Process Factors Influence on Cavity Pressure Behavior in Microinjection Moulding

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
C. A. Griffiths ◽  
S. S. Dimov ◽  
S. Scholz ◽  
H. Hirshy ◽  
G. Tosello
Keyword(s):  
Polymer Materials ◽  
Similar Process ◽  
Cavity Pressure ◽  
Mould Temperature ◽  
Quality Factors ◽  
Melt Temperature ◽  
Pressure Work ◽  
Injection Speed ◽  
Process Factors ◽  
Microinjection Moulding

Process monitoring of microinjection moulding (μIM) is of crucial importance when analysing the effect of different parameter settings on the process and then in assessing its quality. Quality factors related to cavity pressure can provide valuable information about the process dynamics and also about the filling behavior of different polymer melts. In this paper, a pressure sensor mounted inside a tool cavity was employed to analyse maximum cavity pressure, pressure increase rate during filling and pressure work. The influence of four μIM parameters, melt temperature, mould temperature, injection speed, and packing pressure on these three pressure-related process parameters was investigated. A design of experiment study was conducted by moulding a test part, a microfluidic component, in three different polymer materials, PP, ABS, and PC. The results show a similar process behavior for all three polymers, in particular a higher injection speed led to a reduction of the pressure work while a lower mould temperature reduces the pressure rate.

Influence of Injection and Cavity Pressure on the Demoulding Force in Micro-Injection Moulding

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
C. A. Griffiths ◽  
S. S. Dimov ◽  
S. G. Scholz ◽  
G. Tosello ◽  
A. Rees
Keyword(s):  
Experimental Study ◽  
Process Parameters ◽  
Design Of Experiment ◽  
Injection Moulding ◽  
Processing Conditions ◽  
Cavity Pressure ◽  
Mould Temperature ◽  
Melt Temperature ◽  
Injection Speed ◽  
Micro Injection Moulding

The paper reports an experimental study that investigates part demoulding behavior in micro-injection moulding with a focus on the effects of pressure and temperature on the demoulding forces. In particular, the demoulding performance of a representative microfluidics part was studied as a function of four process parameters, melt temperature, mould temperature, holding pressure, and injection speed, employing the design of experiment approach. In addition, the results obtained using different combinations of process parameters were analyzed to identify the best processing conditions in regards to demoulding behavior of microparts when utilizing a COC polymer to mould them.

Experimental Study on the Crystallinity and Mechanical Properties of the Injection Molded Polypropylene

2011 ◽  
Vol 239-242 ◽  
pp. 2809-2812 ◽  
Author(s):  
Xiao Xun Zhang ◽  
Luo Wang ◽  
Qiu Hui Liao
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Diffraction Method ◽  
Processing Conditions ◽  
Mould Temperature ◽  
X Ray Diffraction ◽  
Melt Temperature ◽  
X Ray ◽  
Injection Speed ◽  
Injection Molded

Polypropylene specimens were made by the injection molding experiments under different processing conditions. The crystallinity of each polypropylene specimen was obtained using the X-ray diffraction method. The effects of the injection molding processes on the crystallinity of polypropylene were revealed: (1) the crystallinity decreases as the melt temperature increases, and the higher the melt temperature, the slower the crystallinity decreases, (2) the crystallinity decreases as the mould temperature increases, and the higher the mould temperature, the faster the crystallinity decreases, (3) the crystallinity increases as the injection speed increases, and the larger the injection speed, the faster the crystallinity increases. By the tensile experiments of the injection molded specimens, it is also found that the crystallinity has a major impact on the mechanical properties of polypropylene. The yield strength and tensile strength of polypropylene specimens increase as the crystallinity increases.

Micro Injection Moulding Process and Product Characterization

2011 ◽  
Author(s):  
Rossella Surace ◽  
Gianluca Trotta ◽  
Alessandro Bongiorno ◽  
Vincenzo Bellantone ◽  
Claudia Pagano ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Injection Moulding ◽  
Process Conditions ◽  
Scale Production ◽  
Mould Temperature ◽  
Melt Temperature ◽  
Injection Speed ◽  
Moulding Process ◽  
Micro Injection Moulding ◽  
Injection Moulding Process

Due to its high efficiency for the large scale production of polymeric parts, micro injection moulding is one of the key technologies of the new millennium. Although a lot of researches have been conducted to identify the most effective processing conditions for micro injection moulding, the comprehension of the influence of all parameters on the quality, the properties and the reliability of the moulded parts is still an issue. In this context, this study aims to evaluate the effects of the micro injection moulding process conditions on the tensile properties of micro parts, investigating the influence of three main process parameters: the injection speed, the mould temperature and the melt temperature. A full factorial plan has been applied to study the contributions of these parameters and a second study has been performed to understand the synergic interaction between the two temperatures on the tensile strength. Due to its high level of potential crystallinity, a typical semi-crystalline thermoplastic resin was used in the experiments. The results of the analysis showed a great influence of the mould temperature (Tmould) on the ultimate tensile strength and of the melt temperature (Tmelt) on the deformation at the point of breaking; whereas the injection speed was significant on the overall mechanical performance. A new studied factor (Tmelt-Tmould) could affect the resulting molecular structure and consequently the mechanical behaviour, but itself is not sufficient to thoroughly explain the observed behaviour. Moreover, the visual inspection of the deformation mechanism at break shows three distinctive trends demonstrating the great variability of the mechanical properties of micro-injected specimens due to process conditions.

scholarly journals Effect of Mould and Melt Temperature on the Properties of Styrene Acrylonitrile Moulded Parts

2018 ◽  
Vol 3 (1) ◽  
pp. 7
Author(s):  
Cahyo Budiantoro ◽  
Adi Nugroho
Keyword(s):  
Temperature Difference ◽  
Mold Temperature ◽  
Processing Parameters ◽  
The Other ◽  
Mould Temperature ◽  
Melt Temperature ◽  
Injection Speed ◽  
Other Hand ◽  
Styrene Acrylonitrile

The quality of injection moulded parts can be influenced by processing parameters. The effect of mould temperature and melt temperature on the weight and shrinkage of Styrene Acrylonitrile moulded part was observed in this research. It was found that by increasing mold temperatures at constant melt temperature and injection speed, the weight of the part decreased and the shrinkage value slightly decreased. On the other hand, by increasing melt temperature at constant mold temperature and injection speed, the part weight increased. Both mold temperature and melt temperature gave only a small effect because the temperature difference was not too large.

scholarly journals Cavity Air Flow Behavior During Filling in Microinjection Molding

2011 ◽  
Vol 133 (1) ◽  
Author(s):  
C. A. Griffiths ◽  
S. S. Dimov ◽  
S. Scholz ◽  
G. Tosello
Keyword(s):  
Flow Behavior ◽  
Air Flow ◽  
Polymer Melt ◽  
Mold Temperature ◽  
Quality Factors ◽  
Melt Temperature ◽  
Injection Speed ◽  
Microinjection Molding ◽  
Process Dynamics ◽  
Flow Length

Process monitoring of microinjection molding (μ-IM) is of crucial importance in understanding the effects of different parameter settings on the process, especially on its performance and consistency with regard to parts’ quality. Quality factors related to mold cavity air evacuation can provide valuable information about the process dynamics and also about the filling of a cavity by a polymer melt. In this paper, a novel experimental setup is proposed to monitor maximum air flow and air flow work as an integral of the air flow over time by employing a microelectromechanical system gas sensor mounted inside the mold. The influence of four μIM parameters, melt temperature, mold temperature, injection speed, and resistance to air evacuation, on two air flow-related output parameters is investigated by carrying out a design of experiment study. The results provide empirical evidences about the effects of process parameters on cavity air evacuation, and the influence of air evacuation on the part flow length.

scholarly journals The effect of foaming agent on mechanical and physical properties of Polypropylene

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
SEDEF CAKIR 1 ◽  
MUHAMMED AYCICEK 1 ◽  
EDIZ ALTUN 2 ◽  
Akin Akinci 1
Keyword(s):  
Mechanical Properties ◽  
Cell Density ◽  
Cell Morphology ◽  
Injection Pressure ◽  
Skin Layer ◽  
Polymer Materials ◽  
Cell Diameter ◽  
Melt Temperature ◽  
Foaming Agent ◽  
Foaming Agents

In this study, Polypropylene (PP) foam materials were used with injection parameters such as melting, molding and injection temperatures. To produce foam materials, chemical foaming agents were used, and added to polymer materials as 1wt.%, 1.5wt.%, 2wt.%, 2.5wt.%, 3wt.%. The mechanical properties of foam samples were determined based on the parameters. Cell morphology characterization such as cell diameter, cell count, skin layer thickness and cell density, and mechanical properties such as tensile and impact strength of polymer foams were examined.Generally, the closed-cell foam structure was obtained. The most important parameters affecting the cell morphology have been injection pressure, melt temperature and amount of foaming agent. With increasing the amount of foaming agent, cell density increased, foam density and mechanical properties decreased.

Effects of process parameters on the formability of sheet metal during plastic injection forming

2020 ◽  
Vol 62 (5) ◽  
pp. 535-543
Author(s):  
Mirigul Altan ◽  
Bora Sener ◽  
Mirigul Altan
Keyword(s):  
Injection Molding ◽  
Sheet Metal ◽  
Injection Pressure ◽  
Industrial Applications ◽  
Effective Parameter ◽  
Melt Temperature ◽  
Injection Speed ◽  
Aluminum Sheets ◽  
Plastic Injection ◽  
Thinning Rate

Abstract Plastic injection forming (PIF) is an alternative sheet metal forming method for complex geometrical parts with dimensions in low tolerance. This method is a combination of injection molding and hydroforming in which a molten polymer material has been injected over a sheet metal via a plastic injection molding machine. In this study, aluminum sheets 1.5 mm thick were shaped by PIF at various injection pressures, melt temperatures and injection speed. The effects of these parameters on the formability of the sheet metal were investigated using the experimental design technique. The thinning rate, flange radius and the hardness values of the shaped sheets were considered in the experimental study. Injection pressure was found to be the most effective parameter and melt temperature was the second degree effective parameter for the thinning rate. The usability of the PIF process in industrial applications as an alternative method was emphasized by comparing PIF with conventional hydroforming by means of the finite element method (Ls-Dyna). A 2.07 % deviation was observed between the FE results for hydroforming and the experimental results for PIF.

scholarly journals Tie-Bar Elongation Based Filling-To-Packing Switchover Control and Prediction of Injection Molding Quality

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1168 ◽  
Author(s):  
Jian-Yu Chen ◽  
Chun-Ying Liu ◽  
Ming-Shyan Huang
Keyword(s):  
Injection Molding ◽  
Pressure Sensors ◽  
Clamping Force ◽  
Cavity Pressure ◽  
Testing Specimen ◽  
Injection Speed ◽  
Novel Approach ◽  
Pressure Profiles ◽  
Molded Parts ◽  
Short Shot

Filling-to-packing switchover (also called V/P switchover) is critical for assuring injection molding quality. An improper V/P switchover setting may result in various defects of injection-molded parts, such as excessive residual stress, flash, short shot, and warpage, etc. To enhance a consistent molding quality, recent V/P switchover approaches adopt cavity pressure profiles requiring sensors embedded in mold cavities, which is invasive to mold cavities and more expensive. Instead of using cavity pressure sensors, by working with the most popular screw position switchover control, this study hereby proposes a novel approach of tuning V/P switchover timing using a tie-bar elongation profile. In this investigation, a dumbbell testing specimen mold is applied to verify the feasibility of the method proposed. The results show that the mold filling and packing stages can be observed along the tie-bar elongation profile, detected by mounting strain gauges on the tie bars. Also, the characteristics of the cavity pressure are similar to those of the tie-bar elongation profile under a proper clamping force condition. Moreover, the varying process parameter settings which include injection speed, V/P switchover point, and holding pressure, can be reflected in these profiles. By extracting their characteristics, the application of the V/P switchover is proved to be realistic. This research conducted an experiment to verify the proposed V/P switchover decision method based on the tie-bar elongation profile. The result showed that the fluctuation of the part’s weight corresponding to a slight change of the barrel’s temperature from 210 °C to 215 °C can be successfully controlled with this method. Besides, the maximum clamping force increment extracted from the tie-bar elongation profile was found to be a good indicator for online monitoring of the reground material variation.

scholarly journals Multiobjective Optimization of Injection Moulding Process Parameters on Mechanical Properties Using Taguchi Method and Grey Relational Analysis

2018 ◽  
Vol 7 (3.7) ◽  
pp. 14 ◽  
Author(s):  
Mohd Amran Md Ali ◽  
Noorfa Idayu ◽  
Raja Izamshah ◽  
Mohd Shahir Kasim ◽  
Mohd Shukor Salleh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Taguchi Method ◽  
Grey Relational Analysis ◽  
Injection Moulding ◽  
Cooling Time ◽  
Mould Temperature ◽  
Plastic Part ◽  
Melt Temperature ◽  
Relational Analysis ◽  
Grey Relational

This study presents an optimization of injection moulding parameters on mechanical properties of plastic part using Taguchi method and Grey Relational Analysis (GRA) approach. The orthogonal array with L9 was used as the experimental design. Grey relational analysis for ultimate tensile strength, modulus and percentage of elongation from the Taguchi method can convert optimization of the multiple performance characteristics into optimization of a single performance characteristic called the grey relational grade (GRG). It is found that mould temperature of 62oC, melt temperature of 280oC, injection time of 0.70s and cooling time 15.4s are found as the optimum process setting. Furthermore, ANOVA result shows that the cooling time is the most influenced factor that affects the mechanical properties of plastic part followed by mould temperature and melt temperature.  

Molding and Optical Performance Simulations of a New Plastic Grating Lens for an Asymmetric LED Fog Lamp

2012 ◽  
Vol 253-255 ◽  
pp. 2223-2226 ◽  
Author(s):  
Yi Cheng Chen ◽  
Yen Chao Wang ◽  
Shi Chang Tseng
Keyword(s):  
Central Zone ◽  
Injection Pressure ◽  
Mold Temperature ◽  
Stray Light ◽  
Optical Simulation ◽  
Melt Temperature ◽  
Injection Speed ◽  
3D Cad ◽  
Multi Stage ◽  
Test Distance

This research focuses on the effect manufacture factors about the brightness and uniformity of multi-stage reflector. Trace-pro and 3D CAD model were used for optical simulations. The optical simulation results of grating lens and reflector were done as well as successfully developed the LED fog lamp. The results meet the regulations, R19 CLASS F3, of Economic Commission for Europe (ECE) at the test distance of 25 meters, and central zone under line6 achieves average over 3200cd. The optimal design of reflector is of third-order paraboloidal one to improve the brightness and uniformity. The acuter the microstructure’s tip is(R below 0.1mm), the better the apparent improving of eliminating stray light. In accordance with microstructure of grating lens, Moldex-3D is used to help the mold flow filling simulation and mold design. The mold cavity with microstructure was manufactured by the wire cutting and polishing processing. And the molding plastic was optics level PC (Polycarbonate). Both Taguchi’s method applied in Moldex-3D and real injection molding experiments showed that high melt temperature, low injection speed and suitable holding time can reduce warpage; in addition, using higher melt temperature, mold temperature and injection pressure can achieve higher degree of replication of micro features.

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