Abstract
In this paper, a feedforward proportional-integral (PI) controller is developed to effectively control and tune the laser cladding melt pool geometry in real time. Width setpoint is included in the computer numerically controlled (CNC) programming, making possible its instantaneous change in relation to the position and time, as opposed to conventional controllers that do not have real-time information about these variables. The new concept of variable setpoint at different positions applied to laser cladding represents a great improvement in its use for changeable geometry applications such as blade fabrication. Several experiments are performed to characterize the behaviour of the system, revealing some key factors from monitoring system and image processing crucial for the controller. Laser power is selected as the input control variable, and the clad width is chosen as the output. The width of the melt pool is obtained based on measurements of CMOS camera images and an in-house image processing software algorithm. Closed-loop parameters are identified from the experimental data and Matlab simulations. The architecture of the controller consists on a conventional PI feedback loop and a feedforward module that shows low overshoot and fast response times. Instantaneous connections between laser, CNC, and PC systems allow for knowing the relationship among the exact position and real and setpoint melt pool values. The performance of the controller is verified in the fabrication of cladded parts with variable widths and in real time.
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Calleja A, Tabernero I, Fernandez A, Celaya A, Lamikiz A, Lopez de la Calle LN (2014) Improvement of strategies and parameters for multi-axis laser cladding operations. Opt Lasers Eng 56:113–120
Hanzl P, Zetek M, Baksa T, Kroupa T (2015) The influence of processing parameters on the mechanical properties of SLM parts. Procedia Eng 100:1405–1413
Everton SK, Hirsch M, Stravroulakis P, Leach RK, Clare AT (2016) Review of in-situ process monitoring and in-situ metrology for metal additive manufacturing. Mater Des 95:431–445
Bi G, Gasser A, Wissenbach K, Drenker A, Poprawe R (2006) Identification and qualification of temperature signal for monitoring and control in laser cladding. Opt Lasers Eng 44:1348–1359
Bi G, Sun CN, Gasser A (2013) Study of influential factors for process monitoring and control in laser aided additive manufacturing. J Mater Process Technol 213:463–468
Krauss H, Zeugner T, Zaeh MF (2014) Layerwise monitoring of the selective laser melting process by thermography. Phys Procedia 56:64–71
Asselin M, Toyserkani E, Irivani-Tabrizipour M, Khajepour A (2005) Development of trinocular CCD-based optical detector for real-time monitoring of laser cladding. P IEEE 3:1190–1196
Toyserkani E, Khajepour A, Corbin SF (2004) Laser cladding. CRC Press, New York
Fathi A, Khajepour A, Durali M, Toyserkani E (2008) Geometry control of the deposited layer in a nonplanar laser cladding process using a variable structure controller. J Manuf Sci Eng T ASME 130(3):0310031–03100311
Song L, Bagavath-Singh V, Dutta B, Mazumder J (2012) Control of melt pool temperature and position height during direct metal deposition process. Int J Adv Manuf Technol 58:247–256
Hofman J, De Lange DF, Meijer J (2006) Camera based feedback control of the laser cladding process. P ICALEO'06 456–460
Rodriguez-Araujo J, Rodriguez-Andina JJ, Farina J, Vidal F, Mato JL, Montealegre MA (2012) Industrial laser cladding systems: FPGA-based adaptive control. IEEE Ind Electron Mag 6:35–46
Doyle J, Francis B, Tannenbaum A (1990) Feedback control theory. Macmillan Publishing Co., New York
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Moralejo, S., Penaranda, X., Nieto, S. et al. A feedforward controller for tuning laser cladding melt pool geometry in real time. Int J Adv Manuf Technol 89, 821–831 (2017). https://doi.org/10.1007/s00170-016-9138-7
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DOI: https://doi.org/10.1007/s00170-016-9138-7