Polymer Flow Influenced by Mold Cavity Surface Roughness

Abstract Generally, the strength at the weld line of the injection molded part is very weak. The heat transfer coefficient (HTC) between the polymer melt and the mold cavity surface was analyzed to solve this problem. The surface roughness of the mold cavity and the material of the mold insert were changed to adjust the interface environment between the polymer melt and the mold cavity surface. HTC was obtained by combing the experimental measurement with the theoretical calculation. In the current study, the influence of HTC on the tensile strength of the weld line of the molded specimen was investigated. The results show that the weld line strength of the molded specimen increases with the decrease in HTC between the polymer and the mold cavity surface. Meanwhile, the decrease in the surface roughness of the mold cavity or replacing the mold material with lower thermal conductivity can reduce the value of the HTC between the polymer and the mold effectively and can delay the cooling rate of the hot polymer melt. This provides a new idea to solve thin-wall injection molding weld line defects.

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Injection Molding of Rubber Compound Influenced by Injection Mold Surface Roughness

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1025-1026.283 ◽

2014 ◽

Vol 1025-1026 ◽

pp. 283-287 ◽

Cited By ~ 1

Author(s):

Michal Stanek ◽

David Manas ◽

Miroslav Manas ◽

Martin Ovsik ◽

Vojtech Senkerik ◽

...

Keyword(s):

Surface Roughness ◽

Injection Molding ◽

Flow Characteristics ◽

Mold Cavity ◽

Cavity Surface ◽

Injection Molding Process ◽

Mold Surface ◽

Technological Parameters ◽

Molding Process ◽

Melt Temperature

Delivery of polymer melts into the mold cavity is the most important stage of the injection molding process. This paper shows the influence of cavity surface roughness and technological parameters on the flow length of rubber into mold cavity. The fluidity of polymers is affected by many parameters (mold design, melt temperature, injection rate and pressures) and by the flow properties of polymers. Results of the experiments carried out with selected types of rubber compounds proved a minimal influence of surface roughness of the runners on the polymer melt flow. This considers excluding (if the conditions allow it) the very complex and expensive finishing operations from the technological process as the influence of the surface roughness on the flow characteristics does not seem to play as important role as was previously thought. Application of the measurement results may have significant influence on the production of shaping parts of the injection molds especially in changing the so far used processes and substituting them by less costly production processes which might increase the competitiveness of the tool producers and shorten the time between product plan and its implementation.

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Fluidity of Rubber and TPE Influenced by Mold Surface Roughness

Materials Science Forum ◽

10.4028/www.scientific.net/msf.952.198 ◽

2019 ◽

Vol 952 ◽

pp. 198-206

Author(s):

Michal Stanek ◽

Martin Ovsik ◽

Miroslav Manas ◽

Martin Reznicek ◽

Petr Fluxa

Keyword(s):

Surface Roughness ◽

Injection Molding ◽

Thermoplastic Elastomers ◽

Mold Cavity ◽

Cavity Surface ◽

Injection Molding Process ◽

Mold Surface ◽

Technological Parameters ◽

Melt Temperature ◽

Processing Technologies

Injection molding is one of the most extended plastic processing technologies. Delivery of polymer melts into the mold cavity is the most important stage of the injection molding process. This paper shows the influence of mold cavity surface roughness and technological parameters on the flow length of thermoplastic elastomers and rubber into mold cavity. The fluidity of polymers is affected by many parameters (mold design, melt temperature, injection rate and pressures) and by the flow properties of polymers. Evaluation of the data obtained by experiments where the testing conditions were widely changed shows that quality of the cavity surface does not affect the length of flow.

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The Effective Measures of Preventing Collapse Angle Problem in Polishing Plastic Mould

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.538-541.1720 ◽

2012 ◽

Vol 538-541 ◽

pp. 1720-1723

Author(s):

Yi Lei Ren ◽

Hong Qi Lin

Keyword(s):

Preventive Measures ◽

Dimensional Accuracy ◽

Machining Process ◽

Mold Cavity ◽

Cavity Surface ◽

Plastic Model ◽

Plastic Parts ◽

Surface Angle ◽

Plastic Mold

Plastic mold polished, in the mold cavity parting collapsed throwing angle appear, which seriously affect the dimensional accuracy and surface quality of the plastic parts, this article proposed two effective preventive measures: (1) cutting the model which having a same size as plastic model of the cavity at the parting surface, sticking the model and cavity parting with 502 glue together, within the required type of alignment, and then thrown together, polished finish will be a model to out; (2) in the plastic model cavity machining process, type in the mold cavity surface set aside allowance 0.5 ~ 1mm, polished until the cavity is completed, the surface of the cavity type 0.5 ~ 1mm rubbed off with a grinding allowance, it will ensure the cavity size and cavity to prevent the collapse of sub-surface angle at the phenomenon.

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Simulations of cyclic transient mold cavity surface temperatures in injection mold-cooling process

International Communications in Heat and Mass Transfer ◽

10.1016/0735-1933(92)90011-6 ◽

1992 ◽

Vol 19 (4) ◽

pp. 559-568 ◽

Cited By ~ 22

Author(s):

Shia-Chung Chen ◽

Yung-Chien Chung

Keyword(s):

Mold Cavity ◽

Cavity Surface ◽

Injection Mold ◽

Cooling Process ◽

Surface Temperatures

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Multi-Objective Optimization of the Heating Rods Layout for Rapid Electrical Heating Cycle Injection Mold

Journal of Mechanical Design ◽

10.1115/1.4001529 ◽

2010 ◽

Vol 132 (6) ◽

Cited By ~ 2

Author(s):

Guoqun Zhao ◽

Xiping Li ◽

Yanjin Guan

Keyword(s):

Temperature Distribution ◽

Injection Molding ◽

Mold Cavity ◽

Electrical Heating ◽

Cavity Surface ◽

Heating Cycle ◽

Multi Objective Optimization ◽

Heating Efficiency ◽

Multi Objective ◽

Distribution Uniformity

Rapid electrical heating cycle injection molding (ERHCM) technology is a promising green manufacturing technology for plastic parts. By using this technology, the defects that usually appear on the surface of conventionally injected parts, such as weld and flow marks, can be avoided effectively. This paper studies rapid electrical heating cycle injection molding technology and its mold structure design techniques. Temperature distribution uniformity and heating efficiency on the mold cavity surface are considered as the major influencing factors on product quality and production efficiency. A multi-objective optimization model for the heating rods layout in the mold cavity plate is formulated to optimize temperature distribution uniformity and heating efficiency with respect to the heating rods layout. An application to a liquid crystal display TV panel is implemented successfully using a genetic algorithm.

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The Production of Plaster Molds with Patternless Process Technology

Archives of Foundry Engineering ◽

10.1515/afe-2015-0045 ◽

2015 ◽

Vol 15 (2) ◽

pp. 91-94 ◽

Cited By ~ 2

Author(s):

R. Pastirčák ◽

A. Sládek ◽

E. Kucharčíková

Keyword(s):

Surface Roughness ◽

Rapid Prototyping ◽

Feed Rate ◽

Manufacturing Process ◽

Dimensional Accuracy ◽

Mold Cavity ◽

Drying Process ◽

Process Technology ◽

Batch Production ◽

Gravity Casting

Abstract The work deals with technology Patternless process that combines 3 manufacturing process mold by using rapid prototyping technology, conventional sand formation and 3D milling. It's unconventional technology that has been developed to produce large-sized and heavyduty castings weighing up to several tons. It is used mainly in prototype and small batch production, because eliminating production of models. The work deals with the production of blocks for making molds of gypsum and gypsum drying process technology Thermomold. Into blocks, where were made cavities by milling were casted test castings from AlSi10MgMn alloy by gravity casting. At machining of the mold cavity was varied feed rate of tool of cemented carbide. Evaluated was the surface roughness of test castings, that was to 5 micrometers with feed from 900 to 1300 mm/min. The dimensional accuracy of castings was high at feed rate of 1000 and 1500 mm/min did not exceed 0.025 mm.

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Mold Cavity Surface Subdivision Method Based on Fuzzy Clustering for Edge Detection

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.430-432.808 ◽

2012 ◽

Vol 430-432 ◽

pp. 808-811

Author(s):

Zhi Xin Feng ◽

Yi Shu Zhai ◽

De Hua Miao

Keyword(s):

High Efficiency ◽

Boundary Detection ◽

Mold Cavity ◽

Cavity Surface ◽

Surface Boundary ◽

Detection Technology ◽

Surface Subdivision ◽

Fuzzy C Means Clustering ◽

System Of Parameters ◽

Cutting Direction

This paper presents a mold cavity surface subdivision method by using image boundary detection technology to realize high efficiency NC machining. From the new perspective of image processing, the method constructed an optimal cutting direction angle field image in the u-v system of parameters according to the relationship between maximum cutting bandwidth and cutting direction in the theory of iso-scallop height firstly, and then fuzzy c - means clustering method was applied for subdivision surface boundary detection. Experimental results demonstrate good performance of the proposed method in distinguishing and extracting boundary points of surface subdivision.

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