scholarly journals Foaming morphology control of microcellular injection molded parts with gas counter pressure and dynamic mold temperature control

2014 ◽  
Author(s):  
Tai-Yi Shiu ◽  
Chao-Tsai Huang ◽  
Rong-Yu Chang ◽  
Shyh-Shin Hwang
Keyword(s):  
Temperature Control ◽  
Morphology Control ◽  
Mold Temperature ◽  
Counter Pressure ◽  
Molded Parts ◽  
Injection Molded

Effects of dynamic mold temperature control on melt pressure, cellular structure, and mechanical properties of microcellular injection-molded parts: An experimental study

2019 ◽  
Vol 38 (5-6) ◽  
pp. 111-130
Author(s):  
Guiwei Dong ◽  
Guoqun Zhao ◽  
Junji Hou ◽  
Guilong Wang ◽  
Yue Mu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Flexural Strength ◽  
Temperature Control ◽  
Cellular Structure ◽  
Weld Line ◽  
Mold Temperature ◽  
Cell Diameter ◽  
Cooling Stage ◽  
Molded Parts

In this work, the effects of dynamic mold temperature control (DMTC) on melt pressure, cellular structure, and mechanical properties of microcellular injection molding (MIM)-molded parts are investigated experimentally. It is found that with the increase of the mold temperature, the duration of foaming pressure in the cooling stage increases. Meanwhile, the average cell diameter and cell diameter dispersion increases as well as the cell density decreases in MIM molded parts. The turning point of mold temperature after which the foaming pressure in the cooling stage and the cellular structure in MIM molded parts generate a significant change is around the glass transition temperature of the used plastic material. Under DMTC conditions, with the increase of mold temperature, the tensile strength, flexural strength, and impact strength of MIM molded specimens of single gate without weld line change a little, while the tensile strength, flexural strength of MIM molded specimens of double gates with weld line increase obviously. When the mold temperature increases to 120°C and over, the tensile strength, flexural strength of MIM molded specimens of double gates with weld line reach an equivalent level of specimens of single gate without weld line.

Warpage Characterization of Thin and Centrally-Gated Injection Molded Part by Applying Cavity Pressure Measurement

2013 ◽  
Vol 446-447 ◽  
pp. 1099-1103 ◽  
Author(s):  
H. Zamani ◽  
S. Azmoudeh ◽  
K. Shelesh-Nezhad
Keyword(s):  
Radial Flow ◽  
Mold Temperature ◽  
Cavity Pressure ◽  
Injection Speed ◽  
Molded Part ◽  
Pressure Time ◽  
Molded Parts ◽  
Injection Molded ◽  
Thin Disks

Two types of injection molded parts including parts with thin shell feature and parts molded with radial flow pattern are highly susceptible to the warpage. In this research, the warpage performance of a thin and centrally-gated disk was experimentally investigated. The melt pressure-time traces of two different locations inside the mold cavity were monitored by employing piezoelectric transducers. The results indicated that the pressure difference magnitude of melt at two locations along the radial flow path is related to the extent of molded part deformation. Moreover, it was pointed out that the high magnitude of warpage is because of two conflicting actions in the molded part comprising expansion as a result of viscoelastic recovery in the central region, and thermal contraction in the edge region of the thin disk. The molding variables encompassing injection speed, holding pressure, back pressure, mold temperature and screw rotational speed affected the thin disks deformation in order of significance.

scholarly journals The use of IR thermography to show the mold and part temperature evolution in injection molding

2016 ◽  
Vol 36 (1) ◽  
pp. 40-43 ◽  
Author(s):  
Karol Bula ◽  
Leszek Różański ◽  
Lidia Marciniak-Podsadna ◽  
Dawid Wróbel
Keyword(s):  
Injection Molding ◽  
Isotactic Polypropylene ◽  
Infrared Camera ◽  
Mold Temperature ◽  
Temperature Evolution ◽  
Injection Mold ◽  
Ir Thermography ◽  
Molded Parts ◽  
Injection Molded

Abstract This study concerns the application of infrared camera for injection molding analysis by measuring temperatures of both injection molded parts and injection mold cavities in a function of injection cycles. The mold with two cavities, differing in thickness (1 and 3 mm), and a cold direct runner was used. Isotactic polypropylene homopolymer was utilized to produce parts. Mold temperature was set at 22°C and controlled by a water chiller. Five measuring points were determined: SP1, SP2 (placed in the 3 mm cavity), SP3, SP4 (located in the 1 mm cavity) and SP5 around an injection molding gate. Our investigations showed that the highest temperature is localized around SP2 point and the lowest at SP4. Also, it was proved that even after 62 injection molding cycles, temperatures of cavities were not stable, revealing their further increase with each cycle.

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