Effects of Injection Moulding Parameters on Dimensional Accuracy of POM/MWCNT Micro Parts

2014 ◽  
Author(s):  
Vincenzo Bellantone ◽  
Rossella Surace ◽  
Irene Fassi
Keyword(s):  
Injection Moulding ◽  
Injection Velocity ◽  
Mechanical And Thermal Properties ◽  
Effective Parameters ◽  
Multi Wall Carbon Nanotubes ◽  
Moulding Process ◽  
Micro Injection Moulding ◽  
Injection Moulding Process ◽  
Micro Parts ◽  
Filler Fraction

Nowadays, the study of polymer nanocomposites is an active area of materials development because nanofillers and in particular Multi-Wall Carbon Nanotubes (MWCNTs) can significantly improve or adjust the properties of the materials into which they were incorporated such as optical, electrical, mechanical and thermal properties. MWCNTs have been adopted in quite a number of applications, but advancements in their properties are needed for spreading their potential. Moreover their behaviour and filling properties in micro injection moulding process have still to be studied. Therefore, in this work, experimental and statistical studies were performed to analyze the parameters effect on replicating capability of micro parts manufactured in POM/MWCNT by micro injection moulding process. Two compounds with different filler fraction (3 and 6 wt%) were tested and processed with different conditions and their operating range have been pointed out and compared with that of pristine POM (PolyOxyMethilene). The results show that the filler content has the effect to change slightly the operative range of the micro injection process parameters and to increase the replicating capability. The most effective parameters on replicating capability of micro ribs, evaluated by a dimensional index, are the mould temperature for the POM/MWCNT 3% and injection velocity for the 6% filler fraction.

Polymeric Micro-Filter Fabrication Using a Micro Injection Moulding Process

2015 ◽  
Author(s):  
Rossella Surace ◽  
Vincenzo Bellantone ◽  
Irene Fassi
Keyword(s):  
Injection Moulding ◽  
Electrical Discharge Machining ◽  
Polymeric Materials ◽  
Machining Process ◽  
Injection Velocity ◽  
Mould Temperature ◽  
Moulding Process ◽  
Micro Injection Moulding ◽  
Injection Moulding Process ◽  
Incomplete Filling

This paper reports on fabrication and characterization of a micro-filter for hearing aid, dialysis media and inhaler. The micro-feature specifications consist in a diameter of 2.3 mm, a thickness of 0.2 mm and it is composed by a mesh with grid of 80 μm and ribs with width of 70 μm. The proposed micro-filter is fabricated by micro injection moulding process adopting a steel mould manufactured by micro Electrical Discharge Machining process (micro EDM). Different polymeric materials (POM, HDPE, LCP), particularly indicated for the injection moulding applications due to their flowability and stability, are tested and evaluated in relation to the process replication capability. Since the polymer micro-filter is made of a complex grid of micro-ribs, the injection moulding process must ensure complete filling of the micro-parts, preventing any defects (i.e. premature solidification, incomplete filling, flash and air traps). To this aim, different system parameters configurations (melt and mould temperature, injection velocity, holding time and pressure, cooling time, pressure limit) are tested for obtaining acceptable part in all polymers grade. Finally, the component is dimensionally characterized by confocal microscopy and its filtration capacity is then verified. Although the feature complexity was high, the results showed that the object could be successfully replicated by filling completely the micro cavities with two of them: POM and HDPE. The most significant parameters influencing the part filling were the mould temperature and the injection velocity. These findings allow to further optimize the micro-injection process parameters to obtain a high quality product.

Effects of Process Parameters on the Properties of Replicated Polymeric Parts

2012 ◽  
Author(s):  
Gianluca Trotta ◽  
Vincenzo Bellantone ◽  
Rossella Surace ◽  
Irene Fassi
Keyword(s):  
Process Parameters ◽  
Injection Moulding ◽  
Low Cost ◽  
Injection Velocity ◽  
Processing Technologies ◽  
Moulding Process ◽  
Micro Injection Moulding ◽  
Technical Requirements ◽  
Dog Bone ◽  
Injection Moulding Process

The increasing demand for small and even micro scale parts is boosting the development of reliable micro system technologies. Micro-fabrication process capabilities should expand to encompass a wider range of materials and geometric forms, by defining processes and related process chains that can satisfy the specific functional and technical requirements of new emerging multi-material products, and ensure the compatibility of materials and processing technologies throughout these manufacturing chains. Micro injection moulding is the process of transferring the micron or even submicron precision of microstructured metallic moulds to a polymeric products. It represents one of the key technologies for micro manufacturing because its mass production capability and relatively low production cost. Polymers have relatively low cost, and offer good mechanical and thermal strength, electrical insulation, optical transparency, chemical stability and biocompatibility. In this work the authors investigate the micro injection moulding process parameters on the overall quality of a miniaturized dog-bone shaped specimen. The aim of the experimentation is to calibrate the process and set the machine for the correct filling of the component. A set of injection parameters are selected for study by experimental plan and simulation tool and then discussed. Simulation results are used to better understand the polymer flow behaviour during the filling phase. A commercial software is used and input data, collected during the micro injection moulding process, are included using as performance indicators flow front position and moulded mass. Process simulation can provide, at the present time, mostly qualitative input to the designer and process engineer. Two different polymers materials are tested and evaluated in relation to the process replication capability: Polyoxymethylene (POM) and Liquid Cristal Polymer (LCP). Finally, the moulding factors with significant statistical effects are identified. The holding pressure and holding time for POM and the holding pressure and injection velocity for LCP show the highest influence on achieving high part mass.

Simulation of the micro-injection moulding process: effect of the thermo-rheological status on the morphology

2011 ◽  
Vol 225 (4) ◽  
pp. 224-238 ◽  
Author(s):  
T Nguyen-Chung ◽  
C Löser ◽  
G Jüttner ◽  
T Pham ◽  
M Obadal ◽  
...  
Keyword(s):  
Injection Moulding ◽  
Process Conditions ◽  
Transfer Coefficients ◽  
Moulding Process ◽  
Micro Injection Moulding ◽  
Mould Filling ◽  
Injection Moulding Process ◽  
Moulding Machine ◽  
Simulation Results ◽  
Micro Cavity

The software package Moldflow Plastics Insights was used to simulate the filling of a micro-cavity by considering precise material data and accurate boundary conditions. Experiments were carried out on an accurately controlled micro-injection moulding machine (formicaPlast) for providing important parameters to verify the simulation results and improve the accuracy of the simulation. Based on the relationship between the cavity pressure and the mould-filling ratio, the heat transfer coefficients can be appropriately determined for different process conditions. Finally, the transient thermo-rheological results were analysed with regard to their influence on the morphology of semi-crystalline (PP) micro-injection moulded parts, which not only give rise to the mechanisms of the morphological formation but also verify the quality of the simulation results.

scholarly journals Micro Injection Moulding Process Parameter Tuning

Procedia CIRP ◽  
2015 ◽  
Vol 33 ◽  
pp. 400-405 ◽  
Author(s):  
Michael Packianather ◽  
Christian Griffiths ◽  
Wan Kadir
Keyword(s):  
Injection Moulding ◽  
Parameter Tuning ◽  
Process Parameter ◽  
Moulding Process ◽  
Micro Injection Moulding ◽  
Injection Moulding Process

scholarly journals Process chain for serial manufacture of polymer components with micro- and nano-scale features: Optimisation issues

2016 ◽  
Vol 231 (11) ◽  
pp. 2000-2020
Author(s):  
Pierre C Vella ◽  
Stefan S Dimov ◽  
Alexander Kolew
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Injection Moulding ◽  
Length Scale ◽  
Process Chain ◽  
Moulding Process ◽  
Nano Scale ◽  
Micro Injection Moulding ◽  
Injection Moulding Process ◽  
Scale Integration

This article reports a follow-up research to investigate further the component technologies of a cost-effective manufacturing route designed to achieve function and length scale integration in products. The route employs a viable master-making process chain that integrates compatible and at the same time complementary, structuring and replication technologies to fabricate Zr-based bulk metallic glass inserts. To validate them, they are subsequently integrated into a micro-injection moulding machine, and polymer structures incorporating both micro- and nano-scale features are replicated. Especially, the masters and/or replicas after each processing step were analysed and the factors affecting its overall performance were identified. The research demonstrated that the master-making process chain can be a viable fabrication route for both fully amorphous and partially crystalline Zr-based bulk metallic glass inserts that incorporate different length scale features. The results also showed that relatively good fidelity of the different scale features can be achieved with the micro-injection moulding process, and thus, it can enable function and length scale integration in thermoplastic components.

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