scholarly journals In situ curing and bonding of epoxy prepregs in epoxy thermoset injection molding

2021 ◽  
Author(s):  
Tim Deringer ◽  
Dietmar Drummer
Keyword(s):  
Injection Molding ◽  
Bond Strength ◽  
Mold Temperature ◽  
Process Window ◽  
Process Conditions ◽  
Integrative Process ◽  
Process Combination ◽  
Initial Process ◽  
Temperature Storage

AbstractIn this study, epoxy molding compounds are combined with fast-curing epoxy prepregs in thermoset injection molding using a new integrative process. The combination is carried out under the varied parameters of mold temperatures and curing times, which are dominant factors in thermoset processing. The focus of the investigations is the bond strength in the interface resulting from these parameters, as the interface is known as the weak point of hybrid components. To identify causes for possible increases and decreases of the bond strength, additional rheological and thermoanalytical analyses are done under near-process conditions. The influence of prepreg pre-crosslinking, a function of the mold temperature, is also described by means of additional tests in which specific pre-crosslinking of the prepreg is adjusted by the temperature storage and then functionalized in integrative process combination. The aim of the study is to identify and understand initial process limits for the integrative process combination for a potential process window.

Effect of Processing Conditions on the Shrinkage and Warpage of Glass Fiber Reinforced PP Using Microcellular Injection Molding

2012 ◽  
Vol 501 ◽  
pp. 294-299 ◽  
Author(s):  
Zhi Bian ◽  
Peng Cheng Xie ◽  
Yu Mei Ding ◽  
Wei Min Yang
Keyword(s):  
Injection Molding ◽  
Glass Fiber ◽  
Injection Pressure ◽  
Mold Temperature ◽  
Process Conditions ◽  
Fiber Reinforced ◽  
Injection Speed ◽  
Glass Fiber Reinforced ◽  
Microcellular Injection Molding ◽  
Molded Parts

This study was aimed at understanding how the process conditions affected the dimensional stability of glass fiber reinforced PP by microcellular injection molding. A design of experiments (DOE) was performed and plane test specimens were produced for the shrinkage and warpage analysis. Injection molding trials were performed by systematically adjusting six process parameters (i.e., Injection speed, Injection pressure, Shot temperature, SCF level, Mold temperature, and Cooling time). By analyzing the statistically significant main and two-factor interaction effects, the results showed that the supercritical fluid (SCF) level and the injection speed affected the shrinkage and warpage of microcellular injection molded parts the most.

Adhesive bonding between multi-material assembly injection molding parts with an adhesive interlayer

2011 ◽  
Vol 31 (8-9) ◽  
Author(s):  
Martina Vetter ◽  
Christoph Heinle ◽  
Dietmar Drummer ◽  
Simon Amesöder
Keyword(s):  
Injection Molding ◽  
Bond Strength ◽  
Adhesive Bonding ◽  
Innovative Technology ◽  
Process Conditions ◽  
Material System ◽  
Thermal Expansion Coefficients ◽  
Wide Range ◽  
Different Types ◽  
Cost Efficient

Abstract As it offers a wide range of benefits, assembly injection molding of plastics represents an innovative technology. In a material, cost efficient and integrative process, the most diverse products for mechatronics applications can be manufactured. The technique can generate multi-material systems combining different parts with special functionality, e.g., plastics casings and circuit boards, in a fully automated process. This automated integration of part structure and functionality makes these products superior to others. However, it implies a great challenge in terms of technology for part development and production. Of vital importance for a media tight and durable connection between individual materials/parts of the assembly, are factors such as the components’ compatibility and chemical-physical adhesion. Thermal stress in hybrid assemblies due to different thermal expansion coefficients is often the reason for part failure. An approach to meeting these challenges is the investigation of the process-integrated application of functional interlayers, in order to improve the formation of adhesion along with the optimization of the stress distribution. The following article will present findings obtained on the bond strength generated by different types of interlayers (hot-melt and pressure-sensitive adhesives) between circuit cards and different types of casing plastics. A fundamental understanding of underlying effects and the tools for predicting process dependent effects is required for the optimization of the systems’ functionality. For this purpose, the interactions between material, system design and process conditions are considered in relation to bond strength.

scholarly journals Welding lines formation in holes obtained by low pressure injection molding of ceramic parts

Cerâmica ◽  
2018 ◽  
Vol 64 (369) ◽  
pp. 97-103 ◽  
Author(s):  
C. A. Costa ◽  
A. F. Michels ◽  
M. E. Kipper
Keyword(s):  
Injection Molding ◽  
Injection Pressure ◽  
Mold Temperature ◽  
Low Pressure ◽  
Process Conditions ◽  
Injection Mold ◽  
Extraction Temperature ◽  
Post Injection ◽  
Injection Process ◽  
Pressure Injection

Abstract This work presents a study to evaluate the process of producing internal holes in ceramic disks produced by low pressure injection molding (LPIM) process. Two process conditions defined as pre-injection and post-injection were used to test the proposition. In the first one the pin cores that produce the holes were positioned in the cavity before the injection of the feedstock; and in the second one, the pin cores were positioned in the cavity, just after the feeding phase of the injection mold. An experimental injection mold designed and manufactured to test both processes was developed to produce ceramic disk with Ø 50 x 2 mm with four holes of Ø 5 mm, equally and radially distributed through the disk. The feedstock was composed of 86 wt% alumina (Al2O3) and 14 wt% organic vehicle based on paraffin wax. Heating and cooling systems controlled by a data acquisition system were included in the mold. The results showed that there were no welding lines with the post-injection process, proving to be an option for creating holes in the ceramic parts produced by LPIM. It was observed that best results were obtained at 58 °C mold temperature. The pins extraction temperature was about 45 °C, and the injection pressure was 170 kPa.

The influence of mold temperature on thermoset in-mold forming

2020 ◽  
Vol 40 (3) ◽  
pp. 256-266
Author(s):  
Tim Deringer ◽  
Dietmar Drummer
Keyword(s):  
Injection Molding ◽  
Bond Strength ◽  
Mechanical Performance ◽  
Mold Temperature ◽  
Short Fiber ◽  
Epoxy Compound ◽  
Fiber Reinforced ◽  
Continuous Fiber ◽  
New Process ◽  
One Step

AbstractA new process, called thermoset in-mold forming, for combining thermoset master forming and thermoset forming in one mold is in development. A pre-impregnated continuous-fiber reinforced sheet based on epoxy (prepreg) is formed in the injection molding machine, followed by instantaneous overmolding of a short-fiber reinforced epoxy compound in one step. Compared with conventional processes in which thermoset injection molding, prepreg compression molding, and hence curing of the materials are separated, the new process allows for the combination in one step and simultaneous curing of both components. The result is a hybrid component, which features a continuous-fiber reinforced part for higher mechanical performance and a short-fiber reinforced part with high design freedom for integration of additional functions. For a successful combination of both materials in one process, it is essential to investigate the bond strength between them in relation to the processing parameters and their influence on the degree of cure. This paper analyzes the influence of the mold temperature in this process on curing degree, bond strength, and the processing viscosity.

Influence of mold temperature and process time on the degree of cure of epoxy-based materials for thermoset injection molding and prepreg compression molding

2018 ◽  
Vol 38 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Tim Deringer ◽  
Christian Gröschel ◽  
Dietmar Drummer
Keyword(s):  
Mold Temperature ◽  
Processing Parameters ◽  
Process Window ◽  
Process Time ◽  
Fiber Reinforced ◽  
Degree Of Cure ◽  
Reinforced Plastics ◽  
One Step ◽  
Fiber Reinforced Plastics ◽  
Process Combination

Abstract A new hybrid process for fiber-reinforced plastics based on thermosets combining master-forming and forming in one tool is currently undergoing development. The advantage of this technique is the integrated forming and overmolding of a thermoset-based continuous fiber-reinforced sheet in one step. Although both components are epoxy based, the resin formulations slightly differ and thus require individual curing parameters. For successful combination into one process, it is essential to investigate both components in relation to the processing parameters and their influence on the degree of cure. Besides the influence on the forming and filling behavior, the degree of cure also has an effect on the resulting mechanical properties. In this investigation, the influence of curing time and temperature on the degree of cure of epoxy-based materials was investigated with regard to identifying a process window for a process combination of master-forming and forming.

Die Pressure Losses During Injection Molding of Rubber Mixes

2009 ◽  
Vol 82 (1) ◽  
pp. 62-93 ◽  
Author(s):  
A. Arrillaga ◽  
A. M. Zaldua ◽  
R. M. Atxurra ◽  
A. S. Farid ◽  
A. S. Farid
Keyword(s):  
Injection Molding ◽  
Pressure Control ◽  
Mold Temperature ◽  
Injection Molding Process ◽  
Process Conditions ◽  
Molding Process ◽  
Pressure Losses ◽  
Pressure Decay ◽  
Rubber Compounds ◽  
Ram Speed

Abstract In order to fill the mold in a rubber injection molding process, it is necessary to inject the material into the closed mold. Rubber is usually injected under ram speed control, but it can be also injected under pressure control. In the present study, we have recorded the signals of pressure at three points during the filling of a spiral shape part. The behaviors of two rubber compounds have been studied using a variety of combinations of process conditions (including mold temperature, mass temperature, ram speed and injection molding with and without pressure holding stage). In all conditions, the transducer located in proximity to the gate exhibits pressure decay at the last stage of mold filling. Initial CAE simulations have been carried out using Moldflow software to check the capability of this sort of software to calculate pressure decay during the filling stage.

Mechanical Properties of PMMA/PC Blend by Injection Molding Process

2020 ◽  
Vol 863 ◽  
pp. 67-71
Author(s):  
Van Thanh Hoang ◽  
Duc Binh Luu ◽  
Quang Bang Tao ◽  
Chao Chang Arthur Chen
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Mold Temperature ◽  
Cooling Time ◽  
Injection Molding Process ◽  
Process Conditions ◽  
Molding Process ◽  
Optical Elements ◽  
Melt Temperature ◽  
Significant Parameter

Polycarbonate (PC) has the high impact strength, whereas Polymethylmethacrylate (PMMA) possesses the high tensile strength. Both of them have been widely used for optical elements in illumination. This paper aims to investigate mechanical properties including tensile and impact strengths of PMMA/PC blend with 50 percent of PC concentration by injection molding process. Tensile and impact specimens were designed following ASTM, type V and were fabricated by injection molding process. Taguchi technique was employed to figure out the optimal process conditions for maximum tensile and impact strengths. The processing conditions such as melt temperature, mold temperature, packing pressure and cooling time were applied and each factor has three levels. As a results, melt temperature has been found to be the most significant parameter for both tensile and impact strengths and cooling time is the least significant parameter for the mechanical properties.

Optimization of Process Parameters for Injection Molding Based on Taguchi Technique

2012 ◽  
Vol 538-541 ◽  
pp. 1170-1174
Author(s):  
Shi Jun Fu
Keyword(s):  
Injection Molding ◽  
Process Parameters ◽  
Orthogonal Design ◽  
Mold Temperature ◽  
Optimum Process ◽  
Process Conditions ◽  
Injection Time ◽  
Melt Temperature ◽  
Injection Process ◽  
Packing Pressure

In this paper, Taguchi and CAE technique are combined to study the influence of process conditions on the warpage of injection molding parts through twice orthogonal design experiments, and the injection process parameters are optimized according to the warpage. For the parameters selected, melt temperature and packing pressure have effects on the warpage of injection molding parts are highly significant, injection time is significant, other parameters have little effects. Within the range of experiments, the warpage decreased with the rise of the melt temperature and packing pressure. At last, the optimum process parameters of injection are that the mold temperature is 60°C, packing time is 10s, melt temperature is240°C, packing pressure is 115MPa and injection time is 0.4s.

scholarly journals Towards Optimization of μ-Injection Molding Process for a New V-shaped Geometrical Component Using X-Ray CT-Based Quality Characterization

2019 ◽  
Vol 3 (1) ◽  
pp. 13
Author(s):  
Jitendra Rathore ◽  
Giovanni Lucchetta ◽  
Simone Carmignato
Keyword(s):  
Injection Molding ◽  
Process Parameters ◽  
Functional Performance ◽  
Quality Criteria ◽  
Mold Temperature ◽  
Process Window ◽  
Injection Molding Process ◽  
Molding Process ◽  
Melt Temperature ◽  
Injection Speed

The influence of micro-injection molding process parameters on a molded component’s quality is very prominent. Depending on the functional performance of the part, the desired quality is defined by several criteria which may include dimensional tolerances, shrinkage/warpage, fiber characteristics, and internal defects. A correlation of process parameters with the defined quality attributes needs to be investigated for a new geometrical component. In this work, a micro-component with a new V-shaped geometry is chosen, as this type of geometry finds potential applications in the medical industry. The parts are manufactured with polyoxymethylene resin with a full-factorial design of experimental plan with investigating parameters of mold temperature, melt temperature, injection speed, and packing pressure. The number of internal pores and amount of volumetric shrinkage are identified as the critical quality criteria and the effect of the process parameters is studied with respect to those criteria. The measurement results indicated that the presence of pores is inevitable within the chosen process window; however, the amount can be minimized with careful selection of process settings. Moreover, the statistical analyses demonstrated the significance levels of the process parameters.

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