3.7.8Postforming

Postforming is a special processing method for HPL. The process aims to produce technically and visually flawless composite elements, whereby wooden materials are preferred. The required HPL with postforming capability has the same structure as standard HPL. Postforming HPL allows forming of concave and convex curves with relatively tight radii. This forming capability opens up special design options and expandable areas of application:

• Soft, joint-free contours can be achieved with postforming HPL sheets
• Rounded edges meet increased safety requirements and are less sensitive to impacts
• Elements with joint-free curves are easy to clean. Ingress of moisture is prevented. These elements are more hygienic as dust and dirt accumulation on the edge is prevented
   

a HPL | b HPL-balancing

For all postforming processes, the HPL sheets have to be heated to the temper- ature required for forming in the forming area. The heat source and its activation period have to be chosen depending on the selected process. The selection essentially depends on:

• form and radius of the desired curve
• available machines
• desired degree of completion
• batch size
• economical considerations
   

In practice, two processes are used:

• Pre-forming the HPL with subsequent bonding to the substrate (separate work step)
• Full-surface bonding of the HPL with subsequent forming of the protruding HPL while simultaneously bonding the curves (stationary or continuous)
   

Konvexe Convex curves can be achieved with all processes mentioned. The passthrough method is ideal for series production. Concave curves can usually only be achieved with stationary methods.