The principle of laser scribing

A process step in the manufacture of the connecting rod is the separation of
the crank hole. There are two basic processes for this – the hole is either
mechanically cut or fracture split under pressure. The fracture split, also
known as “cracking” is the more economical method as the complete process
only has around only half as many process steps.

Before it can be cracked, a notch must be created on the inner side of the
crank hole. This notch represents the weak point for the breaking tension
and thus controls the location of the break. There are two standard methods
for creating this notch:

  • Mechanical broaching
  • Laser marking or laser scribing


Laser marking of the connecting rod is the most modern method with the
lowest production cost and short production times. The switch from
mechanical tools for different materials and material strengths is no longer
necessary and there is no tool deterioration whatsoever. In contrast to the
other processing methods, the processed crank hole remains completely
undamaged with laser marking. With the patented processing heads for
notches, LASAG has made laser marking the simplest and most versatile

Depending on requirements, LASAG can offer varied solutions which all
guarantee a high-quality scribing process:

  • The cross head, which is used with fixed body lasers, enables the shortest process times without panning of the processing head. It is assembled onto the LASAG interface plate, which enables simple switching with all other LASAG processing heads. This ensures that your production is flexible and efficient.
  • The scribing rotating head FLBK SC enables you to achieve the same process flexibility as with a fiber laser. This processing head can be used with a pulsed or with a Q-Switch fiber laser.

If you would like to have sample parts processed in our Application
Laboratory, we would be happy for you to contact our Sales department.
For questions on applications or problems, our Application Laboratory is
happy to help you.