Residual Stress and Warpage Models for Complex Injection Molded Parts

2002 ◽  
Vol 17 (3) ◽  
pp. 271-278 ◽  
Author(s):  
W.-B. Young ◽  
J. Wang
Keyword(s):  
Residual Stress ◽  
Molded Parts ◽  
Injection Molded

Numerical simulation and experimental validation of residual stress induced constrained shrinkage of injection molded parts

Polimery ◽  
2008 ◽  
Vol 53 (04) ◽  
pp. 304-310 ◽  
Author(s):  
TAHER AZDAST ◽  
AMIR HOSSEIN BEHRAVESH ◽  
KIUMARS MAZAHERI ◽  
MOHAMMAD MEHDI DARVISHI
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Experimental Validation ◽  
Molded Parts ◽  
Injection Molded

scholarly journals Surface strengthening of injection molded parts by applying a thermal insulation film

RSC Advances ◽  
2017 ◽  
Vol 7 (23) ◽  
pp. 14302-14308 ◽  
Author(s):  
Hwa Jin Oh ◽  
Young Seok Song
Keyword(s):  
Residual Stress ◽  
Thermal Insulation ◽  
Compressive Residual Stress ◽  
Surface Strengthening ◽  
Molded Parts ◽  
Injection Molded

The main objective of this study is to strengthen the surface of injection molded parts by building up the compressive residual stress at the surface of the product.

scholarly journals Study about the technique of determining residual stress of loading measuring method

2021 ◽  
Vol 13 (5) ◽  
pp. 168781402110169
Author(s):  
Liu Hong ◽  
Jiang Zheqi ◽  
Pan Danqi
Keyword(s):  
Residual Stress ◽  
Nondestructive Test ◽  
Measuring Method ◽  
Test Method ◽  
Hole Drilling ◽  
Hole Drilling Method ◽  
Molded Part ◽  
Molded Parts ◽  
Injection Molded ◽  
A New Technique

Nondestructive test method for residual stress in a structural member is always an important research subject, as a new technique for measuring residual stress loading measuring method needs to consummate for the convenience of engineering. The paper proves that nondestructive test loading measuring method is effective and accurate when compared with the result from hole-drilling method. Taking the measurement of residual stress of injection-molded part in automotive lamp as example, the residual stresses in the surface of injection-molded parts of automotive lamp measured by the two methods are very close based on the two measuring results. It shows that loading measuring method, a new method is used to measure the residual stress, has enough accuracy and credibility when it is used to measure the residual stress of complicated injection-molded part. It provides a basis for popularization and application of loading measuring method in engineering. The paper discusses the basic principles of loading measuring method and detailed procedure of the measurement of residual stress by loading measuring method; it gives out some advices to reduce the test errors.

Effect of gate size on the melt filling behavior and residual stress of injection molded parts

2014 ◽  
Vol 53 ◽  
pp. 366-372 ◽  
Author(s):  
Pengcheng Xie ◽  
Fengxia Guo ◽  
Zhiwei Jiao ◽  
Yumei Ding ◽  
Weimin Yang
Keyword(s):  
Residual Stress ◽  
Molded Parts ◽  
Injection Molded ◽  
Gate Size

Effects of Process Conditions on Shrinkage and Warpage: Experiments and Simulations

2000 ◽  
Author(s):  
James T. Wang ◽  
C. K. Yoon
Keyword(s):  
Residual Stress ◽  
Mold Wall ◽  
Polymer Melt ◽  
Process Conditions ◽  
Cooling Channels ◽  
Part Quality ◽  
Molded Part ◽  
Packing Pressure ◽  
Molded Parts ◽  
Injection Molded

Abstract In the injection mold process, a pressure gradient exists from the polymer entrance to the last-fill location. At different planar locations of a part, when the polymer melt cools down to the transition temperature and freezes (changes from liquid to solid) at different pressures, shrinkage at the various locations will be different. If cooling channels are not arranged properly, the mold wall temperatures on the cavity and core sides can be different. This unbalanced cooling can also cause the melt at the upper and lower halves of the cavity to shrink differently, because they freeze at different times and different pressures. These two types of non-uniform shrinkage will cause parts to warp. Reducing shrinkage and warpage is one of the top priorities for improving the quality of injection molded parts. In addition to part design and material properties, process conditions are the most important determinants of part quality. In this paper, the relationship between process conditions and in-cavity residual stress will be studied. In-cavity residual stress is the driving force that causes parts to deform after they are taken out of the mold. The effects of process conditions on injection-molded part quality (in terms of shrinkage and warpage) will be discussed. Different packing pressure levels, together with unbalanced cooling from mold wall temperatures, will be examined. Deformation of injection molded parts will be measured. Comparisons between experimental and numerical simulation results will be reported.

Comparative Analysis of Different Methods in Residual Stress Measurement for Polymeric Parts

2013 ◽  
Vol 837 ◽  
pp. 175-178
Author(s):  
Alexandra Raicu
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Polymeric Materials ◽  
Injection Molding Process ◽  
Uniform Temperature ◽  
Molding Process ◽  
Molded Parts ◽  
Injection Molded ◽  
Technological Constraints

This paper presents the measurements of the residual stresses for polymeric parts using different methods. The residual stresses are usually introduced during manufacturing and are caused by processes such as molding. In order to optimize injection molding process with polymeric material, it is important to predict the internal stress development during molding. The residual stresses are caused mainly by non-uniform temperature profile in the cavity during filling, packing and cooling stages. This research offers information and a methodology which may be applied in practical conditions for a large number of parts manufactured from the different polymeric materials and for several technological constraints. The author confirmed that all this methods which measure the residual stresses can be applied to injection molded parts.

A Study on the Birefringence Measurement in Injection Molded Parts Using Two Different Laser Sources and R-G-B Separation of White Light

2006 ◽  
Vol 326-328 ◽  
pp. 187-190
Author(s):  
Jong Sun Kim ◽  
Chul Jin Hwang ◽  
Kyung Hwan Yoon
Keyword(s):  
White Light ◽  
Low Cost ◽  
Main Idea ◽  
Injection Molding Process ◽  
Molding Process ◽  
Laser Method ◽  
High Productivity ◽  
Molded Parts ◽  
Injection Molded ◽  
Plastic Parts

Recently, injection molded plastic optical products are widely used in many fields, because injection molding process has advantages of low cost and high productivity. However, there remains residual birefringence and residual stresses originated from flow history and differential cooling. The present study focused on developing a technique to measure the birefringence in transparent injection-molded optical plastic parts using two methods as follows: (i) the two colored laser method, (ii) the R-G-B separation method of white light. The main idea of both methods came from the fact that more information can be obtained from the distribution of retardation caused by different wavelengths. The comparison between two methods is demonstrated for the same sample of which retardation is up to 850 nm.

scholarly journals Silane-Functionalized Sheep Wool Fibers from Dairy Industry Waste for the Development of Plasticized PLA Composites with Maleinized Linseed Oil for Injection-Molded Parts

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2523
Author(s):  
Franciszek Pawlak ◽  
Miguel Aldas ◽  
Francisco Parres ◽  
Juan López-Martínez ◽  
Marina Patricia Arrieta
Keyword(s):  
Linseed Oil ◽  
Microstructural Analysis ◽  
Dairy Industry ◽  
Poly Lactic Acid ◽  
Industry Waste ◽  
Wool Fibers ◽  
Molded Parts ◽  
Silane Modification ◽  
Injection Molded ◽  
Sheep Wool

Poly(lactic acid) (PLA) was plasticized with maleinized linseed oil (MLO) and further reinforced with sheep wool fibers recovered from the dairy industry. The wool fibers were firstly functionalized with 1 and 2.5 phr of tris(2-methoxyethoxy)(vinyl) (TVS) silane coupling agent and were further used in 1, 5, and 10 phr to reinforce the PLA/MLO matrix. Then, the composite materials were processed by extrusion, followed by injection-molding processes. The mechanical, thermal, microstructural, and surface properties were assessed. While the addition of untreated wool fibers to the plasticized PLA/MLO matrix caused a general decrease in the mechanical properties, the TVS treatment was able to slightly compensate for such mechanical losses. Additionally, a shift in cold crystallization and a decrease in the degree of crystallization were observed due to the fiber silane modification. The microstructural analysis confirmed enhanced interaction between silane-modified fibers and the polymeric matrix. The inclusion of the fiber into the PLA/MLO matrix made the obtained material more hydrophobic, while the yellowish color of the material increased with the fiber content.

scholarly journals Development of a novel color inhomogeneity test method for injection molded parts

2014 ◽  
Vol 37 ◽  
pp. 112-116 ◽  
Author(s):  
L. Zsíros ◽  
A. Suplicz ◽  
G. Romhány ◽  
T. Tábi ◽  
J.G. Kovács
Keyword(s):  
Test Method ◽  
Molded Parts ◽  
Injection Molded
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