Effect of Surface Roughness in Micro Injection Moulding Process of Thin Cavities

2016 ◽  
Author(s):  
Vincenzo Bellantone ◽  
Rossella Surace ◽  
Francesco Modica ◽  
Irene Fassi
Keyword(s):  
Surface Roughness ◽  
Injection Moulding ◽  
Electrical Discharge Machining ◽  
Low Cost ◽  
Wall Slip ◽  
Machining Process ◽  
Cavity Surface ◽  
Moulding Process ◽  
Micro Injection Moulding ◽  
Injection Moulding Process

Due to its ability to produce low-cost and high repeatable micro polymeric parts, injection moulding of micro components is emerging as one of the most promising enabling technologies for the manufacturing of polymeric micro-parts in in many different fields, from IT to Healthcare, to Medicine. However, when approaching the micro-scale, different issues related to the process should be addressed, especially as the depth of the mould cavity becomes very thin. In particular, the mould roughness could affect the surface quality of the produced micro components, like in macro moulding, as well as the complete filling of the parts. Although micro-injection moulding process has been extensively studied, further research on the effect of mould roughness conditions and on non-Newtonian fluid flow in micro-cavities are required. This will shed a light and open up new paths for a deeper understanding of the moulding scenario. The main objective of the present paper is the evaluation of the influence of the mould roughness on the polymer flow during micro injection moulding process. The test parts have been realized in POM material and have thickness lower than 250 μm. The test part design has been properly conceived in order to neglect the effect of dimensions and geometry and to highlight the roughness contribution during the filling phase of micro injection moulding process. The experimentation has been performed considering cavities with different roughness values (3 levels) and decreasing depths (3 levels), for a total of nine test parts manufactured by micro-electrical discharge machining process (μ-EDM). The results of the experiments are discussed in the paper and show that cavity surface roughness affects the injection process as the moulding scale level is decreased. In particular, when the cavity depths are reduced, higher surface roughness promotes the filling of components and this finding could be ascribed to the increase of wall slip effect.

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.

scholarly journals Polymer based microneedle patch fabricated using microinjection moulding

2018 ◽  
Vol 192 ◽  
pp. 01039 ◽  
Author(s):  
Pattanaphong Janphuang ◽  
Mongkhol Laebua ◽  
Chanwut Sriphung ◽  
Phatsakon Taweewat ◽  
Anan Sirichalarmkul ◽  
...  
Keyword(s):  
Injection Moulding ◽  
Production Efficiency ◽  
Electrical Discharge Machining ◽  
Low Cost ◽  
Injection Pressure ◽  
Mould Insert ◽  
Moulding Process ◽  
Injection Moulding Process ◽  
Microneedle Patch ◽  
Microinjection Moulding

This paper presents the development of a polymer based microneedle patch for transdermal drug delivery application using plastic microinjection moulding. Design and analysis of the microneedle cavities and mould insert used in the injection moulding process were carried out using Computer-Aided Engineering (CAE) software. A mould insert with low surface roughness was fabricated using Micro Electrical Discharge Machining (μ-EDM). The injection moulding parameters including clamping force, temperature, injection pressure and velocity were characterized in order to obtain the optimum reproducibility. Solid truncated cone microneedles, made of biocompatible polymethyl methacrylate (PMMA), with a round tip radius of 50 μm and 500 μm in height have been realized by microinjection moulding process demonstrating the potential of a low cost, high production efficiency, and suitable for mass production. In addition, a mould insert of cylindrical microneedles fabricated using X-ray LIGA has been proposed.

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.

Investigating the Effects of Injection Moulding Process Parameters on Multiple Tensile Characteristics of Plastic Spur Gear via Experimental Approach

2013 ◽  
Vol 748 ◽  
pp. 544-548 ◽  
Author(s):  
Nik Mizamzul Mehat ◽  
Shahrul Kamaruddin ◽  
Abdul Rahim Othman
Keyword(s):  
Process Parameters ◽  
Injection Moulding ◽  
Experimental Approach ◽  
Low Cost ◽  
Spur Gear ◽  
Melt Temperature ◽  
Moulding Process ◽  
Packing Pressure ◽  
Injection Moulding Process ◽  
State Of Tension

This paper presents the original development of an experimental approach in studying the multiple tensile characterizations as key quality characteristics for several different plastic gear materials related to various parameters in injection moulding process. In this study, emphases are given on a new low-cost mechanism for the testing of the injection moulded plastic spur gear specimens with various teeth module. The testing fixture are developed and validated to provide uniform state of tension with series of plastic gear specimens produced in accordance with the systematically designed of experiment. The effects of changes in the process parameters including melt temperature, packing pressure, packing time and cooling time at three different levels on the elongation at break and ultimate strength of plastic gear is evaluated and studied through the proposed experimental approach.

scholarly journals Design of an Experimental Injection Moulding Tool for Testing Microstructured Cavity Surfaces

2021 ◽  
Vol 4 (2) ◽  
pp. 97-102
Author(s):  
Krisztián Kun
Keyword(s):  
Injection Moulding ◽  
Uniform Structure ◽  
Cavity Surface ◽  
Moulding Process ◽  
Injection Moulding Process ◽  
Tool Surface ◽  
Degree Of Orientation ◽  
High Degree ◽  
The Impact

Abstract This research is based on the impact assessment of the active element of injection moulding tools. The quality of the tool surface has a significant effect on the filling and cooling efficiency. Our goal is to create a uniform structure on the cavity’s surface that results in a high degree of orientation during the injection moulding process. A special experimental tool is needed for the research. Our design was based on the results of previous experimental research and preliminary criteria. The design was based on the size and position tolerances of the A side of the tool. As the previous study has shown, there are three main points to consider when designing an experimental moulding tool. These are the applied manufacturing technology, Design for Assembly, and the expansion of the measurement possibilities by using different sensors. The small beam size of the femtosecond laser also allows the machining of microscopic-sized details, a technology used to structure the cavity surface. The success of this was analyzed by microscopic examination.

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