DEVELOPMENT OF A COOLING DIE USED IN PLASTIC PIPE PROCESSING: NUMERICAL AND EXPERIMENTAL ANALYSIS

Abstract

In this study, cooling of a plastic pipe-end during a hot-forming process that is one of the commonly used forming methods in plastic pipe production to get seal housing place (muff) was investigated numerically and experimentally. The aim of this study was development of a cooling die that has higher cooling performance and easier manufacturability. Cooling is supplied by the circulation of conditioned water in the channels located in the die in plastic production. The geometry of these channels and mass flow rate and temperature of the cooling water are the parameters affecting the quality of the formed region and process time. In the study, experimental analyses were performed, then numerical analyses were realised and validated with the experimental results for the existing die geometry. Continuity, momentum and energy equations were solved all together and heat transfer was investigated. After validating the model, a few different alternative die models were proposed and analysed to get an optimum which has highest cooling capacity and process ability. At the end of these studies, optimum alternative die geometry was determined. The channels in the suggested die were developed to increase the homogeneity of the cooling by changing the existing channel’s shape which can be produced by only longitudinal holes. A simple production method was also suggested for the new die to locate the channels following the circumference of the pipe, like conformal cooling channels. Additionally, aluminium material was also used to decrease the pipe temperature and die weight in the analyses. In conclusion, although cooling process time and mean temperature of the pipe-end were 30 secs and 43.9 ^oC respectively for the existing cooling die, these values were determined as 30 secs and 39.5 ^oC for the optimised aluminium die. If the temperature of the cooled pipe is taken as the same with the existing cooling, the cooling time decreases to around 20 secs for the suggested die. The weight of the die was reduced from 86.57 kg to 16.22 kg.

Keywords

• Plastic Pipe,Muff,Hot-forming,Cooling,Numerical and Experimental Analysi

References

1. [1] Crawford, R. J. (1998). Plastics engineering. Elsevier.
2. [2] Korff, W. G., Emery, V. V., & Bond, J. K. (1982). U.S. Patent No. 4,323,337. Washington, DC: U.S. Patent and Trademark Office.
3. [3] Tabanelli, G., & Altini, P. (2013). U.S. Patent No. 8,512,027. Washington, DC: U.S. Patent and Trademark Office.
4. [4] Matsumori, T., & Yamazaki, K. (2011). Design improvement of cooling channel layout for plastic injection moulding. Engineering Optimization, 43(8), 891-909.
5. [5] Park, S. J., & Kwon, T. H. (1998). Optimal cooling system design for the injection molding process. Polymer Engineering & Science, 38(9), 1450-1462.
6. [6] Hsu, F. H., Wang, K., Huang, C. T., & Chang, R. (2013). Investigation on conformal cooling system design in injection molding. Advances in Production Engineering & Management, 8(2), 107.
7. [7] Hassan, H., Regnier, N., Le Bot, C., & Defaye, G. (2010). 3D study of cooling system effect on the heat transfer during polymer injection molding. International Journal of Thermal Sciences, 49(1), 161-169.
8. [8] Rännar, L. E. (2008). On optimization of injection molding cooling.

9. [9] Xu, X., Sachs, E., & Allen, S. (2001). The design of conformal cooling channels in injection molding tooling. Polymer Engineering & Science, 41(7), 1265-1279.
10. [10] Altan, T., Lilly, B., & Yen, Y. C. (2001). Manufacturing of dies and molds. CIRP Annals, 50(2), 404-422.
11. [11] Li, C. L. (2001). A feature-based approach to injection mould cooling system design. Computer-Aided Design, 33(14), 1073-1090.
12. [12] Ferreira, J. C., & Mateus, A. (2003). Studies of rapid soft tooling with conformal cooling channels for plastic injection moulding. Journal of Materials Processing Technology, 142(2), 508-516.
13. [13] Dimla, D. E., Camilotto, M., & Miani, F. (2005). Design and optimisation of conformal cooling channels in injection moulding tools. Journal of Materials Processing Technology, 164, 1294-1300.
14. [14] Li, C. G., & Li, C. L. (2008). Plastic injection mould cooling system design by the configuration space method. Computer-Aided Design, 40(3), 334-349.
15. [15] Au, K. M., Yu, K. M., & Chiu, W. K. (2011). Visibility-based conformal cooling channel generation for rapid tooling. Computer-Aided Design, 43(4), 356-373.
16. [16] Wang, Y., Yu, K. M., Wang, C. C., & Zhang, Y. (2011). Automatic design of conformal cooling circuits for rapid tooling. Computer-Aided Design, 43(8), 1001-1010.
17. [17] Sánchez, R., Aisa, J., Martinez, A., & Mercado, D. (2012). On the relationship between cooling setup and warpage in injection molding. Measurement, 45(5), 1051-1056.
18. [18] Shayfull, Z., Sharif, S., Zain, A. M., Ghazali, M. F., & Saad, R. M. (2014). Potential of conformal cooling channels in rapid heat cycle molding: a review. Advances in Polymer Technology, 33(1).
19. [19] Wang, G., Zhao, G., & Wang, X. (2014). Development and evaluation of a new rapid mold heating and cooling method for rapid heat cycle molding. International Journal of Heat and Mass Transfer, 78, 99-111.
20. [20] Wang, G. L., Zhao, G. Q., & Wang, X. X. (2014). Heating/cooling channels design for an automotive interior part and its evaluation in rapid heat cycle molding. Materials & Design, 59, 310-322.
21. [21] Nian, S. C., Wu, C. Y., & Huang, M. S. (2015). Warpage control of thin-walled injection molding using local mold temperatures. International Communications in Heat and Mass Transfer, 61, 102-110.
22. [22] Hölker, R., Haase, M., Khalifa, N. B., & Tekkaya, A. E. (2015). Hot extrusion dies with conformal cooling channels produced by additive manufacturing. Materials Today: Proceedings, 2(10), 4838-4846.
23. [23] Becker, J. M. J., & Wits, W. W. (2015). Enabling lean design through computer aided synthesis: the injection moulding cooling case. Procedia CIRP, 37, 260-264.
24. [24] Wu, T., Jahan, S. A., Kumaar, P., Tovar, A., El-Mounayri, H., Zhang, Y., ... & Nalim, R. (2015). A framework for optimizing the design of injection molds with conformal cooling for additive manufacturing. Procedia Manufacturing, 1, 404-415.
25. [25] Vojnová, E. (2016). The benefits of a conforming cooling systems the molds in injection moulding process. Procedia Engineering, 149, 535-543.
26. [26] Rahim, S. Z. A., Sharif, S., Zain, A. M., Nasir, S. M., & Mohd Saad, R. (2016). Improving the quality and productivity of molded parts with a new design of conformal cooling channels for the injection molding process. Advances in Polymer Technology, 35(1).
27. [27] Jahan, S. A., & El-Mounayri, H. (2016). Optimal Conformal Cooling Channels in 3D Printed Dies for Plastic Injection Molding. Procedia Manufacturing, 5, 888-900.
28. [28] Behrens, B. A., Bouguecha, A., Vucetic, M., Bonhage, M., & Malik, I. Y. (2016). Numerical investigation for the design of a hot forging die with integrated cooling channels. Procedia Technology, 26, 51-58.
29. [29] Jahan, S. A., Wu, T., Zhang, Y., El-Mounayri, H., Tovar, A., Zhang, J., ... & Lee, W. H. (2016). Implementation of conformal cooling & topology optimization in 3D printed stainless steel porous structure injection molds. Procedia Manufacturing, 5, 901-915.
30. [30] Jahan, S. A., Wu, T., Zhang, Y., Zhang, J., Tovar, A., & Elmounayri, H. (2017). Thermo-mechanical design optimization of conformal cooling channels using design of experiments approach. Procedia Manufacturing, 10, 898-911.
31. [31] Venkatesh, G., & Kumar, Y. R. (2017). Thermal Analysis for Conformal Cooling Channel. Materials Today: Proceedings, 4(2), 2592-2598.
32. [32] Reddy, K. P., & Panitapu, B. (2017). High thermal conductivity mould insert materials for cooling time reduction in thermoplastic injection moulds. Materials Today: Proceedings, 4(2), 519-526.
33. [33] Park, H. S., & Dang, X. P. (2017). Development of a smart plastic injection mold with conformal cooling channels. Procedia Manufacturing, 10, 48-59.
34. [34] Wu, T., Jahan, S. A., Zhang, Y., Zhang, J., Elmounayri, H., & Tovar, A. (2017). Design optimization of plastic injection tooling for additive manufacturing. Procedia Manufacturing, 10, 923-934.
35. [35] Venkatesh, G., Kumar, Y. R., & Raghavendra, G. (2017). Comparison of Straight Line to Conformal Cooling Channel in Injection Molding. Materials Today: Proceedings, 4(2), 1167-1173.
36. [36] Everett, S. E., & Dubay, R. (2017). A sub-space artificial neural network for mold cooling in injection molding. Expert Systems with Applications, 79, 358-371.
37. [37] Pignon, B., Sobotka, V., Boyard, N., & Delaunay, D. (2018). Improvement of heat transfer analytical models for thermoplastic injection molding and comparison with experiments. International Journal of Heat and Mass Transfer, 118, 14-26.
38. [38] Mennig, G., & Stoeckhert, K. (Eds.). (2013). Mold-making handbook. Carl Hanser Verlag GmbH Co KG. [39] Fluent, A. N. S. Y. S. (2013). ANSYS Inc.
39. [40] Fluent, A. N. S. Y. S. (2013). Release 15.0. Theory Guide, November.