Innovations in manufacturing processes

The future of emerging smart manufacturing technologies is undoubtedly affected by the innovations in manufacturing processes and next-generation materials manufacture and characterization together with data science and AI. Towards this, my research presents innovations in two key areas:

  1. Intelligent sensing for rapid characterization: My research has demonstrated that HM platforms, along with high-resolution acoustic emission sensors, could be employed to study the material characteristics. Processes such as machining/scratching allow us to probe into the “rich”, mostly unexplored material structure.
  2. Surface quality and integrity assurance of AM components: Additive manufacturing limited in terms of controlling the surface morphologies to less than a few micrometers. My research focuses on developing advanced post-processing strategies, both from experimental as well as analytical standpoint, to address questions such as finishing complex surfaces, effect of different post-processing strategies on the surface integrity, and modeling the evolution of surface and microstructure during various post-processing steps.

Publications

  1. Jin, S., Iquebal A. S., Bukkapatnam, S., Gaynor, A., Ding, Y. (2019) A Gaussian Process Model-Guided Surface Polishing Process in Additive Manufacturing. Journal of Manufacturing Science and Engineering. (accepted with pending revision)
  2. Iquebal, A. S., Sagapuram, D., & Bukkapatnam, S. T. S.(2019). Surface plastic flow in polishing of rough surfaces. Scientific reports , 9, 10617.
  3. Bukkapatnam, S. T. S., Iquebal, A. S., & Kumara, S. R. (2018). Planar random graph representations of spatiotemporal surface morphology: Application to finishing of 3-D printed components. CIRP Annals, 67(1), 495-498.
  4. El-Amri, I., Iquebal, A. S., Srinivasa, A., & Bukkapatnam, S. (2018). Localized magnetic fluid finishing of freeform surfaces using electropermanent magnets and magnetic concentration. Journal of Manufacturing Processes, 34, 802-808.
  5. Iquebal, A. S., El Amri, S., Shrestha, S., Wang, Z., Manogharan, G. P., & Bukkapatnam, S. (2017). Longitudinal milling and fine abrasive finishing operations to improve surface integrity of metal AM components. Procedia Manufacturing, 10, 990-996.
  6. Iquebal, A. S., Shrestha, S., Wang, Z., Manogharan, G. P., & Bukkapatnam, S. (2016). Influence of Milling and Non-Traditional Machining on Surface Properties of Ti6Al4V EBM Components. In Proceedings of the 2016 Industrial and Systems Engineering Research Conference.

Unsupervised and streaming data analytics

Streaming data analytics forms the backbone of smart manufacturing systems to facilitate “real-time” decision-making.

For time series data, my research focused on harnessing the signal phase information (mostly neglected in the current literature) from noisy and transient streaming data via intrinsic time-scale decomposition and phase synchronization for fast and causal detection of process anomalies and change points.

For streaming image data, we developed an unsupervised image segmentation approach, with statistical consistency, by iteratively identifying the optimal graph cut and learning the parameters of the graph cut via maximum a posteriori estimation.

Publications

  1. Iquebal, A. S., Pandagare, S., & Bukkapatnam, S. T. S. (2019) Learning acoustic emission signatures from a nanoindentation-based lithography process: Towards rapid microstructure characterization. Tribology International (accepted with minor revision).
  2. Iquebal, A. S., Botcha, B., Panda, I., & Bukkapatnam, S. T. S. (2019) Automated identification and tracking of multiple surface defect types in additive manufacturing using a novel P-spline based image analysis. Journal of Manufacturing Science and Engineering (under review).
  3. Iquebal, A. S., & Bukkapatnam, S. T. S. (2018) Consistent estimation of the max-flow problem: Towards unsupervised image segmentation, IEEE Transactions on Pattern Analysis and Machine Intelligence (under review).
  4. Iquebal, A. S., Bukkapatnam, S. T. S, & Srinivasa, A. (2018) Change detection in complex dynamical systems using intrinsic phase and amplitude synchronization, IEEE Transactions on Signal Processing (revised and resubmitted).

Active learning for autonomous experimentation/discovery

Most, if not all manufacturing processes involve some aspect of optimizing certain "objectives" of interest, e.g., increasing the material strength. Traditional solutions are either based on passive experimental design approaches or sometimes just on past experience. Accelerating the experimental process by adaptively updating the experimental design is the key to reducing the cycle time and material costs.

My research focuses on active learning models and approaches to integrate the knowledge of the process physics into enabling high fidelity search in the state space. On the methodological side, we will focus on the challenges emerging from the process uncertainty where it may not be feasible to guarantee strict improvements. Under such circumstances, how can we generate solutions that are correct with some “confidence”, i.e., Probably Approximately Correct. Applications include: identifying optimal process parameters in additive manufacturing, discovery of materials with novel properties, etc.

Publications

  1. Iquebal, A. S., Botcha, B., & Bukkapatnam, S. T. S. (2019). Machine learning-enabled high throughput synthesis and microstructure characterization of low carbon stainless steel within a hybrid manufacturing platform. Manufacturing Letters (resubmitted with minor revision).
  2. Botcha, B., Iquebal, A. S., & Bukkapatnam, S. T. S. (2019). Instrumenting a smart manufacturing multiplex for custom manufacturing. Manufacturing Letters (under review).
  3. Iquebal, A. S., Pandagare, S., & Bukkapatnam, S. T. S. (2019) Learning acoustic emission signatures from a nanoindentation-based lithography process: Towards rapid microstructure characterization. Tribology International (under review).
  4. Iquebal, A. S., Botcha, B. and Bukkapatnam, S. T. S. (2019+) Autonomous experimental design via active learning: Application to surface grinding. To be submitted to IISE Transactions, 2019.

Image-based representation and quantification

Quantification of process evolution is critical to realizing autonomous decision making in SM, yet only a handful of methods have addressed this problem. My research focuses on physics-based graph representations to capture the evolution in the morphology of manufacturing processes such as polishing and nanoparticle synthesis.

We employ a copula-based approach to learn the joint evolution of morphological features as gathered by images. Spectral characteristics of the resulting graphs showed significantly improved resolution (up to an order of magnitude) in terms of accurately resolving the process endpoints—deciding when to stop the process—as compared to conventionally employed surface roughness measurements. We also studied the robustness of the spectral characteristics under different graph perturbations. Via theoretical and numerical results, we established that the planar graphs achieve an average connectivity of six in the final stages of the polishing processes.

Publications

  1. Iquebal, A. S., Cline, D. and Bukkapatnam, S. T. S. (2019+) Planar graph representation of surface morphology: A copula-based approach for modeling spatial random fields. To be submitted to Technometrics.
  2. Bukkapatnam, S. T. S., Iquebal, A. S., & Kumara, S. R. (2018). Planar random graph representations of spatiotemporal surface morphology: Application to finishing of 3-D printed components. CIRP Annals, 67(1), 495-498.