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Project

Foamed injection molding of lightweight plastic products

Foamed injection molding has a lot of potential as a production technology for plastic products: lightweight design, the possibility of very thin-walled products thanks to viscosity reduction, lower material consumption and cost savings. However, there are also a number of material and process technological challenges that must be addressed in order to successfully apply foamed injection molding. Examples include the negative aesthetic impact on the products (e.g. silver streaks), lower impact strength and the need for an optimized product design. A foamed structure in an injection molded product can be obtained in two ways: via chemical blowing agents or via a physical foaming process. Chemical blowing agents are added to the basic polymer granulate in the form of a masterbatch and processed as a mixture on the injection molding machine. Both exothermic and endothermic blowing agents are commercially available. Advantages and disadvantages of different blowing agents will be investigated. In order to optimize the product design, the necessary attention will also be paid to the correct setting of the process parameters. After all, foamed injection molding requires specific settings such as injecting with a high flow rate, applying little or no emphasis in combination with an adapted switching point and correct timing during dosing. In addition to the influence of the process parameters, it is also important to select suitable polymers with good foamability. The foamability of polymers is, in addition to the process parameters and techniques, mainly determined by the intrinsic properties of the polymer material such as rheology and melt strength. Once the basic necessities for foamability are in place, the process can be tuned for optimal results and final product properties.

Date:7 Dec 2022 →  Today
Keywords:injection molding, product design, process optimization, chemical blowing agents, polymer rheology
Disciplines:Polymer processing, Polymers and plastics, Manufacturing processes, methods and technologies, Rheology
Project type:PhD project