OCT Weld Depth Monitoring for Laser Welding

Beipin Laser (Kunshan, Suzhou, China) integrates spectral-domain OCT (SD-OCT) with laser welding heads and galvo wobble heads to measure a depth-related signal during welding and record it as a curve along the seam. Before production use, each project is calibrated against metallographic cross-sections using your own samples.

Published test: 0.8 + 1.5 mm copper lap weld

• Five laser power groups, 1500–2300 W; 8 samples per group (40 in total).
• Measuring points at 2, 4, 6 and 8 mm along a 9 mm seam (160 comparison points).
• Welding speed 17 mm/s; wobble amplitude 0.8 mm at 90 Hz.

Error = OCT depth − metallographic depth. 2.07%–5.09% is the MAPE of this copper lap-weld test only. It is not a general accuracy specification for other materials, joints or process conditions.

How a project runs

1. Confirm inputs: material and coating, top/bottom thickness, joint type, target depth, seam path and existing equipment.
2. Sample welding inside the agreed process window, recording OCT curves and surface condition.
3. Same-position metallography: cut agreed points and align OCT and metallographic data.
4. Rules and acceptance: thresholds, re-check frequency, data output and interfaces are agreed in writing.

Integration

Works with a laser welding head or a galvo wobble head. PLC, database and MES interfaces are evaluated per project; fields and response time are confirmed in writing. For post-weld surface defects (pores, offset, seam width), combine OCT with our 3D weld seam inspection.

Choosing an OCT weld depth monitoring supplier: 6 things to check

1. Same-position metallography data, not only principle diagrams.
2. Which error metric, under which conditions (samples, measuring points, power range).
3. Calibration with your own material, coating and joint.
4. Coaxial integration with your welding head, galvo or wobble mode.
5. PLC / database / MES fields and response time confirmed in writing.
6. Thresholds and metallography re-check frequency written into the acceptance plan.

FAQ

Can OCT measure weld depth during welding?

It captures a depth-related distance signal in process and builds a curve along the seam. Whether a stable, valid signal is obtained in your process must be verified with real samples.

Can OCT replace metallographic cross-sections?

No. OCT is for in-line monitoring and screening in production; new materials, joints or processes still need metallographic calibration and periodic re-checks.

Which materials can be evaluated?

Copper, aluminum, stainless steel and coated materials can be evaluated with samples. We make no general suitability claim; valid signal range, calibration and thresholds come from your sample results.

Can OCT be combined with 3D weld seam inspection?

Yes. OCT answers "is it welded through?"; post-weld 3D inspection answers "any pores, any offset, is the seam wide enough?".

Where are you? Can we visit?

We are in Kunshan (Suzhou), China. Send samples for evaluation, or book a visit to see the OCT test bench.