Lightweight Laser Welded Profiles for Hydraulic Drilling Masts
On a portable drilling unit, every structural component has to do more than one job, because anything that only carries load is weight the machine has to be transported with. The profile developed for this hydraulic drilling mast joins two hollow sections of 30x30x3 mm to a central plate across an overall width of 140 mm, so that it guides the drilling chain, carries the load and ties the mast together in a single geometry. Montanstahl produced it in stainless steel 304 by laser welding, with width tolerances held within 0.5 mm.
One Section Doing Three Jobs
Lightweight portable drilling units need structural components that combine load bearing capacity with reduced weight and guiding functionality, three demands that ordinarily belong to three different parts. Inside a hydraulic drilling mast the profile has to maintain alignment, allow the drilling chain to move smoothly and transfer load reliably under dynamic conditions, where the forces reverse as the tool advances and retracts. Standard sections rarely satisfy that combination, since a catalogue profile is designed to be efficient in bending or in torsion rather than to provide a running surface and a load path at the same time. Customised laser welded profiles allow several functions to be integrated into one geometry while keeping tight tolerances and consistent structural behaviour, an approach that recurs throughout the machinery sector whenever weight and function have to be reconciled.
Precision in a Multi-Functional Welded Section
Four aspects had to be controlled at once. The two hollow sections needed to stay aligned with each other, because they define the track the chain runs on and any relative rotation between them twists that track along the mast. The central plate had to remain flat, since it is the reference that positions both tubes and also the surface other components locate against. Width tolerances had to be held within 0.5 mm across the 140 mm overall dimension, which is demanding for an assembly built from three separate pieces rather than formed from one. The fourth aspect underlies the other three, which is limiting the distortion welding introduces, given that a section combining thin plate and closed tubes has very different local stiffness along its width, so heat applied on one side pulls the geometry in ways that are not symmetrical and not easy to correct afterwards.
Application Context
The answer came from controlling each stage rather than relying on a single operation. The central plate was laser cut and then machined for flatness and dimensional accuracy, which establishes a reliable reference before anything is joined. The hot rolled hollow sections arrived with consistent geometry along their length, so the two tubes behave the same way during assembly. Laser welding with controlled heat input then minimised distortion and preserved the alignment established beforehand, which is what makes a lightweight component with tight tolerances and dependable structural performance achievable in one piece rather than as a fabricated frame. Combining a cut and machined plate with rolled sections in this way is standard practice within the range of special profiles, and questions on multi-functional geometries are answered in the technical Q&A.