technique. Fig 4b (left): Die temperature profile taken at hottestmold/casting interface, (right): cross section of the die showing the influence water coolants just before the mold is opened. porosity free. ProCAST’s APM porosity results of automatization of simulation set-ups, for very capture these locations well, highlighting the early simulations or for more complex steps. highest risks of porosity as seen in the ear- lier porosity images. Fig 5b summarizes the Use of simulation is necessary to pre-validate shrinkage porosity comparison vs reality for the part quality achievement, to prevent costly all thee bosses at different steps of simulation die reworking, shorten development loop lead loop and confirms good alignment with reality. time and then start production with already pre-validated manufacturing parameters. >>> SUMMARY & CONCLUSION For instance, engineering to manufacturing handover can include piston position/velocity A sum-up table is made available in Table 1, curve, die cooling water T° and flows, shot cycle Fig 4a: Die cooling circuits; to classify the requirements and expected sequence and casting T°. results to be analyzed in each of these simula- tion steps used to develop and validate a pro- Each of these 4 development steps that were on this die were the way it was developed for duct design for manufacturing and die design applied on this housing are very important the initial 2011 die, and not based on the out- to manufacture high quality castings. It also to build a robust virtual casting part and die come of Step 3 (already explained in the Step highlights use of specific Macros designed for before manufacturing. Some results fields 3, Simulation results and analysis section). Renault processes and the HPDC Workflows seem to be relevant from the early and Moreover, in Step 1, Manufacturability check, it from the powerful GUI of ProCAST called the simple simulation steps such as part fill time was identified that the bosses and ribs around Visual Environment, reducing the set-up time and shrinkage porosity using APM module. this region are quite thick, making it difficult of different simulation steps to a few minutes. to get them cooled quicker, and drastically Finally, no more excuse not to use simulation reduce the porosity. A product design change Executing Step 1 at early stages of product during the whole part and die design, as they was the best solution analyzed at the begin- design, helps to identify the challenges of are convenient helping on achieving top quality, ning, but not considered for this paper, as it manufacturability, and provides time to low cost compared to physical trials loops and was not adopted in the 2011 die at the begin- iterate with the product designers for any leads to development loop time reduction. ning but considered later after exhausting requested design modification. Step 3 indi- different options from physical trials. cates the importance of simulation to posi- >>> FUTURE WORK tion the cooling perfectly aligned with the hot spots, else, some counterproductive results It is known that castings need to be produced >>> OBSERVATION: COMPARISON shall follow as shown in Step 4. with multiple process variations occurring on OF SIMULATION VS REALITY the shop floor. A very basic instance of this, Simulation is no more a digital expert domain is the alloy temperature variation in the fur- Fig 5a shows the 3 main zones (boss) which but is now open to wider personas of casting nace. These are not the only parameters that are mandatory for this part to be considered technicians and engineers due to this possibility can change during production. Hence the Fig 4c: Progressive filling starting from the sleeve filling and plunger movement in the sleeve to cavity filling. 40 • N°10 • AVRIL 2019