Optimizacija odzračevalnih kanalov oblikovnega dela orodja pri brizganju duroplastičnih izdelkov

Ribič, Jaka (author), Pepelnjak, Tomaž (mentor)

Pri brizganju duroplastičnih izdelkov iz fenol formaldehidnih smol prihaja pri segrevanju orodja do zamreževanja, ki poteče s polikondenzacijo, pri čemer se voda izloči v obliki vodne pare, izločajo pa se še nekatere druge spojine v plinastem stanju, med katerimi je tudi amonijak. Poleg odvoda zgoraj omenjene vodne pare in plinov je potrebno med polnjenjem orodne votline poskrbeti še za odvod ujetega zraka v njej. Za odvod vseh zgoraj navedenih spojin uporabljamo odzračevalne kanale. Ti ne smejo biti preveliki, da jih masa pri polnjenju ne prelije, pa tudi ne premajhni, saj bi bilo v tem primeru odzračevanje škodljivih spojin nezadostno. Posledica nezadostnega odzračevanja bi bil nastanek »diesel efekta«, na kosih pa bi bile zaradi slednjega vidne ožganine. V tem diplomskem delu smo najprej opravili pregled literature in teorije za področje injekcijskega brizganja plastike in odzračevanje orodij ter analizirali primer slabega in dobrega orodja v proizvodnji. Na koncu smo primerjali predpisana priporočila za izdelavo kanalov z dimenzijami kanalov, izmerjenih iz primera dobrega in slabega orodja, ter naredili analitični preračun, ki je prikazan v literaturi. Ugotovili smo, da se da s preračunom predvideti dimenzije in zasnovati odzračevanje, ki pa potrebuje optimizacijo s praktičnim pristopom.

• Language: Slovenian
• Keywords: odzračevanje, orodja, duroplasti, oblikovni del, optimizacija
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [J. Ribič]
• Year: 2021
• Number of pages: XXII, 76 str.
• PID: 20.500.12556/RUL-129182
• UDC: 621.6.057:678.027.74(043.2)
• COBISS.SI-ID: 76588803
• Publication date in RUL: 28.08.2021

Secondary language

• Language: English
• Title: Optimization of vent channels of the mould used in moulding of termoset products

Abstract

During injection molding of parts made from phenol formaldehyde resin, polycondensation process takes place. When polycondensation occurs, volatiles are produced. In our case byproduct is steam, ammonium and other gases. If they are not allowed to escape through the vents than the product ends up with burn marks or other visual problems on top of dimensional faults and less than expected physical and strength properties. But there is a certain level of caution and expertise required when dimensioning and constructing the vents otherwise we may end up with vents to big which result in spews or with vents too small which prevent volatiles from escaping and we end up with burnt parts as we mentioned above. In this thesis we first checked the available literature for injection molding and venting. Next step was analysis of good and bad tool example. In the end we compared recommendations for venting with vent dimensions on our “good and bad” tool example and conducted a theoretical calculation based on a literature. What we found was that you can foresee vent dimensions and make a venting concept but have also reached the conclusion that the concept will need further optimisation by practical means.

• Keywords: venting, tools, thermosets, mould, optimization