Optimization of Injection Molding Process by using different types of Conformal Cooling Channels

Srijan Kumar¹*, Santosh Kumar Mishra²

¹M.Tech. (Production Engineering), Department of Mechanical Engineering, Bhilai Institute of Technology, Durg, India.

²Department of Mechanical Engineering, Bhilai Institute of Technology, Durg, India.

*Corresponding Author E-mail: srijankumarshrivastava@gmail.com

ABSTRACT:

This paper objects to deliver a brief summary on different types of Conformal cooling channel designs available for injection molding process, Also, the conformal cooling channel plays very important role in plastic injection process of injection molding by improving its efficiency and quality thus, reducing the whole cycle time of production. A comparative study of different conformal cooling channels like Series and parallel Conformal cooling channel, square section conformal cooling channel (SSCCC), Spiral cooling channel, Scaffold conformal cooling channel, array of baffle conformal cooling channel, micro cooling channel and their effects on injection molding based manufacturing process are shown. Study related to the performance analysis of different conformal cooling channels is done by using “Autodesk moldflow Advisor”. This paper presents a succinct review of recent progress in Conformal cooling channels.

KEYWORDS: Injection Molding, Micro Channel, Scaffold based conformal cooling channel, array of baffles-based cooling channels, AutoDesk Moldflow Adviser.

INTRODUCTION:

Industry of Plastic is among the fastest growing industries in the world. Almost all the product that comes in use in our day-to-day life includes the usage of plastics and most of them can be made by using plastic injection molding method.

Plastic Injection molding technique is being widely used as a common manufacturing method for the fabrication of a wide range of complex shape products with precise dimensions at low cost. The phases of plastic injection molding consist of Filling phase, packing phase, cooling phase and ejection phase. Cooling phase is one of the most Predominant phases among the all-other phases because a considerable amount of time (e.g.,50-80%) Involved in the overall molding cycle is consumed in cooling phase so that part which is being molded can get hardened with the desired shape. To reduce the duration of cooling phase in injection molding cycle Conventional cooling channels are deployed with the mold. Conventional cooling channels are generally simple in shape fabricated by drilling holes in straight lines shown in Figure 1(a). Generally cooling phase duration depends upon the Geometry of the cooling channels that are being taken into use. The use of a cooling channel which is conventional permits a coolant, to circulate inside the injection mould and this eliminate the heat with the help of conduction. Straight drilled holes conventional cooling channel leads to longer cooling time and improper cooling all over the mold cavity due to which defects like warpage, scrap, differential shrinkage and sink mark arises. To eliminate above-mentioned problems Conformal Cooling Channels comes into existence. In simple words, conformal cooling channels are the channels which are compliance to the shape of the part shown in Figure 1(b). The main edge of conformal cooling channel was found that its cycle time is approximately 20% less than to that of Conventional cooling channels. Although the process to construct cooling channel with conformal architecture is more complex in comparison with Conventional cooling channel. As Direct Metal Laser for Sintering technique is taken into use to manufacture the inserts of injection mold. The merit of this system is the flexibility with which different cross-sectional shape conformal cooling channels like oval, rectangular, circular etc can be made nearer to the plastic part also in addition to this its cooling is more uniform which means less prone to defects. Furthermore, Direct Metal Laser for Sintering technique can also be taken into use to construct flow lines for coolants together with plastic part shape.

Factors affecting cooling efficiency of a cooling system are-

· Velocity of coolant

· Perimeter and diameter of cooling channel

· Distance among the channels and surface of cavity

· Distance among the channels

The designing and manufacturing process for polymeric parts of desirable properties through injection molding is expensive as it involves profound study together with repetitive alteration of actual tooling. Between the processes of making mold architecture the designing of mould concentrated additional geometry on the center is very intricate due to the presence of depression with projection.

In demand to construct architecture of a mould, there are several vital designing aspects which are to be taken into contemplation which are as follows

· Dimensions of the mould

· Design of the cavity

· Number of cavities

· Systems of runner

· Gating system

· Contraction

· Structure of Ejection

Figure1(a)- Cooling Channel Conventional in nature                               Figure1(b)- Cooling Channel Conformal in nature

1.1 Simulate and Model

The advancement in design Conformal Cooling Channels with the help of CAD is making progress swiftly in various applications such as i.e., casting, Blow mold, extrusion Hot in nature and Injection molding. Modern CAD software packages are very efficient in designing Intricate, Complicated and compact size conformal cooling channels, which significantly reduces the cooling time, defects associated to it and maintains the uniformity of cooling thus giving a proper desired shape as result.

Various CAD software packages such as Creo Parametric, AutoCAD, Rhinoceros 4.0, Solidworks are being taken into use to design Conformal Cooling Channels based on design of the part. ABAQUS and ANSYS are used quite often for analysis of thermal conditions, whereas Autodesk Moldflow Adviser, Moldex 3D and C- Mold are particularly developed for Conformal cooling channel analysis in dies. 

1.2 Various Proposed Constructions of Conformal Cooling Channels

On advanced CAD software packages, the Conformal Cooling Channel fabrication and design process for different complex parts became lot easier. Various authors for unvarying cooling and deduction of cooling time have evaluated the viability of various Conformal Cooling Channel structures. Various researchers using different experimental designs assessed the Advantages of different Conformal cooling channel structures for injection molding. Same is being shown in systematic way with their observed outcome in the following table-1 given below.

2. Table-1 Different types of simulation based conformal cooling channels and their details

S.No	Researcher	Type of cooling	Part material	Mold material	Parameters	Simulation Software/ Machine	Result
1.	Yu Wang a, ∗ , Wang^2. Base Paper: Y, Yu K-M, Wang CCL, Zhang Y^1.	Base Paper methodology Centroidal Voronoi Diagram based New methodology Spiral conformal Cooling Channel based	ABS-Toy Helmet Polypropylene (PP)- Mobile Phone	Steel P20	Melting temp: 230℃, channel dimension: [12 mm, coolant: 25℃ water	Moldflow	Spiral cooling channel is more efficient as compare to the Voronoi Diagram based cooling channel in the field of uniformity of temperature, attaining cooling time as well as in terms of heat transfer.
2.	Himanshu Gangber , S.K.Ganguly, Santosh Kumar Mishra^4. Base Paper- Muhammad,1 S. Kamran Afaq,1 Nizar,2 and Ahmad^3.	Base Paper methodology 1.Cooling Channels (Conventional)(CCC) 2.Cooling Channels (Series)(SCC) 3. Cooling Channels (Parallel conformal) (PCC) 4.Addittive cooling lines based cooling channel with conformal architecture” (CCAL) New Methodology 1.Straight micro cooling channel of 2mm dia. 2.Micro cooling channel of Spiral design of 2mm dia.	Polypropylene (PP) Purell HM671T (density 0.9 g/cm^3 , melt temperature 168℃, thermal conductivity 2.8 x10^-4 cal/sec cm℃ and heat capacity 0.9 cal/g ℃)	P20 steel	Temperature of mold (38.89℃), Melt temperature (225℃), time for injection .6912 and proper gate is fixed at the centre of the base.	Moldflow - The mold flow analysis is performed after assigning material to plastic part. Using these input parameter Fill + Pack + Warp + Cool analysis is performed.	The micro cooling channel (Straight)and Spiral micro cooling channels which are near to core and the cavity and designed with lower pitch gap and lower cooling channel dia are more efficient thus leading to a good quality of part with decreased cycle time, reduced warpage of part
3.	KM Au and KM Yu^5.	Scaffold type of CCC	Acrylonitrile butadiene styrene (ABS)	P20 steel, H13 steel, A2 steel	Cooling channel diameter: 8 mm, cooling pitch: 16 mm	Moldflow, COMSOS/ SolidWorks	Uniform heat distribution resulting an improved cooling in cavity of the mold due to its larger surface area present in scaffolding architecture-based cooling structure as compare to conventional cooling channel and Bended copper tube cooling channel
4.	A B M Saifullah, Masood and Sbarski^6.	Conventional straight cooling channel (CSCC) and Square shaped section conformal cooling channel (SSCCC)	Polypropylene (PP)	Steel	Melting temp: 230℃, channel dimension: [12 mm, coolant: 25℃ H2O	ANSYS moldflow plastic insight	Cooling time and the cycle time in Square profile conformal cooling channel (SSCCC) is measured to be 35% and 20% lesser respectively than the cycle time of Conventional straight cooling channel (CSCC).
5.	Park and Dang^7.	Straight drilled and cooling channel with array of baffles	Amoco 1046 (crystalline ), ABS 750	P20 steel	Melting temperature: 240℃, ejection temperature 93℃, melting temperature: 230C, ejection temperature: 90℃	Moldflow	Temperature change in Conformal Cooling channels with array of baffles have shown 49.41% improvement leading to more uniform cooling as compare to straight drilled conventional cooling channels
6.	Hamdy, Nicolas, Ce´dric Le Defaye^8.	Circular, square and rectangular cooling channels.	Hot polymer: polystyrene material	P20 steel	Inlet temp. of the Coolant fluid 30^oC injection stage time 4.2s Injected polymertemperature 220^oC cooling stage time 37.5s	Unspecified	Cooling channel containing the longest perimeter resulted the lowest cooling time
7.	Khurram, Ahmad Majdi, Rani, Vijay R. ^9	Circular cross section with profiled cross section.	Polystyrene	Epoxy mould with aluminium	Injection temp: 318^oC. Ejection temp: 358^oC. Injection time: 5.5 s. flow rate water: 4 l/min.	IM Machine based	The time occupied for the part to reach ejection temp of 35^oC by Circular cross section cooling channel is 983seconds and by Profiled cross-sectional cooling channel is 807seconds.
8.	Hearunyakij M, Sontikaew S and Sriprapai D^10	Circular cross section with fins	Polypropylene (PP) grade C705-44 NAH of DOW Company	Mold steel grade P20	Initial mold temperature: 35 °C Initial coolant temperature: 35 °C Coolant velocity: 60 cm3/sec Coolant type: Oil	Rhinoceros 4.0 Moldex 3D	Increasing the number of fins in cooling channels the average temperature of cavity surface was reduced drastically, also the heat flux up by 22.6% cooling time deducted by 6.5 seconds with increased rate of heat transfer
S.No	Researcher	Type of cooling	Part material	Mold material	Parameters	Simulation Software/ Machine	Result
9.	Au KM and Yu KM.^11	Multiconnected porous passageways	Plastic	Mold steel grade P20	Fluid (water) fall in pressure (Pa) Even decomposition (×10^6) Octree-based decomposition approach (×10^6) (a) at input 29.03, 4.49 (b) At output 2.57, 1.29	SolidWorks 2007 and 3D Quick Mould, COSMOS/ Flow	Unvarying temperature distribution amid the cooling passageways and the surface due to its conformal design towards mould surface geometry. Hence, leading to uniform cooling and lower formation of injection mould defects
10.	Au and Yu.^12	Variable Distance Conformal cooling channel	Plastic	Mold steel grade P20	MPI Cooling channel dia 08 mm Coolant: Water Coolant temp: 20 °C Coolant flow rate: 121/min Melt temp: 300 °C	Rhinoceros 3D 4.0, Moldflow advisor MPI3.1	Cycle time is reduced cooling time in Variable Distance Conformal cooling channel is (3.744 s) which is 0.33s lesser as compare to conformal cooling channel (4.079 s). Also, volumetric shrinkage Variable Distance Conformal cooling channel is (11.17%) which is 0.9% lower than to that of Conformal cooling channel (12.06%))

The paper by Yu Wang a et al ² S.No -1 table-1 gives the comparative study between the two Conformal Cooling channels in which first was generated by a Centroidal Voronoi Diagram based cooling system and second based on Spiral cooling channel based Conformal cooling channel. As per the details provided by author in paper that Voronoi diagram-based cooling circuits have complex connectivity the rate of flow for coolant and the temp are non-uniform nature thus increasing pumping costs for good efficacy of heat dissipation and uniformity of coolant and its temp. In addition to this the fabrication of such complex structure of cooling system the additive  based mfg. method Selective Laser Sintering (SLS) is used which is costly. So, their new approach of Spiral Cooling Channel came into existence by taking following things into consideration like the shape of cooling circuit should be more conformal to mold surface for uniform cooling effect which can only attained by reducing the coolant inlet and outlet temperature difference. Also, the heat transfer efficiency is taken into consideration because it is much higher in convection as compare to conduction which drastically increases turbulent flow².

In designing of Spiral conformal cooling channel for injection molding parameters such as runner system, coolant pressure drop, coolant composition, channel connections and its layout with 3D shapes are taken into consideration. Cooling channel axes in both the works Voronoi Diagram based as well as Spiral based were given for the employed surface that is an mold surface offset. Part surface model offset falling on mold upside is taken as employed surface for upper mold for development of channel².

3.1 Case Study-1 Simulation analysis on Toy Helmet

In first case researcher taken a toy helmet for molding with parameter, mold material, part material mentioned in table-1 S. No-1 and performed simulation in Autodesk Mold flow Adviser. The result drawn from simulation are shown in figure 2(a), (b). It’s clearly found that the chilling time deducted from 42.73 seconds to 37.91 seconds. Simulation also shows a uniform cooling in spiral cooling channel as compare to Voronoi based cooling channel. Also, there is drastic change in temperature difference As of Voronoi diagram-based cooling channel temperature difference was between 28.69℃ to 60.47℃ and for Spiral cooling channel its reduced to 26.90℃-53.10℃ range. Thus, giving clear evidence of improvement in Cooling efficiency. Reynold number and flow rates are better in spiral cooling channel as compare to Voronoi based cooling channel respectively thus improving heat transfer effectively. Also, the coolant temperature difference between inlet and outlet points is 2.2℃ for Voronoi diagram which is reduced to 0.82℃ in spiral cooling channel².

2(a) Voronoi Diagram-based cooling channels.                                     2(b) Spiral based cooling channels.

Figure 2. Cooling time required by Voronoi Diagram based cooling channel Vs Spiral cooling channel-based cooling channel for attaining ejection temperature from Plastic Part freezing temperature².

3.2 Case Study-2 Simulation analysis on Mobile phone

In second case researcher taken a cell phone for molding with parameter, mold material, part material mentioned in table-1 S. No-1 and performed simulation in Autodesk Mold flow Adviser. The simulation shows that to attain the same Reynolds number as spiral cooling channel attained at inlet that is Re= 5000, The pumping cost increased severely in Voronoi diagram-based cooling channel. Flow rate of 3.388lit/min required by Voronoi Diagram based cooling channel at inlet on the other side Spiral cooling channel requires only 1.694lit/min flow rate at inlet to achieve a same Reynolds number R_e=5000. Apart from this Reynolds number in Voronoi diagram-based cooling channel drops notably which results in non-turbulent flow and improper heat transfer. In addition to this it can be seen in figure 3(a) and (b) that the temp alteration amid the inlet and outlet temperature of the coolant is 2.32℃ for the Voronoi Diagram based cooling circuit, whereas for Spiral cooling channel it is only 0.39℃².

3(a) V-D-based cooling channels.                                             3(b) Spiral built cooling channels.

Figure 3. Temperature difference at inlet and outlet in Voronoi Diag. based cooling channel Vs Spiral built cooling channel².

The above results projects that Spiral-cooling channel is more efficient as compare to the Voronoi Diagram based cooling channel in the field of uniformity of temperature, attaining cooling time as well as in terms of heat transfer. However, the limitation of this method is that it will be problematic for parts with more complicated geometry and varying thickness due to which it requires optimization in cooling channels by rectifying the proper cycle time².

Himanshu Gangber et al⁴ investigated different types of cooling channels designed by Muhammad et al [3] namely Conventional cooling channel, CCC parallel , CCC series and CCC with cooling lines additive which was designed to cool down food container refer figure 4³.

Figure-4. 1. Conventional cooling channel³, 2. Series CCC³, 3. Parallel CCC³, 4.CCC with additive cooling lines³.

Himanshu Gangber et al⁴ also introduced an alternative design in which they designed various type of Cooling channels which are Straight built Micro cooling channel of 2mm dia, Spiral built micro cooling channel of 2mm dia. As in the proposed cooling channel design “Micro Cooling Channel” is mentioned which defines about the cooling channel size which is about 1mm-2mm. In previous analysis its proven that micro channel cooling is more complying to theoretical minimum cooling time as compare to standard cooling channel which was used in base paper of Muhammad et al³ which is more conforming to the adjusted theoretical value. This phenomenon of higher efficiency in Micro cooling channel as compare to standard cooling channel is caused due to the less diameter of channels and minimal pitch gap present in micro cooling channel in comparison with standard cooling channel which allows the complete flow of coolant close to the part surface without effecting the mold strength. Thus, allowing them to provide a micro built channel as near as conceivable to the surfaces of the void and the core⁴.

Simulate and Analyse

In base research paper, Muhammad et al³ taken Straight drilled channels as Conventional cooling channel (CCC). In second design he made conformal cooling channels attached in series to each other named it as Series conformal cooling channel (SCC).  However, in third design researcher attached cooling channels in parallel conformal in nature to each other and termed it as Parallel conformal cooling channel (PCC) and finally in last design Additive lines for cooling were added with conformal cooling channel named it as Conformal cooling channel with additive cooling line (CCAL). In new approach Himanshu Gangber et al ⁴ taken the same food container with exactly the same dimension as designed in base paper Cycle Time Reduction by Selection of vigorous Cooling Channel architecture by Muhammad et al³. In addition to this part material, mold material, and other parameters were also taken same as mentioned in base paper. The parameters, mold material and part material are stated in Table-1. S. No-2. The simulation was performed in Autodesk Moldflow Adviser. The result drawn from the simulation analysis depicts (Conventional) that Micro cooling channel takes less time to reach ejection temp as compare to cooling channel  (CCC), conformal cooling channels (Series) (SCC), conformal cooling channels (Parallel) (PCC) and Conformal cooling channel with additive cooling lines can be seen in figure 5⁴.

Figure.5. Time taken to Reach Ejection Temperature (a) CCC⁴ (b) SCC⁴ (c) PCC⁴ (d) CCAL⁴.

In addition to this Micro cooling channels have lower temperature variance and also it takes lesser time for attaining the part ejection temperature as compare to (CCC), (SCC), (PCC) and Conformal cooling channel with additive cooling lines (CCAL) ⁴. Similarly, Lower volumetric shrinkage see figure 6 evident in Micro cooling channels in comparison to (CCC), Series conformal cooling channels (SCC), (PCC), (CCAL) leading to lower part warpage ⁴.

Figure.6. Volumetric Shrinkage at ejection (a) CCC⁴ (b) SCC⁴ (c) PCC⁴ (d) CCAL⁴.

The above results convey that The Straight MCC and Spiral MCC which are near to core and the cavity and designed with lower pitch gap and lower cooling channel dia are more efficient thus leading to a better part quality with decreased cycle time, reduced warpage of the part.⁴

Au and Yu⁵ proposed a Scaffolding Construction design for conformal cooling channel see figure 7(b). For mold materials, part material and other parameters in analysis refer table-1 S. No-3. In this paper researcher compared condition of mold cavity firstly by applying Scaffolding cooling system, then by removing Scaffolding cooling system refer figure 7(a). The study and analysis were done by using Moldflow plastic insight 3.1. The Simulation analysis represented that the porous scaffolded architecture-based cooling system resulted uniform heat distribution thus providing an improved cooling in cavity of the mold because of its larger surface area present in scaffolding architecture-based cooling system as compare to Straight conventional drilled cooling channel and Bended copper pipe cooling channel⁵.

Figure 7(a) Conventional drilled Straight hole cooling channel⁵ (b) Scaffolded cooling channel⁵

Saifullah et al⁶ using Pro/mold design module of the Pro Engineer system made a mold design then by using CNC they made the Square section conformal cooling channel (SSCCC) around the cavity of length 12mm figure Then moldflow plastic insight software is used for part sequential analysis of flow+cool+wrap type. The mold material and part material and other parameters used are mentioned in table-1 S.no-4. The comparison of Square segment conformal cooling channel (SSCCC) was done with straight conventional cooling channel (CSCC) which have a diameter of 12mm see figure 8(b). Comparative study shows that (SSCCC) maintain the better temperature distribution with lower part freezing time as compare to (CSCC). The time taken to freeze by to (CSCC) is between 0.46seconds to 93.7 seconds on the other hand Square section conformal cooling channel (SSCCC) takes 0.3 seconds to 87.15 seconds to freeze. Also, cooling time of part was observed to be 24 seconds excluding top areas, whereas cooling time of Square section conformal cooling channel (SSCCC) is less than 20 seconds. Therefore, the result shows Cooling time is reduced by 35% in (SSCCC) as compare to (CSCC). Also, the cycle time in (SSCCC) is measured to be 20% lesser than the cycle time of Conventional straight cooling channel (CSCC). Refer 8(a) for Cooling time and freezing time analysis in CSCC and figure 8(b) for Cooling time and freezing time analysis in SSCCC⁶.

Figure 8(a) Cooling time and freezing time analysis in CSCC⁶. Figure 8(b) Cooling time and freezing time analysis in SSCCC⁶.

Park and Dang ⁷ investigated array of baffles based Conformal cooling channel see figure 9 for the plastic mold injection in the grill of radiator with part material, mold material, and other parameters mentioned in table-1 S.no 5. Efficiency of baffle based conformal cooling channel were assessed using moldflow adviser and compared with drilled cooling channels straight in nature. As a result, it is found that temperature change in Conformal Cooling channels with array of baffles have shown 49.41% improvement leading to more unvarying cooling as compare to drilled Straight conventional cooling channel⁷.

Figure 9. baffles-based cooling channels⁷.

Hamdy Hassan et al⁸ compared the output efficiency of square, rectangular and circular cooling channels. These cooling channels are of different perimeter but they all contains same surface area. The result disclosed that the cooling channel containing the longest perimeter resulted the lowest cooling time⁸.

Fig. 10. The dissimilarity of the max temp alteration inside the product at the finish of cooling phase with injection molding order at several chilling channels position⁸.

Altaf et al.⁹ examined the conformal cooling channel structure by linking profiled cross segment and circular segment. Epoxywas used with aluminium in construction of mold. The outcome of his investigation illustrates that cross-sectional change in shape varies the cooling time due to the variation in hydraulic diameter and its perimeter. The cooling channel perimeter increases whenever diameter of the cooling channel is increased in conventional cooling system. According to his techniques the time elapsed for the part for eject temperature of 35^oC by Circular cross section cooling channel is 983seconds and by Profiled cross-sectional cooling channel is 807seconds⁹.

Figure 11. CCCC and PCCC mould cavities^9.

Figure 12. Cut away sections⁹

Figure 13. Chilling time comparision⁹

In this method because of the mold stiffness it becomes important to increase the distance amid the surface of the crater and the channel. Hereafter, the efficiency of cooling channel falls due to the increased heat transmission distance between molten plastic and coolant. In order to increase the efficiency of heat conviction fin - a surface extension has been taken into use in radiators, heat exchangers and in electrical equipment. The objective of this method is to increase the interaction surface area between the object and the fluid.

Manat Hearunyakij et al.¹⁰ research work includes fin concept for increasing the efficacy of conformal chilling systems in injection molding. In their research work circular section with fins are deployed as cooling channels. Effect on cooling time and cooling efficiency of varying number of fins was examined by Plastic flow analysis and Simulation software Moldex 3D. The outcome of the simulation revealed that cooling time is cut by 6.5 seconds for the 7-fin cooling channel as related to the circular cross-section cooling channel Shown in figure 14. Also, there is increment of 22.6% in heat flux accompanied with significant improvement in Coolant rate and rate of heat transmission from liquefied plastic to coolant shown in figure 15(a), (c). The result also disclosed that on increasing the number of fins in cooling channels the average temperature of cavity surface was reduced drastically shown in Figure15(b)¹⁰.

                            Figure 14(a).                                                                          Figure 14(b).

Fig. 14 Mold temperature distribution in (a) CC section Vs (b)7- fin circular cross-section¹⁰.

                            Figure 15(a).                                                                                  Figure 15(b). Figure 15(c).

Fig.15 (a)Cooling heat flux and cross section¹⁰ (b) Part average temperature¹⁰ and cross section (c) Cooling time and coolant rate¹⁰.

Au KM and YuKM.¹¹ proposed an alternative designing technique with multi-connected spongy cooling passageway. In this method, surface cooling representative (quasi-2D area) is used in place of existing conventional cooling channel, which leads to more uniform cooling performance. By the help of the spatial computed cell decomposition and the skeleton shaped within the mould plate model by using duality relationship between the primal cubelike cells and double edges a multiconnected porous passageways are generated within the plate. The flow of coolant from inlet to outlet inside this multiconnected porous passageways have multiple paths. The viability of the cooling and performance of fluid flow by uniform decomposition technique and octree-based decomposition technique. are evaluated by Computational Fluid Dynamics Analysis. From the CFD analysis it was found that the even deposition technique delivers a uniform temperature distribution between the cooling passageways and the surface due to its conformal design towards mould surface geometry. Hence, leading to uniform cooling and lower formation of injection mould defects shown in figure 16 ¹¹.

Figure 16. Surface temp from the passageways amid, (a) undeviating disintegration technique¹¹ and (b) octree-decay technique¹¹.

Au KM and Yu KM¹² in another research work proposed a modification in distance between the Conformal cooling channel and its mold crater (or central) surface in the cooling channel design named it as Distance  variable Conformal cooling channel (VDCCC) shown in figure 17. The technique can neutralize the upsurge of coolant temperature from inlet of the coolant to outlet of the coolant by transferring more heat from mold surface to (VDCCC) near the coolant outlet. Test performed in MPI analysis (Cool and flow Analysis) shown result that, cycle time is reduced, the maximum temperature of the part in Variable Distance Conformal cooling channel is (37.19°C) which is lower than to that of Conformal cooling channel (40.39 °C) by 3.2^oC shown in figure 28. Cooling time in Variable Distance Conformal cooling channel is (3.744 s) which is 0.33 s lesser as compare to conformal cooling channel (4.079 s). Also, volumetric shrinkage Variable Distance Conformal cooling channel is (11.17%) which is 0.9% lower than to that of Conformal cooling channel (12.06%)) shown in figure 29 ¹².

Fig 17.CCC- Conventional and variable  ¹²

Fig. 18 Extreme part temp, °C, (a) CCC¹² and (b) VDCCC¹²

Fig. 19 Shrinkage Volumetric, %, (a)CCC¹² and (b) VDCCC¹²

4. CONCLUSION:

In this review paper, the conclusions based on different research papers and their instance study are debated. In future Conformal cooling channel may become a standardized system in design of cooling channel circuits. After an in-depth study of available published research, it is proved that Conformal cooling channel provides quicker and more uniform cooling effect over conventional cooling channels which will definitely improve quality of injection moulded parts and productivity by reducing production cycle time and defects like sink mark, part warpage, scrap and differential shrinkage.

5. REFERENCES:

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2. Yu Wang a,∗ , Kai-Min Yua , Charlie C.L. (2015). Wang Spiral and conformal cooling in plastic injection molding. J. Comput. Aided Des. 63C (2015) 1–11 https://doi.org/10.1016/j.cad.2014.11.012

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4. Himanshu Gangber , S.K.Ganguly, Santosh Kumar Mishra. (2017). Modeling and Analysis of Micro Cooling Channel for Plastics Injection Mould by using Moldflow Adviser. 2017. Volume 7 Issue No.7

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10. Hearunyakij M, Sontikaew S and Sriprapai D. (2014) Improvement in the cooling performance of conformal mold cooling by using fin concept. Int J Min Metall Mech Eng 2014; 2: 41–46.

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Received on 30.07.2022            Accepted on 26.08.2022

©A&V Publications all right reserved

Research J. Engineering and Tech. 2022; 13(2):47-60.

DOI: 10.52711/2321-581X.2022.00006