Laser marking

In 2016, LASIT created a robotic system for laser marking engine block castings with an anthropomorphic ABB robot with six axes integrated in a cell.

The collaboration with ABB has allowed us to create an innovative system with technology capable of implementing the productivity of one of the largest and most famous Italian Automotive companies.

The epicenter of this laser system is the welded steel cell housing the 20kg ABB robot arm which is able with its 6 axes to reach any position on the exposed sides of the casting, ensuring maximum flexibility for code laser marking.

After the regular finishing operations, the operators load the castings on the three shuttles which enter into the cell one by one.

Each shuttle is moved by means of a Siemens servomotor equipped with a rectified rack and is equipped with a scanning system which verifies the shape of the piece and its position. Each station has its own console, while a fourth one is used for set-up and diagnostics.

The shuttles are an essential component for the efficiency of the entire system and consist of a mobile platform that fits flush with the deburring bench, creating a continuous surface on which the operator can work easily. The platform has two fixed polyzene edges that limit the mobility of the piece to avoid compromising its position.

Their movement is managed by Star Rexroth ball-bearing guides, protected from dust and mounted under the profile so as to prevent further contamination due to sand residues. We have also equipped the system with a pneumatic damper that closes the compartment left empty by the carriage.

The shuttles do not require any specialization as it is the vision system that deals with objectification of the details to be marked, covering the whole area of the working field. Let’s examine the case in which the casting is incorrectly placed, not aligned or positioned beyond a limit angle: the machine generates an audible alarm and the shuttle leaves the cell so that the operator can reposition the piece.

The machine, if connected to an SMTP server, can automatically forward an email to one or more pre-set addresses with specifications about the fault.

The heart of this cell is naturally the six-axis robot, to which the 3D scanning head, the laser, the vision system and the distance meter are attached.

The vision system for identification of the marking area consists of a camera complete with a marking head that identifies the rectangle arranged on the casting where marking will take place and allows the laser to orient itself correctly.

While the casting enters the cell, the robot positions the 3D system in order to completely scan it: as a result, we obtain a complete 3D photograph of the piece that allows us to uniquely identify the piece within the laser marker database. At this point, the software instructs the robot to allow it to reach the desired marking position regardless of the orientation of the piece on the plane. At the same time, the marking layout is sent to the layer, updating the content of the Datamatrix with the data taken from the customer’s factory system. A moment before marking starts, a laser measurement system corrects the position of the robot to ensure laser focusing.

At the end of the process, the robot positions the Cognex Datamatrix reader exactly on the marking so as to verify its grading. The outcome of the marking is sent both to the factory system and to the operator’s monitor, then the shuttle is returned to the bench and the operator can unload it and load the next piece.

We have also installed a video surveillance system inside the marking cell that records all activities in order to be able to trace the causes in the event of system malfunctions, such as incorrect reading of the vision system or a robot error.

Finally, interfacing with MES allows the machine to dialog with the customer’s production traceability system.