značajki osjetljivih na promjene u stupnju istrošenosti alata i raslojavanje obratka.

Abstract (english)

Composite materials are widely used in a number of different industries such as shipbuilding, automotive, aviation, etc. One of the main reasons for their wide application range is possibility of customizing their mechanical properties. Polymer Composites with various types of reinforcements are most commonly used types of composites. Production technology for manufacturing parts of polymer composites enables the production of parts in net shape or a near net shape form which reduces or even eliminates the need for machining. However, drilling is still commonly used for machining polymer composites, mostly for making holes that typically serve for assembly purposes. The biggest problem related to drilling is delamination. High delamination amount can significantly impair material properties around processing zone and its progression along the matrix may compromise the structural integrity. Recent research reports show that the greatest impact on delamination in processing zone have the cutting parameters (cutting speed and feed rate), tool geometry and the tool wear. In this work the influence of processing parameters and the tool wear on the delamination is examined. The experiment was conducted by drilling a composite material using standard twist drill in a way that a several combinations of cutting parameters have been repeated several times for different degrees of tool wear. During the experiment, cutting force and motor drive currents were recorded to be processed by filtering and extracting a number of features potentially sensitive to the changes in tool wear. Delamination for each hole was analyzed in order to be correlated to the cutting parameters and the wear of the tool.

• Keywords: bušenje; kompozitni materijali; raslojavanje
• Keywords (english): drilling; polymer composites; delamination
• Language: croatian
• URN:NBN: urn:nbn:hr:235:310925
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-05-22 13:32:03