Injection Molding with Natural Rubber

1971 ◽  
Vol 44 (3) ◽  
pp. 620-641 ◽  
Author(s):  
M. A. Wheelans
Keyword(s):  
Injection Molding ◽  
Natural Rubber ◽  
Injection Pressure ◽  
Orifice Diameter ◽  
Thin Sections ◽  
Wide Range ◽  
Filling Time ◽  
Cure Time ◽  
Injection Molded ◽  
Injection Temperature

Abstract Injection moldings with natural rubber compounds having sections varying between 0.16 and 10 cm thick have been prepared. Almost any natural rubber compound can be satisfactorily injection molded. Cure time, and hence cycle time, is highly dependent on injection temperature and the art of injection molding is to inject at the highest possible temperature consistent with freedom from scorch. The injection temperature of natural rubber depends on the injection molding machine variables such as screw speed, screw back pressure and barrel temperature. Injection and mold filling time are dependent on injection pressure and nozzle orifice diameter. Rubber compounding variables influence injection molding behavior. A curing system with a relatively long, safe Mooney scorch time permits a reduction in the cure time of rubber by allowing a high injection temperature. Conventional curing systems are suitable for a wide range of injection moldings but “Efficient Vulcanization ” systems have special advantages in curing thin sections adjacent to thick ones because of their superior reversion resistance. The effects of compound viscosity are described. Extenders are shown to reduce injection temperatures and thus increase cure times. Black and white fillers are examined in their effect on injection temperature, injection time and cure time. Injection molded vulcanizates are similar in mechanical properties and oven aging resistance to vulcanizates prepared by conventional press methods.

Effects of Molding Parameters on MIM’s Material Distribution using Numerical Simulation Method

2012 ◽  
Vol 59 (2) ◽  
Author(s):  
Mohd Fazuri Abdullah ◽  
Abu Bakar Sulong ◽  
Norhamidi Muhamad ◽  
Muhamad Afkar Husin
Keyword(s):  
Injection Molding ◽  
Flow Rate ◽  
Computer Aided Design ◽  
Manufacturing Industry ◽  
Injection Pressure ◽  
Global Market ◽  
Element Analysis ◽  
Percentage Difference ◽  
Filling Time ◽  
Injection Temperature

In the competitive world in the global market, manufacturing industry is striving to produce products at high quality, shorter time and low cost. This can be achieved through proper design activities, with assist of finite element analysis (FEA) and computer aided design (CAD). The objective of this project is to study the effect of the molding parameters on the physical characteristics of surgery tool via MIM based on design of experiment (Taguchi method). This numerical results show the behavior of feedstock entering the mould during injection process and the possibility defects that might occur. The quality of the injected product depends on the selection of the feedstock as well as the parameters for injection molding such as injection temperature (A), mold temperature (B), flow rate (C) and injection pressure (D). From the analysis of Taguchi, the optimal levels of process parameters for the shortest filling time is [A3(200ºC), B1(80ºC), C3(20 cm3/s), D3(260 MPa)]. Set of optimal parameters for the smallest shrinkage percentage difference is [A1(180ºC), B3(100ºC), C3(20 cm3/s), D2(255 MPa)]. The most influence injection molding parameters are injection temperature and injection pressure. Follow by the flow rate.

Warpage Measurement of a Micro Electrical Fan on Micro-Injection Molding

2012 ◽  
Vol 184-185 ◽  
pp. 1651-1654
Author(s):  
Jeou Long Lee ◽  
Y. Lin ◽  
Y.K. Shen
Keyword(s):  
Injection Molding ◽  
Injection Pressure ◽  
Acrylonitrile Butadiene Styrene ◽  
Mold Temperature ◽  
Micro Injection Molding ◽  
Optimum Result ◽  
Suitable Material ◽  
Packing Pressure ◽  
Injection Molded ◽  
Packing Time

This study characterizes warpage of a micro-injection molded micro electrical fan using the Michelson interference method. This study conducts experiments to analyze different polymers-polypropylene (PP), polyamide (PA), acrylonitrile-butadiene styrene (ABS), ABS+ polycarbonate (PC), and polyoxymethylene (POM)-process parameters, such as mold temperature, injection temperature, injection pressure, injection time, packing time, and packing pressure, for a micro electrical fan. To obtain the optimum result (minimum warpage), this study assesses the effect (warpage) of each material on micro-injection molding. PA plastic is the very suitable material for micro electrical fan with Michelson interference analysis on micro-injection molding.

Optimizing Injection Parameters of Kenaf Filler Polypropylene Composite by Taguchi Method

2017 ◽  
Vol 894 ◽  
pp. 81-84 ◽  
Author(s):  
Mohd Khairul Fadzly Md Radzi ◽  
Norhamidi Muhamad ◽  
Abu Bakar Sulong ◽  
Zakaria Razak
Keyword(s):  
Injection Molding ◽  
Taguchi Method ◽  
Process Condition ◽  
Injection Pressure ◽  
Poor Quality ◽  
Injection Molding Process ◽  
Molding Process ◽  
Injection Parameters ◽  
Pp Composites ◽  
Injection Temperature

Optimization of injection molding parameters provided a solution to achieve strength improvement of kenaf filler polypropylene composites. Since, molded polymers composites possibility being effected by machine parameters and other process condition that may cause poor quality of composites product. Thus in this study, composite of kenal filler reinforced with thermoplastic polypropylene (PP) were prepared using a sigma blade mixer, followed by an injection molding process. To determine the optimal processing of injection parameters, Taguchi method with L27 orthogonal array was used on statistical analysis of tensile properties of kenaf/PP composites. The results obtained the optimum parameters which were injection temperature 190°C, injection pressure 1300 bar, holding pressure 1900 bar and injection rate 20cm3/s. From the analysis of variance (ANOVA), both flow rate and injection temperature give highest contribution factor to the mechanical properties of the kenaf/PP composites.

Injection Molding of Rubber

1978 ◽  
Vol 51 (5) ◽  
pp. 1023-1043 ◽  
Author(s):  
M. A. Wheelans
Keyword(s):  
Injection Molding ◽  
Mold Temperature ◽  
Flow Lines ◽  
Wide Range ◽  
Cure Time ◽  
Degree Of Anisotropy ◽  
The Mean ◽  
Mold Flow ◽  
Optimum Modulus ◽  
Maximum Minimum

Abstract The outline of a strategy for the injection molding of a safe mix is described. Safe accelerators, safe curing systems, and mixes are suggested with machine conditions which should yield short curing times for a wide range of products. Comparisons have been made of the vulcanizate properties of injection and compression moldings prepared from the same mix in the same mold and press at the same temperature. Results have shown that, although anisotropy is more pronounced in injection moldings, the mean of values for modulus along and at 90° to radial mold flow lines of an optimum modulus cure are the same (within experimental error) as the mean of values for modulus along and at 90° to mill flow lines in a compression molding also cured to its optimum modulus. Injection moldings are similar to compression moldings in volume swelling and hardness but they have marginally higher rebound resilience and marginally lower compression set. The effect of an increase in mold temperature is to give a valuable reduction in cure time, but it also causes a reduction in modulus and modulus dependent vulcanizate properties. Optimum values for maximum-minimum Monsanto Rheometer torque, relaxed modulus, and 300% modulus are reduced to 77– 79% of their optimum values at 160°C when cured at 200°C, but this reduction can be compensated for by adding higher levels of accelerator or accelerator and sulphur. Although a certain degree of anisotropy may have to be tolerated, the analysis of vulcanizate properties has provided a means of understanding and correcting an injection molding mix which fails to pass a specification. It gives confidence that NR can be cured at relatively high temperatures such as 180–190°C, which make injection molding profitable.

Numerical and Experimental Study on the Injection Moulding of a Thin-Wall Complex Part

2008 ◽  
Author(s):  
Catalin Fetecau ◽  
Ion Postolache ◽  
Felicia Stan
Keyword(s):  
Injection Molding ◽  
Injection Pressure ◽  
Mold Temperature ◽  
Processing Parameters ◽  
Injection Molding Process ◽  
Thin Wall ◽  
Molding Process ◽  
Complex Part ◽  
Filling Time ◽  
Wall Injection

The research presented in this paper involves numerical and experimental efforts to investigate the relative thin-wall injection molding process in order to obtain high dimensional quality complex parts. To better understand the effects of various processing parameters (the filling time, injection pressure, the melting temperature, the mold temperature) on the injection molding of a thin-wall complex part, the molding experiments are regenerated into the computer model using the Moldflow Plastics Insight (MPI) 6.1 software. The computer visualization of the filling phase allows accurate prediction of the location of the flow front, welding lines and air traps. Furthermore, in order to optimize the injection molding process, the effects of the geometry of the runner system on the filling and packing phases are also investigated. It is shown that computational modeling could be used to help the process and mold designer to produce accurate parts.

Characterization of Micro Metal Injection Molding by Using PMMA & PEG

2013 ◽  
Vol 315 ◽  
pp. 992-996
Author(s):  
Mohd Halim Irwan Ibrahim ◽  
Norhamidi Muhamad ◽  
A.B. Sulong
Keyword(s):  
Stainless Steel ◽  
Injection Molding ◽  
Injection Pressure ◽  
Steel Powder ◽  
Mold Temperature ◽  
Point Of View ◽  
Metal Injection Molding ◽  
Volume Percentage ◽  
Shape Retention ◽  
Injection Temperature

Due to its versatility, micro metal injection molding has become an alternative method in powder metallurgy where it can produce small part with a minimal number of waste. The success of micro MIM is greatly influenced by feedstock characteristics. This paper investigated the characterization and optimization which both of them plays an important characteristic in determining the successful of micro MIM. In this paper, stainless steel SS 316L was used with composite binder, which consists of PEG (Polyethelena Glycol), PMMA (Polymethyl Methacrilate) and SA (Stearic Acid). The rheology properties are investigated using Shimadzu Flowtester CFT-500D capillary rheometer. The geometry of water atomised stainless steel powder are irregular shape, therefore it is expected significant changes in the rheological results that can influence the microcomponent, surface quality, shape retention and resolution capabilities. From rheological characteristics, feedstock with 61.5% shows a significant value with several injection parameters were optimized through screening experiment such as injection pressure (A), injection temperature (B), mold temperature (C), injection time (D) and holding time (E). Besides that, interaction effects between injection pressure, injection temperature and mold temperature were also considered to optimize in the Taguchis orthogonal array. Result shows that 61.5%vol contributes a significant stability over a range of temperature and the best powder loading from a critical powder volume percentage (CPVP) and rheological point of view. Furthermore interaction between injection temperature and mold temperature (BxC) give highest significant factor followed by interaction between injection pressure and mold temperature (AxC).

Dynamic Response Optimization for Cemented Carbide Injection Molding

2014 ◽  
Vol 68 (4) ◽  
Author(s):  
Sri Yulis M. Amin ◽  
Norhamidi Muhamad ◽  
Khairur Rijal Jamaludin
Keyword(s):  
Injection Molding ◽  
Palm Stearin ◽  
Processing Parameters ◽  
Cemented Carbide ◽  
Metal Injection Molding ◽  
Injection Molding Process ◽  
Molding Process ◽  
Response Optimization ◽  
Injection Molded ◽  
Injection Temperature

The need to optimize the injection molding parameters for producing cemented carbide parts via Metal Injection Molding process is crucial to ensure the system’s robustness towards manufacturer and customer’s satisfactions. Defect free product with best density can be produced while reducing time and cost in manufacturing. In this work, the feedstock consisting of WC-Co powders, mixed with palm stearin and polyethylene binder system was injection molded to produce green parts. Several processing variables, namely powder loading, injection temperature, holding pressure and flowrate, were optimized towards the density of the green body, as the response factor. By considering humidity level at morning and evening conditions as the noise factor, the results show the optimum combination of injection molding parameters that produces best green density. The green part exhibited best density by following this optimum processing parameters, A2B3C1D1, that are flowrate at 20 ccm/s, powder loading at 63% vol., injection temperature at 140°C, and holding pressure at 1700 bar.

Correlation of 13C NMR Analysis and Physical Testing Results of Natural Rubber

2003 ◽  
Vol 76 (1) ◽  
pp. 212-219 ◽  
Author(s):  
Dallas D. Parker ◽  
J. L. Koenig ◽  
Makio Mori
Keyword(s):  
Natural Rubber ◽  
13C Nmr ◽  
Nmr Analysis ◽  
Testing Methods ◽  
13C Nmr Analysis ◽  
Wide Range ◽  
Physical Testing ◽  
Cure Time ◽  
Small Change ◽  
Cure Temperature

Abstract The methods of solid-state 13C NMR and physical testing were used to examine carbon black filled natural rubber samples. The rubber samples were vulcanized under varying parameters of sulfur loading, cure times, and cure temperature. At constant cure time and cure temperature, the two testing methods correlate well over a wide range of sulfur concentrations. Varying cure time and cure temperature produced large changes in the mechanical testing results but small change in the 13C NMR analysis of the sulfur vulcanizates.

scholarly journals Optimization on the Injection Molding Propypopylene Parameters Using Central Composite Design for Minimizing Defects

2020 ◽  
Vol 55 (2) ◽  
Author(s):  
Moh. Hartono ◽  
Pratikto ◽  
Purnomo B. Santoso ◽  
Sugiono
Keyword(s):  
Injection Molding ◽  
Central Composite Design ◽  
Injection Pressure ◽  
Holding Time ◽  
Clamping Force ◽  
Molding Process ◽  
Injection Speed ◽  
Injection Temperature ◽  
Central Composite ◽  
Plastic Products

This study aims to simultaneously forecast and investigate the optimization process characterization of the design of controlled parameters in the injection process of polypropylene molding including injection pressure combination, clamping force, injection temperature, injection speed, and holding time, and their interaction to produce qualified plastic by minimizing defects. The experimental methods used the central composite design of response surface method with five factors and a variety of levels. This method is more effective because it is an improvement on and a development from previous studies—especially those related to the plastic molding process. Additionally, it can simultaneously predict and optimize the obtaining of the highest quality plastic products as well as minimizing defects. The results are in the form of a combination of control level factors and interactions among the factors that generate the robust output of plastic products with minimum defects. Moreover, the optimum settings of the parameters provides a global solution at an injection temperature of 275°C, injection pressure of 75 bar, injection speed of 98%, clamping force of 88 tons, and a holding time of 8 seconds to generate a response to product probability defects by 0.0062. The benefit is that it can reveal the behavior and characteristics of parameter design and their interactions in the plastic injection molding process to produce qualified plastics and minimize product defects.

Application of Taguchi Method to Improve Resistance Quality of Graphene/Polypropylene Composites

2019 ◽  
Vol 818 ◽  
pp. 118-122
Author(s):  
Ching Been Yang ◽  
Wei Chang Peng ◽  
Yan Wen Huang ◽  
Hsiu Lu Chiang
Keyword(s):  
Injection Molding ◽  
Taguchi Method ◽  
Optimal Parameter ◽  
Impact Resistance ◽  
Injection Pressure ◽  
High Impact ◽  
Polypropylene Composites ◽  
Injection Temperature ◽  
New Generation

Polypropylene is a widely used thermoplastic with high impact resistance and strong mechanical properties. Graphene has exhibited in a new generation of electronic component materials owing to its high thermal conductivity and low resistivity. In this study, a composite of graphene and polypropylene for injection molding purposes was created. In Taguchi method, an L9 orthogonal array for injection molding experiments was adopted. The process parameters included injection temperature (A), holding time (B), injection pressure (C), and graphene ratio (D). Optimal parameter combinations were determined according to resistivity, and the results were A3B2C1D3: 2956.333 MΩ by original and A1B2C1D3: 2802 MΩ Taguchi analysis, respectively, where the improvement was 5.2%.

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