Pulsed Nd:YAG spot welder · front-panel calculator
The ends of the ranges on your own panel. Values outside them turn the row red instead of being silently clamped.
Until you enter one, everything runs off a placeholder lamp curve — right shape, wrong numbers. Lamp current is not watts: output climbs from a threshold, so one real shot fixes the whole curve. On the 200P it is voltage, and stored energy goes as V². Leave the threshold at 0 if you don't know it.
A lamp-pumped Nd:YAG rod gives a rounded pulse and runs highly multimode, so the focused spot is closer to a flat top than a Gaussian. Those are the defaults.
Stainless steel, gold, silver, copper and aluminum come from manufacturer parameter tables for this class of machine; the 230B and 200P start from the 200B numbers. Steel, inconel, platinum and brass are marked derived — scaled from those by 1064 nm absorptivity, thermal conductivity and melting point. A place to begin, not a spec. Always test on scrap first.
The current knob drives the flashlamp, and laser output climbs roughly linearly once the lamp is over the lasing threshold. It is not volts × amps, which is why the tool wants one measured shot instead of guessing.
Joules are the area under the shot. Wider pulse at the same current means more energy into the same spot — more melt depth, more heat into the part, more risk of blowing thin sections.
Every shot is identical; frequency only decides how many per second. This is the number the machine's rating caps, and it is what limits how fast you can run a seam.
The same joules through a smaller spot is a completely different weld. Roughly: under about 0.3 kW/mm² you are only heating the surface; from there up to about 10 kW/mm² is conduction welding, a shallow rounded bead; above that you are into a keyhole — deep, narrow, and easy to overdo on a thin edge. Silver and copper sit high on that scale on purpose, because most of the beam bounces straight off.
Two limits, whichever bites first. Energy: the absorbed joules can only melt so much metal — depth = A × E divided by spot area, density, specific heat to the melting point and latent heat of fusion. Conduction: heat only travels √(4 α t) into the part during the pulse, so nothing deeper than that gets hot. The two are combined with a melting efficiency that falls as heat runs sideways out of the spot — which is why silver and copper give thin welds for a lot of energy.
Treat it as ±50 %, and as a comparison tool rather than a measurement. It assumes a clean, flat, well-fitted surface and a conduction weld. It does not model keyhole drilling, weld-pool convection, joint gaps, surface finish, oxide, shielding gas, or heat left over from the previous shot. Absorptivity in particular is a moving target: a polished silver surface reflects about 97 % cold, but once a melt pool forms coupling climbs steeply, so the figures used here are effective weld-time values, not room-temperature ones.
From a published welding-trial study. Note the interaction times: 0.1–0.19 s, roughly a hundred times longer than a 2 ms spot shot, so the penetration column does not transfer directly to this machine. The power-density column does — it is the same axis your shot is measured on above.
| # | Laser power | Scan speed | Power density | Interaction time | Point energy | Penetration | Intermetallic |
|---|
Shape and driver background — RP Photonics: lamp-pumped lasers · AMADA WELD TECH: Nd:YAG vs fiber · Laser Welding Fundamentals (PDF)