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Method for aligning multiple lasers using axial sensor data.

Engineering & Physical Sciences
College of Engineering (COE)
Rindler, Jacob
Licensing Manager
Zinn, Ryan

T2019-314 This technology improves the additive manufacturing process by aligning the multiple lasers to one reference point. The reference laser provides real time feedback to the other lasers thereby minimizing seam defects resulting in a higher quality print.
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The Need

The additive manufacturing (AM) market has been steadily growing and has recently surpassed the $10 billion in market revenue. To keep up with this demand for less expensive, larger parts, users are turning to multi-laser machines to scale the technology.

Each machine has a coordinate system with a X, Y, and Z axis. Each laser then has a coordinate system. The machine's coordinates and laser coordinates should be aligned perfectly to build a product to specification. Over time each laser may become misaligned, causing seams to not meet correctly ruining a project. Currently, to fix and prevent misalignment during the building process, lasers are focused on reference point multiple times during one project. This reference process stops production, costing time and money. To ensure accurate seams, there is a need for an innovation to actively correct laser alignment without stopping production.

The Technology

Dr. Jacob Rindler with the Center for Design and Manufacturing Excellence at The Ohio University has solved this problem with a reference laser in combination with co-axial sensors to monitor, measure, and correct alignment in real time. Most machines already have co-axial melt-pool sensors in place; however, a reference laser and software are added to monitor where the adjacent lasers are to automatically correct the lasers.

The reference laser is directed to stay stationary at a known point in the scan field. The reference laser’s co-axial sensors observe electromagnetic radiation across a set of know wavelengths to establish a collection area. As the other lasers move through the collection area, the sensors for the reference laser can us the electromagnetic energy made by the moving laser to calculate where exactly that laser is, and software is used to calculate where that laser should be. The software would then automatically correct the laser if it were not perfect. This new method would ensure a quality product with real time correction of lasers, saving time, money, and resources manually correcting the lasers.

Commercial Applications

  • Metal multi-laser printers
  • Polymer multi-laser printers


  • Seam alignment
  • Save time by correcting lasers actively