Technical Paper Overview
Wobble-Based Laser Scanning for Additive Manufacturing
Scan strategy, not just laser power, decides metal AM part quality.
Laser powder bed fusion (LPBF) productivity is dominated by scan strategy as much as by laser power. Traditional vector-based hatching limits how the designer influences the melt pool — which is exactly where part quality is determined, in thermal gradients of 5-20 K/µm. Closed-loop melt-pool control is effectively impossible (sensor data is always historical), so scan-pattern design is the practical lever.
This peer-reviewed conference paper (Lasers in Manufacturing 2019) from four Novanta authors introduces three wobble-scanning modes — two based on pure circular geometry, and a third Lissajous-equation-based mode (X/Y galvo position controlled via amplitude, frequency 0.1-10 kHz, and phase) — that enable scan patterns impossible to define with vector hatching.
Key takeaways include:
- Why scan strategy — not just laser power and speed — drives melt-pool dynamics and end-part microstructure in LPBF
- How wobble-based scanning borrows a decades-old welding technique and applies it to powder-bed AM at frequencies up to 10 kHz
- When to choose each mode: constant-period (Mode 1), constant-overlap (Mode 2), or Lissajous-equation-based (Mode 3)
- What Lissajous wobble parameters control: X/Y amplitude, X/Y frequency (kHz), phase (±180°)
- A practical scan-time comparison: 20,455 ms reference reduced to 677 ms with Lissajous wobble on a square fill
Download the full peer-reviewed paper for the Lissajous-wobble equations, parameter tables from the Novanta applications-lab tests (square fills, wall fills, thin-walled rectangles), and the welding-to-additive-manufacturing precedent that justifies wobble scanning as a path to better LPBF part quality and productivity.
