Laser Additive Maintenance

LASER ADDITIVE MAINTENANCE™

In the conventional industrial maintenance process, the raw material is transformed through several stages until it reaches the final product configuration. To minimize the risk of missing parts, whether in the preventive or corrective maintenance process, companies tend to build physical stocks of spare parts. In some industrial sectors, e.g. oil and gas, the risk of lack of parts is even more critical due to the loss of profits that occur when an oil exploration platform stops operating due to lack of parts. Typically, on an off-shore oil rig that extracts 18,000 barrels of oil/day, lost profit is estimated at USD 2,000,000/hour. The risk of this loss justifies the construction and maintenance of physical stocks of spare parts in the order of USD billions only for platforms operating on the Brazilian coast. The proposal of the Additive Maintenance project is to replace physical stocks of spare parts with digital stocks of those same parts, associated with 3D printing processing windows in laser additive manufacturing machines. The direct consequence of this approach is to eliminate the costs of (a) space (b) capital (c) storage services and (d) storage risks. The additive maintenance process has been successfully applied to companies in the oil and electrical sectors. The laser additive maintenance process consists of the following activities: 1) Identification of critical maintenance parts: a team formed by researchers from the SENAI Institute of Innovation in Laser Processing of Joinville (ISI-Laser) and employees from the partner company, identify the critical parts of the various systems and equipment using consolidated methods available in literature e.g. FMEA - Failure Mode and Effect Analysis; 2) Digitization of critical parts: if 3D CAD models of critical parts are available, they are stored in the digital warehouse; otherwise, the part is digitized, respecting functional operating restrictions and cataloged in the digital warehouse; 3) Definition of the printer processing window: to operate the ISI-JVL metal laser 3D printers, it is necessary to define and configure 15 parameters (average value), including part material, laser source power, thickness powder-metal layer, inert gas mass flow rate etc. The Design of Experiments and Orthogonal Arrangements method is used to define the values of these parameters, establishing a number of experiments and, consequently, of specimens, lower than that defined in a saturated factorial experiment; 4) Tests with specimens: the identification of the critical maintenance part brings with it its functional history: it operates subject to compression, tension, fatigue loads etc. Based on this history, the relevant tests to be carried out with the specimens are defined. The analysis of the test results determines the processing window that will be used in the additive manufacturing of the critical part; 5) Laser Additive Manufacturing of the critical part: at ISI-JVL there are printers for two types of additive manufacturing processes, namely, L -PBF (Laser Powder Bed Fusion) and L-DED (Laser Direct Energy Deposition). Choosing one of them depends on the printing time and desired surface finish: L-PBF has a better surface finish and is slower; L-DED is faster and has a worse surface finish; 6) Post-processing: all additively manufactured parts must undergo normalization heat treatment to relieve stresses generated in the printing process. If the surface finish requirement is beyond those obtained by L-PBF or L-DED, a conventional machining process or even grinding is used; 7) Operational tests: the critical part must be subjected to operational conditions that it will encounter in the field. 8) Approval of the additively manufactured part: after a period of testing (2 months) and with the test results on the printed part approved, the digital part is confirmed in the digital warehouse and will be printed on demand for preventive, corrective or predictive maintenance.