scholarly journals Experimental analysis of generation process of white tree-ring-like surface defects in injection molding

2016 ◽  
Author(s):  
N. Masuda ◽  
H. Yokoi
Keyword(s):  
Injection Molding ◽  
Tree Ring ◽  
Experimental Analysis ◽  
Surface Defects ◽  
Generation Process

Investigation of Flash Generation Process for Engineering Plastic by Flash Generation-Evaluating Mold

2017 ◽  
Vol 11 (1) ◽  
pp. 90-96 ◽  
Author(s):  
Yasuhiko Murata ◽  
◽  
Tomoki Inoue ◽  
Tomonari Fujibayashi
Keyword(s):  
Injection Molding ◽  
Nylon 6 ◽  
Generation Process ◽  
Engineering Plastic

Flash is an appearance defect that arises in injection molding. In this paper, a flash generation-evaluating mold developed by the authors was improved to evaluate the ease of occurrence of flashes in resins, such as engineering plastic, molded at high mold temperatures and melt pressures in the cavity. Using the improved mold, we evaluated the occurrence conditions of secondary flash in polyoxymethylene (POM), polyamide PA6 (nylon-6), and polycarbonate (PC). The secondary flash occurred most easily for PA6, second most easily for POM, and least easily for PC. A correlation between the ease of occurrence of secondary flash and the crystallization of the resin was also clarified.

scholarly journals Experimental Analysis of Solidification Behaviors in Thin-wall LCP Injection Molding

Seikei-Kakou ◽  
2017 ◽  
Vol 29 (7) ◽  
pp. 265-271
Author(s):  
Toshio Sugita ◽  
Masahiro Seto ◽  
Masashi Yamabe
Keyword(s):  
Injection Molding ◽  
Experimental Analysis ◽  
Thin Wall

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.

Research Progress of Improving Surface Quality of Microcellular Foam Injection Parts

2011 ◽  
Vol 66-68 ◽  
pp. 2010-2016 ◽  
Author(s):  
Yue Wang ◽  
Guang Hong Hu
Keyword(s):  
Injection Molding ◽  
Surface Quality ◽  
Dimensional Stability ◽  
Surface Defects ◽  
Research Progress ◽  
Microcellular Foam ◽  
Counter Pressure ◽  
Foam Injection Molding ◽  
Application Scope

Microcellular foam injection parts have many advantages such as saving material and energy, reducing cycle time, and processing excellent dimensional stability. Despite these advantages, the low surface quality problems limit its application scope seriously. In this study, the microcellular foam injection molding principle and some surface defects were introduced, and the technologies to improve surface quality, such as Gas Counter Pressure (GCP), Rapid Heat Cycle Molding (RHCM), and Film Insulation were summarized in detail. Finally, the prospect of CAE technologies about microcellular foam injection molding was proposed.

An Integrated Approach to Evaluate the Cycle Time in Injection Molding

2000 ◽  
Author(s):  
D. M. Gao ◽  
W. C. Bushko
Keyword(s):  
Injection Molding ◽  
Production Rate ◽  
Friction Force ◽  
Cycle Time ◽  
Surface Defects ◽  
Integrated Approach ◽  
Critical Issue ◽  
Material Behavior ◽  
Time Duration ◽  
Ejection Force

Abstract The cycle time prediction is considered as a critical issue in injection molding. It relates directly to the production rate and the part quality. It is commonly defined as the time duration between the start of the injection and the ejection of the part. When the cycle time exceeds the desired range, the production rate will be compromised. In some cases, due to excessively increased friction force, the part may be subject to severe failure such as breakage during ejection. Another possible situation is that the ejector pins can be damaged because the friction force exceeds the maximum ejection force that the machine can provide through the ejectors. If the part is ejected too early, only a thin layer of polymer is solidified and the ejection may cause the part to be deformed permanently which generally leads to surface defects. For most injection molders, the cycle time is estimated through molding trials, which is very costly and time consuming. In the case of testing a new material, it is even more difficult to determine a proper cycle time ranger due to the lack of knowledge on the material behavior.

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