scholarly journals Experimental And Numerical Studies of Shrinkage and Sink Marks On Injection Molded Polymer Gears

2021 ◽  
Author(s):  
Bikram Solanki ◽  
Hapreet Singh ◽  
Tanuja Sheorey
Keyword(s):  
Injection Molding ◽  
Injection Molding Process ◽  
Molding Process ◽  
Melt Temperature ◽  
Numerical Studies ◽  
Packing Pressure ◽  
Injection Molded ◽  
Sink Marks ◽  
Plastic Gears ◽  
Packing Time

Abstract Injection molding is an efficient and most economical process employed for the mass production of plastic gears and helps to reduce the processing time and cost required to produce the desired geometry. However, significant process and product qualification of plastic gears face the shrinkage and sink marks issues during cooling and after ejection. In present work, the best gate locations and flow resistance analysis along with a polypropylene (PP) were carried out using Autodesk Moldflow Insight 2019.05. The numerical and experimental study was conducted to evaluate the effect of packing pressure, packing time, and melt temperature on diametric shrinkage, mass, and sink marks of PP gear. The results show that by increasing packing pressure and packing time, the diametric shrinkage decreased but mass increased. However, as the melt temperature increased the diametric shrinkage also increased but the mass decreased. The minimum diametric shrinkage of 0.562% was found in numerical analysis and 1.619% found in an experimental analysis at the same injection molding process parameters. Mostly, the sink marks were observed in the gear surface between hub and dedendum circle.

The simulation of the warpage rule of the thin-walled part of polypropylene composite based on the coupling effect of mold deformation and injection molding process

2018 ◽  
Vol 25 (3) ◽  
pp. 593-601 ◽  
Author(s):  
Jixiang Zhang ◽  
Xiaoyi Yin ◽  
Fengzhi Liu ◽  
Pan Yang
Keyword(s):  
Injection Molding ◽  
Coupling Effect ◽  
Mold Temperature ◽  
Injection Molding Process ◽  
Plastic Part ◽  
Molding Process ◽  
Melt Temperature ◽  
Packing Pressure ◽  
Thin Walled ◽  
Packing Time

Abstract Aiming at the problem that a thin-walled plastic part easily produces warpage, an orthogonal experimental method was used for multiparameter coupling analysis, with mold structure parameters and injection molding process parameters considered synthetically. The plastic part deformation under different experiment schemes was comparatively studied, and the key factors affecting the plastic part warpage were analyzed. Then the injection molding process was optimized. The results showed that the important order of the influence factors for the plastic part warpage was packing pressure, packing time, cooling plan, mold temperature, and melt temperature. Among them, packing pressure was the most significant factor. The optimal injection molding process schemes reducing the plastic part warpage were melt temperature (260°C), mold temperature (60°C), packing pressure (150 MPa), packing time (2 s), and cooling plan 3. In this situation, the forming plate flatness was better.

Influence of Injection Molding Process Parameters on Sink Marks of Injection Parts Based on Moldflow

2013 ◽  
Vol 347-350 ◽  
pp. 1163-1167
Author(s):  
Ling Bai ◽  
Hai Ying Zhang ◽  
Wen Liu
Keyword(s):  
Injection Molding ◽  
Process Parameters ◽  
Mold Temperature ◽  
Processing Parameters ◽  
Injection Molding Process ◽  
Molding Process ◽  
Melt Temperature ◽  
Packing Pressure ◽  
Sink Marks ◽  
Research Show

Moldflow software was used to obtain the best gate location and count. Influence of injection molding processing parameters on sink marks of injection-piece was studied based on orthogonal test. The effects of different process parameters were analyzed and better process parameters were obtained. Results of research show that decreasing melt temperature, mold temperature, the increasing injection time and packing pressure can effectively reduce the sink marks index.

Comparison between Single and Multi Gates for Minimization of Warpage Using Taguchi Method in Injection Molding Process for ABS Material

2013 ◽  
Vol 594-595 ◽  
pp. 842-851 ◽  
Author(s):  
S.M. Nasir ◽  
Khairul Azwan Ismail ◽  
Z. Shayfull ◽  
Norshah Afizi Shuaib
Keyword(s):  
Injection Molding ◽  
Acrylonitrile Butadiene Styrene ◽  
Mold Material ◽  
Injection Molding Process ◽  
Inlet Temperature ◽  
Molding Process ◽  
Melt Temperature ◽  
Thermoplastic Material ◽  
Packing Pressure ◽  
Packing Time

In this study, a mold is designed in single and dual type of gate in order to investigate the deflection of warpage for thick component in injection molding process. Autodesk Moldflow Insight software was used as a medium for experimental tested. Nessei NEX 1000 injection molding machine and P20 mold material details were entered in this study to get more accurate data on top of Acrylonitrile Butadiene Styrene (ABS) as a molded thermoplastic material. Taguchi orthogonal array, analysis of Signal to Noise (S/N) ratio and Analysis of Variance (ANOVA) were implemented to get the best combination of parameter and significant factor that affect the warpage problem for both types of gates. Coolant inlet temperature, melt temperature, packing pressure and packing time are the selected parameter that used in this study. A conformation test is conducted to verify the combination parameters optimized. From the result, multi gates used was founded that can decrease the deflection of warpage for thick product. From ANOVA, the most significant factor is melt temperature for single gate, and coolant inlet temperature for multi gate. Packing pressure and packing time were slightly influence on warpage problem for both studies.

Effect of gas counter pressure on shrinkage and residual stress for injection molding process

2017 ◽  
Vol 37 (5) ◽  
pp. 505-520 ◽  
Author(s):  
Wen-Ren Jong ◽  
Shyh-Shin Hwang ◽  
Ming-Chieh Tsai ◽  
Chien-Chou Wu ◽  
Chi-Hung Kao ◽  
...  
Keyword(s):  
Residual Stress ◽  
Injection Molding ◽  
Flow Direction ◽  
Injection Molding Process ◽  
Molding Process ◽  
Daily Lives ◽  
Counter Pressure ◽  
Packing Pressure ◽  
Sink Marks ◽  
Feedback Data

Abstract Plastic products are common in contemporary daily lives. In the plastics industry, the injection molding process is advantageous for features such as mass production and stable quality. The problem, however, is that the melt will be affected by the residual stress and shrinkage generated in the process of filling and cooling; hence, defects such as warping, deformation, and sink marks will occur. In order to reduce product deformation and shrinkage during the process of molding, the screw of the injection molding machine will start the packing stage when filling is completed, which continuously pushes the melt into the cavity, thus making up for product shrinkage and improving their appearance, quality, and strength. If the packing pressure is too high, however, the internal residual stress will increase accordingly. This study set out to apply gas counter pressure (GCP) in the injection molding process. By importing gas through the ends of the cavity, the melt was exposed to a melt front pressure, which, together with the packing pressure from the screw, is supposed to reduce product shrinkage. The aim was to investigate the impacts of GCP on the process parameters via the changes in machine feedback data, such as pressure and the remaining injection resin. This study also used a relatively thin plate-shaped product and measurements, such as the photoelastic effect and luminance meter, to probe into the impacts of GCP on product residual stress, while a relatively thick paper-clip-shaped product was used to see the impacts of GCP on shrinkage in thick parts. According to the experimental results, the addition of GCP resulted in increased filling volume, improvement of product weight and stability, and effective reduction of section shrinkage, which was most obvious at the point closest to the gas entrance. The shrinkage of the sections parallel and vertical to the flow direction was proved to be reduced by 32% and 16%, respectively. Moreover, observations made via the polarizing stress viewer and luminance meter showed that the internal residual stress of a product could be effectively reduced by a proper amount of GCP.

The Application of Moldflow in Injection Molding of the Helmet

2015 ◽  
Vol 1096 ◽  
pp. 366-370
Author(s):  
Yong Cheng Huang ◽  
Hong Bin Liu ◽  
Hai Tao Wu
Keyword(s):  
Injection Molding ◽  
Process Parameters ◽  
Hold Time ◽  
Mold Temperature ◽  
Appropriate Technology ◽  
Injection Molding Process ◽  
Injection Time ◽  
Molding Process ◽  
Melt Temperature ◽  
Packing Pressure

Considering the importance of the reasonable injection molding technology.Based on the application of moldflow in injection molding of the helmet .By adjusting the mold temperature, melt temperature, injection time, packing pressure, hold time and so on the injection molding process parameters to develop appropriate technology methods to get the best injection molding parameters.

Influence of Process Parameters on Plastic Injection Molding of Automobile Interior Trim

2011 ◽  
Vol 189-193 ◽  
pp. 1675-1680
Author(s):  
Qing Qing Liu ◽  
Lin Hua ◽  
Wei Guo
Keyword(s):  
Mold Temperature ◽  
Process Conditions ◽  
Injection Time ◽  
Molding Process ◽  
Melt Temperature ◽  
Influence Of Process Parameters ◽  
Packing Pressure ◽  
Optimal Setting ◽  
Injection Molded ◽  
Packing Time

The influence of process conditions on the formability of injection-molded PX0034 (9% talc-filled PP) automobile B column mounting trim applied as a model has been studied in current work. This study has been focused on the interactive influence of melt temperature and mold temperature, the interactive influences of injection time and packing time and the influences of packing pressure. Weighting the effect of optimization is by formability including the values of pressure at V/P switchover, volumetric shrinkage differential at ejection, and maximum warpage. Aforementioned values were obtained by numerical simulation of the whole molding process using commercial dedicated code Moldflow. Results indicate that the combination of mold temperature at 25 °C, melt temperature at 220 °C, injection time at 2.2 s, packing time at 16 s and packing pressure at 90% of the filling pressure is the optimal setting for formability of this trim. The simulation results obtained under the optimized parameters are that the pressure at V/P switchover is 27.29 Mpa, the shrinkage differential at ejection is 6.55 %, and maximum warpage is 3.072 mm. Good correlation is highlighted between the experiments and the simulations by comparing effects of the global optimization in formability, which verifies the validity of the optimal combination.

scholarly journals The Study of Optimal Molding of a LED Lens with Grey Relational Analysis and Molding Simulation

2019 ◽  
Vol 63 (4) ◽  
pp. 278-294 ◽  
Author(s):  
Min-Wen Wang ◽  
Fatahul Arifin ◽  
Van-Hanh Vu
Keyword(s):  
Injection Molding ◽  
Mold Temperature ◽  
Injection Molding Process ◽  
Molding Process ◽  
Melt Temperature ◽  
Injection Speed ◽  
Relational Analysis ◽  
Total Displacement ◽  
Packing Pressure ◽  
Grey Relational

Injection molding technology is known as the most widely used method in mass production of plastic products. To meet the quality requirements, a lot of methods were applied in optimization of injection molding process parameter. In this study the optimization based on Taguchi orthogonal array and Grey relational analysis (GRA) is used to optimize the injection molding process parameters on a LED lens. The four process parameters are: packing pressure, injection speed, melt temperature and mold temperature. The multi-response quality characteristics are total displacement, volumetric shrinkage, and thermal residual stress. The optimal molding parameters are packing pressure (90 MPa), injection speed (300 mm/sec), melt temperature (270 °C) and mold temperature (90 °C). The luminous uniformity of the LED is 92.61 % and the viewing angle of the LED is 124.76°. Among the four factors, packing pressure plays the key role in reducing total displacement, volumetric shrinkage, and thermal residual stress.

scholarly journals Effect of micro injection molding parameters on cavity pressure and temperature assisted by Taguchi method

Mechanika ◽  
2019 ◽  
Vol 25 (4) ◽  
pp. 261-268
Author(s):  
Quan Wang ◽  
Chongying Yang ◽  
Kaihui Du ◽  
Zhenghuan Wu
Keyword(s):  
Injection Molding ◽  
Experimental Work ◽  
Complex Geometry ◽  
Mold Temperature ◽  
Mold Cavity ◽  
Injection Molding Process ◽  
Cavity Pressure ◽  
Molding Process ◽  
Melt Temperature ◽  
Packing Pressure

The injection molding process is one of the most efficient processes where mass production through automation is feasible and products with complex geometry at low cost are easily attained. In this study, an experimental work is performed on the effect of injection molding parameters on the polymer pressure and temperature inside the mold cavity. Different process parameters of the injection molding are considered during the experimental work including packing pressure, packing time, injection pressure, mold temperature, and melt temperature. The cavity pressure is measured with time by using Kistler pressure sensor at different injection molding cycles. The results show the packing pressure is significant factor of affecting the maximum of diverse spline cavity pressure. The mold temperature is significant factor of affecting the maximum cavity temperature. The results obtained specify well the developing of the cavity pressure and temperature inside the mold cavity during the injection molding cycles.

An effective approach to measuring real-time mold deflection during injection molding

2011 ◽  
Vol 31 (8-9) ◽  
Author(s):  
Chung-Ching Huang ◽  
Thanh-Cong Truong ◽  
Shen-Hong Chen
Keyword(s):  
Injection Molding ◽  
Real Time ◽  
Plate Thickness ◽  
Displacement Sensor ◽  
Injection Molding Process ◽  
Molding Process ◽  
Packing Pressure ◽  
Mold Deformation ◽  
Deflection Analysis ◽  
Injection Molded

Abstract This study develops an effective approach to measure real-time mold plate flexion, namely a displacement of a cavity plate. A mold-filling program was used to simulate the injection molding process. The predicted cavity pressure was then applied as an input for the subsequent mold deflection analysis. In this work, an amorphous polymethyl methacrylate (PMMA) was injection-molded into a 6-inch light guide plate (LGP) cavity, with cavity plate thicknesses of 35 mm, 55 mm, and 100 mm. To validate the predicted mold deflection, an inductive displacement sensor was placed underneath the cavity plate, and experiments were conducted using process variables identical to those of the simulation. Comparison between the simulated results and the experimental data shows that when the cavity plate thickness is reduced, the mold deformation increases significantly, and results in an increase in part thickness. In addition, an increase in packing pressure caused a rise in mold deformation. This study demonstrates that the proposed approach is able to measure the mold deflection.

scholarly journals Investigation of injection molding process parameters characteristics using RSM approach

2020 ◽  
Vol 12 (3) ◽  
pp. 16-25
Author(s):  
Ashish Goyal ◽  
Vimal Kumar Pathak ◽  
Siddharth Ogra ◽  
Anand Pandey
Keyword(s):  
Injection Molding ◽  
Process Parameters ◽  
Tensile Modulus ◽  
Injection Pressure ◽  
Machining Process ◽  
Injection Molding Process ◽  
Molding Process ◽  
Melt Temperature ◽  
Packing Pressure ◽  
Selection Of

The present study analyzes the important characteristics of plastic injection molding machining process. The polypropylene (PP) material has used as a specimen and effect of melt temperature, packing pressure and injection pressure has been investigated on the tensile modulus and elongation. Total 20 experiments have been performed to analyses the results. Response surface methodology (RSM) was adopted for optimization of injection molding process parameters. The experiments were conducted by using central composite design. The analysis of variance (ANOVA) techniques was used for selection of significant and non-significant parameters. The experimental results show that the RSM influence elongation by 87.04%, 11.52%, 1.43% and tensile modulus by 85.35%, 11.4%, 3.25%. Keywords: Injection molding; polypropylene; tensile modulus; elongation

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