Manufacturing Processes

Sinks Franke uses a proprietary deep draw manufacturing process that also includes annealing when necessary.

The deep draw is the method used for creating parts from flat sheet metal. The process involves pressing a disk into a die with a punch to form a variety of shapes, radii, diameters and lengths as the metal progresses through several work stations. Since existing technology does not enable the draw to create as deep a shape as desired in one draw, greater depths require multiple steps called “draw reductions.” The greater the depth, the more reductions are required.

Deep drawing may also be accomplished with fewer reductions by using an annealing process in which the piece is heated. While it adds cost to the manufacturing process, it is done to prevent the stainless steel from thinning out to a lesser gauge in the course of manufacturing. The duration of time the piece is exposed to this temperature is kept to a minimum to prevent surface scaling and to control grain growth. This is how Franke eliminates the occurrence of "orange peel“ texture on the stainless steel and maintains its smoothness to the touch.

In order to maximize sink capacity, Franke raises the bar on sheet metal tolerances, by developing and perfecting processes that enable us still to use a deep draw process on tight radii in deep bowls. While this is the most advantageous process, unfortunately, these tight tolerances raise the cost of manufacturing significantly in order to deliver benefits expected by Franke’s discerning consumers.

The joints are welded together and then a molten filler material is applied further to achieve a more perfect joining of the sink sides and corners. Here, the “Franke difference” is that we avoid Intergranular corrosion, which means:

• Austenitic stainless steels contain a small amount of carbon.
• Upon exposure to drastically high temperature, such as welding, the carbon causes ingrained chrome to develop chromium carbide around it, blocking adjoining sections of the chrome it needs to prevent its own corrosion. The Franke solution to this problem is to use a minimum carbon content stainless to avoid such corrosion.

For Franke multi-bowl configurations, each bowl is circle welded to the frame, not seam welded. This prevents any unsightly weld seams from showing on the center saddle of the sink. This, of course, costs more than seam welding, but it is the Franke difference that helps us meet the expectations our customers have of a high-end luxury stainless steel kitchen sink.