Laser Materials Processing
08 - Laser Welding
08 - Laser Welding
Fichier Détails
| Cartes-fiches | 14 |
|---|---|
| Langue | English |
| Catégorie | Technique |
| Niveau | Université |
| Crée / Actualisé | 16.01.2015 / 16.05.2016 |
| Lien de web |
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Wich two types of laser welding exist?
- Deep-penetration laser-welding
- Heat-conduction laser-welding
Explain how deep-penetration-welding works.
• Vaporization-temperature of the workpiece is exceeded due to high laserpower and good focussing (small df), which leads to high intensity.
• Metal-vapour streams vertically up, the resulting recoil (Rückstoß) onto the liquid melt-pool-surface causes the creation of a deep and narrow vapourchannel (D„ ampfkapillare)“, often called a „keyhole)“.
• Through the keyhole (D„ ampfkapillare)“ the laser-beam enters the workpiece into deep depths and such warms it up „from the inner“(and not only „from the surface)“.
Explain the "multi-reflections-effect" during deep-penetration-welding.
Wich ammount of energy can be absorbed using a high sophisticated process?
During the multiple reflections of the laser-beam inside the keyhole (Dampfkapillare) every time a ray (Teilstrahl) touches the keyhole-walls, an amount of it´s energy is absorbed there.
Touching the keyhole-walls sufficiently frequent, the total amount of absorption in practice can reach high numbers of up to > 90%.
How does a typical setup of a laser welduing optic look like?
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Wich laser suits for the follwowing application(s)?
Delicate (filigran) components, with only low allowed thermal stresses (wenig wärmebelastbar), e.g. microtechnology
Wich laser suits for the follwowing application(s)?
Thin walled (dünnwandig) components ( < ca. 0,4 mm )
Wich laser suits for the follwowing application(s)?
3D-Welding-Paths
Wich laser suits for the follwowing application(s)?
Non ferrous (NE-) metals with high reflectivity (e.g. Al, Cu)
Wich laser suits for the follwowing application(s)?
Steel and low-reflecting metals (e.g. Ti) in 2D-applications
Wich laser suits for the follwowing application(s)?
Thick-walled (dickwandig) components ( > ca. 8 mm )
Gaps between two welding parts can lead to problems during the process. Wich of the following two setus would you recommend for laser-welding?
Wich Problems can occur during laser-weldung of zink-coated sheet-steels?
During the welding process the zink layer between the sheet-steels vaporizes. This vapor builts up a pressure inside the melt-pool until it becomes too high. The vapor exits the melt-pool towarts the laser optic and on its way the vapor rips parts of the melt-pool out. This causes damages on the workpice and pollutions on the lense/shielding glass.
Think of possinle solutions for the problems during laser-welding of zink-coated sheet-steels.
Solutions -->
Name 5 examples of innovative applications of laser-welding and laser-hard-brazing
- Welding of heat-sensitive components
- Welding components with delicate (filigran) dimensions
- Production of „Tailored-Blanks“for deep-drawing-pplications (Tiefziehen)
- Welding or Hard-Brazing of welds with extremely smooth surfaces in the viewing-range (Sichtbereich) of a product
- Laser-Transmission-Welding (Durchstrahlschweißen) of plastic parts
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