Dental Lab Laser Welding: Welding a Connector
Tips for Welding a Connector with a Laser Welder
C&B Method - Direct Welding
When laser welding a connector, the following steps and tips are recommended.
Separate the Connector with a Thin Disc
When separating a bridge, use the thinnest disc available, this will remove the least amount of metal and enable the bridge connection to touch once it’s back on the model.
Prep the Connector
Remove any burs left over from the separating process to give the connectors a clean, flush fit. If the connectors do not touch when the bridge is on the model, use either the Capping Method or the Insert Method.
Use Proper Joint Preparation
First, determine the alloy and gauge of the connector to be welded. Is the connector thick or thin? Select the proper joining method and prepare the connection accordingly making sure the joint is flush and is touching
Keyhole Weld- Used for Thick Connector
A Keyhole Weld is a deep core penetrating weld that will hold the parts together. A proper Keyhole Weld will penetrate at least halfway into the gauge of the parts to be welded.
Surface Weld – Used for Thin Connectors
Thin connectors need less penetration, thus, a Surface Weld is recommended.
Metal contracts and expands during the welding process, for this reason, we must tack the connector in diametrically opposed quadrants. The quadrants are to be welded as follows:
To maintain equal, consistent heating, and equal metal displacement of the structure, we must weld the connector in Diametrically Opposed Quadrants as well. This procedure prevents distortion of the metal during the welding process.
Using the overlapping welds technique; weld the connector in Diametrically Opposed Quadrants.
Add Metal if Needed
If the original diameter of the connector was reduced by a joint preparation technique, or by the keyhole weld itself, metal of the same alloy can be added. Filler materials should also be added by using the Quadrant Welding and Diametrically Opposed welds techniques.
Note: Small connectors can be Keyhole Welded while adding wire during the same pass, this allows for less laser passes.
Grind if Needed
Using a grinding wheel, grind off any excess metal.
Sample of finished welded bridge connection shown.