scholarly journals Modification of the Cavity of Plastic Injection Molds: A Brief Review of Materials and Influence on the Cooling Rates

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7249
Author(s):  
Maria C. Carrupt ◽  
Ana P. Piedade
Keyword(s):  
Injection Molding ◽  
Surface Coating ◽  
Surface Defects ◽  
Process Time ◽  
Cooling Rates ◽  
Cooling Channels ◽  
Injection Process ◽  
Molded Parts ◽  
Plastic Components ◽  
Injection Cycle

In the 21st century, a great percentage of the plastic industry production is associated with both injection molding and extrusion processes. Manufactured plastic components/parts are used in several industry sectors, where the automotive and aeronautic stand out. In the injection process cycle, the cooling step represents 60% to 80% of the total injection process time, and it is used to estimate the production capabilities and costs. Therefore, efforts have been focused on obtaining more efficient cooling systems, seeking the best relationship between the shape, the quantity, and the distribution of the cooling channels into the injection molds. Concomitantly, the surface coating of the mold cavity also assumes great importance as it can provide increased hardness and a more straightforward demolding process. These aspects contribute to the decrease of rejected parts due to surface defects. However, the effect of the coated cavity on the heat transfer and, consequently, on the time of the injection cycle is not often addressed. This paper reviews the effects of the materials and surface coatings of molds cavity on the filling and cooling of the injection molding cycle. It shows how the design of cooling channels affects the cooling rates and warpage for molded parts. It also addresses how the surface coating influence the mold filling patterns and mold cooling. This review shows, more specifically, the influence of the coating process on the cooling step of the injection cycle and, consequently, in the productivity of the process.

Application of Taguchi Method to the Optimal Parameters of Injection Molding for the Plastic Components of the Braille Display Cell

2014 ◽  
Vol 1052 ◽  
pp. 495-502
Author(s):  
Fung Huei Yeh ◽  
Ching Lun Li ◽  
Bing Ming Chen
Keyword(s):  
Injection Molding ◽  
Taguchi Method ◽  
Surface Defects ◽  
Optimal Parameters ◽  
Melt Temperature ◽  
Filling Time ◽  
Short Shot ◽  
Plastic Components ◽  
Mold Flow ◽  
Braille Display

The paper studies the optimal parameters of injection molding to avoid the deformation, warping, short shot, and surface defects for the plastic components of Braille display cell. At first the Pro/Engineer parametric software is applied for the entity design and rendering. Then the Mold-Flow software is used for mold flow analysis on the influence of each injection parameters. The results show mold temperature, melt temperature, injection pressure, and filling time are the most influential factors on reducing component deformation. Besides, the L9 orthogonal array of Taguchi method is applied to find out the optimal parameters of injection molding. The deformation, short shot and surface defects of the plastic components in Braille display cell are reduced.

scholarly journals The Effect of Masterbatch Recipes on the Homogenization Properties of Injection Molded Parts

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
László Zsíros ◽  
Dániel Török ◽  
József Gábor Kovács
Keyword(s):  
Injection Molding ◽  
Evaluation Method ◽  
Surface Defects ◽  
Visual Appearance ◽  
Individual Effects ◽  
Key Factor ◽  
Molded Parts ◽  
Injection Molded ◽  
The Individual

Appearance is a key factor in most injection molding applications. Unfortunately, there is no widespread method to objectively test visual appearance, such as color inhomogeneity of the parts or other surface defects. We developed an evaluation method to characterize the color inhomogeneity of injection molded parts. First, we examined manufacturing conditions and masterbatch recipes and then the individual effects of the components and their interactions on homogeneity.

scholarly journals A Recurrent Neural Network for Warpage Prediction in Injection Molding

2012 ◽  
Vol 10 (6) ◽  
Author(s):  
A. Alvarado-Iniesta ◽  
D.J. Valles-Rosales ◽  
J.L. García-Alcaraz ◽  
A. Maldonado-Macias
Keyword(s):  
Neural Network ◽  
Injection Molding ◽  
Recurrent Neural Network ◽  
Injection Molding Process ◽  
Molding Process ◽  
Element Analysis ◽  
Vast Number ◽  
Production Run ◽  
Molded Parts ◽  
Plastic Components

Injection molding is classified as one of the most flexible and economical manufacturing processes with high volumeof plastic molded parts. Causes of variations in the process are related to the vast number of factors acting during aregular production run, which directly impacts the quality of final products. A common quality trouble in finishedproducts is the presence of warpage. Thus, this study aimed to design a system based on recurrent neural networksto predict warpage defects in products manufactured through injection molding. Five process parameters areemployed for being considered to be critical and have a great impact on the warpage of plastic components. Thisstudy used the finite element analysis software Moldflow to simulate the injection molding process to collect data inorder to train and test the recurrent neural network. Recurrent neural networks were used to understand the dynamicsof the process and due to their memorization ability, warpage values might be predicted accurately. Results show thedesigned network works well in prediction tasks, overcoming those predictions generated by feedforward neuralnetworks.

scholarly journals Injection Molding and Near-Complete Densification of Monolithic and Al2O3 Fiber-Reinforced Ti2AlC MAX Phase Composites

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3632
Author(s):  
Sylvain Badie ◽  
Rimy Gabriel ◽  
Doris Sebold ◽  
Robert Vaßen ◽  
Olivier Guillon ◽  
...  
Keyword(s):  
Injection Molding ◽  
Graphite Powder ◽  
Max Phase ◽  
Powder Injection ◽  
Fiber Reinforced ◽  
Ceramic Fibers ◽  
Plasma Sintering ◽  
Molded Parts ◽  
Al2o3 Fiber ◽  
Induced Velocity

Near-net shape components composed of monolithic Ti2AlC and composites thereof, containing up to 20 vol.% Al2O3 fibers, were fabricated by powder injection molding. Fibers were homogeneously dispersed and preferentially oriented, due to flow constriction and shear-induced velocity gradients. After a two-stage debinding procedure, the injection-molded parts were sintered by pressureless sintering at 1250 °C and 1400 °C under argon, leading to relative densities of up to 70% and 92%, respectively. In order to achieve near-complete densification, field assisted sintering technology/spark plasma sintering in a graphite powder bed was used, yielding final relative densities of up to 98.6% and 97.2% for monolithic and composite parts, respectively. While the monolithic parts shrank isotropically, composite assemblies underwent anisotropic densification due to constrained sintering, on account of the ceramic fibers and their specific orientation. No significant increase, either in hardness or in toughness, upon the incorporation of Al2O3 fibers was observed. The 20 vol.% Al2O3 fiber-reinforced specimen accommodated deformation by producing neat and well-defined pyramidal indents at every load up to a 30 kgf (~294 N).

Increased Productivity in Hot Aluminum Extrusion by Using Extrusion Dies with Inner Cooling Channels Manufactured by Rapid Tooling

2014 ◽  
Vol 611-612 ◽  
pp. 981-988 ◽  
Author(s):  
Ramona Hölker ◽  
Matthias Haase ◽  
Nooman Ben Khalifa ◽  
A. Erman Tekkaya
Keyword(s):  
Surface Defects ◽  
Experimental Investigations ◽  
Extrusion Force ◽  
Aluminum Extrusion ◽  
Thermally Induced ◽  
Manufacturing Method ◽  
Cooling Channels ◽  
Extrusion Dies ◽  
Exit Temperature ◽  
Tooling Technology

The influence of local inner die cooling on the heat balance in hot aluminum extrusion was investigated. For the manufacturing of the die with cooling channels close to the forming zone, the layer-laminated manufacturing method was applied. The new tooling technology was applied in order to decrease the profiles exit temperature and to avoid thermally induced surface defects with the aim to raise the productivity in hot aluminum extrusion processes. Numerical and experimental investigations revealed that, while maintaining the exit temperature of the extrudate, a distinct increase of the production speed up to 300% can be realized, while the extrusion force increases only slightly. An effect on the profiles microstructure was also detected. By applying die cooling, grain coarsening can be significantly limited or even be avoided.

The Use of Advanced Aluminum Alloys for Enhanced Productivity in Plastic Injection Molding

2000 ◽  
Author(s):  
Jim Nerone ◽  
Karthik Ramani
Keyword(s):  
Aluminum Alloys ◽  
Injection Molding ◽  
Wall Thickness ◽  
Simulation Software ◽  
Cooling Time ◽  
Coolant Temperature ◽  
Steel Mold ◽  
Cooling Channels ◽  
Injection Molding Simulation ◽  
Increased Strength

Abstract New aluminum alloys, QC-7® and QE-7®, have thermal conductivities four times greater than traditional tool steels, and have significantly increased strength and hardness compared to traditional aluminum materials. Molds were constructed of P-20 tool steel and QE-7® aluminum and were used to provide experimental data regarding thermal mold characteristic and confirm injection molding simulation predictions using C-Mold®. The relationships between cooling time reduction (using aluminum alloys) and polymer type, cooling channel depth, part wall thickness, and coolant temperature were explored both experimentally and using simulation software. It was shown that the potential reduction in cooling time varied from 5% to 25%. The most significant percentage improvements were observed in parts with part wall thickness of 0.05″ to 0.10″ and in molds with cooling channels at a depth ratio (D/d) of 2.0. The thermal pulses in the steel mold 0.10″ from the surface were approximately 63% larger than in aluminum mold.

Influence of deforming of common rail diesel injectors parts on the fuel injection process

2021 ◽  
pp. 4-12
Author(s):  
Keyword(s):  
High Pressures ◽  
Fuel Injection ◽  
Experimental Studies ◽  
Common Rail ◽  
Electronic Control ◽  
Fuel System ◽  
Fuel Supply ◽  
Injection Process ◽  
Injection Cycle

Experimental studies have revealed a significant impact of deformation of Сommon Rail injector parts on the fuel supply process. High pressures alter the structure of the fuel supply cy-cle. Theforward front of the fuel supply cycle begins with the stage of unloading the deformed parts of the injector. The rear front of the fuel supply cycle ends with the stage of deformation of the injector parts. The calculated and experimental determination of cyclic fuel supply gave similar results. The developed method of determining the duration of the injection cycle stages creates a basis for experimental verification of mathematical models. Keywords: injector, Common Rail, diesel, fuel system, electronic control, needle, fuel injection

Robust Parameter Design of the Precision Injection Molding Process

1994 ◽  
Author(s):  
Sornkrit Leartcheongchowasak ◽  
Merwan Mehta ◽  
Hamid Al-Kadi ◽  
Keith Sequeira ◽  
Brian Snow ◽  
...  
Keyword(s):  
Injection Molding ◽  
Taguchi Methods ◽  
Injection Molding Process ◽  
Robust Parameter Design ◽  
Molding Process ◽  
Product Lines ◽  
Molded Parts ◽  
Robust Parameter ◽  
Independent Process ◽  
The Right

Abstract The most important problem, causing defective parts, in the injection molding process, is nonuniform shrinkage of molded parts. This leads to an iterative trial-and-error cycles of modification of mold cavity and core to arrive at the right dimensional size required which can occasionally to complete retooling. For this process, there are many factors that can be thrown out of control. Using the traditional scientific approach, engineers have longed to understand the mechanics of the process to control it, with limited success. In this paper, a design of experiments setup, using the Taguchi Methods, was done to reduce the nonuniform shrinkage. The company where the experiment was carried out is a precision parts molder for their own product lines. By using the internal experts from the company, a list of independent process parameters with no interactions which were thought the most responsible for dimensional size were listed. As there were 13 such parameters, it was decided to use the L27 orthogonal array. The optimum value that the company experts thought would produce the right part were used as the settings for the initial experiment. The 27 experiments were then performed, allowing sufficient time to let the machine stabilized between the experiments. The S/N ratio calculation for 27 experiments was explained. Next the calculations for the percentage that each parameter contributes to the dimension was determined. Finally, a confirmation experiment was performed to verify the results.

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