Source: Deutsche Nachrichten
The welding task selects the beam source: Nd:YAG with up to 170 J of pulse energy for deep repair seams, the fibre laser for fine seams and long runs.
Many buyers start from catalogue power rather than from the seam they have to produce. A shorter path runs through three questions: which material and which allowed heat input, which seam geometry, and which operating mode the task needs. The technical background is set out in Sigma Laser’s guide to fibre laser welding machines.
Question one: how deep must the pulse go?
Pulse energy, not average power. A lamp-pumped Nd:YAG laser at 1064 nm runs in pulsed mode and delivers up to 170 J of pulse energy with peak power up to 13 kW. That reserve sets deep repair seams in a single pulse, for example in tool and mould making on tool steel 1.2343. In pulsed welding the pulse energy sets the penetration per pulse; the average power only describes continuous operation over time. All Sigma Laser systems run at an average power below one kilowatt while the peak power is in the kilowatt range.
Question two: fine, long or heat-sensitive?
Pulsed and continuous wave. The ytterbium fibre source at 1070 nm runs pulsed and in CW, in power classes up to 600 W, with pulse durations from 0.05 ms to 50 ms and a focus in the tenth-of-a-millimetre range. The fibre delivery needs no lamp change and keeps maintenance low. Typical tasks:thin sections and edges that must keep their shape with minimal distortion
- long CW seams on covers, guide rails or housings without restarts
- fine seams near seals or electronics that cannot take a wide heat input
- narrow cosmetic seams that have to stay uniform over their whole length
Question three: what does the sample weld show?
Let the real part decide. Both series, Light and Fibre, come mobile and stationary as 5-axis systems; the design decides mobility, not the beam source. Super Pulse Technology on both sources shapes the pulse on a microsecond scale and keeps the heat-affected zone small. The choice becomes reliable only on the customer’s own part: Sigma Laser welds samples on the customer’s material and assesses seam appearance, penetration, heat-affected zone and geometry. “The catalogue states powers, the seam states requirements. Whoever sends us the part gets the answer as a welded sample, not as a table,” says Alexander Bellouzi, Senior Design & Engineering at Sigma Laser.
Anyone planning deep repair seams in tool and mould making tests the pulsed Nd:YAG on the real part first. The background is collected in the guide to Nd:YAG laser welding machines.