TM401 joint geometries and plate offset compensation in brief
The TM401 is programmed for four circumferential weld joint geometries: same-thickness joints, thickness-transition joints with a welded taper, thickness-transition joints with a 1:4 plate taper, and inside conical top joints. Across same-thickness and thickness-transition joints, it also automatically adjusts for localised plate offset (misalignment) of up to ±3 mm, using laser-guided sensing to detect and compensate for the offset during profiling.
Four circumferential weld joint geometries supported by the TM401
The Maxars TM401 performs single-pass weld profiling and geometric improvement on four specific circumferential weld joint geometries encountered in monopile and tower fabrication: same-thickness weld joints, thickness-transition joints with a welded taper, thickness-transition joints with a 1:4 plate taper, and inside conical top joints.
Profiling same-thickness and thickness-transition (tapered) weld joints
Same-thickness weld joints are the standard case: two plates of equal thickness joined by a circumferential butt weld, which the TM401 profiles into a uniform, large-radius transition on both sides of the seam.
Where the design calls for a change in plate thickness across a joint, the TM401 is programmed for two different transition configurations: a thickness-transition joint with a welded taper, and a thickness-transition joint with a 1:4 plate taper. Both represent ways of accommodating a step change in plate thickness at the joint, and the TM401 applies a geometry-specific profiling program to each so that the resulting weld transition meets the same large-radius, flush-profile target regardless of which transition configuration was used in fabrication.
Automatic plate offset (misalignment) compensation up to ±3 mm
Plate offset is a localised misalignment between the two plate edges either side of a circumferential weld and is handled by the TM401 as an automatic adjustment rather than as a separate joint geometry.
On both same-thickness and thickness-transition weld joints, the system automatically compensates for plate offset of up to ±3 mm without requiring a different program or manual intervention.
TM401 operating envelope: diameter, taper, weld width and cap height
These joint geometries and the plate offset adjustment are designed for use on wind turbine support structures with a diameter greater than 5 metres and a taper of less than 5 degrees in conical sections, and across a weld seam width range of 15-80 mm and weld cap height range of 0.5-6 mm (up to 8 mm localised).
In its current configuration, the TM401 can address approximately 90 percent of the circumferential weld seams used to produce a typical XXL monopile. The remaining exceptions are the inside flange-mount weld seam, which is not addressable; outside circumferential weld seams in conical sections, which are not currently addressable; and a minimum lateral clearance requirement of 1,000 mm to roller beds (for outside welds) or flanges (for inside welds).
Sources: Maxars TM401 Operational Performance and Technical Data Sheet. Maxars TM401 Elevation Platform Technical Data Sheet.