SLM tooling for die casting with conformal cooling channels

Abstract

The paper reports an experimental study of die-casting dies with conformal cooling fabricated by direct-metal additive techniques. The main objective is to compare the benefits and limitations of the application to what has been widely discussed in literature in the context of plastics injection molding.Selective laser melting was used to fabricate an impression block with conformal cooling channels, designed according to part geometry with the aid of process simulation. The tool was used in the manufacture of sample batches of zinc alloy castings, after being fitted on an existing die in place of a machined impression block with conventional straight-line cooling channels. Different combinations of process parameters were tested to exploit the improved performance of the cooling system. Test results show that conformal cooling improves the surface finish of castings due to a reduced need of spray cooling, which is allowed by a higher and more uniform cooling rate. Secondary benefits include reduction of cycle time and shrinkage porosity. KeywordsSelective laser melting; rapid tooling; die casting; conformal cooling; spray cooling; surface finish. 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 1 Title pageClick here to download Manuscript: titlepage.doc Click here to view linked References 1 2 3 4 5 6 7 8 SLM tooling for die casting with conformal cooling channels AbstractThe paper reports an experimental study of die-casting dies with conformal cooling fabricated by direct-metal additive techniques. The main objective is to compare the benefits and limitations of the application to what has been widely discussed in literature in the context of plastics injection molding.Selective laser melting was used to fabricate an impression block with conformal cooling channels, designed according to part geometry with the aid of process simulation. The tool was used in the manufacture of sample batches of zinc alloy castings, after being fitted on an existing die in place of a machined impression block with conventional straight-line cooling channels. Different combinations of process parameters were tested to exploit the improved performance of the cooling system. Test results show that conformal cooling improves the surface finish of castings due to a reduced need of spray cooling, which is allowed by a higher and more uniform cooling rate. Secondary benefits include reduction of cycle time and shrinkage porosity.

Additive manufacturing–assisted conformal cooling channels in mold manufacturing processes

“…Hybrid construction of casting die. 40 RP technique could replace conventional manufacturing for complicated structured CCC which improves quality and productivity. In this field, the main focus is based on simulation work; still, more research is required for fabrication of mold with CCC.…”

“…Secondary benefits include reduction of cycle time and shrinkage porosity. Armillotta et al 40 fabricated casting die with CCC by hybrid method half portion with CNC and half portion with SLM ( Figure 19). …”

Additive Manufacturing for Enhanced Cooling in Moulds for Casting

“…It is therefore a suitable process for making complex parts, especially parts with complex internal shapes. One benefit of using additive manufacturing in casting dies is the possibility to create conformal cooling channels that follows the geometry of the cast part [2]. The technology is already used in the making of tools in the plastic injection moulding industry [3,4], but the use of additive manufacturing in the making of dies for low pressure die casting is still limited.…”

Cold flow defects in zinc die casting: prevention criteria using simulation and experimental investigations

“…The optimal size and location of the runners and gates has been investigated through rules [44], predictive models [45], and CADbased procedures [46,47]. Internal cooling systems have been optimized using simulations and experimental tests for different design issues, including the heat transfer coefficient between the die steel and the cooling medium [48], size of the channel sections [49], use of non-circular and variable-size channels [50], use of high-conductivity die materials [51], and design of conformal channels in the tool inserts [52]. External cooling has been studied using the temperature and thermal flow measurements of the heated specimens in hot-worked steel [53] or a heat flux sensor [54] to identify operating windows of the die surface temperature and the die spray parameters.…”