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Today, there are many commercial CAM systems available capable of generating NC codes for milling free-form geometries up to 5-axis. However, the quality of these NC codes has not yet been well discussed so far. Apparently, on the computer screen and the geometrical simulation provided by CAM, tool paths calculated by different CAM systems seem to be the same. However, as observed in this work, NC codes differ expressively according to the CAM software applied, and it affects the productivity and quality of the machined surface. Thus, a study was carried out to investigate this issue. A representative workpiece with free-form geometries was designed; a data acquisition system from an open architecture CNC was developed and NC codes were generated by five worldwide commercial CAM systems. The finishing milling operation was evaluated. The results presented difference of up to 30% on the real machining time, differences in the feed rate oscillation and up to 2 times the surface roughness value. This work reveals an essential limitation on the CAM algorithm and arises a new point for benchmarking CAM systems, which brings an opportunity to improve the calculation of tool paths for milling free-form geometries.

The development of additive manufacturing using metallic materials, such as the selective laser melting, has allowed the manufacture of free form cooling channels inside the molds for plastic injection. Reduction on the injection cycle time and product quality are expected using such cooling channels (also known as conformal cooling channels). The knowledge to design such cooling system are limited today. This work aims to collaborate with this issue. A new design of cooling channels using series and parallel concept are proposed and its efficiency were analyzed against some conformal cooling geometry found on the literature today. The analyses were carried out by a Computer Aided Engineering software using an automotive component as a workpiece. The results show that the design of the new approach of conformal cooling channels has an influence on the cooling performance and if the conformal cooling was not carefully designed, it cannot achieve the expected benefits. POLYM. ENG. SCI., 58:552–559, 2018. © 2017 Society of Plastics Engineers

Although computer-aided engineering (CAE) software has been used for many years in the plastic industry, identifying the most appropriate mesh geometry and density remains a challenge. It can affect the accuracy of the simulation, the time and the costs. The evaluation of the most suitable mesh is not easy because the difficulties to obtain the real the values of the pressure and temperature inside the mold. The current work investigates this issue. A mold was manufactured and sensors were installed in its interior. CAE simulations using different mesh geometries and densities were evaluated against the experimental data. The results showed that the computational time was mostly influenced by the mesh geometry. The use of 2D mesh and lower density can lead to a faster and more precise simulation of pressure inside the mold and 3D mesh with lower density can provide a faster and precise simulation of the temperature.

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