Metal AM like laser powder bed forming (L-PBF) have low process MRL and part-to-part inconsistencies. In process inspection (IPI) can detect inconsistencies and potential defects on a layer-by-layer basis, offering lower rejections, higher yield, closed loop process control and in process repair. We will develop a novel IPI method called Layer Topographic Mapping (LTM). Surface morphology of every layer is measured after melting to very fine detail at high speed using a COTS laser profilometer (LP) sensor. Dense 3D point clouds (LTMs) of the top layer of the surface are created with high accuracy and spatial resolution. The LTM map describes detailed surface morphology of the layer and also is used to calculate the incremental thickness distribution of the formed layer. The data is analyzed in several ways to detect, classify and locate layer defects such as pores, balling and unfused powder. Both 1D and 2D frequency analysis of the surface profile has been shown effective detecting atypical or aberrant layer topography features that may correspond with flaws. Computer vision tools developed to reliably detect subtle defects in textured surfaces will also be employed, analyzing statistical variation of regions of the image from the overall image. These methods are effective detecting texture abnormalities without any a priori knowledge of the texture itself and are successfully used in high speed industrial inspection applications such as textile production. Flightware has teamed with Edison Welding Institute (EWI) who built and operate a dedicated L-PBF Test Bed to develop effective IPI methods and closed loop process control. This includes several local and area sensors, including a Laser Profilometer mounted on the powder Recoater. EWI's Test Bed is operational today; no SBIR investment is required. In Phase I we will acquire extensive LTM data with the LP sensor and analyze it to detect, classify and locate specific defect conditions in in L-PBF process. Anticipated
Benefits: Space applications such as the 3D Printer operating on the International Space Station are especially appealing opportunities for AM processes to provide functional replacements part in space, where spare parts logistics are very challenging. Unlike the ISS proof-of-concept device, mission critical AM parts require a high level of QA to assure functionality, where in process inspection can be extremely beneficial. For terrestrial applications laser powder bed forming (L-PBF) offers compelling advantages such as parts integration, facilitating design complexity and drastically shortening supply chains and lead times. For example, an Inconel 635 LH2 Injector made for NASA was produced in two pieces, replacing more than 150 separate parts that were previously assembled, and was fabricated in 10 days compared with months for the conventional injector. NASA parts often are made in low volume, are very complex and made from high temperature alloys metals. L-PBF fits these needs very well, enabling parts that otherwise could not be made, at lower cost and much faster delivery. The market for Aerospace Metal AM including Equipment and associated software, services and materials is forecast at $805 million in 2019 growing to $1.2 billion by 2023. The Equipment sector is the largest segment of the market. About 800 metal AM printers were sold in 2015, growing at a CAGR of 37%. Virtually every aerospace organization is a potential user of metal AM and LTM in process inspection. Flightware's direct customers/partners for LTM technology are Equipment OEM's, where LTM is integrated with metal L-PBF printers. OEM's like EOS, 3D Systems, Concept Laser, ExOne, Trumpf, Matsuura, Renishaw, Realizer, Sciaky, Sisma Group, SLM Solutions, ARCAM are expected to be very interested in offering their customers LTM capability if it can be shown to reliable, effective and affordable.
