Stitching – Man and machine hand in hand

An experienced stitcher needs about half an hour to stitch the entire shoe upper of a sports shoe. Our robots get the same job done in less than two minutes. However, stitching robots are out of their depth as soon as it comes to giving the shoe its form. This is production step when the skill and precision of our experienced stitchers comes into the equation.

The stitching room is where the cut pieces are stitched together as a shoe. The robots stitch together the entire shoe upper, with the exception of the lining, according to the programmed designs.

Despite state-of-the-art robots, stitching is essentially work done by hand.

The eye of the robot

The various different components that are to be stitched are positioned on a special plate and then fed into the robot. The key problem in this step is the fact that, despite the greatest care being taken, the parts can still shift by fractions of a millimetre. This is of course not a problem for the stability of the shoe, but let us face it, a stitch that is out of place looks simply terrible. In order to prevent this from happening, the robot produces a stereo image of the parts that are to be stitched with the help of two cameras. If the parts have moved, the robot spots it and automatically adjusts its stitching path. Therefore as you can see, the robot sees where it has to stitch.

When things get complicated, the stitchers come into play

The robots reach their limits as soon as it comes to giving the stitched shoe upper its form; they are out of their depth with the complex, three-dimensional structure that now develops. This is the production step where the skill and precision of our stitchers is required.

The handling of the shoe becomes more complex and difficult with every further step of the process. The next step involves the lining being stitched into the shoe. Foam components and heel stabilization components are then integrated between lining and the shoe upper.

The stitching of the insole to the shoe upper is the final step of the stitching process. This is referred to as the Strobel-stitched method (or sew in sock). The Strobel-stitched method involves the stitching of the insole to the shoe upper with a zigzag stitch. The semi-finished product already resembles a shoe.