Perfect in every detail.



1. Complete removal of the welding joint - perfectly flat, uniform surface
without the need for further milling or modification.
2. Perfect shaping even on curved profiles - curved corners are smooth
and flawless so there is no risk of scratching.
3. Aesthetically flawless even in exposed parts - the welded profile has
no defects and is continuous along its entire length.

The technology of the SL4-FF EVO welding machine opens up a new world in which you can choose PVC profiles with classic coloured film or wood effect and they also allow freedom of application - with previously unimaginable results - of surfaces such as anodized aluminium, painted aluminium, painted PVC , PVC with acrylic layer, PVC coated with natural wood, reinforced PVC with fiberglass, printed PVC.

Standard weld
 (Finishing work required)

V-Perfect  weld
(No further adjustments required)

Almost endless possibilities with even higher strength!

You no longer have to limit yourself due to design trade-offs in the surface treatment.

Suitable materials: laminate, film-coated PVC, PVC/real wood, painted PVC, PVC, Aluminium/PVC

Even higher strength

Higher weld strength can be achieved thanks to perfect welding without the need to disturb the weld during its aesthetic treatment


Technology hidden behind a perfect weld
Graf-Synergy SL4-FF EVO


1. Absolute precision

Thanks to 19 CNC axes, which guarantee absolute dimensional accuracy, the SL4-FF EVO provides welding with precision.

2. Perfect welding

By completely removing the weld seam, the SL4-FF EVO ensures perfect welding and surfaces that are completely flat and homogeneous, and this exceptional quality is achieved without the need for further milling.

3. Solves the problem of profile tolerances

The SL4-FF EVO is equipped with a special automatic calibration system, the only technology on the market that allows us to compensate for profile tolerances.

4. It can work with any type of surface treatment

The SL4-FF EVO allows us to work with profiles coated with any type of film, such as anodized aluminium, painted aluminium, PVC coated with natural wood and PVC coated with acrylic, all without the need for retouching after cleaning.

5. Allows welding of profiles produced by coextrusion

The technology behind the SL4-FF EVO also allows the machining of profiles that contain non-weldable elements inside, such as glass fibres, aluminium or other components, instead of metal reinforcement.

6. Perfect seal

Thanks to the innovative SL4-FF EVO process, the seal is machined directly during welding, allowing the joint area to be soft and not flattened, thus ensuring proper frame operation.

7. User-friendly technology

The software developed by Graf Synergy’s R&D laboratory technicians is highly intuitive and offers a simple menu that presents all the information needed for correct and error-free use. Changing the mould to flat or V-welding or changing the machining to be performed based on the desired surface treatment are simple operations that anyone can perform.

8. Reduction of overall dimensions

The SL4-FF EVO is an extremely compact machine that no longer requires a cleaning machine or an automatic turntable, allowing us to reduce investment or further increase production by introducing multiple machines that work simultaneously.

9. Workforce reduction

It is no longer necessary to complete the corners after the welding cycle on an automatic line, such as the SL4-FF EVO line, so it requires only one operator to load the profiles.

10. Smooth corners without defects

The SL4-FF EVO uses innovative counterparts that act on the welded corner, unlike traditional bars made of steel or aluminium, which act on the sides of the profile. This ensures that smooth corners are achieved without imperfections and it avoids the risk of scratching or retaining dirt by removing sharp edges. In addition, the SL4-FF EVO welding machine guarantees, thanks to its special top and bottom 'marks', that each profile has perfect coplanarity in the welding area.