1 / 9

Moving Laser Heater

Moving Laser Heater. Introduction. Lasers are commonly used to achieve precision heating or welding. The beam often moves over the surface of the substrate.

chaney-morris
Download Presentation

Moving Laser Heater

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Moving Laser Heater

  2. Introduction • Lasers are commonly used to achieve precision heating or welding. The beam often moves over the surface of the substrate. • One difficulty with modeling a laser heat source is the fact that the beam is very narrow (nm-mm). Another is that the laser has a certain penetration depth which may be important. • The purpose of this model is to demonstrate how to model a moving depth-distributed line heat source in COMSOL Multiphysics using a 3D-1D coupling. • The results show that the penetration depth plays an important role in the heating process.

  3. Model Definition – Geometries • The model is based on a 3D energy balance coupled to a 1D model of the laser intensity in the depth of the substrate. thickness: 1 mm 3D: 1D (thickness):

  4. Model Definition – Equations • In the 3D domain an ordinary energy balance is used, for example using a Conduction application mode. • In the 1D domain a Weak application mode is used. The equation is: • (Ix-k_abs*T*I)*I_test+I*P_in*T_test => • General transformation Extrusion Coupling is used to couple the moving laser source to the energy balance. • Transformation: x=r*(sin(w*t), y=r*cos(w*t), z=x2 • Results in a line heat source, xy-dimension limited by one element in the 3D geometry. • A very good representation of a laser heat source.

  5. Model Definition – Parameters & Boundary Conditions • Parameters: • kT(silicon)=(163,163,1) • P_in (laser)=100 W • 3D energy balance BCs: • Isolating conditions on all boundaries • 1D intensity model BCs: • x=1e-3, I =1 (incoming laser intensity=1) • x=0, zero flux • The coupling variable causes a heat souce to occur in the 3D model: • QT=I*P_in_laser

  6. Model Definition – Mesh, Solver • 2D triangular mesh is extruded to achieve hex-elements. • Advantages: • control of element thickness • Mesh finer along laser track => reduced mesh size and improved speed • 3144 elements • 2175 DOFs • Solver: • Solution form Weak • Time dependent with UMFPACK • Solution time: approx 20 sec (on 1.6 GHz PC-laptop)

  7. Results – local temperature in solid • Local temperature distribution within the solid at the laser position. • Show Movie of T=f(t)

  8. Results – local temperature at surface • Local temperature distribution along the laser beam track on the incident surface

  9. Results – Intensity distribution • Laser intensity distribution in the depth of the sample at t=1sec. • The laser is fully absorbed - approximately 400 mm into the silicon sample.

More Related