## 1 Introduction
The influence of injection parameters on the mechanical properties of the parts obtained was also studied through a Design of Experiments (DoE) by [PERSON] and [PERSON] [15], using polypropylene as a raw material. In this study, it was emphasized that the mechanical properties of polypropylene are essentially conditioned by the mold temperature and packing pressure. However, the latter should not be excessive, as being under penalty of the injected parts can exhibit fragile behavior. Mold wear is another constant concern for researchers. [PERSON] et al. [16] started from the typical classification of wear mechanisms normally attributed to molds, then studied the effect of mold cavity surface treatment, considering the injection of different polymers, such as reinforced polyamide, thermoplastic polyester, or acrylic resin. In the molds, there is usually abrasion created by the entrainment of particles, additives or reinforcements included in the injected plastic flow, or erosion when the polymer flow collides with the mold walls head-on during the filling phase. These wear mechanisms must also be joined by corrosion, as some polymers and additives are increasingly aggressive in conventional steels. In the study by [PERSON] et al., the Ni-PTFE coating significantly improved performance in terms of corrosion resistance, while the TiN coating caused a reduction in the friction of polymer flow and a better performance in terms of abrasion and erosion resistance. The introduction of fibers enabled new applications for thermoplastic polymers, but also created new problems to be solved: the wear of molds and some components of injection machines [17]. This wear and how to minimize it is the subject of several studies, which essentially involve the use of coatings. Thus, studies were published that argued that TiB2 coatings made by PVD had excellent wear minimizing characteristics, significantly extending mold life [18; 19]. However, other studies suggested coatings of (Cr, Al) N/(Cr, Al) ON [20], TiAlSiN [9] or CrN/CrCN/DLC [21]. Even using high levels of short fiberglass as reinforcement, these PVD-coated molds demonstrated in practical terms a significant increase in wear resistance, having shown very low levels of wear. In fact, these coated molds showed almost imperceptible levels of wear when compared to uncoated steel mold cavities, even after having performed triple injections. Regarding mold design, one of the critical tasks is the identification of the parting line, due to the often-complex geometry of the part that is produced. [PERSON] et al. [22] developed a methodology based on the visibility and moldability of the surface. To this end, they defined an algorithm that starts by identifying and defining the core, the cavity, the local tool-molded surfaces, and, based on those, establishes the most suitable parting line for the part in question. This is a very complex phase in the process of creating a mold, so algorithms of this nature are extremely useful to the designer, saving a lot of design time and avoiding possible design errors. This model has been successfully tested in practice, so it can be used even on complex parts. The previous group of authors, in a work published five years earlier [23], used additions and found that the parting lines, core mechanisms, lifters, sliders and the overall structure of the mold were conditioned by the quantity and geometry of the undercuts that the part requires for the mold. To resolve this constraint at the design stage, these researchers developed software capable of automatically recognizing and identifying undercuts based on geometric characteristics and the relationship with the surfaces molded from the 3D model of the part. The ideal partition direction is selected based on the proposed criterion of considering the number of possible undercuts and the respective volume of each undercut. Molds remain tools that are subjected to a very high number of thermal cycles, which cause the induction of internal stresses in molds and in produced parts. [PERSON] et al.