Simulation and Prototyping as an aid to the design and development of new Investment Casting components

Simulation and prototyping processes are fundamental to efficiently manufacture final parts, reducing costs and meeting customer’s technical requirements. In this article we explain key technical aspects of both processes.

Simulation in the design phase to ensure efficient production and early problem solving.

At Ecrimesa Group we have two simulation softwares: MAGMA and INSPIRECAST. They have been adapted by us – with the support of the Technological Center of Components and the University of Cantabria through R&D projects – to the physical properties of our ceramic shell. Simulation allows us to accurately replicate the reality we will encounter in production and optimize the final manufacturing results.

In the design phase, the simulation of the “unit” part (without yet defining the cluster/assembly) can be used to predict possible design problems and reduce costs, for example, by adapting the initial design to the particularities of the Investment Casting technology. This is of great help, both for our customers and for the technical-commercial team, in the initial exchange of ideas and proposals with the customer’s designers. Simulation allows to bring the design closer to the needs of the technology in a primary phase of the negotiations, and also, to arrive at a final design that allows to manufacture in a more efficient way a final part, reducing costs.

Let’s look at an example. This “HOTSPOT” includes the 3D of the design, the physical properties of the steel and those of our ceramics, as well as the calculated casting temperature conditions, among other aspects. All this information will help us to identify the areas that will store more heat and the isolated areas that will require extra attacks or “gates”, and will guide us to give the casting more heat.
This simulation process is quite fast and can be done in hours, so that several iterations can be carried out, if necessary.

After the simulation of the unit part, the next step is to simulate the complete cluster. Here we can simulate several options, obtaining the porosity prediction, which allows us to reduce sample phase testing, and therefore, the development time and associated costs.
This simulation is more laborious, as it requires drawing the different 3D of the cluster with the parts, and also involves additional design time for our Technical Office. Exceptionally, it is possible to perform one simulation per day, depending on the required detail.

It is in this design phase and by means of simulation, when we can give an anticipated solution to the problems that we are going to find. By means of simulation, we can detect the areas with predicted porosity. Those that are higher than 15% are considered problematic for mass production. On the other hand, it is often advantageous to evaluate the possibility of increasing the number of parts per assembly, in order to improve the net ratio of parts per cast assembly.

Prototypes in printed wax or silicone molds

Prototyping makes it possible to launch physical samples taking into account what has already been learned through the simulation process, but without having yet manufactured the metal mold. Prototyping therefore makes it possible to optimize important stages of the process, such as the creation of the ceramic mold that covers the models. It also allows comparison of the results of the deformations and the absence of internal defects, by means of dimensional scanning and radioscopy controls.

At the same time and when there is a final agreement with the customer, we move forward with the construction of the permanent mold. In this way, we can reduce the time to market of the new parts, since the development phase overlaps with the construction of the series metal mold.

In Ecrimesa Group we have a wax printer for Investment Casting parts, which allows us to perform these jobs internally. When the silicone mold is required due to the volume of prototypes needed, we have suppliers in the area that provide this service efficiently.

Printed waxes can be used to test different orientations and design changes (covering holes, for example) in order to analyze results and choose the best option. In any case, based on the information obtained in the previous simulation and the experience of our technicians in more than 6,200 references developed, it is possible to reduce the test matrices.

Prototyping with waxes allows to advance the tests to the official samples of the permanent mold and thus, to take into account the different variables that intervene in the quality of the ceramic coating: the difficulty of the part, the different programs of number of layers, the movements of the ceramic application robot and the ceramic drying times, among others. Once the parts have been cast from prototypes, the metallurgical quality is analyzed by visual inspection, Rx and dimensional (comparative scanning with 3D).

Based on experience with prototypes and customer functional tests, improvements can be added to the Investment Casting process, for example, adding small process-friendly creases or eliminating some drills.
The samples are also controlled in their mechanical properties after heat treatments and NDT, such as the control of absence of cracks, tests that in Ecrimesa Group we carry out by means of magnetic particles or penetrating liquids by accredited personnel.

Conclusions

By using simulation, a more accurate quotation can be made for complex parts, helping to adapt the design to the casting process.

Simulation reduces costly testing during the physical sample phase. Prototyping with printed waxes helps to develop the manufacturing process while the permanent mold is being designed and built, as well as to supply temporary parts to the customer for functional testing.
Having these services in-house allows us to improve customer service, both in the design and supply phases. It also improves sample development times by being able to overlap mold construction with testing on printed parts.
Finally, in the event that the customer requires prototypes for testing at their facilities before the final design, these can be manufactured with the aforementioned technologies, even adding the different additional variants required by our customers.

Simulation and prototyping processes are essential to efficiently manufacture final parts, reducing costs and meeting customer’s technical requirements.

Meet our design, simulation and prototyping office for Investment Casting: