PSI - Issue 77

Vasco Gomes et al. / Procedia Structural Integrity 77 (2026) 559–566 Gomes et al./ Structural Integrity Procedia 00 (2026) 000–000

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Fig. 3. 1D model of the servo press.

3.2. Pneumatic and stamping loads Unlike the 3D model created, for the 1D system it was not possible to model the pneumatic counterbalance system previously explained using pneumatic elements due to limitation regarding the software license. However, this was overcome by using two external forces that act on the vertically moving system (one in each branch) whose curve is extracted from the 3D model, henceforth the complementary aspect of these two models, the 1D and 3D. In regards to the stamping loads, and similarly to the 3D system, it was applied external forces were applied to each single branch (two loads in total). 3.3. Hydraulic overload protection system The hydraulic overload protection system, shortly known as HOLP, is constituted by two elements, each one located at the end of its respective rod and rigidly connected to the slide on its bottom region. Its function is to prevent any damage to the press when an overload situation occurs. For that purpose, it possesses a chamber, with 17 mm in height, filled with pressurized fluid. This fluid will be forced out of the HOLP’s chamber, when the overload is detected by a pressure limiting valve. In this model, the HOLP functions independently from the kinematics, serving only as an alarm: when the maximum pressure is reached, a pressure switch sends a signal, while the rest of the simulation continues unaffected. The component used for the recreation of the HOLP was a plunger cylinder, since there is only one chamber per HOLP, with a rod representing the moving part when the overload occurs. The hydraulic circuit was completed with: • check valve (also known as non-return valve) which prevents counter flow (fluid flows in just one direction); • hydraulic pump, that supplies the fluid until the chambers are filled; • pressure relief valve to control the internal pressure on the HOLP chamber. In Table 3 it can be seen some parameters defined when building this model.

Table 3. Hydraulic overload protection system parameters. Parameter

Dimension

Unit mm mm mm

HOLP – Maximum stroke HOLP – Cylinder diameter

17

444.125

HOLP – Rod diameter Circuit – Set pressure

390 200 220

bar bar

Pressure switch – Switching pressure