Controlling cellular structure in thermoplastic foam injection molding – influence of processing and mold technologies

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dc.contributor.corporatenameKassel, Universität Kassel, Fachbereich Maschinenbauger
dc.contributor.refereeHeim, Hans-Peter (Prof. Dr.)
dc.contributor.refereeSteinbichler, Georg (Prof. Dr.)
dc.date.accessioned2021-02-08T08:58:50Z
dc.date.available2021-02-08T08:58:50Z
dc.date.issued2020
dc.descriptionZugleich: Dissertation, Universität Kassel, 2020ger
dc.identifierdoi:10.17170/kobra-202008261646
dc.identifier.urihttp://hdl.handle.net/123456789/12466
dc.language.isoengeng
dc.publisherkassel university press
dc.publisher.placeKassel
dc.relation.isbn978-3-7376-0887-9
dc.rightsNamensnennung - Weitergabe unter gleichen Bedingungen 4.0 International*
dc.rights.urihttp://creativecommons.org/licenses/by-sa/4.0/*
dc.subjectfoam injection moldingeng
dc.subjectcore-backeng
dc.subjectmold-openingeng
dc.subjectcellular plasticseng
dc.subjectstructure developmenteng
dc.subjectprocess-structure relationshipeng
dc.subjectlightweight constructioneng
dc.subject.ddc600
dc.subject.ddc660
dc.subject.swdSpritzgießenger
dc.subject.swdSchaumkunststoffger
dc.subject.swdMechanische Eigenschaftger
dc.subject.swdProzessentwicklung <Technik>ger
dc.subject.swdWerkzeugger
dc.subject.swdLeichtbauger
dc.subject.swdChemische Strukturger
dc.titleControlling cellular structure in thermoplastic foam injection molding – influence of processing and mold technologieseng
dc.typeBuch
dc.type.versionpublishedVersion
dcterms.abstractFoam injection molding is a processing technology to produce foamed plastic parts in serials production, attaining an increasing interest and use in industry. However, the applications are limited due to insufficient knowledge of processing and mechanical properties, limited use of light-weight potential as well restricted surface qualities. All these drawbacks are associated with the cellular structure. The structure characteristics like skin layer thickness, cell size, density and uniformity are developed during procedure. Thus, controlling the cell formation process is the key to work against the restrictions and optimize mechanical properties. In conventional or low-pressure foam injection molding procedure, mold filling and foaming occur simultaneously. The cellular characteristics can only be controlled in a very limited range and are often non-uniform by flow length and cross-section, not allowing a precise prediction of the mechanical performance. These limitations can be counteracted by high-pressure foam injection molding with volume-expandable molds. This special process variant may decouple filling and foaming phase and allow an active control of cellular characteristics. Cell formation mechanism may actively be shifted from cell growth to nucleation. Thus, finer-celled, homogeneous, less flowpath dependent structures with density reductions > 50 % can be achieved, and the mechanical properties can actively be influenced. This potential is often unknown due to insufficient knowledge about the process parameters and its effects on structure formation. While the conventional or low-pressure procedure has been asserted and is used in industrial applications, high-pressure procedure with volumeexpandable molds is often unknown or used in a very limited range. This thesis deals with formation of cellular structure in thermoplastic foam injection molding process. The work focusses on influences by processing and mold technologies. High-pressure procedure in combination with volume-expandable molds – mold opening or core-back - is in focus. As a new process variant, the local core-back procedure (local mold volume expansion) is introduced, enabling a local customization of foam structures. The differences in procedures and the influence of additional process parameters are worked out. Here, especially the role of packing pressure as a key factor for structure development is discussed. To get more information on boundary conditions inside the mold during procedure and make the process more transparent, numerical simulation has been used and visualization Abstract molding trials were conducted to monitor the cell development inside the mold during processing. Furthermore, a new mold, i.a. allowing an active control of pressure drop rate was built and used. To analyze the structure and quantify the structural parameters, besides light microscopy and SEM, also x-ray tomography (μCT) was used to allow a three-dimensional characterization of structures.eng
dcterms.accessRightsopen access
dcterms.creatorTromm, Mike
dcterms.dateAccepted2020-06-25
dcterms.extentIX, 233 Seiten
dcterms.isPartOfSchriftenreihe des Instituts für Werkstofftechnik / Kunststofftechnik ;; Band 11ger
dcterms.source.seriesSchriftenreihe des Instituts für Werkstofftechnik / Kunststofftechnikger
dcterms.source.volumeBand 11ger
kup.bindingSoftcover
kup.institutionFB 15 / Maschinenbau
kup.iskuptrue
kup.price39,00
kup.seriesSchriftenreihe des Instituts für Werkstofftechnik / Kunststofftechnik
kup.sizeDIN A5
kup.subjectNaturwissenschaft, Technik, Informatik, Medizin
kup.typDissertation

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