Automatic single head welding machine for right angle corners and also corners in the range 30° to 180° with descending heating plate. SM 1LV is provided with heated welding bead restrictors adjustable in the configuration phase, in a range from 0.2 to 2 mm; it also has vertical vices running on linear slideways. Depth of fusion can be set at 2.5 or 3 mm while the support arms feature adjustable height. SM 1LV can be equipped with counterblocks (optional) and can handle all types of standard profile (included acrylic and coated) as well as large profiles (solid profiles). The machine, provided with a quick change system, allows easy cleaning of the teflon film. The work cycle is controlled by a PLC while the heating plate has a digital temperature controller (settable in both °C and °F); the heating and welding time can be set via the LCD display.