With the introduction of robot automation in gigacasting, SIR Soluzioni Industriali Robotizzate has opened a significant niche in the aluminum foundry sector. With customized applications, high precision, speed and user-friendly robots, the company offers solutions that significantly increase production levels in terms of efficiency and quality. In the production of large high-pressure aluminum castings, SIR performs removal, degassing (shearing and/or plasma cutting) and fine deburring with precision, speed and reliability. Through these characteristics, SIR is a major player in automation technology for the foundry and automotive industry.
The extraction of Elements from Gigapress
The production of components using gigapresses is a complex and technologically advanced process, where the interaction between the press and the robot assigned to element extraction plays a crucial role. Due to the significant size of the gigapress and the casting, robots typically used in this application have a high payload at the wrist and are mounted on a rail with a transverse travel path, suitable for reaching the center of the mold and then moving outside the machine’s doors: this considerably increases the robot's already extensive action area. The casting comprises the main figure (representing the final component to be produced), the gating system, and the overflows and vacuum channels needed to ensure its integrity. Once the casting is accessible, the robot enters the machine and, using a multi-grip tool, grabs the casting by the figure. To facilitate and make the extraction effective, the gigapress partially detaches the casting from the mold using integrated ejectors.
To avoid deformations due to high temperature (around 600°C) and the weight of the element, the robot grabs the casting at predefined points, generally agreed upon with the customer. An integrated sensor system in the robot's gripping tool detects the presence of the gating system and of some overflows in specific strategic positions, ensuring the element has been correctly cast. Additional checks can be performed, depending on the customer's requirements, with fixed sensors, 3D vision systems, or thermal cameras. Once the robot has exited the machine's footprint and the various quality and integrity checks have been performed, the management program authorizes the mold blowing and lubrication system to start its cycle so that the gigapress can proceed with the next casting. The sequence of movements and checks is aimed at optimizing cycle time and increasing production.
The De-Gating of the Casting
After extraction, the production cycle includes a de-gating phase to remove the gating system and overflows. This process can be done via trimming, using a giga trim press: in this case, the casting must be quenched by immersion in a water tank. The alternative method used by SIR for de-gating is based on plasma cutting: this solution allows processing the casting at temperatures close to extraction, avoiding quenching. After de-gating, if required for logistical reasons, the element can be air-cooled, with significantly reduced times thanks to the previous removal of the gating system, which represents a significant percentage of the casting's total mass. Air cooling is generally much less stressful than quenching, better preserving the casting's geometry. After de-gating, for production data traceability, the element is identified with a data matrix code marked on it with a laser unit.
The Advantages of Plasma Cutting: Flexibility and Quality of Cut
Thanks to fruitful collaboration with some expert plasma generator manufacturers, SIR optimized the cutting process by moving the plasma torch onboard the robot. The resulting solution proved to be the most cost-effective and efficient alternative to trimming for removing overflows and gating systems in single-piece frame castings, offering convenience, flexibility, and ease of use. The robots, due to their adaptability, can perform different cutting paths on various components, allowing significant economic savings. Plasma torches ensure lower consumption and costs compared to alternatives, besides achieving clean cuts that require fewer finishing operations in subsequent steps. There is no longer a need to replace costly and bulky molds when changing the element type in production: a simple reprogramming of the robot paths, combined with a possible adjustment of the reference tool and casting support, is sufficient. To address possible element deformations, the robotic cutting cell is equipped with a 3D vision system capable of identifying the three-dimensional differences between the current casting and the nominal element, consequently adjusting the robot's local path.
From Extraction to Fine Deburring: A Success Story in the Automotive Industry
A recently developed application by SIR for a major automotive client demonstrated the effectiveness of this solution. The robotic line in question performs the de-gating of aluminum castings, particularly front and rear automotive subframes. The system comprises handling robots that load and unload elements onto several process cells, where other robots perform plasma cutting and subsequent removal of overflows and gating systems. The robotic system can be integrated downstream with additional fine deburring cells. Using pneumatic spindles with compensation, equipped with rotary files or abrasive belts, fine deburring aims to remove burrs generated at the mold joint profiles.
For deburring large elements, like those produced by gigapresses, to ensure the required final quality, a TOB (Tool on Board) deburring solution is necessary, with the element to be worked positioned on a fixed tool or a housed on a controlled-axis rotator tool. Pneumatic compensation of the deburring units is generally applied in all SIR process operations: it allows managing the variability of burr sizes, as the rigidity of the compensation can be programmatically adjusted according to specific needs.
The pneumatic spindles on the robot are equipped with automatic tool changers: this allows the use of different tool types during the work cycle, often necessary due to the type and position of the burrs to be removed. If necessary, an automatic EOAT (End of Arm Tooling) replacement system is provided: this becomes essential when the tools used in the process require rotational speeds and/or powers incompatible with the technical characteristics of a single pneumatic spindle. The automatic EOAT replacement system even allows the use of onboard robot deburring units (designed and patented by SIR) employing abrasive belts: these, also equipped with pneumatic compensation, enable automatic belt replacement.
SIR deburring cells are therefore equipped with internal storage dedicated to tool replacement (both multi-edged and abrasive belts) and possibly EOATs replacement during the machining process. The tools are also equipped with an automatic device for reconditioning them when worn: thanks to a rotating table, the operator can load new tools from outside the cell without interrupting the robot's work cycle. Tool lubrication and presence checks are, of course, planned cyclically as needed. The machining residues are extracted with a conveyor made of a metal mesh belt that channels them into a container outside the cell. Once deburring is complete, the element can undergo a 3D vision inspection to verify the successful outcome of the work. The entire process, from extraction from the gigapress to the final element inspection, is designed to increase productivity, ensuring the highest efficiency and quality of the produced parts.
