This project evaluates fibre length dispersion and distribution within the injection moulding process of long glass fibre reinforced polypropylene, sponsored by Autodesk Simulation. The primary material used in this investigation was a 15 mm long glass fibre reinforced polypropylene consisting of two fibre content levels, 20 wt. % and 40 wt. %. A review of previous research was compiled in this study to evaluate various glass fibre measurement methods and fibre breakage studies to establish where along the injection moulding process fibre breakage predominantly occurs and which process parameters have the greatest influence on fibre length distribution along the screw. Based on literature findings, a manual fibre length measurement method was developed and applied in this study and benchmarked against existing commercially available automated software programs and found to be more accurate in obtaining a reliable fibre length distribution within a glass fibre reinforced sample. Fibre length measurements from the nozzle confirmed that the majority of fibre breakage had already occurred in the screw. Measurements taken along the screw showed a drastic decrease in weighted average glass fibre length from initial pellet form to the end of the metering zone with sudden transitions to lower weighted average values seen at the beginning of the feeding zone and along the compression zone. Fibre dispersion results from the nozzle and along the screw through the use of a μ-CT scanner showed a complex fibre flow and orientation of fibres with the preservation of fibre clusters being seen all along the injection moulding process but chiefly in the feeding and compression zones of the screw.

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Yes / In polymer melt processing, the heat transfer coefficient (HTC) determines the heat flux across the interface of the polymer melt and the mould wall. The HTC is a dominant parameter in cooling simulations especially for microinjection moulding, where the high surface to volume ratio of the part results in very rapid cooling. Moreover, the cooling rate can have a significant influence on internal structure, morphology and resulting physical properties. HTC values are therefore important and yet are not well quantified. To measure HTC in micromoulding, we have developed an experimental setup consisting of a special mould, and an ultra-high speed thermal camera in combination with a range of windows. The windows were laser machined on their inside surfaces to produce a range of surface topographies. Cooling curves were obtained for two materials at different processing conditions, the processing variables explored being melt and mould temperature, injection speed, packing pressure and surface topography. The finite element package Moldflow was used to simulate the experiments and to find the HTC values that best fitted the cooling curves, so that HTC is known as a function of the process variables explored. These results are presented and statistically analysed. An increase in HTC from the standard value of 2500 W/m2C to values in the region 7700 W/m2C was required to accurately model the observations. / EPSRC

This project is concerned with the issue of the thickness optimalization of the wall thickness of the plascics headlamp housing by the simulation Moldflow analyse. There are mentioned the basic information about the plastic materials and their dividing over there. Furthermore the description of the injection process, the injection machines and the tools is included. The principles of the proposal and the construction of the plastics part is also mentioned here. In the application of the Moldflow Plastics Insight 6.0 there is provided the simulation of the melt moldflow for the proposed headlamp housing. Based on this analyse the proposal of the thickness reduction of the wall thickness of the headlamp housing is worked out with the aspect on the required qualities. It also contains the technoeconomic estimation of the benefit optimalization.

This thesis describes the optimalization of technological parameters during commissioning of injection mold manufacturing. In the introduction, there is general literary studies of plastics, injection molds, injection holding machine, injection holding technology and their effect on quality. The practical part includes an analysis of current state, calculation of injection parameters, moldflow analysis and sampling on the machine. Finally, there is choice of optimal injection holding parameters, design of workplace and technical-economic evaluation.

Straight cooling channels are the most common method of controlling part temperature in injection molding process. However, straight cooling channels are not enough to manage temperature uniformity of the parts. In this work, a numerical study is conducted to decrease cycle time and cost of the injection molded parts by using conformal cooling channels. For this purpose, the commercial injection molding simulation program Moldflow is used. The governing physical equations for injection molding were derived and presented. The assumptions of the model were checked for simple geometries by comparing analytical results and numerical results of Moldflow. Then, the effect of conformal cooling channels is investigated for injection molding of a half cylinder shell part. It was seen that conformal cooling channels cools part faster and more uniform than straight cooling channels without corruption on the surface appearance. Finally, a real life case study was presented. For this purpose, a refrigerator shelf that is manufactured by the Ar&ccedil / elik Company was studied. The process was simulated using actual process parameters and simulation results were compared with production results. Then, the process was simulated using conformal cooling channels and compared with production results. It is seen that the cycle time of the refrigerator shelf was decreased considerably while preserving surface quality appearance.

Die Produktqualität und Kosten sind ein eindeutiger Indikator für die Wettbewerbsfähigkeit innovativer Produkte. Toleranzen steuern hier nicht nur die Prozesskosten in der Fertigung und Montage, sondern auch die endgültige Produktqualität. Mit der statistischen Toleranzanalyse werden diese Indikatoren vorhersagbar. Eine fertigungsprozessorientierte Toleranzvergabe ist heute unabdingbar, um Produkte schon frühzeitig in der Produktentwicklung mit den Mitteln der CAD-Umgebung robust nach den Grundsätzen von Design for Six Sigma auszulegen (DfSS=kein Ausschuss bei hoher Funktionalität). Viele innovative Produkte und Funktionsprinzipien würden ohne diese Vorgehensweise am Markt nicht bestehen können. Einige Beispiele aus der Praxis werden das im Rahmen dieses Vortrages aufzeigen.

This master thesis deals with computing of mechanicals properties of parts of headlamps. Parts of headlamps are defined with two different material models, linear material model and material model from Moldflow method. The problem is solved by computational modeling with finite element method using Autodesk Moldflow Insight, Ansys 17.2 and Ansys 18.2 with included Moldsim tool. The outputs are calculations of mechanical properties and comparison of both material models.

This project is dealt with optimalization of moulding procedure of plastic housing of headlamp for project DCW 204 Mopf halogen. The aim is reach a shorter injection moulding cycle time with keeping of claim quality of plastic part. Optimalization will be done based on modification of moulding pressing time. We observe warpage in axis X in the most problematical points of housing by using of contactless measuring optical technologie ATOS III Triple Scan. Simulation analysis for injection moulding was used for prediction of housing warpage up to unforming in every chosen moulding pressing time. According to reaching data in this way comparison of predicted warpage was able to done up to unforming time and real warpage of housing after unforming. According to reaching data in a different period of time warpage of housing during time flowing was observed.

<p>The heat transfer in the filling phase of injection moulding is studied, based on Gunnar Aronsson’s distance model for flow expansion ([Aronsson], 1996).</p><p>The choice of a thermoplastic materials model is motivated by general physical properties, admitting temperature and pressure dependence. Two-phase, per-phase-incompressible, power-law fluids are considered. The shear rate expression takes into account pseudo-radial flow from a point inlet.</p><p>Instead of using a finite element (FEM) solver for the momentum equations a general analytical viscosity expression is used, adjusted to current axial temperature profiles and yielding expressions for axial velocity profile, pressure distribution, frozen layer expansion and special front convection.</p><p>The nonlinear energy partial differential equation is transformed into its conservative form, expressed by the internal energy, and is solved differently in the regions of streaming and stagnant flow, respectively. A finite difference (FD) scheme is chosen using control volume discretization to keep truncation errors small in the presence of non-uniform axial node spacing. Time and pseudo-radial marching is used. A local system of nonlinear FD equations is solved. In an outer iterative procedure the position of the boundary between the “solid” and “liquid” fluid cavity parts is determined. The uniqueness of the solution is claimed. In an inner iterative procedure the axial node temperatures are found. For all physically realistic material properties the convergence is proved. In particular the assumptions needed for the Newton-Mysovskii theorem are secured. The metal mould PDE is locally solved by a series expansion. For particular material properties the same technique can be applied to the “solid” fluid.</p><p>In the circular plate application, comparisons with the commercial FEM-FD program Moldflow (Mfl) are made, on two Mfl-database materials, for which model parameters are estimated/adjusted. The resulting time evolutions of pressures and temperatures are analysed, as well as the radial and axial profiles of temperature and frozen layer. The greatest differences occur at the flow front, where Mfl neglects axial heat convection. The effects of using more and more complex material models are also investigated. Our method performance is reported.</p><p>In the polygonal star-shaped plate application a geometric cavity model is developed. Comparison runs with the commercial FEM-FD program Cadmould (Cmd) are performed, on two Cmd-database materials, in an equilateral triangular mould cavity, and materials model parameters are estimated/adjusted. The resulting average temperatures at the end of filling are compared, on rays of different angular deviation from the closest corner ray and on different concentric circles, using angular and axial (cavity-halves) symmetry. The greatest differences occur in narrow flow sectors, fatal for our 2D model for a material with non-realistic viscosity model. We present some colour plots, e.g. for the residence time.</p><p>The classical square-root increase by time of the frozen layer is used for extrapolation. It may also be part of the front model in the initial collision with the cold metal mould. An extension of the model is found which describes the radial profile of the frozen layer in the circular plate application accurately also close to the inlet.</p><p>The well-posedness of the corresponding linearized problem is studied, as well as the stability of the linearized FD-scheme.</p> / Report code: LiU-TEK-LIC-2002:66.