scholarly journals Application of New Triple Hook-Shaped Conformal Cooling Channels for Cores and Sliders in Injection Molding to Reduce Residual Stress and Warping in Complex Plastic Optical Parts

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2944
Author(s):  
Abelardo Torres-Alba ◽  
Jorge Manuel Mercado-Colmenero ◽  
Juan de Dios Caballero-Garcia ◽  
Cristina Martin-Doñate
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Cooling System ◽  
Plastic Part ◽  
Correct Operation ◽  
Conformal Cooling ◽  
Cooling Channels ◽  
Geometric Conditions ◽  
Optical Part ◽  
Conformal Cooling Channels

The paper presents a new design of a triple hook-shaped conformal cooling channels for application in optical parts of great thickness, deep cores, and high dimensional and optical requirements. In these cases, the small dimensions of the core and the high requirements regarding warping and residual stresses prevent the use of traditional and standard conformal cooling channels. The research combines the use of a new triple hook-shaped conformal cooling system with the use of three independent conformal cooling sub-systems adapted to the complex geometric conditions of the sliders that completely surround the optical part under study. Finally, the new proposed conformal cooling design is complemented with a small insert manufactured with a new Fastcool material located in the internal area of the optical part beside the optical facets. A transient numerical analysis validates the set of improvements of the new proposed conformal cooling system presented. The results show an upgrade in thermal efficiency of 267.10% in comparison with the traditional solution. The increase in uniformity in the temperature gradient of the surface of the plastic part causes an enhancement in the field of displacement and in the map of residual stresses reducing the total maximum displacements by 36.343% and the Von—Mises maximum residual stress by 69.280% in comparison with the results obtained for the traditional cooling system. Additionally, the new design of cooling presented in this paper reduces the cycle time of the plastic part under study by 32.61%, compared to the traditional cooling geometry. This fact causes a very high economic and energy saving in line with the sustainability of a green mold. The improvement obtained in the technological parameters will make it possible to achieve the optical and functional requirements established for the correct operation of complex optical parts, where it is not possible to use traditional cooling channels or standard conformal cooling layouts.

Optimum Cooling Channels Design and Thermal Analysis of an Injection Moulded Plastic Part Mould

2007 ◽  
Vol 561-565 ◽  
pp. 1999-2002 ◽  
Author(s):  
Abul B.M. Saifullah ◽  
Syed H. Masood
Keyword(s):  
Cooling Time ◽  
Free Form ◽  
Cooling Channel ◽  
Channel Design ◽  
Conformal Cooling Channel ◽  
Plastic Part ◽  
Element Analysis ◽  
Conformal Cooling ◽  
Cooling Channels ◽  
Conformal Cooling Channels

Cooling channel design is important in mould designs to achieve shorter cycles, dimensional stability and reduced part stresses. Traditionally, cooling channels have been machined into mould components to avoid interference with the ejection system, coring, cavity and other mould details. Over the years straight drilled cooling channels have given away, in part, to conformal cooling technique often using free form fabrication techniques. This paper presents a study of optimised mould design with conformal cooling channel using finite element analysis. Various configurations of conformal cooling channels have been developed. The part cooling time using the conformal cooling channels and the straight cooling channels in the mould are computed using the Pro/Mechanica Thermal FEA software. Results are presented based on temperature distribution and cooling time using steady state and transient analysis conditions. The results show a reduction in cycle time for the plastic part with conformal cooling channel design.

scholarly journals Use of Maraging Steel 1.2709 for Implementing Parts of Pressure Mold Devices with Conformal Cooling System

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5533
Author(s):  
Jarosław Piekło ◽  
Aldona Garbacz-Klempka
Keyword(s):  
Cooling System ◽  
Casting Machine ◽  
Steel Powder ◽  
Experimental Tests ◽  
Test Material ◽  
Conformal Cooling ◽  
Temperature Changes ◽  
Cooling Channels ◽  
Conformal Cooling Channels ◽  
Conventional Solution

In this paper, we present the results of experimental tests and numerical calculations for parts of foundry mold devices made by selective laser melting (SLM). The main aim of this research was to compare the heat conduction efficiency of the conformal and the traditional channel arrangement. The infusion spreader with a conformal channel arrangement and the test material were made with an M2 Concept Laser Cusing machine using 1.2709 steel powder. Temperature changes in the spreaders were compared between conventional and conformal cooling channels using finite element method (FEM) calculations. The position of the so-called “thermal equilibrium isotherm” was determined for both sprue spreaders, which separate the area of the mold with a constant temperature from the zone of cyclic temperature changes. The components of the sprue spreaders in a stress state caused by temperature changes during the operation of the pressure machine were determined using the FEM model. It was found that the cooling system shortened the time of solidification and cooling of the alloy. Based on the analysis of the strength test results and the fracture surface of the samples, the relationship between heat treatment parameters and the strength, hardness, and elongation of the tested material was determined. The sprue spreaders were installed under a pressure machine and tested under production conditions. The use of a sprue spreader with a conformal cooling system shortened the time of a single cycle of the casting machine compared to the conventional solution.

scholarly journals A New Conformal Cooling System for Plastic Collimators Based on the Use of Complex Geometries and Optimization of Temperature Profiles

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2744
Author(s):  
Jorge Manuel Mercado-Colmenero ◽  
Abelardo Torres-Alba ◽  
Javier Catalan-Requena ◽  
Cristina Martin-Doñate
Keyword(s):  
Thermal Performance ◽  
Cycle Time ◽  
Cooling System ◽  
Plastic Material ◽  
Dynamic Performance ◽  
Conformal Cooling ◽  
Cooling Channels ◽  
Optical Part ◽  
Part Surface ◽  
Plastic Parts

The paper presents a new design of conformal cooling channels, for application in collimator-type optical plastic parts. The conformal channels that are presented exceed the thermal and dynamic performance of traditional and standard conformal channels, since they implement new sections of complex topology, capable of meeting the high geometric and functional specifications of the optical part, as well as the technological requirements of the additive manufacturing of the mold cavities. In order to evaluate the improvement and efficiency of the thermal performance of the solution presented, a transient numerical analysis of the cooling phase has been carried out, comparing the traditional cooling with the new geometry that is proposed. The evolution of the temperature profile versus the thickness of the part in the collimating core with greater thickness and temperature, has been evaluated in a transient mode. The analysis of the thermal profiles, the calculation of the integral mean ejection temperature at each time of the transient analysis, and the use of the Fourier formula, show great improvement in the cycle time in comparison with the traditional cooling. The application of the new conformal design reduces the manufacturing cycle time of the collimator part by 10 s, with this value being 13% of the total manufacturing cycle of the plastic part. As a further improvement, the use of the new cooling system reduces the amount of thickness in the collimator core, which is above the ejection temperature of the plastic material. The improvement in the thermal performance of the design of the parametric cooling channels that are presented not only has a significant reduction in the cycle time, but also improves the uniformity in the temperature map of the collimating part surface, the displacement field, and the stresses that are associated with the temperature gradient on the surface of the optical part.

scholarly journals A Hybrid Cooling Model Based on the Use of Newly Designed Fluted Conformal Cooling Channels and Fastcool Inserts for Green Molds

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3115
Author(s):  
Abelardo Torres-Alba ◽  
Jorge Manuel Mercado-Colmenero ◽  
Juan De Dios Caballero-Garcia ◽  
Cristina Martin-Doñate
Keyword(s):  
Cooling Channel ◽  
Conformal Cooling Channel ◽  
Plastic Part ◽  
Conformal Cooling ◽  
Thermal Exchange ◽  
Cooling Channels ◽  
Hybrid Cooling ◽  
Conformal Cooling Channels ◽  
Industrial Part ◽  
Cooling Model

The paper presents a hybrid cooling model based on the use of newly designed fluted conformal cooling channels in combination with inserts manufactured with Fastcool material. The hybrid cooling design was applied to an industrial part with complex geometry, high rates of thickness, and deep internal concavities. The geometry of the industrial part, besides the ejection system requirements of the mold, makes it impossible to cool it adequately using traditional or conformal standard methods. The addition of helical flutes in the circular conformal cooling channel surfaces generates a high number of vortexes and turbulences in the coolant flow, fostering the thermal exchange between the flow and the plastic part. The use of a Fastcool insert allows an optimal transfer of the heat flow in the slender core of the plastic part. An additional conformal cooling channel layout was required, not for the cooling of the plastic part, but for cooling the Fastcool insert, improving the thermal exchange between the Fastcool insert and the coolant flow. In this way, it is possible to maintain a constant heat exchange throughout the manufacturing cycle of the plastic part. A transient numerical analysis validated the improvements of the hybrid design presented, obtaining reductions in cycle time for the analyzed part by 27.442% in comparison with traditional cooling systems. The design of the 1 mm helical fluted conformal cooling channels and the use of the Fastcool insert cooled by a conformal cooling channel improves by 4334.9% the thermal exchange between the cooling elements and the plastic part. Additionally, it improves by 51.666% the uniformity and the gradient of the temperature map in comparison with the traditional cooling solution. The results obtained in this paper are in line with the sustainability criteria of green molds, centered on reducing the cycle time and improving the quality of the complex molded parts.

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