Cooling simulation of conformal cooling injection mould insert produced by hybrid manufacturing

Injection moulding is one the most familiar processes for manufacturing of plastic parts by injecting molten thermoplastic polymers into a metallic mould. The cycle time of this process consists of the phases of injection, packing, cooling, and ejection of the final product. Shortening of cycle time is a key consideration to increase productivity. Therefore, in this manuscript the adoption of additively manufactured mould inserts with conformal cooling channels by means of selective laser melting (SLM) with the aim to reduce process cycles is presented. The design and manufacture of a mould insert with conformal cooling channels for producing pressure fitting thermoplastic parts is described. Numerical analysis of the injection process and simulation of shape distortions after SLM were conducted providing useful results for the design and manufacture of the mould insert. The results of the numerical analyses are compared with experimental 3D geometrical data of the additively manufactured mould insert. Temperature measurements during the real injection moulding process demonstrating promising findings. The adoption of the introduced method for the series production of injection moulded thermoplastics proves a shortening of cycle times of up to 32% and a final product shape quality improvement of up to 77% when using mould inserts with conformal cooling channels over the conventional mould inserts.

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Variable Radius Conformal Cooling Channel for Rapid Tool

Materials Science Forum ◽

10.4028/www.scientific.net/msf.532-533.520 ◽

2006 ◽

Vol 532-533 ◽

pp. 520-523 ◽

Cited By ~ 5

Author(s):

Kin Man Au ◽

Kai Ming Yu

Keyword(s):

Cooling System ◽

Solid Freeform Fabrication ◽

Flow Analysis ◽

Cooling Channel ◽

Conformal Cooling Channel ◽

Mould Insert ◽

Conformal Cooling ◽

Variable Radius ◽

Plastic Injection Mould ◽

Rapid Tool

The cooling system of a plastic injection mould is important as it affects the quality and productivity of the polymeric components or assemblies. Contemporary cooling channel design is confined to simple configurations of straight-drilled coolant passageway around the mould insert. Undesirable defects resulted during injection moulding, such as warpage, are inevitable. The application of rapid tool (RT) based on solid freeform fabrication (SFF) technologies with conformal cooling channel (CCC) design has provided a profound opportunity in quality improvement of polymeric components. In this study, a novel design of variable radius conformal cooling channel (VRCCC) is proposed to achieve better uniform cooling performance. Thermal-FEA and melt flow analysis are used to validate the method.

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Manufacture of Production Quality Injection Mold Tools Using SLS and HSM

ASME 2007 International Manufacturing Science and Engineering Conference ◽

10.1115/msec2007-31030 ◽

2007 ◽

Cited By ~ 1

Author(s):

C. M. Taylor ◽

I. P. Ilyas ◽

K. W. Dalgarno ◽

J. Gosden

Keyword(s):

Case Studies ◽

Rapid Manufacturing ◽

Injection Mold ◽

Metal Composite ◽

Injection Mould ◽

Conformal Cooling ◽

Cooling Channels ◽

Conformal Cooling Channels ◽

Near Net Shape ◽

The Impact

The use of a rapid manufacturing method to create injection mould tools offers the opportunity to create conformal cooling channels in the core/cavity inserts. Conformal cooling channels allow for better thermal management of the injection mold tool through the cycle, with the potential to reduce cycle times and/or improve product quality. However, currently available rapid manufacturing methods do not deliver the levels of accuracy and surface finish required to meet typical injection mould tool specifications. This paper reports on a hybrid approach to developing the mold inserts, which uses the rapid manufacturing process of indirect selective laser sintering (SLS), using the 3D Systems LaserForm process, to create a near net shape insert with conformal cooling channels, and then produces the net shape inserts by using high speed machining (HSM) as a finishing process. This approach to injection mold tool development has been tested through three industrial case studies. In each study existing injection mold inserts have been redesigned to give a conformally cooled tool. These have then been manufactured to near net shape in a steel/bronze metal composite through indirect SLS, and finished to production specification using HSM, EDM and polishing. Within the case studies the main aim has been to improve productivity, and the inserts have been evaluated in industrial trials in order to assess their performance in terms of cycle time, energy usage, durability and quality. The results show that significant productivity improvements and energy use reductions in injection molding are possible through the implementation of conformal cooling. Consistency of part quality and material durability have been assessed through extended molding trials, and in some cases there is a clear economic benefit to using the inserts. However, the importance of up front modelling to understand the impact of conformal cooling channels, the need for careful planning in manufacture to ensure that the required internal geometry is created, and the need for multiple representations of the required geometry to inform the different stages of the manufacture process are highlighted.

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Manufacture of production injection mould tooling incorporating conformal cooling channels via indirect selective laser sintering

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1243/0954405011519042 ◽

2001 ◽

Vol 215 (10) ◽

pp. 1323-1332 ◽

Cited By ~ 25

Author(s):

K W Dalgarno ◽

T D Stewart

Keyword(s):

Selective Laser Sintering ◽

Laser Sintering ◽

Injection Mould ◽

Conformal Cooling ◽

Cooling Channels ◽

Conformal Cooling Channels

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Turbulators for Temperature Control of Injection Moulding

International Polymer Science and Technology ◽

10.1177/0307174x1704400201 ◽

2017 ◽

Vol 44 (2) ◽

pp. 1-8

Author(s):

C. Hopmann ◽

P. Nikoleizig ◽

H. Dornebusch

Keyword(s):

Fluid Dynamic ◽

Heat Removal ◽

Major Influence ◽

Cooling Channel ◽

Injection Mould ◽

Mould Insert ◽

Dynamic Simulations ◽

Channel System ◽

Effect Analysis ◽

Successful Production

The design of a cooling channel system in an injection mould is key to successful production. Locally controlled heat removal is targeted by introducing disturbances inside the cooling channel using so called turbulators. Computational fluid dynamic simulations show different levels of heat removal depending on the shape and configuration of the turbulators, but also an increased pressure drop. Suitable turbulators are then introduced into the cooling channel of an injection mould insert. Within the scope of a design of experiments, no significant influence of the turbulators can be identified with regard to part warpage. However, an effect analysis indicates that the temperature of the thermal fluid has a major influence if using turbulators and that solidification is more homogeneous.

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