Milling weld preparations versus cutting weld preparations in plates

Cutting weld preparations

Material removal rates for creating a weld prep, vary greatly with tooling, machinability of the material and machine rigidity. But let’s just take an example. With standard mild steels, 45 degree bevels in 15 mm and up, milling the bevel in general will take approximately 2-3 times longer than to cut the bevel with plasma. The more material that has to be removed, the more time it takes to mill the bevel while plasma cutting mainly depends on the thickness and bevel angle (which defines the actual cut length).

Milling weld preparations

But when is milling weld preparations interesting? For instance when beveling forms only a minor portion of the production and does not justify the capital expenditure of a beveling unit.

Of course, the assumption here is that milling is already available as a process on the machine. But milling can also be interesting when tolerances with plasma bevel cutting increase due to warping because of heat input. Warping because of heat input depends on product thickness, general heat input created due to a large amount of inner contours and skewed length/width ratios of products.

An advantage of milling a weld preparation is also that J-groove weld preparations are possible which aren’t possible with plasma beveling. The advantage of a J-groove compared to standard Y or V-grooves is that a more narrow welding gap can be created for the same welding strength. This narrow welding gap requires less filler material, which can save welding time especially with thicker materials.