For the collision analysis, in the first step critical areas were marked on the inner parts of the door and numbered measuring points were recorded.
With a CNC-controlled three-dimensional Zeiss coordinate measuring machine, the xyz coordinates of the point cloud were measured.
With Euclid 2.1, a meshed 3D CAD model was created, which was then imported into the collision analysis simulation program USIS.
The fillet weld shown on the left is advantageous, because the material can flow during melting. Similar to the use of filler material in conventional welding, this causes a uniform temperature distribution. Namely, a balance is formed between the volume of the melt and the supplied energy, which causes a constant adjustment of the temperature of the melt. However, the required inclination of the welding head of 20° towards the inner part leads to conflicts, when large windows are to be accommodated in the door. In comparison to overlap welding shown on the right, the fillet weld requires less energy for the same welded cross-section. As a result, higher process speeds and less heat distortion can be achieved.
In areas that can not be accessed with
a sufficient inclination of the welding head without colliding with the inner parts due to the shape of the inner parts, can be created well with the help of holes well remedy. Although
this type of seam can transfer forces, it does not work because it is not waterproof.
If the deepformed sheets are sufficiently elastic to transmit resilient forces, it would be possible to make first the fold and then push the door inner parts underneath. In this case could the parts would not need to be pressed together during welding, because the joint gap would be kept sufficiently small by the pressure of the fold.
To avoid problems during installation, in this case, at least three internal parts should be provided: If the front and rear inner parts should be inserted into the corners of the door first, then the upper part could be placed between these parts.
This component Joint is already used in plastic bodies of French manufacturers. doors and tailgates are assembled in this way using screws and adhesives instead of laser welding. They are easy to
join because they compensate even large tolerances. However, because the sheets used in laser welding are much thinner than the corresponding plastic parts, this seam shape does not seem suitable
for sheet metal constructions due to the sensitivity to bending on the sheet edge and because of the risk of injury.
In addition, the effect of the heat probably changes the zinc layer of the outer skin, which would also be visible after painting. It should be assessed, whether the heat will be dissipated well enough.
This component design is already used in plastic bodies of French manufacturers. Doors and tailgates are assembled in this way, which are easy to join because of the large tolerances. However, adhesives and screws are used for joining instead of laser welding. As the sheets used in laser welding are much thinner than those of the corresponding plastic parts, this seam shape does not seem suitable for sheet metal constructions because of the sensitivity to bending on the sheet edge and because of the risk of injury.
In addition, the effect of the heat would probably change the zinc layer of the outer skin, which would be visible even after painting. Preliminary tests to assess, whether the heat will be discipated well enough, would therefore be absolutely necessary.
Since this is a fillet weld in a lap joint, the zinc fumes produced during welding can easily escape. Especially in conjunction with a pressure roller, or better pressure ball, this is an elegant and robot-friendly way of welding car doors.