Automatic in-line 3-head welding machine for right angle corners and also corners in the range 30° to 180°, T, H and cross welding. SM 3 TVH comes in 2 working lengths (3440 and 4440 mm) and offers the possibility of welding up to 2 frames simultaneously with 1 or more heads. SM 3 TVH is provided with heated welding bead restrictors adjustable in the configuration phase, in a range from 0.5 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 3 TVH can be fitted with counterblocks (optional) and can handle all types of standard profiles (including 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 time can be set via the LCD display.