Project overview
Laser welding, cutting, marking and heat treatment all depend on the same thing: how a part responds when a beam delivers a lot of energy into a very small spot. How hot it gets under the beam, and how quickly the material conducts that heat away, decide whether the process works or damages the part.
In this project we modelled a laser as a concentrated heat source on a plate in Ansys Mechanical and moved it along the length of the plate, solving the temperature and the total heat flux at each position of the beam. Two results tell the story: the temperature shows how hot the plate gets and where, and the heat flux shows how the energy actually moves through the material.
Objectives
Setup
| Setting | Value | Notes |
|---|---|---|
| Software | Ansys Mechanical | Steady-State Thermal analysis system |
| Heat source | Laser spot | A concentrated heat input on the plate surface |
| Path | Along the plate | The beam stepped from one end of the plate to the other |
| Mesh | Fine and uniform | Small, even elements across the plate to resolve the hot spot |
| Results | Temperature and heat flux | At each position of the beam |
Each position is solved to equilibrium, so the plots show the temperature field the plate settles to with the beam at that point. That makes it quick to map the hot spot and the heat flow along the whole path. A transient analysis is the natural next step when it matters how fast the plate heats up, or how much heat the beam leaves behind in the track it has just crossed.
Results: temperature
A sharp hot spot forms right where the beam lands and moves with it along the plate. The temperature falls off steeply with distance from the spot, so the heating stays local: the rest of the plate stays far cooler than the material directly under the beam.
The peak of 61.4 °C sits at the centre of the spot, and the halo around it shows how far the heat reaches into the surrounding material: the information needed to judge whether nearby features or coatings will see too much heat.
Results: total heat flux
Heat flux shows how the heat energy moves through the plate, rather than how hot it is. It peaks right at the laser spot, where the energy enters the plate, and falls away in rings as the heat is conducted outward into the cooler material.
The rings show the heat leaving the spot in every direction and spreading out through the material. The size of the region carrying significant flux shows how much of the plate is working to take the laser's energy away.
Conclusion
Together the two results give a full read on the laser heating: the temperature shows how hot the plate gets and where, and the total heat flux shows how that heat travels through the material, at every point along the beam's path. The same approach applies to any concentrated heat source, from laser welding and cutting to heat treatment and additive manufacturing, and it scales up to a full transient analysis when the timing of the heating matters.
Frequently asked questions
What does a laser heat source simulation show?
Where the part gets hot, how hot it gets and how the heat flows away from the spot. In this study the temperature peaked at 61.4 °C under the beam, with the heat flux concentrated at the spot and falling away in rings around it.
Why look at heat flux as well as temperature?
Temperature shows how hot each point is; heat flux shows where the heat is going and how fast. Together they show both the hot spot and how effectively the material carries the energy away from it.
Steady-state or transient: which does a laser analysis need?
A steady-state solution shows the temperature a part settles to with the heat source at a given position, which is quick and maps the hot spot along a path. A transient analysis adds the part's thermal inertia, so it shows how fast the part heats and the warm track a moving beam leaves behind it. Fast-moving beams in welding and cutting usually call for a transient analysis.
Where is this kind of analysis used?
Laser welding, cutting, marking and heat treatment, additive manufacturing, and any part that takes a concentrated heat input, wherever the peak temperature or the spread of heat around the spot matters.
