4. Results and Discussions
4.1 The Plant
Figure 86. Real plant. (From Serecchia, G. 2018)
A sophisticate robotic system owned by ARTIMO s.r.l., was fabricated. This plant is use for modeling stock material through an anthropomorphic robot with 6-degrees of freedom, installed on a portal compose by one traversal slider and two longitudinal sliders that permit to obtain two further degrees of freedom. In particular, the whole plant is compose by a system with 8-degrees of freedom. The robot model is a KR90 R3100 extra C, that is placed on a ceiling linear slider of 8 meters of length. The slider is driven by an electric motors controlled by the KUKA robot controller (KRC 4). The longitudinal sliders are installed on a portal of equal width and characterized by a height of 4 meters. This portal moves on two parallel guides supplied by Güdel with a length of 50 meters, driven by two electric motors controlled by the KUKA controller as additional external axes to the anthropomorphic robot. This configuration allows the operator to create from the scratch different kinds of models that cover not only the nautical industry but also other ambients of the industry such
as car building, furnishings, customized pieces, etc. It can be fit in different production fields as long as the desire sample respects the dimensions of the robot operating space (50x8x4 meters). Briefly, it can be compare as a large 3D printer except that CNC machine starts with a block of stock material and shapes it with a rotating tool, carving away excess until the finished product is obtained.
4.2 Preliminary Test
The first test of the CNC machine have been made with two materials, plywood and polystyrene. There was shaped the writing ARTIMO (The name of the laboratory where has been constructed the system) on the two stock materials. In Figure 87 (b) and (d) is possible to have a view of the results obtained after the machining. There were some problems with the spindle as the rotation frequency, the direction of rotation and the torque applied. Those issues were resolved looking at the DTM(Device Type Manager) of the inverter and configuring the parameters of it. Afterwards the outcome of these test were satisfied with a good finish and delineations. The next step was to start the modelling of a real boat.
Figure 87. Preliminary Test. (a) Plywood processing. (b) Plywood result test. (c) Polystyrene
processing. (d) Polystyrene result test. (From Serecchia, G.2018)
a b
Then the next step was the model of an inflatable raft. The model was initially created offline in a graphic software, Figure 88 after that given to a CAM software that creates the trajectories that needs to follow the robot to shape the piece of material, simulated to avoid collisions troubles, synthesized the g-code and for last passed to the CNC through a directory loader inside the KRC (folder created to simplify the work of the operator because in a normal situation is needed to access the programmation core of the robot). A strength of this system is that it can be managed in broad terms as a 3D printer, so it’s very intuitive. In Figure 90 is possible to appreciate the initial result of this first project. After obtained the boat model the next step is to set on all the furniture, as motor, seats and all the electrical connections.
Figure 88. Transformation flow from the 3D model to the g-code. (From Serecchia, G. 2018)
An important feature is the implementation of a “Directory Loader”, in this folder the operator will place all the g-codes generated for modelling the pieces. Without this instrument the operator is forced to get inside the KUKA software (WorkVisual) and do the work of programmer, that results harder because needs more time to activate the machining, an expert operator that has the knowledge of programming and a harder process. This feature is part of an industry 4.0. created to facilitated the processes in a production chain.
The operator has an important role both in the planning of the mission and during its execution, the operator must command, check analyze the information coming from the sensors, make sure that the implemented automation "works" and, if it does not
work, to intervene. This allows to operate on the machine in total safety and to perform service diagnostics in an easy and efficient way. In particular, the man-machine interface the operator can act directly on the robot by changing its position and on the electro-spindle. The existing B&R security system, consisting of the X20 SafeIO, SafeLogic and SafeDESIGNER toolset from Automation Studio, is enhanced with the addition of ACOPOSmulti inverter units with Integrated Safety Technology (SafeMC). All B&R products with "Integrated Safety Technology" are optimized to work together. This makes possible to create highly effective application solutions with integrated security technology. The approach adopted is based on the use of full field OpenSAFETY.
Figure 89. Preliminary processing of the inflatable raft. (From Serecchia, G. 2018)
4.3 Further Results
Regarding to the entire system, one integrated safety functions such as speed limitation (SLS) to be activated directly on the network. The information is acquired from the respective sources via safe digital inputs and outputs, and then distributed to the respective sensors and actuators, in this case the drives with integrated safety functions, via a safe CPU: the SafeLOGIC controller. The connection via POWERLINK guaranteed the best possible communications between the SafeLOGIC controllers and the standard ones used to create programs not associated with security.
Figure 90. Final model of the inflatable raft. (From Serecchia, G. 2018)
Due to the control and supervision software allowed both the correct interaction of the robot's implementation system and the completion of the composite manufacturing process functions and the remote monitoring and supervision of productivity, working hours and control charts. The plant is certified in compliance with the dictates of "Industry 4.0". The system allows the milling and sanding of large surfaces, using robots equipped with anthropomorphic arms with wide freedom of movement. The system management software allowed the complete automation of the entire machining, thanks to the availability of different tools and robot heads in the fully sensorized storage, all these configurations consented the optimization of the work process; time savings, costs and effectiveness of the intervention; improvement of health and safety of workers.
The results achieved where the optimization of the work process; time savings, costs and effectiveness of the intervention; improving health and safety of workers. The philosophy of this project was to provide hardware and development tools to implement complete solutions, robust and validated, highly configurable and customize.
