knurling→strip insertion → rolling pressing.

Today we will discuss the production process of insulated strip insertion for window fabrication.

The strip insertion process consists of three steps: knurling→strip insertion → rolling pressing. Let’s start with knurling.

Knurling is a key criterion to distinguish high-quality windows from inferior ones, as well as genuine and counterfeit system windows. Windows without knurling are inferior and non-standard system windows(except for Schüco products).

Knurling uses a knurling machine to carve tooth marks on the grooves of aluminum profiles for heat insulation strips. It increases the roughness of grooves, boosting friction and shear force between aluminum profiles and insulation strips, just like teeth firmly gripping the strips.

Tooth depth is the core factor in knurling, the figure below:

Standard knurling depth: 0.5-0.9mm, tooth pitch: around 1.14mm, with sharp horn-shaped tooth tips.

A graduated magnifier can be used to measure tooth depth. Equipment shall be adjusted and worn knurling cutters replaced timely